O pensamento de rede liga de forma inovadora a conservação e o uso dos recursos naturais
Rafael L. G. Raimundo
29 de setembro de 2023
Estudante de biologia no ano 2000, um dia eu cruzava a Unicamp rumo a uma reunião no Instituto de Filosofia e Ciências Humanas. Contrariado, pensava como um antropólogo poderia me ajudar na aplicação da ecologia teórica para a conservação da natureza. Prossegui com resignação e certa curiosidade. Afinal, quem me havia mandado ali fora Keith Brown Jr., um dos fundadores da ciência ecológica brasileira e meu professor à época. Ele sabia da minha visão sobre a falta de serventia das ciências humanas para as abordagens quantitativas em pesquisa ambiental que me interessavam. Também sabia que eu estava errado.
Ainda alheio à dimensão do caminho entre a biologia e as humanidades, cheguei à sala da reunião para, desavisadamente, encontrar outro nome lendário da ciência ambiental. O antropólogo Mauro Almeida cochilava em sua escrivaninha, mas abriu os olhos e se pôs a digitar quando entrei. Logo me encarou: “Você deve ser o rapaz da biologia que quer falar de evolução e conservação, não?”.
Uma década antes, Almeida e Brown Jr. haviam liderado o movimento científico que apoiou a criação da primeira reserva extrativista brasileira, no Alto Juruá acreano. Combinando ecologia, antropologia e ideias inovadoras sobre governança, fizeram história. A questão que os movia era: podem comunidades locais gerar dados sobre ecossistemas, produção e qualidade de vida para gerir recursos com autonomia? Essa pergunta, bem sabiam, cruzava as fronteiras da ciência.
A gestão com pesquisa participativa no Juruá era uma dentre as múltiplas respostas ao influente artigo do ecólogo norte-americano Garrett Hardin, “A tragédia dos comuns”, publicado em 1968 na revista Science. Hardin havia delimitado um problema ainda atualíssimo: como evitar que indivíduos livres ajam de forma egoísta, maximizando lucros imediatos, destruindo recursos comuns e degradando suas condições de vida?
A norte-americana Elinor Ostrom, que recebeu o Nobel de Economia em 2009, superou a dicotomia radical entre privatização e controle estatal como possíveis soluções ao mostrar que o comportamento coletivo humano pode, sim, ser compatível com a conservação em condições de autogoverno. Podemos extrair princípios de boa governança coletiva de recursos a partir de diversos exemplos.
Mas as soluções propostas para a tragédia dos comuns ainda não consideravam adequadamente os processos ecológicos e evolutivos que geram e mantêm a biodiversidade. E a aceleração do Antropoceno – a época geológica moldada pela atividade humana – intensificava uma realidade de colapso ecossistêmico crescente. A tragédia seguia seu curso.
Estimulado por Mauro Almeida, me fixei no Juruá entre 2006 e 2009. Trabalhei em gestão e delineamento de políticas públicas voltadas à sustentabilidade. Entretanto, a interface entre ciência e governança ainda parecia fragmentada. Buscando mais integração, voltei para a universidade.
Em meu doutorado na USP, revisitei minha velha conhecida ecologia teórica, agora sob um olhar de redes complexas. Contrastando com o senso comum, a palavra “complexa” aqui não significa “complicada”, mas descreve um sistema que não pode ser compreendido pela soma de seus componentes. A ciência da complexidade estuda as interações entre os componentes do sistema, como conexões entre bairros que formam a rede de mobilidade de uma metrópole, fluxos entre os setores de uma empresa ou interações entre as espécies de um ecossistema.
Na natureza, as redes ecológicas descrevem os múltiplos efeitos que as espécies geram ao interagir. Toda vez que um beija-flor visita uma flor, que uma lagarta consome uma folha ou que uma onça mata uma presa, haverá consequências diretas e indiretas para as populações de outras espécies na intrincada rede da vida. Ao desvendar a organização e as dinâmicas das interações, a ciência de redes desvenda cascatas ecológicas e outros processos que moldam o funcionamento de florestas, lagos ou recifes de coral.
Quando ingressei na UFPB como professor, publiquei um artigo sobre a aplicação de redes adaptativas para restauração ecológica na revista Trends in Ecology and Evolution. O conceito de rede adaptativa se refere às retroalimentações entre mudanças nas características dos componentes (nós) da rede e a estrutura das conexões entre esses componentes (topologia), as quais desencadeiam alterações de estado e comportamentos emergentes no sistema.
Por exemplo, se um predador de topo passa a predar um grande herbívoro ao qual antes ele não tinha acesso, pode desencadear uma cascata de efeitos ecossistêmicos, aliviando a pressão do herbívoro sobre as plantas e influenciando a produtividade primária. A maior disponibilidade de vegetais pode alavancar o crescimento das populações de outros animais que, eventualmente, servirão como novas opções de presas para predadores, gerando mais respostas comportamentais ou evolutivas e, finalmente, reconfigurando a rede de interações.
Modelos de redes adaptativas tratam matematicamente desse vai e vem de cascatas ecológicas que moldam os ecossistemas. Eles são úteis para tentar prever a propagação de efeitos da adição e remoção de espécies no contexto da restauração de ecossistemas. Por exemplo, a erradicação de uma espécie invasora pode gerar cascatas ecológicas ao alterar tamanhos populacionais, interações e características ecológicas das outras espécies.
Essas cascatas também podem surgir da reintrodução de espécies de animais que haviam sido extintas localmente e cumpriam funções ecológicas-chave — as chamadas “engenheiras do ecossistema” — como grandes felinos predadores de topo ou aves frugívoras dispersoras de sementes que faziam a biodiversidade vegetal fluir na paisagem.
Precisamos agora avançar rumo a empreendimentos que combinem modelos de redes adaptativas com experimentos de restauração ecológica em larga escala, criando uma via de mão dupla entre abordagens teóricas e empíricas para viabilizar uma “engenharia da biodiversidade“. Ousar aplicar amplamente a ciência da complexidade é urgente para fazer frente ao colapso funcional dos ecossistemas que testemunhamos de forma generalizada.
Meu próximo passo nessa interface entre ambiente e sociedade será usar modelos de redes adaptativas para entender como mudanças simples na organização socioprodutiva podem se propagar como catalisadoras de sustentabilidade ao reconstruir a biodiversidade e a funcionalidade dos ecossistemas e, ao mesmo tempo, gerar inclusão social e inovação econômica. Ou seja, sigo buscando respostas para a tragédia dos comuns que incluam a perspectiva da ecologia evolutiva para fazer frente aos desafios do Antropoceno.
*
Rafael L. G. Raimundo é professor do Departamento de Engenharia e Meio Ambiente e coordenador do Programa de Pós-Graduação em Ecologia e Monitoramento Ambiental da Universidade Federal da Paraíba – Campus IV.
O blog Ciência Fundamental é editado pelo Serrapilheira, um instituto privado, sem fins lucrativos, que promove a ciência no Brasil. Inscreva-se na newsletter do Serrapilheira para acompanhar as novidades do instituto e do blog.
All of these countries are considered to have a so-called Mediterranean climate, as does California. But, are they all the same in their Mediterraneanness?
A Mediterranean climate has been identified in Chile, Australia, South Africa, California and, of course, around the Mediterranean. Characterized by cool wet winters, hot dry summers and endemic plants that thrive under such conditions, they are considered among the most endangered ecosystems on the planet due to their restricted geographical area. Interestingly, most environmentalists and scientists seem to be concerned about forest fires in these regions, not about the scrubby plants that predominate the coastal areas and that tend to be the ones most endangered, not even so much by fire, but by urban encroachment.
It’s time now, though, we recognize that Algerian landscapes, like those of California, are colonial ones. These landscapes were transformed to fit an European idea of Mediterranean-ness. The consequences of this misunderstanding of natural ecosystems as preserved by Indigenous peoples, and of the damage inflicted in these regions are now evident in the wildfires in North Africa.
Although 90% of Algeria is made up of the Sahara Desert, French colonialists believed the country was once lushly forested. The French imposed laws to criminalize the use of forest fires (which are an integral part of the ecosystem) and to forbid the traditional multiple uses of the forest by Indigenous people. Likewise, in California, forest fires were also suppressed and Indigenous inhabitants removed.
In Algeria, in the early 20th century, the French started planting eucalyptus, which are highly flammable, as a timber source. The French Forest Code was derived mostly from tropical islands and brought to its North African colonies. In California, the suppression of forest fires was an intrinsic part of remaking the forest and rejecting all traditional Indigenous practices.
Despite poor success in afforestation in Algeria, the notion that the country should be forested was undeterred, persisting to the present. The 1960s Algerian Green Dam project was initiated to plant trees to stop the northward advancement of the Sahara, under the misapprehension that the Sahara was growing north. Flammable Aleppo pine was planted. Pine caterpillar invasions devastated the trees, and humans contributed to deforestation. Still, this effort continues to be funded by the African Union, the World Bank and the European Union, part of a larger project of a green band of trees and vegetation across the entire length of the Sahara that will likely fail.
In California, forest practices that suppressed naturally occurring fires and traditionally set fires have resulted in dense, overgrown forests, where trees compete for light and water, are more susceptible to disease and of course, even more at risk for extreme fire. The state’s recent megafires show the result of this management, exacerbated by a hotter, drier climate.
Diana K. Davis, a professor of history at UC Davis, has suggested in her book “The Arid Lands” that the Middle East is part of a dryland complex, including North Africa, raising the question of whether Algeria has a Mediterranean climate at all but instead its own semi-arid ecological condition.
If so, then perhaps investing in protecting and reviving the various systems of precolonial practices and land uses might make more sense than planting trees. Instead of homogenizing areas across the world into equivalents, paying attention to difference and specificity might produce land management that is not so prone to fire, and might also help make those landscapes healthier.
California’s landscapes too could be less fire-prone if urbanization in terrain at high risk were curtailed and fires reintroduced into its forests in a systematic way. By classifying landscapes and regions by type — Mediterranean being one such type — Western European science and values have distorted Indigenous landscapes so that they have become far more susceptible to climate change and fire. The assumption that these lands are all the same means that ideas of their management transfer across borders to great damage.
Algeria is a desert-dominated, semi-arid place where development policies and urbanization practices have put people in altered landscapes at great risk of fire. California too has suffered from a scientific approach that overlooked its ecology and the ways in which people lived here in the landscapes. Fire, disaster and death are likely to continue until we reckon with this colonial legacy.
Stephanie Pincetl is a professor at the UCLA Institute of the Environment and Sustainability. She conducts research on California land use, energy and water.
Bioturbation is the mixing of (plant) residues into soils and sediments by biotic activity. It is one of the fundamental processes in ecology, as it stimulates decomposition, creates habitats for other (micro)fauna and increases gas- and water flow through the soil. Here you can see a system without (left) and with (right) soil fauna such as earthworms, potworms, collembola, mites and isopods over a 15 weeks period. During this period, whereas only small fungal activity can be seen on the left side, the layer of leaves on the right side is almost completely incorporated in the soil due to the interaction between microbes, microfauna and mesofauna.
This video is part of the Soil Life in Action project. The movie can be used for education in classrooms and for lectures. For other use please contact: egmond(at)tip.nl
Edward O. Wilson, who passed away at the age of 92 on December 26, 2021, is widely recognized as a giant of the Arts and Sciences. I include the Arts because Wilson regarded the creative dimension of science as an artistic endeavor, worked toward unifying the Arts and Sciences, and wrote beautifully for the general public, resulting in two Pulitzer prizes for nonfiction and one novel.
Wilson’s stature is so great, and reflections on his legacy upon his death are so numerous, that another reflection might seem unnecessary. The purpose of my reflection, however, is to make a novel point: Wilson left at least six legacies, which need to be combined to fully realize his vision. Combining the legacies of Edward O. Wilson requires first identifying them separately and then integrating them with each other.
The six legacies are:
1) His contributions to evolutionary biology.
2) His contributions to the conservation of biodiversity.
3) His contributions to a sociobiology that includes humans.
4) His contributions to the unification of knowledge.
5) His encouraging stance toward young scientists and other learners.
6) The new frontier that he was working on at the time of his death was ecosystems.
My relationship with Edward O. Wilson
Before turning to these legacies and their integration, I will briefly recount my own relationship with Ed. I am 20 years younger so that he was already famous as a Harvard professor when I entered graduate school at Michigan State University in 1971. I first met him during the summer of that year. I was a student in an ecology course at the Marine Biological Laboratory in Woods Hole, Massachusetts. He was sitting in on the student project reports. After I reported my experiments on food size selection in zooplankton, Ed remarked “That’s new, isn’t it?” I was so proud to have impressed the great E.O. Wilson and contributed to the vast storehouse of scientific knowledge that I have remembered his comment ever since!
My graduate education was shaped in part by Ed’s influence on evolutionary biology, as I will elaborate below. My next personal interaction came near the end of my graduate career. I had constructed a mathematical model that provided support for the theory of group selection, which had been almost universally rejected by evolutionary biologists, as I will also elaborate below. Convinced of its importance, I wrote Ed asking if he would consider sponsoring it for the Proceedings of the National Academy of Sciences. Ed invited me to visit him at Harvard’s Museum of Comparative Zoology. As with my first encounter, I have a vivid memory of the visit, which began with a tour of his ant laboratory. Then he stood me in front of a blackboard, sat down in a chair, and said “you have 30 minutes until my next appointment.”
I talked like an auctioneer, filling the board with my equations. Ed was sufficiently intrigued to sponsor my article for PNAS after sending it out for review by two experts in theoretical biology. The article became my Ph.D. thesis, which is probably the shortest in the history of evolutionary science (four pages).
In the years that followed, I became one of the main advocates of group selection without directly crossing paths with Ed. I also took part in most of the other initiatives associated with Ed’s legacies without directly interacting with him. We were both involved in the formation of the Human Behavior and Evolution Society (HBES) and I hosted its third annual conference in 1993. On the theme of consilience, I started the first campus-wide program for teaching evolution across the curriculum and wrote one of the first book-length accounts of religion from an evolutionary perspective. It might seem strange that Ed and I shared so many interests without directly interacting, but just about everything associated with Ed’s legacies are in fact broad developments in the history of science involving many protagonists, a point to which I will return.
My next and by far most substantive interaction with Ed began at the 2006 annual conference of HBES. Ed was a plenary speaker and I was in the audience. Even though HBES members were in the avant-garde of studying human behavior from an evolutionary perspective, most of them were doctrinaire in their rejection of group selection. On his own, Ed had embraced group selection, converging on my own advocacy, and chose to break the news to the unsuspecting audience in his plenary. You could have heard a pin drop. Afterward, we found a corner of the lobby to talk alone.
“Did you like the grenade that I tossed in their midst?” Ed asked with a conspiratorial smile. On the spot, I suggested that we write a major article together, which became “Rethinking the Theoretical Foundation of Sociobiology”, published in the Quarterly Review of Biology in 2007. To reach a larger audience, we also wrote “Evolution for the Good of the Group”, which was published in the American Scientist in 2008. These were written by trading drafts and discussing them by email and phone. I still remember his voicemails, which sometimes went on for several minutes and were spoken in flawless extemporaneous prose.
At the end of our “Rethinking” article, we summarized our argument for group selection as the theoretical foundation of sociobiology by stealing from Rabbi Hillel, who was reputedly asked to explain the meaning of the Torah while standing on one foot and replied “What is hateful to you, do not do to your neighbor. Everything else is commentary.” Our one-foot version of sociobiology was: “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.” This meme has become widely known and Ed repeated it all the way up to his final publications and interviews.
After this intense collaboration, Ed and I went our separate ways to continue pursuing our largely overlapping interests. The last time I saw him was at a conference at MIT, which was close enough to his home that he could attend without arduous travel. In the few minutes that we spoke together, he told me excitedly about ecosystems as the next big topic that he planned to synthesize. He retained his youthful spirit of exploration right up to the end.
I have one more story about Ed to tell before turning to his six legacies. In 2014, the evolutionary psychologist Barry X. Kuhle recorded a series of interviews with pioneers of HBES, including both Ed and myself. Ed must have relished the opportunity to talk at a professional level with someone as well informed as Barry because his interview lasted two hours. I was president of the newly founded Evolution Institute and Editor in Chief of its online magazine This View of Life(TVOL), which was named after the final passage of Darwin’s On the Origin of Species (“There is grandeur in this view of life…”). I was eager to feature a print version of Barry’s interview with Ed on TVOL, so I offered to transcribe it myself. There is something about transcribing a recording, word by word, that burns it into your memory more than merely listening to the recording or reading the transcription. This experience adds to my knowledge of Ed and his legacies, along with his published work and my personal relationship with him.
The Six Legacies
History—including the history of science–is a complex systemic process involving many actors and environmental (including cultural) contingencies. Attention often becomes focused on a few key people, such Albert Einstein, Sigmund Freud, and B.F. Skinner, which under-represents the contributions of many dozens of others. Iconic status is thrust upon a person as much as actively sought by the person. There seems to be a need to personify ideas as a form of simplification, among the general public and even, to a degree, among the experts.
A few evolutionary biologists such as Ed Wilson, Richard Dawkins, and the late Stephen Jay Gould have achieved this iconic status. Yes, they made outsized contributions as individuals, but they also represent something larger than themselves. I think that Ed would agree. In his book Sociobiology: The New Synthesis, for example, he was relying upon the work of many hundreds of scientists to support his claim that there can be a single theory of social behavior informed by evolution.
The world “catalyst” also bears examination. In chemistry, a catalyst is a substance that increases the rate of a chemical reaction without being used up in the process. The way a catalytic molecule works is by holding other molecules in an orientation that binds them to each other and releases the catalytic molecule to repeat the operation. A person can play a catalytic role in cultural change in much the same way. As we will see, Ed was a catalyst par excellence. He made things happen that otherwise would have occurred much more slowly or not at all.
Against this background, calling Ed an “icon” and a “catalyst” honors the individual while also going beyond the individual to examine systemic trends in the history of science. It is in this spirit that I will review his six legacies.
1) His contributions to evolutionary biology.
Here is how Ed described his contribution to evolutionary biology in his interview with Barry Khule:
We have to go back to the 1950’s. In the 1950’s, the molecular revolution had begun. It was clear that the golden age of modern biology was going to be molecular and would endure a long time. In fact, it did occupy the second half of the 20th century and beyond. We felt here at Harvard immediately the pressure to start giving up positions to molecular biology. The Dean of the faculty and the President at that time were entirely in accord. We found—I say we, the organismic and evolutionary biologists here, comparative anatomists, comparative zoologists and so on–realized that we would not to be given much additional space anymore, that we probably would not get many if any new positions for a long time. They would be reserved to build up Harvard’s strength in molecular and cellular biology. What this did was have a tremendous impact on me personally because I realized…that those of us, my generation of what we came to call evolutionary biologists and organismic biologists, were not going to get anywhere by complaining by any means but we were going to have to—and we should be tremendously excited to plan this—develop an equivalent to molecular biology on our own.
Ed then set about trying to modernize the biology of whole organisms, as part of a younger generation following the architects of the Modern Synthesis, which included names such as Ernst Mayr, Julian Huxley, and George Gaylord Simpson. This required finding and collaborating with people who had complementary expertise—especially the ability to build mathematical models of ecological and evolutionary processes. Names that Ed mentions as part of this younger generation include Robert MacArthur, Larry Slobodkin, and Richard Lewontin. These were some of the rock stars whose work I avidly read as a graduate student in the 1970s.
One of Ed’s most productive collaborations was with Robert MacArthur, an ecologist with mathematical training, leading to their landmark book The Theory of Island Biogeography, published by Princeton University Press in 1967 with Ed as the second author. What made the book so important was a theoretical framework that made sense of the great mass of natural history information on the distribution and abundance of species on islands—some of it collected by Ed for ant species around the world. The theory applied not only to actual islands but to all habitats that are island-like, such as mountains separated by valleys or patches of forest separated by deforested areas.
While Ed played a prominent role in modernizing whole organism biology, he was by no means alone. Also during my time as a graduate student, a Nobel prize was awarded to Konrad Lorenz, Niko Tinbergen, and Carl von Frisch for pioneering the study of animal behavior and the geneticist Theodosius Dobzhansky titled an article for biology teachers “Nothing in biology makes sense except in the light of evolution”. Evolutionary theory was proving its explanatory scope and many people were taking part in the effort. What this meant to me as a graduate student was that I could choose any topic, begin asking intelligent questions based on evolutionary theory (often with the help of mathematical models), and then test my hypotheses on any appropriate organism. I didn’t need to become a taxonomic specialist and I could change topics at will. In short, I could become a polymath, based not on my personal attributes but on a theory that anyone can learn. This is the legacy of evolutionary biology, to which Ed made an outsized contribution.
2) His contributions to the conservation of biodiversity
As first and foremost a naturalist and ant taxonomic expert, Ed was passionate about the conservation of biological diversity and made room for it alongside his scientific career. His book Biophilia argued that we are genetically adapted to be surrounded by nature, with mental and physical health consequences if we are not. This bold conjecture has been largely supported by research. For example, hospital patients recover faster if their room has a window or is decorated with foliage and flowers.
Ed collaborated with Thomas Lovejoy, who coincidentally passed away just a day earlier at the age of 80, to preserve the biodiversity of the Amazon. According to a remembrance in the New Yorker magazine, it was they who coined the term biological diversity, which became shortened to biodiversity. They even drew upon the theory of Island Biogeography by studying the effect of the size of forest reserves on species loss.
With his gift for marketing whole disciplines and initiatives, Ed coined the term “Half Earth” for the goal of preserving half of the earth for nature and the other half for humankind—not in separation, but in a way that is interdigitated, so that humans can live within nature and nature can flow along corridors. Anyone who values nature should want to continue this legacy but doing so requires changing the minds and hearts of people, along with their cultural practices, in the real world.
3) His contributions to a sociobiology that includes humans
Ed’s 1975 book, Sociobiology: The New Synthesis, was in the same mold as Darwin’s “there is grandeur in his view of life” and Dobzhansky’s “nothing in biology makes sense except in the light of evolution”. Ed’s claim was that evolutionary theory provides a single conceptual toolkit for studying the social behaviors of all creatures great and small. Thanks to Ed’s gift for identifying whole fields of inquiry and writing for non-specialists, Sociobiology combined the authority of an academic tome with the look and feel of a coffee table book, complete with over 200 illustrations by the artist Sarah Landry. Thanks to his stature and gift for promotion, its publication was noted on the front page of the New York Times.
It was the last chapter on human social behavior that landed Ed in trouble and a systemic view of the history of science is needed to understand why. For all its explanatory scope, the study of evolution was restricted to genetic evolution for most of the 20th century, as if the only way that offspring can resemble their parents is by sharing the same genes. This is patently false when stated directly since it ignores the cultural transmission of traits entirely, but it essentially describes what became known as the modern synthesis and was consolidated by the molecular biology revolution described by Ed in his interview with Barry Kuhle.
What became of the study of cultural evolution? It was ceded to other disciplines in the human social sciences and humanities. Each discipline developed into a sophisticated body of knowledge, but not in reference and sometimes in perceived opposition to evolutionary theory. And all of those disciplines did not remotely become integrated with each other. Instead, they became an archipelago of knowledge with little communication among the islands. The lack of consilience for human-related knowledge stands in stark contrast with the consilience of biological knowledge, at least when it comes to genetic evolution.
Darwin’s theory is often said to have earned a bad reputation for itself in the human-related disciplines by providing a moral justification for inequality (Social Darwinism). The real history of Darwinism in relation to human affairs is more complex and interesting. Socialists such as Peter Kropotkin and progressive thinkers such as William James and John Dewey were inspired by Darwin along with “nature red and truth in claw” types. The bottom line is that any powerful tool can also be used as a weapon and Darwin’s theory is no different than any other theory in this regard.1
Returning to the reception to Sociobiology, when critics accused Ed of genetic determinism, they were absolutely right. The entire field of evolutionary biology was gene-centric and Ed was no exception. Yet, critics from the human social sciences and humanities had no synthesis of their own.
Only after the publication of Sociobiology did evolutionary thinkers begin to take cultural evolution seriously. Ed was among them with books such as On Human Nature, Genes, Mind, and Culture (with Charles J. Lumsden), Promethean Fire (also with Lumsden), and The Social Conquest of Earth. Other major thinkers included Richard Dawkins and his concept of memes, Luigi Luca Cavalli-Sforza and Marcus Feldman (Cultural Transmission and Evolution), and Robert Boyd and Peter Richerson (Culture and the Evolutionary Process, Not By Genes Alone). The importance of symbolic thought began to occupy center stage with books such as The Symbolic Species by Terrence Deacon and Evolution in Four Dimensions by Eva Jablonka and Marion Lamb.
Today, Darwinian evolution is widely defined as any process that combines the three ingredients of variation, selection, and replication, no matter what the mechanism of replication. This definition is true to Darwin’s thought (since he knew nothing about genes) and can accommodate a plurality of inheritance mechanisms such as epigenetics (based on changes in gene expression rather than gene frequency), forms of social learning found in many species, and forms of symbolic thought that are distinctively human. While human cultural inheritance mechanisms evolved by genetic evolution, that doesn’t make them subordinate, as if genes hold cultures on a leash (one of Ed’s metaphors). On the contrary, as the faster evolutionary process, cultural evolution often takes the lead in adapting humans to their environments, with genetic evolution playing a following role (gene-culture co-evolution).
Part of the maturation of human cultural evolutionary theory is the recognition of group selection as an exceptionally strong force in human evolution—something else that Ed got right. According to Harvard evolutionary anthropologist Richard Wrangham in his book The Goodness Paradox, naked aggression is over 100 times more frequent in a chimpanzee community than in small-scale human communities. This is due largely to social control mechanisms in human communities that suppress bullying and other forms of disruptive self-serving behaviors so that cooperation becomes the primary social strategy (this is called a major evolutionary transition). Nearly everything distinctive about our species is a form of cooperation, including our ability to maintain an inventory of symbols with shared meaning that is transmitted across generations. Our capacity for symbolic thought became a full-blown inheritance system that operates alongside genetic inheritance (dual inheritance theory). Cultural evolution is a multilevel process, no less than genetic evolution, and the increasing scale of cooperation over the course of human history can be seen as a process of multilevel cultural evolution.
While the critique of genetic determinism was accurate for Sociobiology and evolutionary biology as a whole in 1975, this is no longer the case for the modern study of humans from an evolutionary perspective—which brings us to Ed’s next legacy.
4) His contributions to the unification of knowledge.
Something that can be said about Ed’s books is that they are all visionary—imagining whole new fields of inquiry—but vary in the degree to which Ed has made progress carrying out the vision. He made the most progress for ants and other social insects, of course, and Sociobiology reflected a thorough reading of the literature on animal social behaviors. A book such as Consilience, however, is long on vision and short on execution.
I do not intend this observation as a criticism. Ed had only 24 hours in a day, like the rest of us, and his visionary gaze is worthwhile even if the execution is left to others. In Consilience, the vision is “a conviction, far deeper than a mere working proposition, that the world is orderly and can be explained by a small number of natural laws (p4)”. While this vision stretches back to antiquity and includes knowledge of the physical world in addition to the living world, there is something about evolutionary theory that fulfills the vision for the living world in an extraordinary way. Here is how Ed describes his first encounter with evolutionary theory in the opening pages of Consilience. He’s an 18-year old kid newly arrived at the University of Alabama, with a passion for identifying plants and animals using field guides.
Then I discovered evolution. Suddenly—that is not too strong a word—I saw the world in a wholly new way. This epiphany I owed to my mentor Ralph Chermock, an intense, chain-smoking young assistant professor newly arrived in the provinces with a Ph.D. in entomology from Cornell University. After listening to me natter for a while about my lofty goal of classifying all the ants of Alabama, he handed me a copy of Ernst Mayr’s 1942 Systematics and the Origin of Species. Read it, he said, if you want to become a real biologist.
The thin volume in the plain blue cover was one of the New Synthesis works, uniting the nineteenth-century Darwinian theory of evolution and modern genetics. By giving a theoretical structure to natural history, it vastly expanded the Linnaean enterprise. A tumbler fell somewhere in my mind, and a door opened to a new world. I was enthralled, couldn’t stop thinking about the implications evolution has for classification and for the rest of biology. And for philosophy. And for just about everything. Static pattern slid into fluid process…A new enthusiasm surged through me. The animals and plants I loved so dearly reentered the stage as lead players in a grand drama. Natural history was validated as real science.
Coincidentally, Ernst Mayr’s Animal Species and Evolution was one of the first evolution books that I read as an undergraduate student. While it was not thin (811 pp!), I was similarly enthralled. Compare Ed’s epiphany with passages from Charles Darwin, such as “I can remember the very spot on the road…” and “he who understands the baboon would do more toward metaphysics than Locke”, which was scribbled in his notebook in 1838. There is something about the simplicity and generality of evolutionary theory that starts working at the very beginning, for Darwin as the originator and Ed Wilson as an unschooled kid. Now recall what I said about being a graduate student in the 1970s—that I could become a polymath, based not on my personal attributes but on a theory that anyone can learn. What this means is that by the 1970s, what Darwin and Ed glimpsed from the start was now proving itself for the length and breadth of the biological sciences. Every time an evolutionary biologist decides to switch to a new topic and/or organism–which happens all the time—consilience is being demonstrated in action.
The prospect that human-related knowledge can become unified in this way is both old and new. It was how Darwin thought and he originated group selection theory as much to explain human morality as “for the good of the group” traits in nonhuman species. But you can’t make sense of humanity without acknowledging its groupish nature and the importance of culturally transmitted symbolic meaning systems. As Emile Durkheim wisely put it: “Social life, then, in every aspect and throughout its history, is only possible thanks to a vast body of symbolism.” Only now are we in a position to synthesize human-related knowledge in the same way as biological knowledge, thanks to an expanded definition of Darwinism as any variation/selection/replication process. Ed’s vision in Consilience is right on and its fulfillment is now in progress.
5) His encouraging stance toward young scientists and other learners.
No remembrance of Ed would be complete without noting the way that he encouraged people to become scientists, to follow their hearts, and to cultivate a reverence for nature. Visit #eowilson on Twitter and you’ll find quotes such as these offered by those whose lives he touched.
“Adults . . . are prone to undervalue the mental growth that occurs during daydreaming and aimless wandering.” — The late great Edward O. Wilson
“Nature first, then theory. Love the organisms for themselves first, then strain for general explanations, and with good fortunes discoveries will follow.”
“You are capable of more than you know. Choose a goal that seems right for you and strive to be the best, however hard the path. Aim high. Behave honorably. Prepare to be alone at times, and to endure failure. Persist! The world needs all you can give.”
“Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction.
“There can be no purpose more enspiriting than to begin the age of restoration, reweaving the wondrous diversity of life that still surrounds us.”
“The evolutionary epic is the best myth we will ever have.”
“You teach me, I forget. You show me, I remember. You involve me, I understand.”
“Humanity is part of nature, a species that evolved among other species. The more closely we identify ourselves with the rest of life, the more quickly we will be able to discover the sources of human sensibility and acquire the knowledge on which an enduring ethic, a sense of preferred direction, can be built.”
Passages such as these spell the difference between science and a science-based worldview. By itself, science merely tells us what is. A worldview provides a sense of values and motivates action. A science-based worldview does this based on reverence of the natural world rather than a supernatural agency. Ed is remembered at least as much for the science-based worldview that he offered as his scientific discoveries.
6) Ecosystems as Ed’s final frontier
Ed’s next book was to be titled “Ecosystems and the Harmony of Nature”. I don’t know if it will be published posthumously but we can get a glimpse of what he had in mind from its title, a brief article on the E.O. Wilson Biodiversity Foundation website,2 and a short lecture on YouTube.3
In the article, Ed is quoted as saying: “We know that ecosystems, which are really what we are trying to protect–not just single species but ensembles of species that have come together and have reached the ability—sometimes over thousands or even in some places millions of years—have formed ecosystems that equilibrate. And we don’t really know how equilibration comes about.” Ed also encourages young people to join “the coming development of a new biological science, one of the next big things, which is ecosystem studies.”
I must confess that I am puzzled by these statements since the study of whole ecosystems dates back to the beginning of the 20th century and has become increasingly integrated with evolutionary ecology over the last 50 years. It turns out that multilevel selection theory is essential for understanding the nature of ecosystems, no less than single species societies. I will be fascinated to know if Ed has converged upon this conclusion.
To explain what I mean, a critical distinction needs to be made between two meanings of the term “complex adaptive system (CAS)”: A complex system that is adaptive as a system (CAS1), and a complex system composed of agents following their respective adaptive strategies (CAS2). A human society in the grip of civil war is an example of CAS2. It can be understood in terms of the conflicting interests of the warring factions, but it does not function well at the level of the whole society (CAS1) and no one would expect it to.
Many single-species societies in nature are like my human civil war example. Members of social groups are largely in conflict with each other and at most cooperate in specific contexts. We need look no further than chimpanzee communities for an example, where naked aggression is over 100 times more frequent than in small-scale human communities and the main context for community-wide cooperation is aggression against neighboring communities. Social strife in chimpanzee communities is stable—there is no reason to expect it to change, given the selection pressures that are operating—but that doesn’t make them harmonious or desirable from a human perspective.
Many multispecies ecosystems are also like this. For example, if you want to understand the nature of beaver ecosystems, ask the question “what’s in it for the beavers?” They are modifying the environment for their own benefit, flooding it to protect themselves from predators and eating the most palatable plants. Consequences for biodiversity and ecosystem processes such as nutrient cycling are collateral effects of beavers pursuing their interests. There is no reason to expect the whole ecosystem to be functionally organized and harmonious, any more than a chimpanzee community or a human society in the grip of civil war.
This is a hard lesson to learn about nature. We want it to be harmonious. Religious cosmologies often portray nature as harmonious (e.g., the Garden of Eden) except when disturbed by humans. The early study of ecosystems often treated them axiomatically as harmonious. But Darwin’s theory of evolution tells a different story. It tells us that functional organization for any given system, at any given scale, requires a process of selection at that scale. That is the only way to achieve the status of CAS1 rather than merely CAS2, where functionally organized agents impose suffering on each other in the course of pursuing their respective adaptive strategies. That statement goes for human society, single-species animal societies, and multispecies ecosystems.
Are there examples of whole ecosystems that have evolved into superorganisms? Yes! Microbiomes are an example. Every multicellular organism is not only a collection of mostly identical genes but also an ecosystem composed of trillions of microbes comprising thousands of species. When the host organisms differentially survive and reproduce, this is due in part to variation in their microbiomes along with variation in their genes. Thanks to selection at this level, microbiomes have evolved to be largely mutualistic with their hosts. There is also potential for selection among microbes within each host, however, leading to the evolution of pathogenic strains. It all depends on the level of selection.
Nowadays, whole forests are being imagined as mutualistic networks, with trees connected into a network by mycorrhizal fungi. Is such a thing possible? Yes, but only if selection has operated at the scale of whole forests with sufficient strength to counteract selection at lower scales. Otherwise, forests become merely CAS2 systems, composed of species that interact at cross purposes, rather than CAS1 systems.
Above all, it is important to avoid confusing “harmony” with “equilibrium”. Ecologists have started to use the word “regime” to describe stable assemblages of species. This is a well-chosen word because it evokes what we already know about human political regimes. All political regimes have a degree of stability, or we wouldn’t call them regimes, but they span the range from despotic (benefitting a few elites at the expense of everyone else) to inclusive (sharing their benefits with all citizens). Some of the worst regimes are also depressingly the most stable. Using the language of complex systems theory, there are multiple local stable equilibria and positive change requires escaping the gravitational pull of one local equilibrium to enter another local equilibrium. This requires active management and will not necessarily happen by itself. The management of ecosystems must itself be a human cultural evolutionary process informed by multilevel selection theory.
Combining the legacies
In this remembrance of Ed Wilson, I have tried to honor the person while also placing him in the context of broad trends in the history of science. Without mentioning Ed, we can say that Darwin’s theory of evolution has an amazing explanatory scope, that this scope was largely restricted to the study of genetic evolution for most of the 20th century, but now is rapidly expanding to include all aspects of humanity in addition to the rest of life. As I put it in my own book This View of Life: Completing the Darwinian Revolution, Dobzhansky’s statement “nothing in biology makes sense except in the light of evolution” can be extended to include everything associated with the words “human”, “culture”, and “policy”.
Without mentioning Ed, we can also say that evolutionary theory is capable of functioning as a worldview in addition to a body of scientific knowledge. Science only tells us what is, whereas a worldview inspires us psychologically and moves us to action. Creating a worldview informed entirely by science, as opposed to supernatural belief, is part of the enlightenment project that led to humanism as a philosophical worldview and social movement. While humanists accept Darwin’s theory as a matter of course, the recent developments that I have recounted have not been incorporated into the humanist movement for the most part. Thus, humanism and what it stands for is due for a renaissance, along with a renaissance of basic scientific knowledge.
Some simple calculations will help to put Ed’s career into historical perspective. Starting from when he received his Ph.D. in 1955 to his death in 2021, his career lasted for 66 years. If we mark the beginning of evolutionary science with the publication of Darwin’s On the Origin of Species in 1859, then Ed was present for 40% of the history of evolutionary thought. If we mark the beginning of the scientific revolution with the publication of Copernicus’s On the Revolution of the Heavenly Spheres in 1543, then Ed was present for 14% of the scientific revolution. As 20 years Ed’s junior, my numbers work out to 28% and 10% respectively.
These numbers remind us that evolutionary science and the scientific revolution are still works in progress. If science in general and evolutionary science, in particular, have revolutionized the way we see and therefore act upon the world, then we can look forward to further improvements in the near future. This leads to a form of hope and optimism, even in the darkest of times, that is part of Ed’s legacy.
For me, the next frontier is not just ecosystems but becoming wise stewards of evolution in all its forms. Variation/selection/replication processes are taking place all around us at different time scales, including genetic evolution, cultural evolution, and intra-generational personal evolution. Without wise stewardship, these evolutionary processes result merely in CAS2—complex systems composed of agents following their respective adaptive strategies, often inflicting harm on each other and on the entire system over the long term. Work is required to transform CAS2 into CAS1—systems that are adaptive as whole systems. This work will be required for all forms of positive change—individual, cultural, and ecosystemic. The ability to see this clearly and to act upon it has only become available during the last few decades and is currently shared by only a tiny fraction of those who need to know about it. Catalysis is needed, so that positive evolution can take place in a matter of years rather than decades or not at all. The best way to honor Ed’s combined legacies is to join in this catalysis.
“Humans have impacted the ocean in a more dramatic fashion than merely capturing fish,” explained marine ecologist Ryan Heneghan from the Queensland University of Technology.
“It seems that we have broken the size spectrum – one of the largest power law distributions known in nature.”
The power law can be used to describe many things in biology, from patterns of cascading neural activity to the foraging journeys of various species. It’s when two quantities, whatever their initial starting point be, change in proportion relative to each other.
In the case of a particular type of power law, first described in a paper led by Raymond W. Sheldon in 1972 and now known as the ‘Sheldon spectrum’, the two quantities are the body size of an organism, scaled in proportion to its abundance. So, the larger they get, there tend to be consistently fewer individuals within a set species size group.
For example, while krill are 12 orders of magnitudes (about a billion) times smaller than tuna, they’re also 12 orders of magnitudes more abundant than tuna. So hypothetically, all the tuna flesh in the world combined (tuna biomass) is roughly the same amount (to within the same order of magnitude at least) as all the krill biomass in the world.
Since it was first proposed in 1972, scientists had only tested for this natural scaling pattern within limited groups of species in aquatic environments, at relatively small scales. From marine plankton, to fish in freshwater this pattern held true – the biomass of larger less abundant species was roughly equivalent to the biomass of the smaller yet more abundant species.
Now, Max Planck Institute ecologist Ian Hatton and colleagues have looked to see if this law also reflects what’s happening on a global scale.
“One of the biggest challenges to comparing organisms spanning bacteria to whales is the enormous differences in scale,” says Hatton.
“The ratio of their masses is equivalent to that between a human being and the entire Earth. We estimated organisms at the small end of the scale from more than 200,000 water samples collected globally, but larger marine life required completely different methods.”
Using historical data, the team confirmed the Sheldon spectrum fit this relationship globally for pre-industrial oceanic conditions (before 1850). Across 12 groups of sea life, including bacteria, algae, zooplankton, fish and mammals, over 33,000 grid points of the global ocean, roughly equal amounts of biomass occurred in each size category of organism.
“We were amazed to see that each order of magnitude size class contains approximately 1 gigaton of biomass globally,” says McGill University geoscientist Eric Galbraith.
(Ian Hatton et al, Science Advances, 2021)
Hatton and team discussed possible explanations for this, including limitations set by factors such as predator-prey interactions, metabolism, growth rates, reproduction and mortality. Many of these factors also scale with an organism’s size. But they’re all speculation at this point.
“The fact that marine life is evenly distributed across sizes is remarkable,” said Galbraith. “We don’t understand why it would need to be this way – why couldn’t there be much more small things than large things? Or an ideal size that lies in the middle? In that sense, the results highlight how much we don’t understand about the ecosystem.”
There were two exceptions to the rule however, at both extremes of the size scale examined. Bacteria were more abundant than the law predicted, and whales far less. Again, why is a complete mystery.
The researchers then compared these findings to the same analysis applied to present day samples and data. While the power law still mostly applied, there was a stark disruption to its pattern evident with larger organisms.
“Human impacts appear to have significantly truncated the upper one-third of the spectrum,” the team wrote in their paper. “Humans have not merely replaced the ocean’s top predators but have instead, through the cumulative impact of the past two centuries, fundamentally altered the flow of energy through the ecosystem.”
(Ian Hatton et al, Science Advances, 2021)
While fishes compose less than 3 percent of annual human food consumption, the team found we’ve reduced fish and marine mammal biomass by 60 percent since the 1800s. It’s even worse for Earth’s most giant living animals – historical hunting has left us with a 90 percent reduction of whales.
This really highlights the inefficiency of industrial fishing, Galbraith notes. Our current strategies are wasting magnitudes more biomass and the energy it holds, than we actually consume. Nor have we replaced the role that biomass once played, despite now being one of the largest vertebrate species by biomass.
Around 2.7 gigatonnes have been lost from the largest species groups in the oceans, whereas humans make up around 0.4 gigatonnes. Further work is needed to understand how this massive loss in biomass affects the oceans, the team wrote.
“The good news is that we can reverse the imbalance we’ve created, by reducing the number of active fishing vessels around the world,” Galbraith says. “Reducing overfishing will also help make fisheries more profitable and sustainable – it’s a potential win-win, if we can get our act together.”
Humans are dismantling and disrupting natural ecosystems around the globe and changing Earth’s climate. Over the past 50 years, actions like farming, logging, hunting, development and global commerce have caused record losses of species on land and at sea. Animals, birds and reptiles are disappearing tens to hundreds of times faster than the natural rate of extinction over the past 10 million years.
Now the world is also contending with a global pandemic. In geographically remote regions such as the Brazilian Amazon, COVID-19 is devastating Indigenous populations, with tragic consequences for both Indigenous peoples and the lands they steward.
My research focuses on ecosystems and climate change from regional to global scales. In 2019, I worked with conservation biologist and strategist Eric Dinerstein and 17 colleagues to develop a road map for simultaneously averting a sixth mass extinction and reducing climate change by protecting half of Earth’s terrestrial, freshwater and marine realms by 2030. We called this plan “A Global Deal for Nature.”
Now we’ve released a follow-on called the “Global Safety Net” that identifies the exact regions on land that must be protected to achieve its goals. Our aim is for nations to pair it with the Paris Climate Agreement and use it as a dynamic tool to assess progress towards our comprehensive conservation targets.
Population size of terrestrial vertebrate species on the brink (i.e., with under 1,000 individuals). Most of these species are especially close to extinction because they consist of fewer than 250 individuals. In most cases, those few individuals are scattered through several small populations. Ceballos et al, 2020., CC BY
What to protect next
The Global Deal for Nature provided a framework for the milestones, targets and policies across terrestrial, freshwater and marine realms required to conserve the vast majority of life on Earth. Yet it didn’t specify where exactly these safeguards were needed. That’s where the new Global Safety Net comes in.
We analyzed unprotected terrestrial areas that, if protected, could sequester carbon and conserve biodiversity as effectively as the 15% of terrestrial areas that are currently protected. Through this analysis, we identified an additional 35% of unprotected lands for conservation, bringing the total percentage of protected nature to 50%.
By setting aside half of Earth’s lands for nature, nations can save our planet’s rich biodiversity, prevent future pandemics and meet the Paris climate target of keeping warming in this century below less than 2.7 degrees F (1.5 degrees C). To meet these goals, 20 countries must contribute disproportionately. Much of the responsibility falls to Russia, the U.S., Brazil, Indonesia, Canada, Australia and China. Why? Because these countries contain massive tracts of land needed to reach the dual goals of reducing climate change and saving biodiversity.
Supporting Indigenous communities
Indigenous peoples make up less than 5% of the total human population, yet they manage or have tenure rights over a quarter of the world’s land surface, representing close to 80% of our planet’s biodiversity. One of our key findings is that 37% of the proposed lands for increased protection overlap with Indigenous lands.
As the world edges closer towards a sixth mass extinction, Indigenous communities stand to lose the most. Forest loss, ecotourism and devastation wrought by climate change have already displaced Indigenous peoples from their traditional territories at unprecedented rates. Now one of the deadliest pandemics in recent history poses an even graver additional threat to Indigenous lives and livelihoods.
To address and alleviate human rights questions, social justice issues and conservation challenges, the Global Safety Net calls for better protection for Indigenous communities. We believe our goals are achievable by upholding existing land tenure rights, addressing Indigenous land claims, and carrying out supportive ecological management programs with indigenous peoples.
Tropical deforestation increases forest edges – areas where forests meet human habitats. These areas greatly increase the potential for contact between humans and animal vectors that serve as viral hosts.
The Global Safety Net’s policy milestones and targets would reduce the illegal wildlife trade and associated wildlife markets – two known sources of zoonotic diseases. Reducing contact zones between animals and humans can decrease the chances of future zoonotic spillovers from occurring.
Our framework also envisions the creation of a Pandemic Prevention Program, which would increase protections for natural habitats at high risk for human-animal interactions. Protecting wildlife in these areas could also reduce the potential for more catastrophic outbreaks.
Nature-based solutions
Achieving the Global Safety Net’s goals will require nature-based solutions – strategies that protect, manage and restore natural or modified ecosystems while providing co-benefits to both people and nature. They are low-cost and readily available today.
The nature-based solutions that we spotlight include: – Identifying biodiverse non-agricultural lands, particularly prevalent in tropical and sub-tropical regions, for increased conservation attention. – Prioritizing ecoregions that optimize carbon storage and drawdown, such as the Amazon and Congo basins. – Aiding species movement and adaptation across ecosystems by creating a comprehensive system of wildlife and climate corridors.
We estimate that an increase of just 2.3% more land in the right places could save our planet’s rarest plant and animal species within five years. Wildlife corridors connect fragmented wild spaces, providing wild animals the space they need to survive.
Leveraging technology for conservation
In the Global Safety Net study, we identified 50 ecoregions where additional conservation attention is most needed to meet the Global Deal for Nature’s targets, and 20 countries that must assume greater responsibility for protecting critical places. We mapped an additional 35% of terrestrial lands that play a critical role in reversing biodiversity loss, enhancing natural carbon removal and preventing further greenhouse gas emissions from land conversion.
But as climate change accelerates, it may scramble those priorities. Staying ahead of the game will require a satellite-driven monitoring system with the capability of tracking real-time land use changes on a global scale. These continuously updated maps would enable dynamic analyses to help sharpen conservation planning and help decision-making.
As director of the Arizona State University Center for Global Discovery and Conservation Science, I lead the development of new technologies that assess and monitor imminent ecological threats, such as coral reef bleaching events and illegal deforestation, as well as progress made toward responding to ecological emergencies. Along with colleagues from other research institutions who are advancing this kind of research, I’m confident that it is possible to develop a global nature monitoring program.
The Global Safety Net pinpoints locations around the globe that must be protected to slow climate change and species loss. And the science shows that there is no time to lose.
The produce section of the grocery store is a botanical disaster. Most people know that a tomato is technically a fruit, but so is an eggplant, a cucumber, and a spaghetti squash. A banana, which grows from a flower with a single ovary, is actually a berry, while a strawberry, which grows from a flower with several ovaries, isn’t a berry at all but an aggregate fruit. The most confusing classification, though, will start showing up on American shelves this month. Shoppers will find mission figs with the grapes, kiwis, and other fruit, but a clever botanist would sell them at the florist, with the fresh-cut roses. Although many people dismiss figs as a geriatric delicacy or the sticky stuff inside bad cookies, they are, in fact, something awesome: enclosed flowers that bloom modestly inward, unlike the flamboyant showoffs on other plants. Bite a fig in half and you’ll discover a core of tiny blossoms.
All kinds of critters, not only humans, frequent fig trees, but the plants owe their existence to what may be evolution’s most intimate partnership between two species. Because a fig is actually a ball of flowers, it requires pollination to reproduce, but, because the flowers are sealed, not just any bug can crawl inside.* That task belongs to a minuscule insect known as the fig wasp, whose life cycle is intertwined with the fig’s. Mother wasps lay their eggs in an unripe fig. After their offspring hatch and mature, the males mate and then chew a tunnel to the surface, dying when their task is complete. The females follow and take flight, riding the winds until they smell another fig tree. (One species of wasp, in Africa, travels ten times farther than any other known pollinator.) When the insects discover the right specimen, they go inside and deposit the pollen from their birthplace. Then the females lay new eggs, and the cycle begins again. For the wasp mother, however, devotion to the fig plant soon turns tragic. A fig’s entranceway is booby-trapped to destroy her wings, so that she can never visit another plant. When you eat a dried fig, you’re probably chewing fig-wasp mummies, too.
The fig and the fig wasp are a superlative example of what biologists call codependent evolution. The plants and insects have been growing old together for more than sixty million years. Almost every species of fig plant—more than seven hundred and fifty in total—has its own species of wasp, although some commercial fig production favors varieties that do not require pollination. (They are grown from cuttings and produce fruit without any seeds.) But codependence hasn’t made the fig and the fig wasp weak, like it can with humans. The figs and fig wasps’ pollination system is extremely efficient compared with that of other plants, some of which just trust the wind to blow their pollen where it needs to go. And the figs’ specialized flowers, far from isolating them in an evolutionary niche, have allowed them to radiate throughout the natural world. Fig plants can be shrubs, vines, or trees. Strangler figs sprout in the branches of another tree, drop their roots to the forest floor, and slowly envelop their host. The branches of a large strangler fig can stretch over acres and produce a million figs in one flowering. Figs themselves can be brown, red, white, orange, yellow, or green. (Wild figs are not as sweet as the plump and purple mission figs you buy at the farmers’ market.) And their seeds sprout where other plants’ would flounder: rooftops, cliff sides, volcanic islands. The fig genus, Ficus, is the most varied one in the tropics. It also routinely shows up in the greenhouse and the garden.
The variety and adaptability of fig plants make them a favorite foodstuff among animals. In 2001, a team of researchers published a review of the scientific literature and found records of fig consumption for nearly thirteen hundred bird and mammal species. One of the researchers, Mike Shanahan—a rain-forest ecologist and the author of a forthcoming book about figs, “Gods, Wasps, and Stranglers”—had spent time studying Malaysian fig trees as a Ph.D. candidate, in 1997. He would sometimes lie beneath a huge strangler fig and record its visitors, returning repeatedly for several days. “I would typically see twenty-five to thirty different species,” Shanahan told me. “The animals would include lots of different squirrel species and some curious creatures called tree shrews. There would be some monkeys and a whole range of different bird species, from tiny little flowerpeckers up to the hornbills, which are the biggest fruit-eating birds in Asia.” There were also pigeons, fruit doves, fairy bluebirds, barbets, and parrots. As the biologist Daniel Janzen put it in “How to Be a Fig,” an article from 1979, “Who eats figs? Everybody.”
With good reason, too. Figs are high in calcium, easy to chew and digest, and, unlike plants that fruit seasonally, can be found year-round. This is the fig plant’s accommodation of the fig wasp. A fig wasp departs a ripe fig to find an unripe fig, which means that there must always be figs at different stages. As a result, an animal can usually fall back on a fig when a mango or a lychee is not in season. Sometimes figs are the only things between an animal and starvation. According to a 2003 study of Uganda’s Budongo Forest, for instance, figs are the sole source of fruit for chimpanzees at certain times of year. Our pre-human ancestors probably filled up on figs, too. The plants are what is known as a keystone species: yank them from the jungle and the whole ecosystem would collapse.
Figs’ popularity means they can play a central role in bringing deforested land back to life. The plants grow quickly in inhospitable places and, thanks to the endurance of the fig wasps, can survive at low densities. And the animals they attract will, to put it politely, deposit nearby the seeds of other fruits they’ve eaten, thereby introducing a healthy variety of new plants. Nigel Tucker, a restoration ecologist in Australia, has recommended that ten per cent of new plants in tropical-reforestation projects be fig seedlings. Rhett Harrison, a former fig biologist, told me that the ratio could be even higher. “My inclination is that we should be going to some of these places and just planting a few figs,” he said.
Fig trees are also sometimes the only trees left standing from former forests. In parts of India, for instance, they are considered holy, and farmers are reluctant to chop them down. “Diverse cultures developed taboos against felling fig trees,” Shanahan told me. “They said they were homes to gods and spirits, and made them places of prayer and symbols of their society.” You can’t really taste the fig’s spiritual aura in a Fig Newton, but it shines in the mythologies of world religions. Buddha found enlightenment under a fig tree, and the Egyptian pharaohs built wooden sarcophagi from Ficus sycomorus. An apple tree might have cost Adam and Eve their innocence, but a fig tree, whose leaves they used to cover their nudity, gave them back some dignity. If only they had preferred figs in the first place, we might all still live in Eden.
*This article has been revised to clarify the fact that not all fig plants require pollination to produce edible fruit.
HUMANS ARE lucky to live a hundred years. Oak trees may live a thousand; mayflies, in their adult form, a single day. But they are all alive in the same way. They are made up of cells which embody flows of energy and stores of information. Their metabolisms make use of that energy, be it from sunlight or food, to build new molecules and break down old ones, using mechanisms described in the genes they inherited and may, or may not, pass on.
It is this endlessly repeated, never quite perfect reproduction which explains why oak trees, humans, and every other plant, fungus or single-celled organism you have ever seen or felt the presence of are all alive in the same way. It is the most fundamental of all family resemblances. Go far enough up any creature’s family tree and you will find an ancestor that sits in your family tree, too. Travel further and you will find what scientists call the last universal common ancestor, LUCA. It was not the first living thing. But it was the one which set the template for the life that exists today.
And then there are viruses. In viruses the link between metabolism and genes that binds together all life to which you are related, from bacteria to blue whales, is broken. Viral genes have no cells, no bodies, no metabolism of their own. The tiny particles, “virions”, in which those genes come packaged—the dot-studded disks of coronaviruses, the sinister, sinuous windings of Ebola, the bacteriophages with their science-fiction landing-legs that prey on microbes—are entirely inanimate. An individual animal, or plant, embodies and maintains the restless metabolism that made it. A virion is just an arrangement of matter.
The virus is not the virion. The virus is a process, not a thing. It is truly alive only in the cells of others, a virtual organism running on borrowed hardware to produce more copies of its genome. Some bide their time, letting the cell they share the life of live on. Others immediately set about producing enough virions to split their hosts from stem to stern.
The virus has no plan or desire. The simplest purposes of the simplest life—to maintain the difference between what is inside the cell and what is outside, to move towards one chemical or away from another—are entirely beyond it. It copies itself in whatever way it does simply because it has copied itself that way before, in other cells, in other hosts.
That is why, asked whether viruses are alive, Eckard Wimmer, a chemist and biologist who works at the State University of New York, Stony Brook, offers a yes-and-no. Viruses, he says, “alternate between nonliving and living phases”. He should know. In 2002 he became the first person in the world to take an array of nonliving chemicals and build a virion from scratch—a virion which was then able to get itself reproduced by infecting cells.
The fact that viruses have only a tenuous claim to being alive, though, hardly reduces their impact on things which are indubitably so. No other biological entities are as ubiquitous, and few as consequential. The number of copies of their genes to be found on Earth is beyond astronomical. There are hundreds of billions of stars in the Milky Way galaxy and a couple of trillion galaxies in the observable universe. The virions in the surface waters of any smallish sea handily outnumber all the stars in all the skies that science could ever speak of.
Back on Earth, viruses kill more living things than any other type of predator. They shape the balance of species in ecosystems ranging from those of the open ocean to that of the human bowel. They spur evolution, driving natural selection and allowing the swapping of genes.
They may have been responsible for some of the most important events in the history of life, from the appearance of complex multicellular organisms to the emergence of DNA as a preferred genetic material. The legacy they have left in the human genome helps produce placentas and may shape the development of the brain. For scientists seeking to understand life’s origin, they offer a route into the past separate from the one mapped by humans, oak trees and their kin. For scientists wanting to reprogram cells and mend metabolisms they offer inspiration—and powerful tools.
II A lifestyle for genes
THE IDEA of a last universal common ancestor provides a plausible and helpful, if incomplete, answer to where humans, oak trees and their ilk come from. There is no such answer for viruses. Being a virus is not something which provides you with a place in a vast, coherent family tree. It is more like a lifestyle—a way of being which different genes have discovered independently at different times. Some viral lineages seem to have begun quite recently. Others have roots that comfortably predate LUCA itself.
Disparate origins are matched by disparate architectures for information storage and retrieval. In eukaryotes—creatures, like humans, mushrooms and kelp, with complex cells—as in their simpler relatives, the bacteria and archaea, the genes that describe proteins are written in double-stranded DNA. When a particular protein is to be made, the DNA sequence of the relevant gene acts as a template for the creation of a complementary molecule made from another nucleic acid, RNA. This messenger RNA (mRNA) is what the cellular machinery tasked with translating genetic information into proteins uses in order to do so.
Because they, too, need to have proteins made to their specifications, viruses also need to produce mRNAs. But they are not restricted to using double-stranded DNA as a template. Viruses store their genes in a number of different ways, all of which require a different mechanism to produce mRNAs. In the early 1970s David Baltimore, one of the great figures of molecular biology, used these different approaches to divide the realm of viruses into seven separate classes (see diagram).
In four of these seven classes the viruses store their genes not in DNA but in RNA. Those of Baltimore group three use double strands of RNA. In Baltimore groups four and five the RNA is single-stranded; in group four the genome can be used directly as an mRNA; in group five it is the template from which mRNA must be made. In group six—the retroviruses, which include HIV—the viral RNA is copied into DNA, which then provides a template for mRNAs.
Because uninfected cells only ever make RNA on the basis of a DNA template, RNA-based viruses need distinctive molecular mechanisms those cells lack. Those mechanisms provide medicine with targets for antiviral attacks. Many drugs against HIV take aim at the system that makes DNA copies of RNA templates. Remdesivir (Veklury), a drug which stymies the mechanism that the simpler RNA viruses use to recreate their RNA genomes, was originally developed to treat hepatitis C (group four) and subsequently tried against the Ebola virus (group five). It is now being used against SARS–CoV-2 (group four), the covid-19 virus.
Studies of the gene for that RNA-copying mechanism, RdRp, reveal just how confusing virus genealogy can be. Some viruses in groups three, four and five seem, on the basis of their RdRp-gene sequence, more closely related to members of one of the other groups than they are to all the other members of their own group. This may mean that quite closely related viruses can differ in the way they store their genomes; it may mean that the viruses concerned have swapped their RdRp genes. When two viruses infect the same cell at the same time such swaps are more or less compulsory. They are, among other things, one of the mechanisms by which viruses native to one species become able to infect another.
How do genes take on the viral lifestyle in the first place? There are two plausible mechanisms. Previously free-living creatures could give up metabolising and become parasitic, using other creatures’ cells as their reproductive stage. Alternatively genes allowed a certain amount of independence within one creature could have evolved the means to get into other creatures.
Living creatures contain various apparently independent bits of nucleic acid with an interest in reproducing themselves. The smallest, found exclusively in plants, are tiny rings of RNA called viroids, just a few hundred genetic letters long. Viroids replicate by hijacking a host enzyme that normally makes mRNAs. Once attached to a viroid ring, the enzyme whizzes round and round it, unable to stop, turning out a new copy of the viroid with each lap.
Viroids describe no proteins and do no good. Plasmids—somewhat larger loops of nucleic acid found in bacteria—do contain genes, and the proteins they describe can be useful to their hosts. Plasmids are sometimes, therefore, regarded as detached parts of a bacteria’s genome. But that detachment provides a degree of autonomy. Plasmids can migrate between bacterial cells, not always of the same species. When they do so they can take genetic traits such as antibiotic resistance from their old host to their new one.
Recently, some plasmids have been implicated in what looks like a progression to true virus-hood. A genetic analysis by Mart Krupovic of the Pasteur Institute suggests that the Circular Rep-Encoding Single-Strand-DNA (CRESS–DNA) viruses, which infect bacteria, evolved from plasmids. He thinks that a DNA copy of the genes that another virus uses to create its virions, copied into a plasmid by chance, provided it with a way out of the cell. The analysis strongly suggests that CRESS–DNA viruses, previously seen as a pretty closely related group, have arisen from plasmids this way on three different occasions.
Such jailbreaks have probably been going on since very early on in the history of life. As soon as they began to metabolise, the first proto-organisms would have constituted a niche in which other parasitic creatures could have lived. And biology abhors a vacuum. No niche goes unfilled if it is fillable.
It is widely believed that much of the evolutionary period between the origin of life and the advent of LUCA was spent in an “RNA world”—one in which that versatile substance both stored information, as DNA now does, and catalysed chemical reactions, as proteins now do. Set alongside the fact that some viruses use RNA as a storage medium today, this strongly suggests that the first to adopt the viral lifestyle did so too. Patrick Forterre, an evolutionary biologist at the Pasteur Institute with a particular interest in viruses (and the man who first popularised the term LUCA) thinks that the “RNA world” was not just rife with viruses. He also thinks they may have brought about its end.
The difference between DNA and RNA is not large: just a small change to one of the “letters” used to store genetic information and a minor modification to the backbone to which these letters are stuck. And DNA is a more stable molecule in which to store lots of information. But that is in part because DNA is inert. An RNA-world organism which rewrote its genes into DNA would cripple its metabolism, because to do so would be to lose the catalytic properties its RNA provided.
An RNA-world virus, having no metabolism of its own to undermine, would have had no such constraints if shifting to DNA offered an advantage. Dr Forterre suggests that this advantage may have lain in DNA’s imperviousness to attack. Host organisms today have all sorts of mechanisms for cutting up viral nucleic acids they don’t like the look of—mechanisms which biotechnologists have been borrowing since the 1970s, most recently in the form of tools based on a bacterial defence called CRISPR. There is no reason to imagine that the RNA-world predecessors of today’s cells did not have similar shears at their disposal. And a virus that made the leap to DNA would have been impervious to their blades.
Genes and the mechanisms they describe pass between viruses and hosts, as between viruses and viruses, all the time. Once some viruses had evolved ways of writing and copying DNA, their hosts would have been able to purloin them in order to make back-up copies of their RNA molecules. And so what began as a way of protecting viral genomes would have become the way life stores all its genes—except for those of some recalcitrant, contrary viruses.
III The scythes of the seas
IT IS A general principle in biology that, although in terms of individual numbers herbivores outnumber carnivores, in terms of the number of species carnivores outnumber herbivores. Viruses, however, outnumber everything else in every way possible.
This makes sense. Though viruses can induce host behaviours that help them spread—such as coughing—an inert virion boasts no behaviour of its own that helps it stalk its prey. It infects only that which it comes into contact with. This is a clear invitation to flood the zone. In 1999 Roger Hendrix, a virologist, suggested that a good rule of thumb might be ten virions for every living individual creature (the overwhelming majority of which are single-celled bacteria and archaea). Estimates of the number of such creatures on the planet come out in the region of 1029-1030. If the whole Earth were broken up into pebbles, and each of those pebbles smashed into tens of thousands of specks of grit, you would still have fewer pieces of grit than the world has virions. Measurements, as opposed to estimates, produce numbers almost as arresting. A litre of seawater may contain more than 100bn virions; a kilogram of dried soil perhaps a trillion.
Metagenomics, a part of biology that looks at all the nucleic acid in a given sample to get a sense of the range of life forms within it, reveals that these tiny throngs are highly diverse. A metagenomic analysis of two surveys of ocean life, the Tara Oceans and Malaspina missions, by Ahmed Zayed of Ohio State University, found evidence of 200,000 different species of virus. These diverse species play an enormous role in the ecology of the oceans.
A litre of seawater may contain 100bn virions; a kilogram of dried soil perhaps a trillion
On land, most of the photosynthesis which provides the biomass and energy needed for life takes place in plants. In the oceans, it is overwhelmingly the business of various sorts of bacteria and algae collectively known as phytoplankton. These creatures reproduce at a terrific rate, and viruses kill them at a terrific rate, too. According to work by Curtis Suttle of the University of British Columbia, bacterial phytoplankton typically last less than a week before being killed by viruses.
This increases the overall productivity of the oceans by helping bacteria recycle organic matter (it is easier for one cell to use the contents of another if a virus helpfully lets them free). It also goes some way towards explaining what the great mid-20th-century ecologist G. Evelyn Hutchinson called “the paradox of the plankton”. Given the limited nature of the resources that single-celled plankton need, you would expect a few species particularly well adapted to their use to dominate the ecosystem. Instead, the plankton display great variety. This may well be because whenever a particular form of plankton becomes dominant, its viruses expand with it, gnawing away at its comparative success.
It is also possible that this endless dance of death between viruses and microbes sets the stage for one of evolution’s great leaps forward. Many forms of single-celled plankton have molecular mechanisms that allow them to kill themselves. They are presumably used when one cell’s sacrifice allows its sister cells—which are genetically identical—to survive. One circumstance in which such sacrifice seems to make sense is when a cell is attacked by a virus. If the infected cell can kill itself quickly (a process called apoptosis) it can limit the number of virions the virus is able to make. This lessens the chances that other related cells nearby will die. Some bacteria have been shown to use this strategy; many other microbes are suspected of it.
There is another situation where self-sacrifice is becoming conduct for a cell: when it is part of a multicellular organism. As such organisms grow, cells that were once useful to them become redundant; they have to be got rid of. Eugene Koonin of America’s National Institutes of Health and his colleagues have explored the idea that virus-thwarting self-sacrifice and complexity-permitting self-sacrifice may be related, with the latter descended from the former. Dr Koonin’s model also suggests that the closer the cells are clustered together, the more likely this act of self-sacrifice is to have beneficial consequences.
For such profound propinquity, move from the free-flowing oceans to the more structured world of soil, where potential self-sacrificers can nestle next to each other. Its structure makes soil harder to sift for genes than water is. But last year Mary Firestone of the University of California, Berkeley, and her colleagues used metagenomics to count 3,884 new viral species in a patch of Californian grassland. That is undoubtedly an underestimate of the total diversity; their technique could see only viruses with RNA genomes, thus missing, among other things, most bacteriophages.
Metagenomics can also be applied to biological samples, such as bat guano in which it picks up viruses from both the bats and their food. But for the most part the finding of animal viruses requires more specific sampling. Over the course of the 2010s PREDICT, an American-government project aimed at finding animal viruses, gathered over 160,000 animal and human tissue samples from 35 countries and discovered 949 novel viruses.
The people who put together PREDICT now have grander plans. They want a Global Virome Project to track down all the viruses native to the world’s 7,400 species of mammals and waterfowl—the reservoirs most likely to harbour viruses capable of making the leap into human beings. In accordance with the more-predator-species-than-prey rule they expect such an effort would find about 1.5m viruses, of which around 700,000 might be able to infect humans. A planning meeting in 2018 suggested that such an undertaking might take ten years and cost $4bn. It looked like a lot of money then. Today those arguing for a system that can provide advance warning of the next pandemic make it sound pretty cheap.
IV Leaving their mark
THE TOLL which viruses have exacted throughout history suggests that they have left their mark on the human genome: things that kill people off in large numbers are powerful agents of natural selection. In 2016 David Enard, then at Stanford University and now at the University of Arizona, made a stab at showing just how much of the genome had been thus affected.
He and his colleagues started by identifying almost 10,000 proteins that seemed to be produced in all the mammals that had had their genomes sequenced up to that point. They then made a painstaking search of the scientific literature looking for proteins that had been shown to interact with viruses in some way or other. About 1,300 of the 10,000 turned up. About one in five of these proteins was connected to the immune system, and thus could be seen as having a professional interest in viral interaction. The others appeared to be proteins which the virus made use of in its attack on the host. The two cell-surface proteins that SARS–CoV-2 uses to make contact with its target cells and inveigle its way into them would fit into this category.
The researchers then compared the human versions of the genes for their 10,000 proteins with those in other mammals, and applied a statistical technique that distinguishes changes that have no real impact from the sort of changes which natural selection finds helpful and thus tries to keep. Genes for virus-associated proteins turned out to be evolutionary hotspots: 30% of all the adaptive change was seen in the genes for the 13% of the proteins which interacted with viruses. As quickly as viruses learn to recognise and subvert such proteins, hosts must learn to modify them.
A couple of years later, working with Dmitri Petrov at Stanford, Dr Enard showed that modern humans have borrowed some of these evolutionary responses to viruses from their nearest relatives. Around 2-3% of the DNA in an average European genome has Neanderthal origins, a result of interbreeding 50,000 to 30,000 years ago. For these genes to have persisted they must be doing something useful—otherwise natural selection would have removed them. Dr Enard and Dr Petrov found that a disproportionate number described virus-interacting proteins; of the bequests humans received from their now vanished relatives, ways to stay ahead of viruses seem to have been among the most important.
Viruses do not just shape the human genome through natural selection, though. They also insert themselves into it. At least a twelfth of the DNA in the human genome is derived from viruses; by some measures the total could be as high as a quarter.
Retroviruses like HIV are called retro because they do things backwards. Where cellular organisms make their RNA from DNA templates, retroviruses do the reverse, making DNA copies of their RNA genomes. The host cell obligingly makes these copies into double-stranded DNA which can be stitched into its own genome. If this happens in a cell destined to give rise to eggs or sperm, the viral genes are passed from parent to offspring, and on down the generations. Such integrated viral sequences, known as endogenous retroviruses (ERVs), account for 8% of the human genome.
This is another example of the way the same viral trick can be discovered a number of times. Many bacteriophages are also able to stitch copies of their genome into their host’s DNA, staying dormant, or “temperate”, for generations. If the cell is doing well and reproducing regularly, this quiescence is a good way for the viral genes to make more copies of themselves. When a virus senses that its easy ride may be coming to an end, though—for example, if the cell it is in shows signs of stress—it will abandon ship. What was latent becomes “lytic” as the viral genes produce a sufficient number of virions to tear the host apart.
Though some of their genes are associated with cancers, in humans ERVs do not burst back into action in later generations. Instead they have proved useful resources of genetic novelty. In the most celebrated example, at least ten different mammalian lineages make use of a retroviral gene for one of their most distinctively mammalian activities: building a placenta.
The placenta is a unique organ because it requires cells from the mother and the fetus to work together in order to pass oxygen and sustenance in one direction and carbon dioxide and waste in the other. One way this intimacy is achieved safely is through the creation of a tissue in which the membranes between cells are broken down to form a continuous sheet of cellular material.
The protein that allows new cells to merge themselves with this layer, syncytin-1, was originally used by retroviruses to join the external membranes of their virions to the external membranes of cells, thus gaining entry for the viral proteins and nucleic acids. Not only have different sorts of mammals co-opted this membrane-merging trick—other creatures have made use of it, too. The mabuya, a long-tailed skink which unusually for a lizard nurtures its young within its body, employs a retroviral syncytin protein to produce a mammalian-looking placenta. The most recent shared ancestor of mabuyas and mammals died out 80m years before the first dinosaur saw the light of day, but both have found the same way to make use of the viral gene.
You put your line-1 in, you take your line-1 out
This is not the only way that animals make use of their ERVs. Evidence has begun to accumulate that genetic sequences derived from ERVs are quite frequently used to regulate the activity of genes of more conventional origin. In particular, RNA molecules transcribed from an ERV called HERV-K play a crucial role in providing the stem cells found in embryos with their “pluripotency”—the ability to create specialised daughter cells of various different types. Unfortunately, when expressed in adults HERV-K can also be responsible for cancers of the testes.
As well as containing lots of semi-decrepit retroviruses that can be stripped for parts, the human genome also holds a great many copies of a “retrotransposon” called LINE-1. This a piece of DNA with a surprisingly virus-like way of life; it is thought by some biologists to have, like ERVs, a viral origin. In its full form, LINE-1 is a 6,000-letter sequence of DNA which describes a “reverse transcriptase” of the sort that retroviruses use to make DNA from their RNA genomes. When LINE-1 is transcribed into an mRNA and that mRNA subsequently translated to make proteins, the reverse transcriptase thus created immediately sets to work on the mRNA used to create it, using it as the template for a new piece of DNA which is then inserted back into the genome. That new piece of DNA is in principle identical to the piece that acted as the mRNA’s original template. The LINE-1 element has made a copy of itself.
In the 100m years or so that this has been going on in humans and the species from which they are descended the LINE-1 element has managed to pepper the genome with a staggering 500,000 copies of itself. All told, 17% of the human genome is taken up by these copies—twice as much as by the ERVs.
Most of the copies are severely truncated and incapable of copying themselves further. But some still have the knack, and this capability may be being put to good use. Fred Gage and his colleagues at the Salk Institute for Biological Studies, in San Diego, argue that LINE-1 elements have an important role in the development of the brain. In 2005 Dr Gage discovered that in mouse embryos—specifically, in the brains of those embryos—about 3,000 LINE-1 elements are still able to operate as retrotransposons, putting new copies of themselves into the genome of a cell and thus of all its descendants.
Brains develop through proliferation followed by pruning. First, nerve cells multiply pell-mell; then the cell-suicide process that makes complex life possible prunes them back in a way that looks a lot like natural selection. Dr Gage suspects that the movement of LINE-1 transposons provides the variety in the cell population needed for this selection process. Choosing between cells with LINE-1 in different places, he thinks, could be a key part of the process from which the eventual neural architecture emerges. What is true in mice is, as he showed in 2009, true in humans, too. He is currently developing a technique for looking at the process in detail by comparing, post mortem, the genomes of different brain cells from single individuals to see if their LINE-1 patterns vary in the ways that his theory would predict.
V Promised lands
HUMAN EVOLUTION may have used viral genes to make big-brained live-born life possible; but viral evolution has used them to kill off those big brains on a scale that is easily forgotten. Compare the toll to that of war. In the 20th century, the bloodiest in human history, somewhere between 100m and 200m people died as a result of warfare. The number killed by measles was somewhere in the same range; the number who died of influenza probably towards the top of it; and the number killed by smallpox—300m-500m—well beyond it. That is why the eradication of smallpox from the wild, achieved in 1979 by a globally co-ordinated set of vaccination campaigns, stands as one of the all-time-great humanitarian triumphs.
Other eradications should eventually follow. Even in their absence, vaccination has led to a steep decline in viral deaths. But viruses against which there is no vaccine, either because they are very new, like SARS–CoV-2, or peculiarly sneaky, like HIV, can still kill millions.
Reducing those tolls is a vital aim both for research and for public-health policy. Understandably, a far lower priority is put on the benefits that viruses can bring. This is mostly because they are as yet much less dramatic. They are also much less well understood.
The viruses most prevalent in the human body are not those which infect human cells. They are those which infect the bacteria that live on the body’s surfaces, internal and external. The average human “microbiome” harbours perhaps 100trn of these bacteria. And where there are bacteria, there are bacteriophages shaping their population.
The microbiome is vital for good health; when it goes wrong it can mess up a lot else. Gut bacteria seem to have a role in maintaining, and possibly also causing, obesity in the well-fed and, conversely, in tipping the poorly fed into a form of malnutrition called kwashiorkor. Ill-regulated gut bacteria have also been linked, if not always conclusively, with diabetes, heart disease, cancers, depression and autism. In light of all this, the question “who guards the bacterial guardians?” is starting to be asked.
The viruses that prey on the bacteria are an obvious answer. Because the health of their host’s host—the possessor of the gut they find themselves in—matters to these phages, they have an interest in keeping the microbiome balanced. Unbalanced microbiomes allow pathogens to get a foothold. This may explain a curious detail of a therapy now being used as a treatment of last resort against Clostridium difficile, a bacterium that causes life-threatening dysentery. The therapy in question uses a transfusion of faecal matter, with its attendant microbes, from a healthy individual to reboot the patient’s microbiome. Such transplants, it appears, are more likely to succeed if their phage population is particularly diverse.
Medicine is a very long way from being able to use phages to fine-tune the microbiome. But if a way of doing so is found, it will not in itself be a revolution. Attempts to use phages to promote human health go back to their discovery in 1917, by Félix d’Hérelle, a French microbiologist, though those early attempts at therapy were not looking to restore balance and harmony. On the basis that the enemy of my enemy is my friend, doctors simply treated bacterial infections with phages thought likely to kill the bacteria.
The arrival of antibiotics saw phage therapy abandoned in most places, though it persisted in the Soviet Union and its satellites. Various biotechnology companies think they may now be able to revive the tradition—and make it more effective. One option is to remove the bits of the viral genome that let phages settle down to a temperate life in a bacterial genome, leaving them no option but to keep on killing. Another is to write their genes in ways that avoid the defences with which bacteria slice up foreign DNA.
The hope is that phage therapy will become a backup in difficult cases, such as infection with antibiotic-resistant bugs. There have been a couple of well-publicised one-off successes outside phage therapy’s post-Soviet homelands. In 2016 Tom Patterson, a researcher at the University of California, San Diego, was successfully treated for an antibiotic-resistant bacterial infection with specially selected (but un-engineered) phages. In 2018 Graham Hatfull of the University of Pittsburgh used a mixture of phages, some engineered so as to be incapable of temperance, to treat a 16-year-old British girl who had a bad bacterial infection after a lung transplant. Clinical trials are now getting under way for phage treatments aimed at urinary-tract infections caused by Escherichia coli, Staphylococcus aureus infections that can lead to sepsis and Pseudomonas aeruginosa infections that cause complications in people who have cystic fibrosis.
Viruses which attack bacteria are not the only ones genetic engineers have their eyes on. Engineered viruses are of increasing interest to vaccine-makers, to cancer researchers and to those who want to treat diseases by either adding new genes to the genome or disabling faulty ones. If you want to get a gene into a specific type of cell, a virion that recognises something about such cells may often prove a good tool.
The vaccine used to contain the Ebola outbreak in the Democratic Republic of Congo over the past two years was made by engineering Indiana vesiculovirus, which infects humans but cannot reproduce in them, so that it expresses a protein found on the surface of the Ebola virus; thus primed, the immune system responds to Ebola much more effectively. The World Health Organisation’s current list of 29 covid-19 vaccines in clinical trials features six versions of other viruses engineered to look a bit like SARS-CoV-2. One is based on a strain of measles that has long been used as a vaccine against that disease.
Viruses engineered to engender immunity against pathogens, to kill cancer cells or to encourage the immune system to attack them, or to deliver needed genes to faulty cells all seem likely to find their way into health care. Other engineered viruses are more worrying. One way to understand how viruses spread and kill is to try and make particularly virulent ones. In 2005, for example, Terrence Tumpey of America’s Centres for Disease Control and Prevention and his colleagues tried to understand the deadliness of the influenza virus responsible for the pandemic of 1918-20 by taking a more benign strain, adding what seemed to be distinctive about the deadlier one and trying out the result on mice. It was every bit as deadly as the original, wholly natural version had been.
The use of engineered pathogens as weapons of war is of dubious utility, completely illegal and repugnant to almost all
Because such “gain of function” research could, if ill-conceived or poorly implemented, do terrible damage, it requires careful monitoring. And although the use of engineered pathogens as weapons of war is of dubious utility—such weapons are hard to aim and hard to stand down, and it is not easy to know how much damage they have done—as well as being completely illegal and repugnant to almost all, such possibilities will and should remain a matter of global concern.
Information which, for billions of years, has only ever come into its own within infected cells can now be inspected on computer screens and rewritten at will. The power that brings is sobering. It marks a change in the history of both viruses and people—a change which is perhaps as important as any of those made by modern biology. It is constraining a small part of the viral world in a way which, so far, has been to people’s benefit. It is revealing that world’s further reaches in a way which cannot but engender awe. ■
Editor’s note: Some of our covid-19 coverage is free for readers of The Economist Today, our daily newsletter. For more stories and our pandemic tracker, see our hub
This article appeared in the Essay section of the print edition under the headline “The outsiders inside”
HUMANS THINK of themselves as the world’s apex predators. Hence the silence of sabre-tooth tigers, the absence of moas from New Zealand and the long list of endangered megafauna. But SARS–CoV-2 shows how people can also end up as prey. Viruses have caused a litany of modern pandemics, from covid-19, to HIV/AIDS to the influenza outbreak in 1918-20, which killed many more people than the first world war. Before that, the colonisation of the Americas by Europeans was abetted—and perhaps made possible—by epidemics of smallpox, measles and influenza brought unwittingly by the invaders, which annihilated many of the original inhabitants.
The influence of viruses on life on Earth, though, goes far beyond the past and present tragedies of a single species, however pressing they seem. Though the study of viruses began as an investigation into what appeared to be a strange subset of pathogens, recent research puts them at the heart of an explanation of the strategies of genes, both selfish and otherwise.
Viruses are unimaginably varied and ubiquitous. And it is becoming clear just how much they have shaped the evolution of all organisms since the very beginnings of life. In this, they demonstrate the blind, pitiless power of natural selection at its most dramatic. And—for one group of brainy bipedal mammals that viruses helped create—they also present a heady mix of threat and opportunity.
As our essay in this week’s issue explains, viruses are best thought of as packages of genetic material that exploit another organism’s metabolism in order to reproduce. They are parasites of the purest kind: they borrow everything from the host except the genetic code that makes them what they are. They strip down life itself to the bare essentials of information and its replication. If the abundance of viruses is anything to go by, that is a very successful strategy indeed.
The world is teeming with them. One analysis of seawater found 200,000 different viral species, and it was not setting out to be comprehensive. Other research suggests that a single litre of seawater may contain more than 100bn virus particles, and a kilo of dried soil ten times that number. Altogether, according to calculations on the back of a very big envelope, the world might contain 1031 of the things—that is one followed by 31 zeros, far outnumbering all other forms of life on the planet.
As far as anyone can tell, viruses—often of many different sorts—have adapted to attack every organism that exists. One reason they are powerhouses of evolution is that they oversee a relentless and prodigious slaughter, mutating as they do so. This is particularly clear in the oceans, where a fifth of single-celled plankton are killed by viruses every day. Ecologically, this promotes diversity by scything down abundant species, thus making room for rarer ones. The more common an organism, the more likely it is that a local plague of viruses specialised to attack it will develop, and so keep it in check.
This propensity to cause plagues is also a powerful evolutionary stimulus for prey to develop defences, and these defences sometimes have wider consequences. For example, one explanation for why a cell may deliberately destroy itself is if its sacrifice lowers the viral load on closely related cells nearby. That way, its genes, copied in neighbouring cells, are more likely to survive. It so happens that such altruistic suicide is a prerequisite for cells to come together and form complex organisms, such as pea plants, mushrooms and human beings.
The other reason viruses are engines of evolution is that they are transport mechanisms for genetic information. Some viral genomes end up integrated into the cells of their hosts, where they can be passed down to those organisms’ descendants. Between 8% and 25% of the human genome seems to have such viral origins. But the viruses themselves can in turn be hijacked, and their genes turned to new uses. For example, the ability of mammals to bear live young is a consequence of a viral gene being modified to permit the formation of placentas. And even human brains may owe their development in part to the movement within them of virus-like elements that create genetic differences between neurons within a single organism.
Evolution’s most enthralling insight is that breathtaking complexity can emerge from the sustained, implacable and nihilistic competition within and between organisms. The fact that the blind watchmaker has equipped you with the capacity to read and understand these words is in part a response to the actions of swarms of tiny, attacking replicators that have been going on, probably, since life first emerged on Earth around 4bn years ago. It is a startling example of that principle in action—and viruses have not finished yet.
Humanity’s unique, virus-chiselled consciousness opens up new avenues to deal with the viral threat and to exploit it. This starts with the miracle of vaccination, which defends against a pathogenic attack before it is launched. Thanks to vaccines, smallpox is no more, having taken some 300m lives in the 20th century. Polio will one day surely follow. New research prompted by the covid-19 pandemic will enhance the power to examine the viral realm and the best responses to it that bodies can muster—taking the defence against viruses to a new level.
Another avenue for progress lies in the tools for manipulating organisms that will come from an understanding of viruses and the defences against them. Early versions of genetic engineering relied on restriction enzymes—molecular scissors with which bacteria cut up viral genes and which biotechnologists employ to move genes around. The latest iteration of biotechnology, gene editing letter by letter, which is known as CRISPR, makes use of a more precise antiviral mechanism.
From the smallest beginnings
The natural world is not kind. A virus-free existence is an impossibility so deeply unachievable that its desirability is meaningless. In any case, the marvellous diversity of life rests on viruses which, as much as they are a source of death, are also a source of richness and of change. Marvellous, too, is the prospect of a world where viruses become a source of new understanding for humans—and kill fewer of them than ever before. ■
Correction: An earlier version of this article got its maths wrong. 1031 is one followed by 31 zeroes, not ten followed by 31 zeroes as we first wrote. Sorry.
Summary: In a comprehensive study of nearly 20,000 species, research shows that plant communities are shifting to include more heat-loving species as a result of climate change.
Although Live Oak trees are common in South Florida today, Ken Feeley, a University of Miami biology professor, said their time here may be fleeting. With climate change pushing up temperatures, the oaks, which favor cooler conditions, could soon decline in the region and be replaced with more tropical, heat-loving species such as Gumbo Limbo or Mahogany trees.
“Live Oaks occur throughout the southeast and all the way up to coastal Virginia, so down here we are in one of the very hottest places in its range,” said Feeley, who is also the University’s Smathers Chair of Tropical Tree Biology. “As temperatures increase, it may simply get too hot in Miami for oaks and other temperate species.”
Likewise, in Canada, as temperatures increase, sugar maple trees — which are used to produce maple syrup — are losing their habitats. And in New York City, trees that are more typical of the balmy South, such as Magnolias, are increasing in abundance and blooming earlier each year, news reports indicate.
These are just a few examples of a larger trend happening across the Americas — from Hudson Bay to Tierra del Fuego — as plant communities shift their ranges and respond to changing climates, Feeley pointed out. In his newest study, published in Nature Climate Change, Feeley, along with three of his graduate students and a visiting graduate student from the Nacional University of Colombia, analyzed more than 20 million records of more than 17,000 plant species from throughout the Western Hemisphere. They found that since the 1970s, entire plant ecosystems have changed directionally over time to include more and more of the species that prefer warmer climates. This process is called thermophilization.
“Almost anywhere you go, the types of species that you encounter now are different than what you would have found in that same spot 40 years ago, and we believe that this pattern is the direct result of rising temperatures and climate change,” Feeley said.
The research of Feeley and his students demonstrates that entire ecosystems are consistently losing the plant species that favor cold temperatures, and that those plants are being replaced by more heat-tolerant species that can withstand the warming climate. Plants favoring cool temperatures are either moving to higher elevations and latitudes, or some species may even be going locally extinct. Feeley and his students are now exploring key focal species that may offer more insight into these processes.
“Some of these changes can be so dramatic that we are shifting entire habitat types from forests to grasslands or vice versa — by looking at all types of plants over long periods of time and over huge areas, we were able to observe those changes,” he explained.
In addition to the effects of rising temperatures, the researchers also looked at how plant communities are being affected by changes in rainfall during the past four decades. Feeley and his team observed shifts in the amounts of drought-tolerant versus drought-sensitive plant species. But in many cases, the observed changes were not connected to the changes in rainfall. In fact, in many areas that are getting drier, the drought-sensitive species have become more common during the past decades. According to Feeley, this may be because of a connection between the species’ heat tolerances and their water demands. Heat tolerant species are typically less drought-tolerant, so as rising temperatures favor the increase of heat-tolerant species, it may also indirectly prompt a rise in water-demanding species. Feeley stressed that this can create dangerous situations in some areas where the plant communities are pushed out of equilibrium with their climate.
“When drought hits, it will be doubly bad for these ecosystems that have lost their tolerance to drought,” he said, adding that “for places where droughts are becoming more severe and frequent — like in California — this could make things a lot worse.”
But the implications of thermophilization go far beyond just the loss of certain plants, according to Feeley. Plants are at the base of the food chain and provide sustenance and habitat for wildlife — so if the plant communities transform, so will the animals that need them.
“All animals — including humans — depend on the plants around them,” Feeley said. “If we lose some plants, we may also lose the insects, birds, and many other forms of wildlife that we are used to seeing in our communities and that are critical to our ways of life. When people think of climate change, they need to realize that it’s not just about losing ice in Antarctica or rising sea levels — climate change affects almost every natural system in every part of the planet.”
Story Source:
Materials provided by University of Miami. Original written by Janette Neuwahl Tannen. Note: Content may be edited for style and length.
Journal Reference:
K. J. Feeley, C. Bravo-Avila, B. Fadrique, T. M. Perez, D. Zuleta. Climate-driven changes in the composition of New World plant communities. Nature Climate Change, 2020; DOI: 10.1038/s41558-020-0873-2
UNIVERSITY PARK, Pa. — In their zeal to promote the importance of climate change as an ecological driver, climate scientists increasingly are ignoring the profound role that indigenous peoples played in fire and vegetation dynamics, not only in the eastern United States but worldwide, according to a Penn State researcher.
“In many locations, evidence shows that indigenous peoples actively managed vast areas and were skilled stewards of the land,” said Marc Abrams, professor of forest ecology and physiology. “The historical record is clear, showing that for thousands of years indigenous peoples set frequent fires to manage forests to produce more food for themselves and the wildlife that they hunted, and practiced extensive agriculture.”
Responding to an article published earlier this year in a top scientific journal that claimed fires set by Native Americans were rare in southern New England and Long Island, New York, and played minor ecological roles, Abrams said there is significant evidence to the contrary.
In an article published today (July 20) in Nature Sustainability, Abrams, who has been studying the historical use of fire in eastern U.S. forests for nearly four decades, refutes those contentions.
“The palaeoecological view — based on a science of analyzing pollen and charcoal in lake sediments — that has arisen over the last few decades, contending that anthropogenic fires were rare and mostly climate-driven, contradicts the proud legacy and heritage of land use by indigenous peoples, worldwide,” he said.
In his article, Abrams, the Nancy and John Steimer Professor of Agricultural Sciences in the College of Agricultural Sciences, argues that the authors of the previous paper assumed that the scarcity of charcoal indicated that there had not been burning. But frequent, low-intensity fires do not create the amount of charcoal that intense, crown-level, forest-consuming wildfires do, he pointed out.
“Surface fires set by indigenous people in oak and pine forests, which dominate southern New England, often produced insufficient charcoal to be noticed in the sediment,” said Abrams. “The authors of the earlier article did not consider charcoal types, which distinguish between crown and surface fires, and charcoal size — macro versus micro — to differentiate local versus regional fires.”
Also, lightning in New England could not account for the ignition of so many fires, Abrams argues. In southern New England, lightning-strike density is low and normally is associated with rain events.
“The region lacks dry lightning needed to sustain large fires,” he said. “Moreover, lightning storms largely are restricted to the summer when humidity is high and vegetation flammability is low, making them an unlikely ignition source.”
Early explorers and colonists of southern New England routinely described open, park-like forests and witnessed, firsthand, Native American vegetation management, Abrams writes in his article, adding that oral history and numerous anthropological studies indicate long-term burning and land-use for thousands of years by indigenous people.
Burning near Native American villages and along their extensive trail systems constitutes large land areas, and fires would have kept burning as long as fuel, weather and terrain allowed, he explained. Following European settlement, these open oak and pine woodlands increasingly became closed by trees that previously were held in check by frequent fire.
The authors of the previous paper also argued that fire should not be used as a present-day management tool, a view that Abrams does not support.
The role of anthropogenic fires is front and center in the long-running climate-disturbance debate, according to Abrams, who notes that fires increased with the rise of human populations. The world would be a very different place without those fires, he contends.
“Surprisingly, the importance of indigenous peoples burning in vegetation-fire dynamics is increasingly downplayed among paleoecologists,” he writes. “This applies to locations where lightning-caused fires are rare.”
Abrams points out that he is not denying the importance of climate in vegetation and fire dynamics or its role in enhancing the extent of human fires. “However,” he writes, “in oak-pine forests of southern New England, Native American populations were high enough, lighting-caused fires rare enough, vegetation flammable enough and the benefits of burning and agriculture great enough for us to have confidence in the importance of historic human land management.”
###
Gregory Nowacki, a scientist in the U.S. Department of Agriculture’s Eastern Regional Forest Service Office in Milwaukee, Wisconsin, contributed to the article.
O ano de 2020 será lembrado como o ano em que a pandemia causada pelo vírus SARS-CoV-2 precipitou uma ruptura maior no funcionamento das sociedades contemporâneas. Será provavelmente lembrado também como o momento de uma ruptura da qual nossas sociedades não mais se recuperaram completamente. Isso porque a atual pandemia intervém num momento em que três crises estruturais na relação entre as sociedades hegemônicas contemporâneas e o sistema Terra se reforçam reciprocamente, convergindo em direção a uma regressão econômica global, ainda que com eventuais surtos conjunturais de recuperação. Essas três crises são, como reiterado pela ciência, a emergência climática, a aniquilação em curso da biodiversidade e o adoecimento coletivo dos organismos, intoxicados pela indústria química.i Os impactos cada vez mais avassaladores decorrentes da sinergia entre essas três crises sistêmicas deixarão doravante as sociedades, mesmo as mais ricas, ainda mais desiguais e mais vulneráveis, menos aptas, portanto, a recuperar seu desempenho anterior. São justamente tais perdas parciais, cada vez mais frequentes, de funcionalidade na relação das sociedades com o meio ambiente que caracterizam essencialmente o processo de colapso socioambiental em curso (Homer-Dixon et al. 2015; Steffen et al. 2018; Marques 2015/2018 e 2020).
O ano da pandemia é o do mais crucial ponto de inflexão da história humana
Por sua extensão global e pelo rastro de mortes deixadas em sua passagem, superior a 250 mil vítimas (oficialmente notificadas) em pouco mais de quatro meses, a atual pandemia é um fato cuja gravidade seria difícil exagerar, tanto mais porque novos surtos podem ainda ocorrer nos próximos dois anos, segundo um relatório do Center for Infectious Disease Research and Policy (CIDRAP), da Universidade de Minnesota (Moore, Lipsitch, Barry & Osterholm 2020).
Mas ainda mais grave que o saldo imenso de mortes, é o momento da incidência da pandemia na história humana. Outras pandemias, algumas muito mais letais, ocorreram no século XX, sem afetar profundamente a capacidade de recuperação das sociedades. O que singulariza a atual pandemia é o fato de se somar a diversas crises sistêmicas que ameaçam a humanidade, e isso justamente no momento em que não é mais possível postergar decisões que afetarão crucialmente, e muito em breve, a habitabilidade do planeta. A ciência condiciona a possibilidade de estabilizar o aquecimento médio global dentro, ou não muito além, dos limites almejados pelo Acordo de Paris a um fato incontornável: as emissões de CO2 devem atingir seu pico em 2020 e começar a declinar fortemente em seguida. O IPCC traçou 196 cenários através dos quais podemos limitar o aquecimento médio global a cerca de 0,5oC acima do aquecimento médio atual em relação ao período pré-industrial (1,2oC em 2019). Nenhum deles, lembram Tom Rivett-Carnac e Christiana Figueres, admite que o pico de emissões de gases de efeito estufa (GEE) seja protelado para além de 2020 (Hooper 2020). Ninguém exprime o significado dessa data-limite de modo mais peremptório que Thomas Stocker, co-diretor do IPCC entre 2008 e 2015:ii
“Mitigação retardada ou insuficiente impossibilita limitar o aquecimento global permanentemente. O ano de 2020 é crucial para a definição das ambições globais sobre a redução das emissões. Se as emissões de CO2 continuarem a aumentar além dessa data, as metas mais ambiciosas de mitigação tornar-se-ão inatingíveis”.
Já em 2017, Jean Jouzel, ex-vice-presidente do IPCC, advertia que “para manter alguma chance de permanecer abaixo dos 2oC é necessário que o pico das emissões seja atingido no mais tardar em 2020” (Le Hir 2017). Em outubro do ano seguinte, comentando o lançamento do relatório especial do IPCC, intitulado Global Warming 1.5oC, Debra Roberts, co-diretora do Grupo de Trabalho 2 desse relatório, reforçava essa percepção: “Os próximos poucos anos serão provavelmente os mais importantes de nossa história”. E Amjad Abdulla, representante dos Pequenos Estados Insulares em Desenvolvimento (SIDS) nas negociações climáticas, acrescentava: “Não tenho dúvidas de que os historiadores olharão retrospectivamente para esses resultados [do relatório especial do IPCC de 2018] como um dos momentos definidores no curso da história humana” (Mathiesen & Sauer 2018). Em The Second Warning: A Documentary Film (2018), divulgação do manifesto The Scientist’s Warning to Humanity: A Second Notice, lançado por William Ripple e colegas em 2017 e endossado por cerca de 20 mil cientistas, a filósofa Kathleen Dean Moore faz suas as declarações acima mencionadas: “Estamos vivendo um ponto de inflexão. Os próximos poucos anos serão os mais importantes da história da humanidade”.
Em abril de 2017, um grupo de cientistas, coordenados por Stephan Rahmstorf, lançava The Climate Turning Point, em cujo Prefácio se reafirma a meta mais ambiciosa do Acordo de Paris (“manter o aumento da temperatura média global bem abaixo de 2oC em relação ao período pré-industrial”), esclarecendo que: “essa meta é considerada necessária para evitar riscos incalculáveis à humanidade, e é factível – mas, realisticamente, apenas se as emissões globais atingirem um pico até o ano de 2020, no mais tardar”. Esse documento norteou então a criação, por diversas lideranças científicas e diplomáticas, da Missão 2020 (https://mission2020.global/). Ela definia metas básicas em energia, transporte, uso da terra, indústria, infraestrutura e finanças, de modo a tornar declinante, a partir de 2020, a curva das emissões de gases de efeito estufa e colocar o planeta numa trajetória consistente com o Acordo de Paris. “Com radical colaboração e teimoso otimismo”, escreve Christiana Figueres e colegas da Missão 2020, “dobraremos a curva das emissões de gases de efeito estufa até 2020, possibilitando à humanidade florescer.” De seu lado, António Guterres, cumprindo sua missão de incentivar e coordenar os esforços de governança global, alertava em setembro de 2018: “Se não mudarmos nossa rota até 2020, corremos o risco de deixar passar o momento em que é ainda possível evitar uma mudança climática desenfreada (arunaway climate change), com consequências desastrosas para a humanidade e para os sistemas naturais que nos sustentam”.
Pois bem, 2020, enfim, chegou. Fazendo em 2019 um balanço dos progressos realizados em direção às metas da Missão 2020, o World Resources Institute (Ge et al., 2019) escreve que “na maioria dos casos, a ação foi insuficiente ou o progresso foi nulo” (in most cases action is insufficient or progress is off track). Nenhuma das metas, em suma, foi alcançada e, em dezembro passado, a COP25 em Madri varreu definitivamente, em grande parte por culpa dos governos dos EUA, Japão, Austrália e Brasil (Irfan 2019), as últimas esperanças de uma diminuição iminente das emissões globais de GEE.
A pandemia entra em cena
Mas eis que a Covid-19 irrompe, deslocando, paralisando e adiando tudo, inclusive a COP26. E em pouco mais de três meses resolveu pelo caos e pelo sofrimento o que mais de três décadas de fatos, de ciência, de campanhas e de esforços diplomáticos para diminuir as emissões de GEE mostraram-se incapazes de realizar (já a Conferência de Toronto, de 1988, recomendava “ações específicas” nesse sentido). Ao invés de um decrescimento econômico racional, gradual e democraticamente planejado, o decrescimento econômico abrupto imposto pela pandemia afigura-se já, segundo Kenneth S. Rogoff, como “a mais profunda queda da economia global em 100 anos” (Goodman 2020). Em 15 de abril, o Carbon Brief estimou que a crise econômica deve provocar uma diminuição estimada em cerca de 5,5% nas emissões globais de CO2 em 2020. Em 30 de abril, a Global Energy Review 2020 – The impacts of the Covid-19 crisis on global energy demand and CO2 emissions, da Agência Internacional de Energia (AIE), vai mais longe e estima que “as emissões globais de CO2 devem cair ainda mais rapidamente ao longo dos nove meses restantes do ano, atingindo 30,6 Gt [bilhões de toneladas] em 2020, quase 8% mais baixas que em 2019. Este seria o nível mais baixo desde 2010. Tal redução seria a maior de todos os tempos, seis vezes maior que a redução precedente de 0,4 Gt em 2009, devido à crise financeira e duas vezes maior que todas as reduções anteriores desde o fim da Segunda Guerra Mundial”. (https://www.iea.org/reports/global-energy-review-2020/global-energy-and-co2-emissions-in-2020). A Figura 1 indica como essa redução das emissões globais de CO2 reflete a queda na demanda de consumo global de energia primária, comparada com as quedas anteriores.
Figura 1 – Taxas de mudança (%) na demanda global de energia primária, 1900 – 2020
Fonte: AIE, Global Energy Review 2020 The impacts of the Covid-19 crisis on global energy demand and CO emissions, Abril 2020, p. 11
A redução das emissões globais de CO2 projetada pela AIE para 2020 equivale ou é até pouco maior que os 7,6% de redução anual até 2030 que o IPCC considera imprescindível para conter o aquecimento aquém de níveis catastróficos (Evans 2020). O relatório da AIE apressa-se, contudo, em advertir que, “tal como nas crises precedentes, (…) o repique das emissões pode ser maior que o declínio, a menos que a onda de investimentos para retomar a economia seja dirigido a uma infraestrutura energética mais limpa e resiliente”. Salvo raras exceções, os fatos até agora não autorizam a expectativa de uma ruptura com os paradigmas energéticos e socioeconômicos anteriores. Malgrado o colapso do preço do petróleo, ou justamente por isso, as petroleiras estão se movendo com vertiginosa velocidade para tirar partido desse momento, obtendo, por exemplo, investimentos de USD 1,1 bilhão para financiar a conclusão do famigerado oleoduto Keystone XL, que ligará o petróleo canadense ao Golfo do México (McKibben 2020). Os exemplos desse tipo de oportunismo são inúmeros, inclusive no Brasil, onde os ruralistas se aproveitam da situação para fazer aprovar da Medida Provisória 910, que anistia a grilagem e eleva ainda mais as ameaças aos indígenas. Como bem afirma Laurent Joffrin, em sua Lettre politique de 30 de abril para o jornal Libération (Le monde d’avant, en pire?), o mundo pós-pandemia “corre o risco de parecer furiosamente, a curto prazo ao menos, com o mundo de antes, mas em versão piorada”. E Joffrin emenda: “o ‘mundo de após’ não mudará sozinho. Como para o ‘mundo de antes’, seu futuro dependerá de um combate político, paciente e árduo”. Político e árduo, sem dúvida, mas definitivamente não há mais tempo para paciência.
De qualquer modo, uma redução de quase 8% nas emissões globais de CO2 num ano apenas não abriu sequer um dente na curva cumulativa das concentrações atmosféricas desse gás, medidas em Mauna Loa (Havaí). Elas bateram mais um recorde em abril de 2020, atingindo 416,76 partes por milhão (ppm), 3,13 ppm acima de 2019, um dos maiores saltos desde o início de suas mensurações em 1958. Não se trata apenas de um número a mais na selva de indicadores climáticos convergentes. É o número decisivo. Como lembra Petteri Taalas, Secretário-Geral da Organização Meteorológica Mundial: “A última vez que a Terra apresentou concentrações atmosféricas de CO2 comparáveis às atuais foi há 3 a 5 milhões de anos. Nessa época, a temperatura estava 2oC a 3oC [acima do período pré-industrial] e o nível do mar estava 10 a 20 metros mais alto que hoje” (McGrath 2019). Faltam agora menos de 35 ppm para atingir 450 ppm, um nível de concentração atmosférica de CO2 largamente associado a um aquecimento médio global de 2oC acima do período pré-industrial, nível que pode ser atingido, mantida a trajetória atual, em pouco mais de 10 anos. O que nos aguarda por volta de 2030, mantida a engrenagem do sistema econômico capitalista globalizado e existencialmente dependente de sua própria reprodução ampliada, é nada menos que um desastre para a humanidade como um todo, bem como para inúmeras outras espécies. A palavra desastre não é uma hipérbole. O já mencionado Relatório do IPCC de 2018 (Global Warming 1.5oC) projeta que o mundo a 2oC em média acima do período pré-industrial terá quase 6 bilhões de pessoas expostas a ondas de calor extremo e mais de 3,5 bilhões de pessoas sujeitas à escassez hídrica, entre outras muitas adversidades. Desastre é a palavra que melhor define o mundo para o qual rumamos no horizonte dos próximos 10 anos (ou 20, pouco importa), e é exatamente o vocábulo empregado por Sir Brian Hoskins, diretor do Grantham Institute for Climate Change, do Imperial College em Londres: “Não temos evidência de que um aquecimento de 1,9oC é algo com que se possa lidar facilmente, e 2,1oC é um desastre” (Simms 2017).
Em consequência dessas altíssimas concentrações atmosféricas de CO2, o ano passado já foi o mais quente dos registros históricos na Europa (1,2oC acima do período 1981 – 2010!) e, mesmo sem El Niño, há agora, segundo o NOAA, 74,67% de chances de que 2020 venha a ser o ano mais quente em um século e meio de registros históricos na média global,iii batendo o recorde precedente de 2016 (1,24oC acima do período pré-industrial, segundo a NASA). Não é no espaço deste artigo que se podem elencar os muitos indícios de que 2020 será o primeiro ou segundo (após 2016) ano mais quente entre os sete mais quentes (2014-2020) da história da civilização humana desde a última deglaciação, cerca de 11.700 anos antes do presente. Baste aqui ter em mente que, se março de 2020 for representativo do ano, já perdemos a meta mais ambiciosa do Acordo de Paris, pois a temperatura média desse mês cravou globalmente 1,51oC acima do período 1880-1920, conforme mostra a Figura 2.
Figura 2 – Anomalias de temperatura em março de 2020 (1,51C na média global), em relação ao período 1880-1920. Fonte: GISS Surface Temperature Analysis (v4), NASA. <https://data.giss.nasa.gov/gistemp/maps/index_v4.html>.
O aquecimento global é uma arma apontada contra a saúde global. Como mostra Sara Goudarzi (2020), temperaturas mais elevadas favorecem a adaptação de micro-organismos a um mundo mais quente, diminuindo a eficácia de duas defesas básicas dos mamíferos contra os patógenos: (1) muitos micro-organismos não sobrevivem ainda a temperaturas superiores a 37oC, mas podem vir a se adaptar rapidamente a elas; (2) o sistema imune dos mamíferos, pois este perde eficiência em temperaturas mais elevadas. Além disso, o aquecimento global amplia o raio de ação de vetores de epidemias, como a dengue, zika e chikungunya, e altera a distribuição geográfica das plantas e animais, levando espécies animais terrestres a se deslocarem em direção a latitudes mais altas a uma taxa média de 17 km por década (Pecl et al. 2017). Aaron Bernstein, diretor do Harvard University’s Center of Climate, Health and the Global Environment, sintetiza bem a interação entre aquecimento global e desmatamento em suas múltiplas relações com novos surtos epidêmicos:iv
“À medida que o planeta se aquece (…) os animais deslocam-se para os polos fugindo do calor. Animais estão entrando em contato com animais com os quais eles normalmente não interagiriam, e isso cria uma oportunidade para patógenos encontrar outros hospedeiros. Muitas das causas primárias das mudanças climáticas também aumentam o risco de pandemias. O desmatamento, causado em geral pela agropecuária é a causa maior da perda de habitat no mundo todo. E essa perda força os animais a migrarem e potencialmente a entrar em contato com outros animais ou pessoas e compartilhar seus germes. Grandes fazendas de gado também servem como uma fonte para a passagem de infecções de animais para pessoas”.
Sem perder de vista as relações entre a emergência climática e essas novas ameaças sanitárias, foquemos em duas questões bem circunscritas e diretamente ligadas à pandemia atual.
A pandemia foi prevista e será, doravante, mais frequente
A primeira questão refere-se ao caráter, por assim dizer, antropogênico da pandemia. Bem longe de ser adventícia, ela é uma consequência, reiteradamente prevista, de um sistema socioeconômico crescentemente disfuncional e destrutivo. Josef Settele, Sandra Díaz, Eduardo Brondizio e Peter Daszak escreveram um artigo, a convite do IPBES, de leitura obrigatória e que me permito citar longamente:
“Há uma única espécie responsável pela pandemia Covid-19: nós. Assim como com as crises climáticas e o declínio da biodiversidade, as pandemias recentes são uma consequência direta da atividade humana – particularmente de nosso sistema financeiro e econômico global baseado num paradigma limitado, que preza o crescimento econômico a qualquer custo. (…) Desmatamento crescente, expansão descontrolada da agropecuária, cultivo e criação intensivos, mineração e aumento da infraestrutura, assim como a exploração de espécies silvestres criaram uma ‘tempestade perfeita’ para o salto de doenças da vida selvagem para as pessoas. (…) E, contudo, isso pode ser apenas o começo. Embora se estime que doenças transmitidas de outros animais para humanos já causem 700 mil mortes por ano, é vasto o potencial para pandemias futuras. Acredita-se que 1,7 milhão de vírus não identificados, dentre os que sabidamente infectam pessoas, ainda existem em mamíferos e pássaros aquáticos. Qualquer um deles pode ser a ‘Doença X’ – potencialmente ainda mais perturbadora e letal que a Covid-19. É provável que pandemias futuras ocorram mais frequentemente, propaguem-se mais rapidamente, tenham maior impacto econômico e matem mais pessoas, se não formos extremamente cuidadosos acerca dos impactos das escolhas que fazemos hoje” (https://ipbes.net/covid19stimulus).
Cada frase dessa citação encerra uma lição de ciência e de lucidez política. A maior frequência recente de epidemias e pandemias tem por causas centrais o desmatamento e a agropecuária, algo bem estabelecido também por Christian Drosten, atual coordenador do combate à Covid-19 na Alemanha, além de diretor do Instituto de Virologia do Hospital Charité de Berlim e um dos cientistas que identificou a pandemia SARS em 2003 (Spinney 2020).
“Desde que tenha oportunidade, o coronavírus está pronto para mudar de hospedeiro e nós criamos essa oportunidade através de nosso uso não natural de animais – a pecuária (livestock). Essa expõe os animais de criação à vida silvestre, mantém esses animais em grandes grupos que podem amplificar o vírus, e os humanos têm intenso contato com eles – por exemplo, através do consumo de carne –, de modo que tais animais certamente representam uma possível trajetória de emergência para o coronavírus. Camelos são animais de criação no Oriente Médio e são os hospedeiros do vírus MERS, assim como do coronavírus 229E – que é uma causa da gripe comum em humanos –, já o gado bovino foi o hospedeiro original do coronavírus OC43, outra causa de gripe”.
Nada disso é novidade para a ciência. Sabemos que a maioria das pandemias emergentes são zoonoses, isto é, doenças infecciosas causadas por bactérias, vírus, parasitas ou príons, que saltaram de hospedeiros não humanos, usualmente vertebrados, para os humanos. Como afirma Ana Lúcia Tourinho, pesquisadora da Universidade Federal de Mato Grosso (UFMT), o desmatamento é uma causa central e uma bomba-relógio em termos de zoonoses: “quando um vírus que não fez parte da nossa história evolutiva sai do seu hospedeiro natural e entra no nosso corpo, é o caos” (Pontes 2020). Esse risco, repita-se, é crescente. Basta ter em mente que “mamíferos domesticados hospedam 50% dos vírus zoonóticos, mas representam apenas 12 espécies” (Johnson et al. 2020). Esse grupo inclui porcos, vacas e carneiros. Em resumo, o aquecimento global, o desmatamento, a destruição dos habitats selvagens, a domesticação e a criação de aves e mamíferos em escala industrial destroem o equilíbrio evolutivo entre as espécies, facilitando as condições para saltos desses vírus de uma espécie a outra, inclusive a nossa.
4.As próximas zoonoses serão gestadas no Brasil?
O segundo ponto, com o qual concluo este artigo, são as consequências especificamente sanitárias da destruição em curso da Amazônia e do Cerrado. Entre as mais funestas está a crescente probabilidade de que o país se torne o foco das próximas pandemias zoonóticas. Na última década, as megacidades da Ásia do leste, principalmente na China, têm sido o principal “hotspot” de infecções zoonóticas (Zhang et al. 2019). Não por acaso. Esses países estão entre os que mais perderam cobertura florestal no mundo em benefício do sistema alimentar carnívoro e globalizado. O caso da China é exemplar. De 2001 a 2018, o país perdeu 94,2 mil km2 de cobertura arbórea, equivalente a uma diminuição de 5,8% em sua cobertura arbórea no período. “Extração de madeira e agropecuária consomem até 5 mil km2 de florestas virgens todo ano. Na China setentrional e central a cobertura florestal foi reduzida pela metade nas últimas duas décadas”.v Em paralelo com a destruição dos habitats selvagens, o crescimento econômico chinês desencadeou uma demanda por proteínas animais, incluindo as provenientes de animais exóticos (Cheng et al. 2007). Entre 1980 e 2015, o consumo de carne na China cresceu sete vezes e 4,7 vezes per capita (de 15 kg para 70 kg per capita por ano ao longo deste período). Com cerca de 18% da população mundial, a China era em 2018 responsável por 28% do consumo de carne no planeta (Rossi 2018). Segundo um relatório de 2017 do Rabobank, intitulado China’s Animal Protein Outlook to 2020: Growth in Demand, Supply and Trade, a demanda adicional por carne a cada ano na China será de cerca de um milhão de toneladas. “A produção local de carne bovina não consegue acompanhar o crescimento da demanda. Na realidade, a China tem uma escassez estrutural de oferta de carne bovina, que necessita ser satisfeita por importações crescentes”.
A cobertura vegetal dos trópicos tem sido destruída para sustentar essa dieta crescentemente carnívora, não apenas na China, mas em vários países do mundo e particularmente entre nós. No Brasil, a remoção de mais de 1,8 milhão de km2 da cobertura vegetal da Amazônia e do Cerrado nos últimos cinquenta anos, para converter suas magníficas paisagens naturais em zonas fornecedoras de carne e ração animal, em escala nacional e global, representa o mais fulminante ecocídio jamais perpetrado pela espécie humana. Nunca, de fato, em nenhuma latitude e em nenhum momento da história humana, destruiu-se tanta vida animal e vegetal em tão pouco tempo, para a degradação de tantos e para o benefício econômico de tão poucos. E nunca, mesmo para os pouquíssimos que enriqueceram com a devastação, esse enriquecimento terá sido tão efêmero, pois a destruição da cobertura vegetal já começa a gerar erosão dos solos e secas recorrentes, solapando as bases de qualquer agricultura nessa região (na realidade, no Brasil, como um todo).
Em decorrência dessa guerra de extermínio contra a natureza deflagrada pela insanidade dos ditadores militares e continuada pelos civis, atualmente o rebanho bovino brasileiro é de aproximadamente 215 milhões de cabeças, sendo que 80% de seu consumo é absorvido pelo mercado interno, que cresceu 14% nos últimos dez anos (Macedo 2019). Além disso, o Brasil tornou-se líder das exportações mundiais de carne bovina (20% dessas exportações) e de soja (56%), basicamente destinada à alimentação animal. A maior parte do rebanho bovino brasileiro concentra-se hoje nas regiões Norte e Centro-Oeste, com crescente participação da Amazônia. Em 2010, 14% do rebanho brasileiro já se encontrava na região norte do país. Em 2016, essa participação saltou para 22%. Juntas, a região norte e centro-oeste abrigam 56% do rebanho bovino brasileiro (Zaia 2018). Em 2017, apenas 19,8% da cobertura vegetal remanescente do Cerrado permanecia ainda intocada. A continuar a devastação, a pecuária e a agricultura de soja levarão em breve à extinção quase 500 espécies de plantas endêmicas – três vezes mais que todas as extinções documentadas desde 1500 (Strassburg et al. 2017). A Amazônia, que perdeu cerca de 800 mil km2 de cobertura florestal em 50 anos e perderá outras muitas dezenas de milhares sob a sanha ecocida de Bolsonaro, tornou-se, em sua porção sul e leste, uma paisagem desolada de pastos em vias de degradação. O caos ecológico produzido pelo desmatamento por corte raso de cerca de 20% da área original da floresta, pela degradação do tecido florestal de pelo menos outros 20% e pela grande concentração de bovinos na região cria as condições para tornar o Brasil um “hotspot” das próximas zoonoses. Em primeiro lugar porque os morcegos são um grande reservatório de vírus e, entre os morcegos brasileiros, cujo habitat são sobretudo as florestas (ou o que resta delas), circulam pelo menos 3.204 tipos de coronavírus (Maxman 2017). Em segundo lugar porque, como mostraram Nardus Mollentze e Daniel Streicker (2020), o grupo taxonômico dos Artiodactyla (de casco fendido), ao qual pertencem os bois, hospedam, juntamente com os primatas, mais vírus, potencialmente zoonóticos, do que seria de se esperar entre os grupos de mamíferos, incluindo os morcegos. Na realidade, a Amazônia já é um “hotspot” de epidemias não virais, como a leishmaniose e a malária, doenças tropicais negligenciadas, mas com alto índice de letalidade. Como afirma a OMS, “a leishmaniose está associada a mudanças ambientais, tais como o desmatamento, o represamento de rios, a esquemas de irrigação e à urbanização”,vi todos eles fatores que concorrem para a destruição da Amazônia e para o aumento do risco de pandemias. A relação entre desmatamento amazônico e a malária foi bem estabelecida em 2015 por uma equipe do IPEA: para cada 1% de floresta derrubada por ano, os casos de malária aumentam 23% (Pontes 2020).
A curva novamente ascendente desde 2013 da destruição da Amazônia e do Cerrado resultou da execrável aliança de Dilma Rousseff com o que há de mais retrógrado na economia brasileira. Já para a necropolítica de Bolsonaro, a destruição da vida, do que resta do patrimônio natural brasileiro, tornou-se um programa de governo e uma verdadeira obsessão. Bolsonaro está levando o país a dar um salto sem retorno no caos ecológico, de onde a necessidade inadiável de neutralizá-lo por impeachment ou qualquer outro mecanismo constitucional. Não há mais tempo a perder. Entre agosto de 2018 e julho de 2019, o desmatamento amazônico atingiu 9.762 km2, quase 30% acima dos 12 meses anteriores e o pior resultado dos últimos dez anos, segundo o INPE. No primeiro trimestre de 2020, que apresenta tipicamente os níveis mais baixos de desmatamento em cada ano, o sistema Deter, do INPE, detectou um aumento de 51% em relação ao mesmo período de 2019, o nível mais alto para esse período desde o início da série, em 2016. Segundo Tasso Azevedo, coordenador-geral do Projeto de Mapeamento Anual da Cobertura e Uso do Solo no Brasil (MapBiomas), “o mais preocupante é que no acumulado de agosto de 2019 até março de 2020, o nível do desmatamento mais do que dobrou” (Menegassi 2020). Ao monopolizar todas as atenções, a pandemia oferece a Bolsonaro uma oportunidade inesperada para acelerar sua obra de destruição da floresta e de seus povos (Barifouse 2020).
Recapitulemos. O que importa aqui, sobretudo, é entender que a pandemia intervém no momento em que o aquecimento global e todos os demais processos de degradação ambiental estão em aceleração. A pandemia pode acelerá-los ainda mais, na ausência de uma reação política vigorosa da sociedade. Ela acrescenta, em todo o caso, mais uma dimensão a esse feixe convergente de crises socioambientais que impõe à humanidade uma situação radicalmente nova. Pode-se assim formular essa novidade: não é mais plausível esperar, passada a pandemia, um novo ciclo de crescimento econômico global e ainda menos nacional. Se algum crescimento voltar a ocorrer, ele será conjuntural e logo truncado pelo caos climático, ecológico e sanitário. O próximo decênio evoluirá sob o signo de regressões socioeconômicas, pois mesmo a se admitir que a economia globalizada tenha trazido benefícios sociais, eles foram parcos e vêm sendo de há muito superados por seus malefícios. A pandemia é apenas um entre esses malefícios, mas certamente não o pior. Não são mais atuais, portanto, em 2020, as variadas agendas desenvolvimentistas, típicas dos embates ideológicos do século XX. É claro que a exigência de justiça social, bandeira histórica da esquerda, permanece mais que nunca atual. Além de ser um valor perene e irrenunciável, a luta pela diminuição da desigualdade social significa, antes de mais nada, retirar das corporações o poder decisório sobre os investimentos estratégicos (energia, alimentação, mobilidade etc.), assumir o controle democrático e sustentável desses investimentos e, assim, atenuar os impactos do colapso socioambiental em curso. É do aprofundamento da democracia que depende crucialmente, hoje, a sobrevivência de qualquer sociedade organizada num mundo que está se tornando sempre mais quente, mais empobrecido biologicamente, mais poluído e, por todas essas razões, mais enfermo. Sobreviver, no contexto de um processo de colapso socioambiental, não é um programa mínimo. Sobreviver requer, hoje, lutar por algo muito mais ambicioso que os programas socialdemocratas ou revolucionários do século XX. Supõe redefinir o próprio sentido e finalidade da atividade econômica, vale dizer, em última instância, redefinir nossa posição como sociedade e como espécie no âmbito da biosfera.
Referências
BARIFOUSE, Rafael, “Pandemia vai permitir aceleração do desmatamento na Amazônia, prevê consultoria”. BBC Brasil, 26/IV/2020.
CHENG, Vincent C. C. et al., “Severe Acute Respiratory Syndrome Coronavirus as an Agent of Emerging and Reemerging Infection”. Clinical Microbiology Reviews, October, 2007, pp. 660-694.
EVANS, Simon, “Analysis: Coronavirus set to cause largest ever annual fall in CO2 emissions”, Carbon Brief, 9/IV/2020, atualizado em 15 de abril.
GE, Mengpin. et al. , “Tracking Progress of the 2020 Climate Turning Point.” World Resources Institute, Washington D.C. 2019.
GOODMAN, Peter, “Why the Global Recession Could Last a Long Time”. The New York Times, 1/IV/2020.
GOUDARZI, Sara, “How a Warming Climate Could Affect the Spread of Diseases Similar to COVID-19”. Scientific American, 29/IV/2020.
HOMER-DIXON, Thomas et al., “Synchronous failure: the emerging causal architecture of global crisis. Ecology and Society, 20, 3, 2015.
HOOPER, Rowan, “Ten years to save the world”. New Scientist, 14/III/2020, pp. 45-47.
IRFAN, Umair, “The US, Japan, and Australia let the whole world down at the UN climate talks”. Vox, 18/XII/2019.
JOHNSON, Christine K. et al., “Global shifts in mammalian population trends reveal key predictors of virus spillover risk”. Proceedings of theRoyal Society B, 8/IV/2020.
LE HIR, Pierre, “Réchauffement climatique: la bataille des 2C est presque perdue”. Le Monde, 31/XII/2017.
MACEDO, Flávia, “Consumo de carne bovina no Brasil cresceu 14% em 10 anos, diz Cepea”. Canal Rural, 9/XII/2019.
MARQUES, Luiz, Capitalismo e Colapso Ambiental (2015). Campinas, Editora da Unicamp, 3ª ed. 2018.
MATHIESEN, Karl & SAUER, Natalie, “‘Most important years in history’: major UN report sounds last-minute climate alarm”. Climate Home News, 8/X/2018.
MAXMAN, Amy, “Bats Are Global Reservoir for Deadly Coronaviruses”. Scientific American, 12/VI/2017.
McGRATH, Matt, “Climate Change. Greenhouse gas concentrations again break records”. BBC, 25/XI/2019.
McKibben, Bill, “Big Oi lis using the coronavirus pandemic to push through the Keystone XL pipeline”. The Guardian, 5/IV/2020.
MENEGASSI, Duda, “Desmatamento na Amazônia atinge nível recorde no primeiro trimestre de 2020”. ((O)) eco, 13/IV/2020.
MOLLENTZE, Nardus & STREICKER, Daniel G., “Viral zoonotic risk is homogenous among taxonomic orders of mammalian and avian reservoir hosts”. PNAS, 13/IV/2020.
MOORE, Kristine A., LIPSITCH, Marc, BARRY, John & OSTERHOLM, Michael, COVID-19: The CIDRAP Viewpoint. University of Minnesota, 20/IV/2020.
MORIYAMA, Miyu & ICHINOHE, Takeshi, “High Ambient Temperature Dampens Adaptative Immune Responses to Influnza A Virus Infection”. PNAS, 116, 8, 19/II/2019, pp. 3118-3125.
PECL, Gretta et al., “Biodiversity redistribution under climate change: Impacts on ecosystems and human well-being”. Science, 355, 6332, 31/III/2017.
PONTES, Nádia, “O elo entre desmatamento e epidemias investigado pela ciência”. DW, 15/IV/2020.
ROSSI, Marcello, “The Chinese Are Eating More Meat Than Ever Before and the Planet Can’t Keep Up”. Mother Jones, 21/VII/2018.
SETTELE, J., DIAZ, S., BRONDIZIO, E. & DASZAK, Peter, “COVID-19 Stimulus Measures Must Save Lives, Protect Livelihoods, and Safeguard Nature to Reduce the Risk of Future Pandemics”. IPBES Expert Guest Article, 27/IV/2020.
SIMMS, Andrew, “A cat in hell’s chance – why we’re losing the battle to keep global warming below 2C”, The Guardian, 19/I/2017.
SPINNEY, Laura, “Germany’s Covid-19 expert: ‘For many, I’m the evil guy crippling the economy”. The Guardian, 26/IV/2020.
STEFFEN, Will et al., “Trajectories of the Earth System in the Anthropocene”. PNAS, 9/VIII/2018.
STRASSBURG, Bernardo B.N. et al., “Moment of truth for the Cerrado hotspot”. Nature Ecology & Evolution, 2017.
ZAIA, Marina, “Rebanho Brasileiro por Região”. Scot Consultoria, 16/IV/2018.
ZHANG, Juanjuan et al., “Patterns of human social contact and contact with animals in Shanghai, China”. Scientific Reports, 9, 2019.
i Segundo a Chemical Data Reporting (CDR) da EPA, nos EUA, em 2016 havia 8.707 substâncias ou compostos químicos largamente comercializados, aos quais somos cotidianamente expostos, ignorando na maior parte dos casos seus efeitos e os de suas interações sobre a saúde humana e demais espécies. <https://www.chemicalsafetyfacts.org/chemistry-context/debunking-myth-chemicals-testing-safety/>.
*** Luiz Marques é professor livre-docente do Departamento de História do IFCH /Unicamp. Pela editora da Unicamp, publicou Giorgio Vasari, Vida de Michelangelo (1568), 2011 e Capitalismo e Colapso ambiental, 2015, 3a edição, 2018. Coordena a coleção Palavra da Arte, dedicada às fontes da historiografia artística, e participa com outros colegas do coletivo Crisálida, Crises SocioAmbientais Labor Interdisciplinar Debate & Atualização (crisalida.eco.br).
Leading US biologist Thomas Lovejoy says to stop future outbreaks we need more respect for natural world
Caged civet cats in a wildlife market in Guangzhou, China. Photograph: Liu Dawei/AP
Phoebe Weston – Published on Sat 25 Apr 2020 06.00 BST
The vast illegal wildlife trade and humanity’s excessive intrusion into nature is to blame for the coronavirus pandemic, according to a leading US scientist who says “this is not nature’s revenge, we did it to ourselves”.
Scientists are discovering two to four new viruses are created every year as a result of human infringement on the natural world, and any one of those could turn into a pandemic, according to Thomas Lovejoy, who coined the term “biological diversity” in 1980 and is often referred to as the godfather of biodiversity.
“This pandemic is the consequence of our persistent and excessive intrusion in nature and the vast illegal wildlife trade, and in particular, the wildlife markets, the wet markets, of south Asia and bush meat markets of Africa… It’s pretty obvious, it was just a matter of time before something like this was going to happen,” said Lovejoy, a senior fellow at the United Nations Foundation and professor of environment science at George Mason University.
His comments were made to mark the release of a report by the Center for American Progress arguing that the US should step up efforts to combat the wildlife trade to help confront pandemics.
Wet markets are traditional markets selling live animals (farmed and wild) as well as fresh fruit, vegetables and fish, often in unhygienic conditions. They are found all over Africa and Asia, providing sustenance for hundreds of millions of people. The wet market in Wuhan believed to be the source of Covid-19 contained a number of wild animals, including foxes, rats, squirrels, wolf pups and salamanders.
Lovejoy said separating wild animals from farmed animals in markets would significantly lower the risk of disease transmission. This is because there would be fewer new species for viruses to latch on to. “[Domesticated animals] can acquire these viruses, but if that’s all there was in the market, it would really lower the probability of a leak from a wild animal to a domesticated animal.”
He told the Guardian: “The name of the game is reducing certain amounts of activity so the probability of that kind of leap becomes small enough that it’s inconsequential. The big difficulty is that if you just shut them down – which in many ways would be the ideal thing – they will be topped up with black markets, and that’s even harder to deal with because it’s clandestine.”
The pandemic will cost the global economy $1tn this year, according to the World Economic Forum, with vulnerable communities impacted the most, and nearly half of all jobs in Africa could be lost. “This is not nature’s revenge, we did it to ourselves. The solution is to have a much more respectful approach to nature, which includes dealing with climate change and all the rest,” Lovejoy said.
Experts are divided about how to regulate the vast trade in animals, with many concerned the poorest are most at risk from a crackdown. Urgent action on the wildlife trade is clearly needed, said Dr Amy Dickman, a conservation biologist from the University of Oxford, but she was “alarmed” by calls for indiscriminate bans on the wildlife trade.
She is one of more than 250 signatories of an open letter to the World Health Organization and United Nations Environment Programme saying any transition must contribute to – and not detract from – the livelihoods of the world’s most vulnerable people, many of whom depend on wild resources for survival. Other signatories include representatives from the African Wildlife Foundation, the Frankfurt Zoological Society and IUCN (International Union for Conservation of Nature).
The letter reads: “Covid-19 is inflicting unprecedented social and economic costs on countries and communities, with the poor and vulnerable hardest hit. The virus’s suspected links with a Chinese ‘wet market’ has led to calls to ban wet markets and restrict or end the trade, medicinal use and consumption of wildlife. However, indiscriminate bans and restrictions risk being inequitable and ineffective.”
Scientists and NGOs are concerned that over-simplistic and indiscriminate restrictions will exacerbate poverty and inequality, resulting in an increase in criminality. This could accelerate the exploitation and extinction of species in the wild, authors of the letter warn.
“People often seem more willing to point the finger at markets far away, as bans there will not affect their everyday lives – although they will often affect the rights of extremely vulnerable people,” said Dickman.
There are also concerns about the impacts of an outright ban on a number of indigenous populations, such as tribes in Orinoquia and Amazonia, with representatives describing it as an “attack” on their livelihoods.
Mama Mouamfon, who is based in Cameroon and directs an NGO called Fondation Camerounaise de la Terre Vivante (FCTV), said banning the trade would damage livelihoods: “Bush meat is very important for people in the forest because it’s one of the best ways to get animal protein. With this issue of poverty and people living in remote areas, it’s not easy for them to look for good meat,” he said.
“Sometimes people take decisions because they are sitting in an office and are very far from reality. If they knew our reality they would not take that [same] decision.”
Rodrigo Bertolotto De Ecoa, em São Paulo 14/04/2020 18h04
“A Amazônia tem a maior quantidade de microorganismos do mundo. E estamos perturbando o sistema o tempo todo, com populações urbanas se aproximando, desmatamento e comércio de animais silvestres. Então, talvez tenha sido sorte que a pandemia não tenha começado no Brasil”, disse Carlos Nobre, presidente do Painel Brasileiro de Mudanças Climáticas e pesquisador sênior do Instituto de Estudos Avançados da USP (Universidade de São Paulo).
O cientista Carlos Nobre, referência brasileira em estudos sobre aquecimento global e pesquisador do Instituto Nacional de Pesquisa Espacial (Inpe) Imagem: Reinaldo Canato/Folhapress
Nobre participou nesta terça de um seminário “Covid-19 e Clima: Como Estão Conectados?” promovido pela Rede Brasil do Pacto Global da ONU (Organização das Nações Unidas) em parceria com Ecoa, que retransmitiu sua palestra, no formato webinar, ou seja, um seminário pela web.
“Pandemia mostra impacto do desequilíbrio do sistema na nossa vida”
Ele lembrou do caso da leishmaniose, endemia típica da Amazônia que tem como causador um protozoário e o vetor é o mosquito palha. A doença se espalhou pelo mundo, devido à aproximação dos homens dos ambientes silvestres, mas agora está controlada, tendo cura e remédio. O problema agora é outro por lá. “Agora, Manaus está entrando em colapso com o coronavírus, e a doença está chegando às aldeias. Temos que lembrar que os indígenas têm menos resistência imunológica a essas contaminações.”
Nobre também falou como a poluição debilita quem tem contado agora com o vírus surgido na China no final de 2019. “A poluição e o vírus atacam o sistema respiratório. Essa combinação é muito perversa”, afirmou o estudioso.
Ele recordou das queimadas na floresta amazônica em 2019, a que ponto isso afetou os ares até da região Sudeste do Brasil e como esse cenário pode se repetir agora em 2020, quando se está verificando novos recordes de desmatamento.
O ar de São Paulo e outras cidades está mais limpo com menos carros em circulação nesses dias de quarentena, mas, se as queimadas recomeçarem, esse cenário vai mudar e criar novas vulnerabilidades. No ano passado, os postos de saúde da Amazônia estavam cheios pela fumaça das queimadas. Agora estão com a Covid-19.
Aprendizados da crise
O cientista discutiu os vários pontos que aproximam o atual surto biológico com os problemas climáticos, sua especialidade.
“Dá para fazer um paralelo entre essas crises globais. Essa pandemia nos mostra o que pode acontecer quando há um desequilíbrio do sistema. Ela é um alerta e um guia para evitarmos grandes riscos, como os que as mudanças climáticas poderão trazer para a vida na Terra. Se a temperatura do planeta subir cinco graus, os humanos vão ter de viver confinados, como agora, porque em determinados horários todos os dias o termômetro vai estar além do limite fisiológico do corpo nas áreas tropicais como o Brasil.”
Nobre falou das lições que podem ficar desta crise global e das possíveis soluções quando o planeta sair das urgências do coronavírus. Para ele, um dos aprendizados é que a economia caminhe para a sustentabilidade.
“Os países europeus estão discutindo agora uma economia mais verde. E a China também está sinalizando nesse mesmo caminho. Se isso acontecer, o pêndulo mundial vai mudar, e o Brasil vai ter de ir atrás. Os EUA são contra, mas isso pode mudar se em janeiro de 2021 não estiver mais o Donald Trump na Casa Branca”, afirmou Nobre, projetando as dificuldades de reeleição do político republicano com a possível recessão provocada pelo afastamento social durante a crise.
O pesquisador também salientou que é importante mudar a matriz energética, e essa crise pode ser o momento de acelerar esse processo. “Precisamos eletrificar os transportes, e criar mais energia solar e eólica, diminuindo o consumo de combustíveis fósseis.”
Para ele, as mudanças climáticas vão trazer riscos maiores que os atuais com o coronavírus se não forem tomadas providências. “É uma catástrofe com um tempo e uma magnitude muito maior. Por isso, é difícil dimensionar. Mas a atual pandemia é uma amostra disso. E um risco maior também, afinal, todo o planeta vai ser afetado, não só o homem, como agora.”
Os Huni Kuin do Acre e do Leste da floresta amazônica peruana compartilham com muitos outros povos indígenas da região uma filosofia de vida que poderíamos chamar de ecosófica[ii] e que atribui a maior parte das doenças ao fato de comermos animais. As pessoas adoecem porque a caça e os peixes, mas também algumas plantas que consumimos e outros seres que agredimos ou com os quais interagimos, se vingam e mandam seu nisun, dor de cabeça e tonteira que pode resultar em doença e morte.
O xamanismo e o uso de plantas psicotrópicas, como tabaco e cipó, servem para descobrir a ação destes agentes invisíveis e de contra-efetuar, através do canto, do sopro, de perfumes e plantas medicinais, o movimento de captura do espírito da vítima por parte dos duplos dos animais mortos. O universo da floresta é, assim, habitado por uma multiplicidade de espécies que são sujeitos e negociam seu direito ao espaço e à própria vida. Neste universo a cosmopolítica dos humanos consiste em matar somente o necessário e em negociar com os donos das espécies ou com os próprios duplos dos animais. Tem-se a aguda (con)ciência de que para viver é preciso matar e de que toda ação, toda predação, desencadeia uma contra-predação.
Quando a quarentena foi anunciada no Brasil, meu amigo, o líder de canto do cipó, Ibã Sales Huni Kuin, se despediu por telefone: “Vamos nos retirar na floresta, vamos ficar quietos e não vamos deixar mais ninguém entrar, porque tudo isso é nisun”. Nada sabia, ainda, sobre as hipóteses de causa do novo vírus, que apontam de fato para o nisun de outras florestas. E apesar do nome dado aos Huni Kuin pelos seus inimigos ser Kaxinawa, povo morcego, não consomem estes animais porque os consideram seres que possuem yuxin, o poder de transformar a forma. O que pode um vírus, no entanto, Ibãe seus parentes indígenas sabem muito bem. Pois vírus importados, como a influenza e a varíola, causaram, no passado, mais mortes na sua população do que as guerras travadas contra eles na época de invasão de suas terras.
A narrativa científica mais aceita do momento, pelo que conseguimos deduzir da literatura disponível e de livre acesso durante a pandemia, atribui o novo corona à passagem do vírus de uma espécie de morcego (horseshoe bat) que vive nas florestas Chinesas para o ser humano[iii]. A hipótese se baseia no sequenciamento do genoma do vírus do COVID-19 e suas grandes semelhanças com um coronavírus presente nestes morcegos. Outro animal que hospeda um vírus geneticamente muito similar é o pangolim, um tipo de tatu asiático muito apreciado por grande parte da população chinesa como iguaria e remédio. Uma das hipóteses é que este poderia ter sido o hospedeiro intermediário do vírus entre o morcego e o humano[iv]; as últimas pesquisas, no entanto, afirmam que o vírus do morcego é mais próximo do COVID-19 do que aquele encontrado nos pangolins. Ambos os animais são consumidos na China e em outros países asiáticos. Os primeiros casos do novo corona vírus foram detectados em um grande mercado de Wuhan na China, onde se vende animais selváticos vivos, entre os quais morcegos e muitos pangolins, apesar de sua captura e comercialização serem proibidas.
O ‘zoonotic spillover’ de viroses que convivem com espécies selváticas, sem causar-lhes mal, para seres humanos, onde causam assustadoras pandemias, não começou nem terminará com o novo coronavírus. Outras epidemias recentes como a malária, a aids e a febre amarela foram resultado do spillover entre floresta e cidade.. O problema é especialmente interessante para a antropologia em geral e a etnologia em particular, porque nossa disciplina se interessou desde o começo pelas complexas relações entre humanos e animais, Natureza e Cultura, cidade e floresta. Agentes patogênicos, que convivem de forma simbiótica com seus hospedeiros animais, podem representar diferentes graus de perigo para os humanos, dependendo da cultura ou sociedade específica em questão. As regras de dieta e de negociação em torno da caça apontam para um saber acumulado, por parte dos povos da floresta, do potencial patogênico dos animais. Estes possuem seus próprios hábitos e habitats que precisam ser respeitados se quiserem que a caça não se vire contra o caçador.
A novidade destas novas epidemias, argumentam epidemiólogos e biólogos, consiste na rapidez com que o vírus viaja e se multiplica no meio humano, por causa da grande aglomeração e circulação de seres da mesma espécie nas cidades e nas regiões transitórias entre as cidades e as florestas. A realidade relacional contemporânea de intensa circulação de pessoas, mercadorias e animais é o cronótopo perfeito para a disseminação desta nova ameaça mundial. Este cronótopo vai acompanhado de uma redução cada vez maior das áreas de floresta onde os hospedeiros dos agentes patogênicos conviviam com os vírus de modo que estes não lhes causavam doenças, nem o transmitiam para os seres humanos.
Em entrevista dada à CNN (20/03/2020), intitulada “the bats are not to blame”, “não são os morcegos os culpados”, Andrew Cunningham, Professor da Zoological Society de Londres, afirma que: “a causa do “zoonotic spillover”, ou o transfer de morcegos ou outras espécies selvagens, é quase sempre o comportamento humano”. O biólogo aponta algumas características interessantes dos morcegos que nos ajudam a entender sua importância e seus perigos para os humanos. Os morcegos são os únicos mamíferos que voam, o que faz com que eles possam cruzar grandes distâncias e disseminar muitos agentes patogênicos. Mas eles também são os polinizadores mais importantes da floresta tropical, e muitas espécies dependem exclusivamente dos morcegos para sobreviver. No mito de origem das plantas cultivadas dos Huni Kuin, foi um quatipuru transformado em homem que ensinou o cultivo das plantas aos humanos. O mesmo quatipuru, no entanto, sabia se transformar também em morcego. Os morcegos, como os humanos, gostam de viver em grandes grupos, o que facilita a disseminação de sementes, pólen e vírus. O voo do morcego requer muita energia, afirma Cunningham, o que produz altas temperaturas no animal, temperaturas que no ser humano significariam febre. É por esta razão que quando passa para o humano, o vírus é tão virulento. Outro elemento interessante é que, como os humanos, os morcegos sentem stress. Quando percebem seu habitat danificado pelo desflorestamento ou quando amontoados vivos em grandes feiras, juntos com outros animais, para serem sacrificados, o aumento do stress pressiona seu sistema imunológico e pode fazer com que um vírus latente se torne manifesto e mais contagioso.
Não é o fato dos humanos comerem caça a causa das epidemias. As epidemias são o resultado do desmatamento e da extinção dos animais que antes eram seus hospedeiros simbióticos. As epidemias são também o resultado de uma relação extrativista das grandes cidades com as florestas. Elas surgem nas franjas das florestas ameaçadas, nos interstícios da fricção interespécie e de lá são rapidamente transportadas para o mundo inteiro através de caminhões, barcos e aviões. E não é somente a caça cujo stress causa pandemias, outros animais também sofrem e causam doenças. Estes são prisioneiros de outra área intersticial entre a floresta e a cidade, a área rural do grande agronegócio alimentício, notória para o surgimento de novas gripes virulentas que podem virar pandemias. É nas grandes criações industrializadas de galinhas e porcos confinados que surgiram há alguns anos a chamada ‘gripe suína’ e outras que foram um prenúncio do vírus que observamos hoje.
A grande rede que conecta humanos e não humanos é a causa e a solução para o problema. Vivemos, em escala planetária, um problema em comum; sua solução também terá de ser comum. Virá da troca interdisciplinar e internacional de informações, mas virá sobretudo do que podemos aprender de outras tradições de pensamento que não se construíram sobre a separação dualista entre natureza e cultura. A substituição de ontologias relacionais pela oposição entre “sujeito” e “objeto”, resultando numa ontologia dualista, possibilitou a empresa modernista e capitalista e sua invenção de uma máquina de conquista do mundo, capturando em suas engrenagens até as mais resistentes minorias humanas e não humanas, que tentam sobreviver em suas margens.
As ontologias dessas minorias, no entanto, falam uma linguagem que contém conhecimentos vitais para o planeta hoje e que precisamos traduzir, com urgência, para a linguagem da ciência. Assim, na sua videoconferência para o Colóquio “Os mil nomes de Gaia” (2014), Donna Haraway apelou para uma consciência renovada de como todos os seres, incluindo os humanos, são compostos de outros seres e emaranhados numa malha densa de devir-com. Em vez de inter-relacionalidade, estamos lidando com intra-relacionalidade; somos entidades compostas de relações, entrecruzadas por outras agências e habitadas por subjetividades diferentes. Somos múltiplos e divíduos em vez de indivíduos; somos fractais. Somos habitados por bactérias e vírus saudáveis e nocivos que travam batalhas intermináveis. Essas novas descobertas cientificas se aproximam cada vez mais do que as filosofias ameríndias há tempos tentam nos ensinar. “A noção de uma entidade somada ao meio ambiente não pode mais ser pensada […]. Temos o que os biólogos chamam de holobiontes, a coleção de entidades tomadas em conjunto na sua relacionalidade que constroem uma entidade boa o suficiente para sobreviver o dia”[v].
A reação em rede planetária à nova pandemia, que se espalha pelo ar em gotículas invisíveis, transforma nossos corpos em campos de batalha invisíveis onde é, às vezes, a própria autodefesa, a reação excessiva do nosso sistema imunológico aos invasores, que mata as células vitais e acaba destruindo nossos órgãos. Ou seja, quando o sistema está muito estressado ele se auto-consome. Não é o fato de comermos porcos, morcegos, galinhas ou pandolins que causa epidemias mundiais, mas o modo como a civilização mundial, que se alimenta do crescimento sem fim das cidades sobre as florestas, as árvores e seus habitantes, parou de escutar a revolta, não das coisas, mais dos animais, das plantas e de Gaia. Ou como diria Ailton Krenak, as pessoas foram alienadas e arrancadas da terra que é viva e com a qual é preciso dialogar, conviver[vi].
__________
[i] Professora Titular de Antropologia na Universidade Federal do Rio de Janeiro, docente e pesquisadora no Programa de Pós Graduação em Sociologia e Antropologia (PPGSA/UFRJ).
[ii] Termo usado por Kay Arhem em “Ecosofia Makuna”, 1993, In La Selva Humanizada: Ecologia Alternativa em el Trópico Húmedo Colombiano. Bogotá: Instituto Colombiano de Antropología, pp. 109-126.
[iii] Wallace, Rob; Liebman, Alex; Chaves, Luis Fernando; Wallace, Rodrick, April 1, 2020, “COVID-19 and Circuits of capital”, in Monthly Review, New York.
[iv] Tommy Tsan-Yuk Lam, Marcus Ho-Hin Shum, Hua-Chen Zhu, Yi-Gang Tong, Xue-Bing Ni, Yun-Shi Liao, Wei Wei, William Yiu-Man Cheung, Wen-Juan Li, Lian-Feng Li, Gabriel M. Leung, Edward C. Holmes, Yan-Ling Hu & Yi Guan. 28.03.2020,“Identifying SARS-CoV-2 related corona viruses in Malayan pangolins”, In Nature, www.nature.com.
Early human ancestors could have stolen food from other animals. Mauricio Antón
By Helen Briggs BBC News
20 January 2020
The impact of humans on nature has been far greater and longer-lasting than we could ever imagine, according to scientists.
Early human ancestors living millions of years ago may have triggered extinctions, even before our species evolved, a study suggests.
A decline in large mammals seen in Eastern Africa may have been due to early humans, researchers propose.
Extinction rates started to increase from around four million years ago.
This coincides with the period when ancient human populations were living in the area, as judged by fossil evidence.
“We are now negatively impacting the world and the species that live in it more than ever before. But this does not mean that we used to live in true harmony with nature in the past,” said study researcher, Dr Søren Faurby of the University of Gothenburg.
“We are extremely successful in monopolising resources today, and our results show that this may have also been the case with our ancestors.”
Getty Images. A lion feasts on the carcass of a rhinoceros in Kenya
The researchers looked at extinction rates of large and small carnivores and how this correlated with environmental changes such as rainfall and temperature.
They also looked at changes in the brain size of human ancestors such as Australopithecus and Ardipithecus.
They found that extinction rates in large carnivores correlated with increased brain size of human ancestors and with vegetation changes, but not with precipitation or temperature changes.
They found the best explanation for carnivore extinction in East Africa was that these animals were in direct competition for food with our ancestors.
They think human ancestors may have stolen freshly-killed prey from the likes of sabre-toothed cats, depriving them of food.
“Our results suggest that substantial anthropogenic influence on biodiversity started millions of years earlier than currently assumed,” the researchers reported in the journal Ecology Letters.
Co-researcher Alexandre Antonelli of the Royal Botanic Gardens, Kew, said the view that our ancestors had little impact on the animals around them is incorrect, as “the impact of our lineage on nature has been far greater and longer-lasting than we ever could ever imagine”.
A landmark report last year warned that as many as one million species of animals and plants are threatened with extinction in the coming decades.
A more recent study found that the growth of cities, the clearing of forests for farming and the soaring demand for fish had significantly altered nearly three-quarters of the land and more than two-thirds of the oceans.
I know what you want from me—what we all want—which is some small solace after the events of Election Day. My wife Sue Halpern and I have been talking nonstop for days, trying to cope with the emotions. I fear I may not be able to provide that balm, but I do offer these remarks in the spirit of resistance to that which we know is coming. We need to figure out how to keep the lights on, literally and figuratively, and all kinds of darkness at bay.
I am grateful to all those who asked me to deliver this inaugural Jonathan Schell Lecture—grateful most of all because it gave me an excuse for extended and happy recollection of one of the most generous friendships of my early adulthood. I arrived at The New Yorker at the age of 21, two weeks out of college, alone in New York City for the first time. The New Yorker was wonderfully quirky, of course, but one of its less wonderful quirks was that most people didn’t talk to each other very much, and especially to newcomers 50 years their junior. There were exceptions, of course, and the foremost exception was Jonathan. He loved to talk, and we had long colloquies nearly every day, mostly about politics.
Ideas—not abstract ideas, but ideas drawn from the world as it wound around him—fascinated him. He always wanted to dig a layer or two deeper; there was never anything superficial or trendy about his analysis. I understood better what he was up to when I came, at the age of 27, to write The End of Nature. It owes more than a small debt to The Fate of the Earth, which let me feel it was possible and permitted to write about the largest questions in the largest ways.
Jonathan Schell
In the years that followed, having helped push action on his greatest cause—the danger of nuclear weapons—that issue began to seem a little less urgent. That perception, of course, is mistaken: Nuclear weapons remain a constant peril, perhaps more than ever in an increasingly multipolar world. But with the end of the Cold War and the build-down of US and Russian weapon stocks, the question compelled people less feverishly. New perils—climate change perhaps chief among them—emerged. Post-9/11, smaller-bore terrors informed our nightmares. We would have been wise, as the rise of a sinister Vladimir Putin and a sinister and clueless Donald Trump remind us, to pay much sharper attention to this existential issue, but the peace dividend turned out mostly to be a relaxing of emotional vigilance.
However, for the moment, we have not exploded nuclear weapons, notwithstanding Trump’s recent query about what good they are if we don’t use them. Our minds can compass the specter of a few mushroom clouds obliterating all that we know and love; those images have fueled a fitful but real effort to contain the problem, resulting most recently in the agreement with Iran. We have not been able to imagine that the billion tiny explosions of a billion pistons in a billion cylinders every second of every day could wreak the same damage, and hence we’ve done very little to ward off climate change.
We are destroying the earth every bit as thoroughly as Jonathan imagined in the famous first chapter of TheFate of the Earth, just a little more slowly. By burning coal and oil and gas and hence injecting carbon dioxide and methane into the atmosphere, we have materially changed its heat-trapping properties; indeed, those man-made greenhouse gases trap the daily heat equivalent of 400,000 Hiroshima-size explosions. That’s enough extra heat that, in the space of a few decades, we have melted most of the summer sea ice in the Arctic—millennia old, meters thick, across a continent-size stretch of ocean that now, in summer, is blue water. (Blue water that absorbs the sun’s incoming rays instead of bouncing them back to space like the white ice it replaced, thus exacerbating the problem even further.) That’s enough heat to warm the tropical oceans to the point where Sue and I watched with our colleagues in the South Pacific as a wave of record-breaking warm water swept across the region this past spring, killing in a matter of weeks vast swaths of coral that had been there since before the beginning of the human experiment. That’s enough heat to seriously disrupt the planet’s hydrological cycles: Since warm air holds more water vapor than cold, we’ve seen steady increases in drought in arid areas (and with it calamities like wildfire) and steady, even shocking, increases in downpour and flood in wet areas. It’s been enough to raise the levels of the ocean—and the extra carbon in the atmosphere has also changed the chemistry of that seawater, making it more acidic and beginning to threaten the base of the marine food chain. We are, it bears remembering, an ocean planet, and the world’s oceanographers warn that we are very rapidly turning the seven seas “hot, sour, and breathless.” To the “republic of insects and grass” that Jonathan imagined in the opening of The Fate of the Earth, we can add a new vision: a hypoxic undersea kingdom of jellyfish.
This is not what will happen if something goes wrong, if some maniac pushes the nuclear button, if some officer turns a key in a silo. This is what has already happened, because all of us normal people have turned the keys to our cars and the thermostat dials on our walls. And we’re still in the relatively early days of climate change, having increased the planet’s temperature not much more than 1 degree Celsius. We’re on a trajectory, even after the conclusion of the Paris climate talks last year, to raise Earth’s temperature by 3.5 degrees Celsius—or more, if the feedback loops we are triggering take full hold. If we do that, then we will not be able to maintain a civilization anything like the one we’ve inherited. Our great cities will be underwater; our fields will not produce the food our bodies require; those bodies will not be able to venture outside in many places to do the work of the world. Already, the World Health Organization estimates, increased heat and humidity have cut the labor a human can perform by 10 percent, a number that will approach 30 percent by midcentury. This July and August were the hottest months in the history of human civilization measured globally; in southern Iraq, very near where scholars situate the Garden of Eden, the mercury in cities like Basra hit 129 degrees—among the highest reliably recorded temperatures in history, temperatures so high that human survival becomes difficult.
Against this crisis, we see sporadic action at best. We know that we could be making huge strides. For instance, engineers have managed to cut the cost of solar panels by 80 percent in the last decade, to the point where they are now among the cheapest methods of generating electricity. A Stanford team headed by Mark Jacobson has shown precisely how all 50 states and virtually every foreign nation could make the switch to renewable energy at an affordable cost in the course of a couple of decades. A few nations have shown that he’s correct: Denmark, for instance, now generates almost half of its power from the wind.
In most places, however, the progress has been slow and fitful at best. In the United States, the Obama administration did more than its predecessors, but far less than physics requires. By reducing our use of coal-fired power, it cut carbon-dioxide emissions by perhaps 10 percent. But because it wouldn’t buck the rest of the fossil-fuel industry, the Obama administration basically substituted fracked natural gas for that coal. This was a mistake: The leakage of methane into the atmosphere means that America’s total greenhouse-gas emissions held relatively steady or perhaps even increased. This willingness to cater to the industry is bipartisan, though in the horror of this past election that was easy to overlook. Here’s President Obama four years ago, speaking to an industry group in Oklahoma: “Now, under my administration, America is producing more oil today than at any time in the last eight years. That’s important to know. Over the last three years, I’ve directed my administration to open up millions of acres for gas and oil exploration across 23 different states. We’re opening up more than 75 percent of our potential oil resources offshore. We’ve quadrupled the number of operating rigs to a record high. We’ve added enough new oil and gas pipeline to encircle the Earth and then some.” Hillary Clinton opened an entire new wing at the State Department charged with promoting fracking around the world. So much for the establishment, now repudiated.
Trump, of course, has famously insisted that global warming is a hoax invented by the Chinese and has promised to abolish the Environmental Protection Agency. His election win is more than just a speed bump in the road to the future—it’s a ditch, and quite likely a crevasse. Even as we gather tonight, international negotiators in Marrakech, stunned by our elections, are doing their best to salvage something of the Paris Agreement, signed just 11 months ago with much fanfare.
* * *
But the real contest here is not between Democrats and Republicans; it’s between human beings and physics. That’s a difficult negotiation, as physics is not prone to compromise. It also imposes a hard time limit on the bargaining; if we don’t move very, very quickly, then any progress will be pointless. And so the question for this lecture, and really the question for the geological future of the planet, becomes: How do we spur much faster and more decisive action from institutions that wish to go slowly, or perhaps don’t wish to act at all? One understands that politicians prize incremental action—but in this case, winning slowly is the same as losing. The planet is clearly outside its comfort zone; how do we get our political institutions out of theirs?
And it is here that I’d like to turn to one of Jonathan’s later books, one that got less attention than it deserved. The Unconquerable World was published in 2003. In it, Jonathan writes, in his distinctive aphoristic style: “Violence is the method by which the ruthless few can subdue the passive many. Nonviolence is a means by which the active many can overcome the ruthless few.” This brings us, I think, to the crux of our moment. Across a wide variety of topics, we see the power of the ruthless few. This is nowhere more evident than in the field of energy, where the ruthless few who lead the fossil-fuel industry have more money at their disposal than any humans in the past. They’ve been willing to deploy this advantage to maintain the status quo, even in the face of clear scientific warnings and now clear scientific proof. They are, for lack of a better word, radicals: If you continue to alter the chemistry of the atmosphere past the point where you’re melting the polar ice caps, then you are engaging in a radicalism unparalleled in human history.
And they’re not doing this unknowingly or out of confusion. Exxon has known all there is to know about climate change for four decades. Its product was carbon, and it had some of the best scientists on earth on its staff; they warned management, in clear and explicit terms, how much and how fast the earth would warm, and management believed them: That’s why, for instance, Exxon’s drilling rigs were built to accommodate the sea-level rise it knew was coming. But Exxon didn’t warn any of the rest of us. Just the opposite: It invested huge sums of money in helping to build an architecture of deceit, denial, and disinformation, which meant humankind wasted a quarter of a century in a ludicrous argument about whether global warming was “real,” a debate that Exxon’s leaders knew was already settled. The company continues to fund politicians who deny climate change and to fight any efforts to hold it accountable. At times, as Steve Coll makes clear in his remarkable book Private Empire, the oil industry has been willing to use explicit violence—those attack dogs in North Dakota have their even more brutal counterparts in distant parts of the planet. More often, the industry has been willing to use the concentrated force of its money. Our largest oil and gas barons, the Koch brothers—two of the richest men on earth, and among the largest leaseholders on Canada’s tar sands—have promised to deploy three-quarters of a billion dollars in this year’s contest. As Jane Mayer put it in a telling phrase, they’ve been able to “weaponize” their money to achieve their ends. So the “ruthless few” are using violence—power in its many forms.
But the other half of that aphorism is hopeful: “Nonviolence is the means by which the active many can overcome the ruthless few.” When the history of the 20th century is written, I’m hopeful that historians will conclude that the most important technology developed during those bloody hundred years wasn’t the atom bomb, or the ability to manipulate genes, or even the Internet, but instead the technology of nonviolence. (I use the word “technology” advisedly here.) We had intimations of its power long before: In a sense, the most resounding moment in Western history, Jesus’s crucifixion, is a prototype of nonviolent action, one that launched the most successful movement in history. Nineteenth-century America saw Thoreau begin to think more systematically about civil disobedience as a technique. But it really fell to the 20th century, and Gandhi, to develop it as a coherent strategy, a process greatly furthered by Dr. Martin Luther King Jr. and his associates in this country, and by adherents around the world: Otpor in Eastern Europe, various participants in the Arab Spring, Buddhist monks in Burma, Wangari Maathai’s tree-planters, and so on.
We have done very little systematic study of these techniques. We have no West Point or Sandhurst for the teaching of nonviolence; indeed, it’s fair to say that the governments of the world have spent far more time figuring out how to stamp out such efforts than to promote them. (And given the level of threat they represent to governments, that is perhaps appropriate.) What we know is what we’ve learned by experience, by trial and error.
In my own case over the last decade, that’s meant helping to organize several large-scale campaigns or social movements. Some have used civil disobedience in particular—I circulated the call for arrestees at the start of the Keystone XL pipeline demonstrations in 2011, and observers said the resulting two weeks of nonviolent direct action resulted in more arrests than any such demonstration on any issue in many years. Others have focused on large-scale rallies—some in this audience attended the massive climate march in New York in the autumn of 2014, organized in part by 350.org, which was apparently the largest demonstration about anything in this country in a long time. Others have been scattered: The fossil-fuel divestment campaign we launched in 2012 has been active on every continent, incorporated a wide variety of tactics, and has become the largest anticorporate campaign of its kind in history, triggering the full or partial divestment of endowments and portfolios with nearly $5 trillion in assets. These actions have helped spur many more such actions: Keystone represented a heretofore very rare big loss for Big Oil, and its success helped prompt many others to follow suit; now every pipeline, fracking well, coal mine, liquid-natural-gas terminal, and oil train is being fought. As an executive at the American Petroleum Institute said recently—and ruefully—to his industry colleagues, they now face the “Keystone-ization” of all their efforts.
And we have by no means been the only, or even the main, actor in these efforts. For instance, indigenous activists have been at the forefront of the climate fight since its inception, here and around the world, and the current fight over the Dakota Access pipeline is no exception. They and the residents of what are often called “frontline” communities, where the effects of climate change and pollution are most intense, have punched far above their weight in these struggles; they have been the real leaders. These fights will go on. They’ll be much harder in the wake of Trump’s election, but they weren’t easy to begin with, and I confess I see little alternative—even under Obama, the chance of meaningful legislation was thin. So, using Jonathan’s template, I’ll try to offer a few lessons from my own experience over the last decade.
* * *
Lesson one: Unearned suffering is a potent tool. Volunteering for pain is an unlikely event in a pleasure-based society, and hence it gets noticed. Nonviolent direct action is just one tool in the activist tool kit, and it should be used sparingly—like any tool, it can easily get dull, both literally and figuratively. But when it is necessary to underline the moral urgency of a case, the willingness to go to jail can be very powerful, precisely because it goes against the bent of normal life.
It is also difficult for most participants. If you’ve been raised to be law-abiding, it’s hard to stay seated in front of, say, the White House when a cop tells you to move. Onlookers understand that difficulty. I remember Gus Speth being arrested at those initial Keystone demonstrations. He’d done everything possible within the system: co-founded the Natural Resources Defense Council, chaired the president’s Council on Environmental Quality, ran the entire UN Development Program, been a dean at Yale. But then he concluded that the systems he’d placed such faith in were not coming close to meeting the climate challenge—so, in his 70s, he joined that small initial demonstration. Because his son was a high-powered lawyer, Gus was the only one of us able to get a message out during our stay in jail. What he told the press stuck with me: “I’ve held many important positions in this town,” he said. “But none seem as important as the one I’m in today.” Indeed, his witness pulled many of the nation’s environmental groups off the sidelines; when we got out, he and I wrote a letter to the CEOs of all those powerful green groups, and in return they wrote a letter to the president saying, “There is not an inch of daylight between our position and those of the people protesting on your lawn.” Without Gus’s willingness to suffer the indignity and discomfort of jail, that wouldn’t have happened, and the subsequent history would have been different.
Because it falls so outside our normal search for comfort, security, and advancement, unearned suffering can be a powerful tool. Whether this will be useful against a crueler White House and a nastier and more empowered right wing remains to be seen, but it will be seen. I imagine that the first place it will see really widespread use is not on the environment, but in regard to immigration. If Trump is serious about his plans for mass deportation, he’ll be met with passive resistance of all kinds—or at least he should be. All of us have grown up with that Nazi-era bromide about “First they came for the Jews, but I was not a Jew…” In this case, there’s no mystery: First they’re coming for the undocumented. It will be a real fight for the soul of our nation, as the people who abstractly backed the idea of a wall with Mexico are forced to look at the faces of the neighbors they intend to toss over it.
Lesson two: These tactics are useful to the degree that they attract large numbers of people to the fight. Those large numbers don’t need to engage in civil disobedience; they just need to engage in the broader battle. If you think about it, numbers are the currency of movements, just as actual cash is the currency of the status quo—at least until such time as the status quo needs to employ the currency of violence. The point of civil disobedience is rarely that it stops some evil by itself; instead, it attracts enough people and hence attention to reach the public at large.
When the Keystone demonstrations began, for instance, no one knew what the pipeline was, and it hadn’t occurred to people to think about climate change in terms of infrastructure. Instead, we thought about it in the terms preferred by politicians, i.e., by thinking about “emissions reductions” far in the future from policies like increased automobile efficiency, which are useful but obviously insufficient. In the early autumn of 2011, as we were beginning the Keystone protests, the National Journal polled its DC “energy insiders,” and 93 percent of them said TransCanada would soon have its permit for the pipeline. But those initial arrests attracted enough people to make it into a national issue. Soon, 15,000 people were surrounding the White House, and then 50,000 were rallying outside its gates, and before long it was on the front pages of newspapers. The information spread, and more importantly the analysis did too: Infrastructure became a recognized point of conflict in the climate fight, because enough people said it was. Politicians were forced to engage on a ground they would rather have avoided.
In much the same way, the divestment movement managed to go from its infancy in 2012 to the stage where, by 2015, the governor of the Bank of England was repeating its main bullet points to the world’s insurance industry in a conference at Lloyd’s of London: The fossil-fuel industry had more carbon in its reserves than we could ever hope to burn, and those reserves posed the financial risk of becoming “stranded assets.” Note that it doesn’t take a majority of people, or anywhere close, to have a significant—even decisive—impact: In an apathetic world, the active involvement of only a few percentage points of the citizenry is sufficient to make a difference. No more than 1 percent of Americans, for instance, ever participated in a civil-rights protest. But it does take a sufficient number to make an impression, whether in the climate movement or the Tea Party.
Lesson three: The real point of civil disobedience and the subsequent movements is less to pass specific legislation than it is to change the zeitgeist. The Occupy movement, for instance, is often faulted for not having produced a long list of actionable demands, but its great achievement was to make, by dint of recognition and repetition, the existing order illegitimate. Once the 99 percent and the 1 percent were seen as categories, our politics began to shift. Bernie Sanders, and to a lesser extent Donald Trump, fed on that energy. That Hillary Clinton was forced to say that she too opposed the Trans-Pacific Partnership trade deal was testimony to the power of the shift in the zeitgeist around inequality. Or take LGBTQ rights: It’s worth remembering that only four years ago, both Barack Obama and Hillary Clinton still opposed same-sex marriage. That’s difficult to recall now, since at this point you’d think they had jointly invented the concept. But it was skillful organizing for many years that changed less the laws of the land than the zeitgeist of the culture. Yes, some of those battles were fought over particular statutes; but the battles in Hollywood, and at high-school proms, and in a dozen other such venues were as important. Once movements shift the zeitgeist, then legislative victory becomes the mopping-up phase; this one Trump won’t even attempt to turn back.
This is not how political scientists tend to see it—or politicians, for that matter. Speaking to Black Lives Matter activists backstage in the course of the primary campaign, Hillary Clinton laid out her essential philosophy: “I don’t believe you change hearts. I believe you change laws, you change allocation of resources, you change the way systems operate.” This is, I think, utterly backward, and it explains much of the intuitive sense among activists of all stripes that Clinton wouldn’t have been a leader. As Monica Reyes, one of the young immigration activists in the Dreamer movement—great organizers who did much to shift public opinion—put it: “You need to change the culture before you can change laws.” Or as that guy Abraham Lincoln once put it: “Public sentiment is everything.”
By forever straddling the middle, centrist politicians delay changes in public sentiment. The viewpoint of the establishment—an appellation that in this case includes everyone from oil companies to presidents—is always the same: We need to be “realistic”; change will come slowly if it comes at all; and so forth. In normal political debates, this is reasonable. Compromise on issues is the way we progress: You want less money in the budget for X, and I want more, and so we meet in the middle and live to fight another day. That’s politics, as distinct from movement politics, which is about changing basic feelings over the great issues of the day. And it’s particularly true in the case of climate change, where political reality, important as it is, comes in a distinct second to reality reality. Chemistry and physics, I repeat, do what they do regardless of our wishes. That’s the difference between political science and science science.
* * *
There are many other points that Jonathan gets at in his book, but there’s one more that bears directly on the current efforts to build a movement around climate change. It comes in his discussion of Hannah Arendt and Mohandas Gandhi. Despite widespread agreement on the sources of power and the possibilities for mobilization, he finds one large difference between the two: Whereas Gandhi saw “spiritual love as the source and inspiration of nonviolent action, Arendt was among those who argued strenuously against introducing such love into the political sphere.” Hers was not an argument against spiritual love, but rather a contention that it mostly belonged in the private sphere, and that “publicity, which is necessary for politics, will coarsen and corrupt it by turning it into a public display, a show.” I will not attempt to flesh out the illuminating arguments on both sides, but I will say that I have changed my mind somewhat over the years on this question, at least as it relates to climate change.
Gandhi, like Thoreau before him, was an ascetic, and people have tended to lump their political and spiritual force together—and, in certain ways, they were very closely linked. Gandhi’s spinning wheel was a powerful symbol, and a powerful reality, in a very poor nation. He emphasized individual action alongside political mobilization, because he believed that Indians needed to awaken a sense of their own agency and strength. This was a necessary step in that movement—but perhaps a trap in our current dilemma. By this I mean that many of the early efforts to fight climate change focused on a kind of personal piety or individual action, reducing one’s impact via lightbulbs or food choices or you name it. And these are useful steps. The house that Sue and I inhabit is covered with solar panels. I turn off lights so assiduously that our daughter, in her Harry Potter days, referred to me as “the Dark Lord.” Often in my early writing, I fixed on such solutions. But in fact, given the pace with which we now know climate change is advancing, they seem not irrelevant but utterly ill-equipped for the task at hand.
Let’s imagine that truly inspired organizing might somehow get 10 percent of the population to become really engaged in this fight. That would be a monumental number: We think 10 percent of Americans participated in some fashion in the first Earth Day in 1970, and that was doubtless the high point of organizing on any topic in my lifetime. If the main contribution of this 10 percent was to reduce its own carbon footprint to zero— itself an impossible task—the total impact on America’s contribution to atmospheric carbon levels would be a 10 percent reduction. Which is helpful, but not very. But that same 10 percent—or even 2 or 3 percent—actually engaged in the work of politics might well be sufficient to produce structural change of the size that would set us on a new course: a price on carbon, a commitment to massive subsidies for renewable energy, a legislative commitment to keep carbon in the ground.
Some people are paralyzed by the piety they think is necessary for involvement. You cannot imagine the anguished and Talmudic discussions I’ve been asked to adjudicate on whether it’s permissible to burn gasoline to attend a climate rally. (In my estimation, it’s not just permissible, it’s very nearly mandatory—the best gas you will burn in the course of a year.) It has also become—and this is much more dangerous—the pet argument of every climate denier that, unless you’re willing to live life in a dark cave, you’re a hypocrite to stand for action on climate change. This attempt to short-circuit people’s desire to act must be rejected. We live in the world we wish to change; some hypocrisy is the price of admission to the fight. In this sense, and this sense only, Gandhi is an unhelpful example, and a bludgeon used to prevent good-hearted people from acting.
In fact, as we confront the blunt reality of a Trump presidency and a GOP Congress, it’s clearer than ever that asceticism is insufficient, and maybe even counterproductive. The only argument that might actually discover a receptive audience in the new Washington is one that says, “We need a rapid build-out of solar and wind power, as much for economic as environmental reasons.” If one wanted to find the mother lode of industrial jobs that Trump has promised, virtually the only possible source is the energy transformation of our society.
I will end by saying that movement-building—the mobilization of large numbers of people, and of deep passion, through the employment of all the tools at a nonviolent activist’s disposal—will continue, though it moves onto very uncertain ground with our new political reality. This work of nonviolent resistance is never easy, and it’s becoming harder. Jonathan’s optimism in The Unconquerable World notwithstanding, more and more countries are moving to prevent real opposition. China and Russia are brutally hard to operate in, and India is reconfiguring its laws to go in the same direction. Environmentalists are now routinely assassinated in Honduras, Brazil, the Philippines. Australia, where mining barons control the government, has passed draconian laws against protest; clearly Trump and his colleagues would like to do the same here, and will doubtless succeed to one extent or another. The savagery of the police response to Native Americans in North Dakota reminds us how close to a full-bore petro-state we are.
And yet the movement builds. I don’t know whether it builds fast enough. Unlike every other challenge we’ve faced, this one comes with a time limit. Martin Luther King would always say, quoting the great Massachusetts abolitionist Theodore Parker, that “the arc of the moral universe is long, but it bends toward justice”—meaning that it may take a while, but we are going to win. By contrast, the arc of the physical universe is short and it bends toward heat. I will not venture to predict if we can, at this point, catch up with physics. Clearly, it has a lot of momentum. It’s a bad sign when your major physical features begin to disappear—that we no longer have the giant ice cap in the Arctic is disconcerting, to say the least. So there’s no guarantee of victory. But I can guarantee that we will fight, in every corner of the earth and with all the nonviolent tools at our disposal. And in so doing, we will discover if these tools are powerful enough to tackle the most disturbing crisis humans have ever faced. We will see if that new technology of the 20th century will serve to solve the greatest dilemma of our new millennium.
“Mais importante do que ser multidisciplinar é ser não-disciplinar, isto é, integrar e dissolver as ‘disciplinas’ em um saber amplo e articulado, sem fronteiras artificiais e domínios de egos”, afirma o cientista do CCST/Inpe
O conhecimento científico não pode cegar a complexa relação entre os inúmeros ecossistemas presentes no planeta. “Tal abordagem gera soluções autistas que não se comunicam, tumores exuberantes cuja expansão danifica tudo que está em volta. Assim, a tecnociência olha o mundo com um microscópio grudado em seus olhos, vê pixel, mas ignora a paisagem”, afirma Antonio Donato Nobre, cientista do Centro de Ciência do Sistema Terrestre do Instituto Nacional de Pesquisas Espaciais – CCST/Inpe.
“A maior parte da agricultura tecnificada adotada pelo agronegócio é pobre em relação à complexidade natural. Ela elimina de saída a capacidade dos organismos manejados de interferir beneficamente no ambiente, introduzindo desequilíbrios e produzindo danos em muitos níveis”, analisa, em entrevista concedida por e-mail à IHU On-Line.
Para Nobre, a saída não é abandonar a ciência e a tecnologia produtiva de alimentos, mas sim associá-las e integrá-las a sistemas complexos de vidas em ecossistemas do Planeta. É entender, por exemplo, que a criação de áreas de plantio e produção agropecuária impactarão na chamada “equação do clima”. “É preciso remover os microscópios dos olhos, olhar o conjunto, perceber as conexões e, assim, aplicar o conhecimento de forma sábia e benéfica”, aponta.
Antonio Donato Nobre é cientista do Centro de Ciência do Sistema Terrestre do Instituto Nacional de Pesquisas Espaciais – CCST/Inpe, autor do relatório O Futuro Climático da Amazônia, lançado no final de 2014.
Tem atuado na divulgação e popularização da ciência, em temas como a Bomba biótica de umidade e sua importância para a valorização das grandes florestas, e os Rios Aéreos de vapor, que transferem umidade da Amazônia para as regiões produtivas do Brasil.
Foi relator nos estudos sobre o Código Florestal promovidos pela Sociedade Brasileira para o Progresso da Ciência – SBPC e Academia Brasileira de Ciências. Possui graduação em Agronomia pela Universidade de São Paulo, mestrado em Biologia Tropical (Ecologia) pelo Instituto Nacional de Pesquisas da Amazônia e é PhD em Earth System Sciences (Biogeochemistry) pela University of New Hampshire.
Atualmente é pesquisador titular do Instituto Nacional de Pesquisas da Amazônia e pesquisador Visitante no Centro de Ciência do Sistema Terrestre, do Instituto Nacional de Pesquisas Espaciais.
Confira a entrevista.
IHU On-Line – Quais os impactos da produção agrícola nas mudanças climáticas? Quais os riscos que o modelo do agronegócio (baseado nas grandes propriedades e produção em larga escala de uma só cultura por vez) representa?
Antonio Donato Nobre – A ocupação desordenada das paisagens produz pesados impactos no funcionamento do sistema de suporte à vida na Terra. A expansão das atividades agrícolas — quase sempre associada à devastação das florestas que têm maior importância na regulação climática — tem consequências que se fazem sentir cada vez mais, e serão devastadoras se não mudarmos a prática da agricultura.
A natureza, ao longo de bilhões de anos, evoluiu um sofisticadíssimo sistema vivo de condicionamento do conforto ambiental. Biodiversidade é o outro nome para competência tecnológica na regulação climática. A maior parte da agricultura tecnificada adotada pelo agronegócio é pobre em relação à complexidade natural. Ela elimina de saída a capacidade dos organismos manejados de interferir beneficamente no ambiente, introduzindo desequilíbrios e produzindo danos em muitos níveis.
IHU On-Line – Como aliar agricultura e pecuária à preservação de florestas e outros ecossistemas? Como o novo Código Florestal brasileiro se insere nesse contexto?
Antonio Donato Nobre – Extensa literatura científica mostra muitos caminhos para unir com vantagens agricultura, criação de animais e a preservação das florestas e de outros importantes ecossistemas. Esse conhecimento disponível assevera não haver conflito legítimo entre proteção dos ecossistemas e produção agrícola. Muito ao contrário, a melhor ciência demonstra a dependência umbilical da agricultura aos serviços ambientais providos pelos ecossistemas nativos.
Em 2012, contrariando a vontade da sociedade, o congresso revogou o código florestal de 1965. A introdução de uma nova lei florestal lasciva e juridicamente confusa já está produzindo efeitos danosos, como aumentos intoleráveis no desmatamento e a eliminação da exigência, ou o estímulo à procrastinação, no que se refere à recuperação de áreas degradadas. Mas a proteção e recuperação de florestas tem direto impacto sobre o regime de chuvas.
Incrível, portanto, que a agricultura, atividade que primeiro sofrerá com o clima inóspito que já bate às portas do Brasil, tenha sido justamente aquela que destruiu e continua destruindo os ecossistemas produtores de clima amigo. Enquanto estiver em vigor essa irresponsável e inconstitucional nova lei florestal, a degradação ambiental somente vai piorar.
IHU On-Line – De que forma o conhecimento mais detalhado sobre as formas de vida, e a relação entre elas, em florestas, como a amazônica, pode inspirar formas mais eficientes de produção de alimentos e, ao mesmo tempo, minimizar impactos ambientais?
Antonio Donato Nobre – A biomimética é uma nova área da tecnologia que copia e adapta soluções engenhosas encontradas pelos organismos para resolver desafios existenciais. Janine Benyus, a pioneira popularizadora desse saber, antes ignorado, costuma dizer que os designs encontrados na natureza são resultados de 3,8 bilhões de anos de evolução tecnológica. Durante esse tempo, somente subsistiram soluções efetivas e eficazes, que de saída determinaram a superioridade da tecnologia natural.
Ora, a agricultura precisa redescobrir a potência sustentável e produtiva que é o manejo inteligente de agroecossistemas inspirados nos ecossistemas naturais, ao invés de se divorciar deste vasto campo de conhecimento e soluções, como fez com seus agrossistemas empobrecidos, envenenados e que exploram organismos geneticamente aberrantes.
IHU On-Line – Qual o papel do solo na “composição da equação do clima” no planeta? Em que medida o desequilíbrio do solo pode influenciar nas mudanças climáticas?
Antonio Donato Nobre – Microrganismos e plantas têm incrível capacidade para adaptar-se ao substrato, seja solo, sedimento ou mesmo rocha. Essa adaptação gera simultaneamente uma formação e condicionamento do substrato, o que o torna fértil para a vida vicejar ali. O metabolismo dos ecossistemas, incluindo sua relação com o substrato, tem íntima relação com os ciclos globais de elementos químicos. A composição e funcionamento da atmosfera depende, para sua estabilidade dinâmica, portanto, para o conforto e favorecimento da própria vida, do funcionamento ótimo dos ecossistemas naturais.
Na equação do clima, os ecossistemas são os órgãos indispensáveis que geram a homeostase ou equilíbrio planetário. A agricultura convencional extermina aquela vida que tem capacidade regulatória, mata o solo, fator chave para sua própria sustentação, e introduz de forma reducionista e irresponsável nutrientes hipersolúveis, substâncias tóxicas desconhecidas da natureza e organismos que podem ser chamados de Frankensteins genéticos.
Todos estes insumos tornam as monoculturas do agronegócio sem qualquer função reguladora para o clima, e muito pior, devido à pesada emissão de gases-estufa e perturbações as mais variadas nos ciclos globais de nutrientes, a agricultura tecnificada é extremamente prejudicial para a estabilidade climática.
IHU On-Line – Desde a perspectiva do antropoceno , como avalia a relação do ser humano com as demais formas de vida do planeta hoje? Qual o papel da tecnologia e da ciência nessa relação?
Antonio Donato Nobre – Esta nova era foi batizada de antropoceno porque os seres humanos tornaram-se capazes de alterações massivas na delgada película esférica que nos permitiu a existência e nos dá abrigo. O maior drama da ocupação humana do ambiente superficial da Terra é que tal capacidade está destruindo o sistema de suporte à vida, sistema esse dependente 100% de todas demais espécies as quais o ser humano tem massacrado em sua expansão explosiva.
Infelizmente, na expansão do antropoceno, o conhecimento científico tem sido apropriado de forma gananciosa por mentes limitadas e arrogantes, e empregado no desenvolvimento sinistro de tecnologias e engenharias que por absoluta ignorância tornaram-se incapazes de valorizar o capital natural da Terra. Este comportamento autodestrutivo tem direta relação com a visão de ganho em curto prazo e a ilusão de poder auferida na aplicação autista de agulhas tecnológicas.
IHU On-Line – Em que medida a aproximação entre ciência e saberes indígenas pode contribuir para um novo caminho em termos de preservação do planeta e produção de alimentos?
Antonio Donato Nobre – Cada pesquisador sincero, inteligente e com mente aberta deve reconhecer a máxima milenar da sabedoria socrática: “somente sei que nada sei”. O conhecimento verdadeiro e sem limites internos impõe uma postura sóbria e humilde diante da enormidade da complexidade do mundo e da natureza. Hoje, a ciência mais avançada dá inteiro e detalhado suporte ao saber ancestral de sociedades tribais, que perduraram por milênios. Descer do salto alto da arrogância que fermentou graças ao individualismo permitirá reconhecer essa sabedoria básica de sustentabilidade, preservada no saber indígena.
Para a ciência, a aprender com o saber nativo está a veneração pela sabedoria da Mãe Terra; a intuição despretensiosa que capta o essencial da complexidade em princípios simples e elegantes; e sua capacidade holística e lúdica de articular a miríade de componentes do ambiente em uma constelação coerente e funcional de elos significativos.
IHU On-Line – De que forma a tecnociência e a tecnocracia impactam na forma de observar o planeta? O que isso significa para a humanidade?
Antonio Donato Nobre – A ciência é esta fascinante aventura humana na busca do conhecimento, evoluída aceleradamente a partir do renascimento na Europa. Muitas são suas virtudes e incríveis suas aplicações. No entanto, tais brilhos parecem infelizmente vir acompanhados quase sempre de alucinantes danos colaterais, nem sempre reconhecidos como tal. Na ciência, que gera o conhecimento básico; na tecnologia, que aplica criativamente esse conhecimento; e na engenharia, que transforma conhecimento em realidade, grassa uma anomalia reducionista que permite a hipertrofia de soluções pontuais, desconectadas entre si e do conjunto.
Tal abordagem gera soluções autistas que não se comunicam, tumores exuberantes cuja expansão danifica tudo que está em volta. Assim, a tecnociência olha o mundo com um microscópio grudado em seus olhos, vê pixel, mas ignora a paisagem. Abre caminhos para que ânimos restritos se apropriem de conhecimentos parciais e destruam o mundo. É preciso remover os microscópios dos olhos, olhar o conjunto, perceber as conexões e, assim, aplicar o conhecimento de forma sábia e benéfica.
IHU On-Line – De que forma conceitos como a Ecologia Integral, presentes na Encíclica Laudato Si’, do papa Francisco, contribuem para o desenvolvimento de uma visão sistêmica do ser humano sobre o planeta? Qual a importância de uma perspectiva multidisciplinar acerca da temática ambiental?
Antonio Donato Nobre – Ecologia Integral deve significar o que o nome diz. Aliás, se não for integral não pode ser denominada ecologia. Isso porque na natureza não existe isolamento, cada partícula, cada componente, cada organismo e cada sistema interage com os demais, sob o sábio comando das leis fundamentais. Por isso a ação humana pode gerar um acorde harmonioso na grande sinfonia universal, ou — se desrespeitar as leis — tornar-se fonte de perturbação e destruição.
Mais importante do que ser multidisciplinar é ser não-disciplinar, isto é, integrar e dissolver as “disciplinas” em um saber amplo e articulado, sem fronteiras artificiais e domínios de egos. A ciência verdadeira é aquela oriunda do livre pensar, do profundo sentir e do intuir espontâneo. A busca da verdade está ao alcance de todas as pessoas, não é nem deveria ser território exclusivo dos iniciados na ciência. Todos somos dotados da capacidade de inquirir e temos como promessa de realização o dom da consciência. Cientistas são facilitadores, e como tal deveriam servir aos semelhantes com boa vontade, iluminando o caminho do conhecimento, guiando na direção do saber.
IHU On-Line – Como avalia a agroecologia no Brasil hoje? O que a ciência e a tecnologia oferecem em termos de avanços para esse campo?
Antonio Donato Nobre – Agroecologia, agrofloresta sintrópica, sistemas agroflorestais, agricultura biodinâmica, trofobiose, agricultura orgânica, agricultura sustentável etc. compõem um rico repertório de abordagens que convergem na aspiração de emular em agroecossistemas a riqueza e funcionamento dos ecossistemas naturais. Uma parte dos desenvolvimentos científicos e tecnológicos autistas de até então pode ser aproveitada para essa nova era de agricultura produtiva, iluminada, respeitadora, harmônica e saudável.
É preciso, porém, que o isolamento acabe, que os conhecimentos sejam transparentes, integrados, articulados, simplificados e recolocados em perspectiva. Se as agulhas tecnológicas foram danosas, como os transgênicos, por exemplo, ainda assim serão úteis para sabermos o que “não” fazer. Na compreensão em detalhe das bases moleculares da vida, abrindo portais para consciência sobre a complexidade astronômica existente e atuante em todos os organismos, a humanidade terá finalmente a prova irrefutável para o acerto das abordagens holísticas e ecológicas.
IHU On-Line – Deseja acrescentar algo?
Antonio Donato Nobre – É preciso iluminar e revelar a imensa teia de mentiras criada em torno da revolução verde com seus exuberantes tumores tecnológicos. As falsidades suportadas por corporações, governos, mídia e educação bitoladora desde a mais tenra idade, implantaram um sistema mundial de dominação que, literalmente, enfia goela abaixo da humanidade um menu infernal de alimentos portadores de doenças.
Esse triunfante modelo de negócio não se contenta em somente alimentar mal, o faz via quantidades crescentes de produtos animais, os quais requerem imensas áreas e grandes quantidades de água e outros insumos para serem produzidos.
Com isso a pegada humana no planeta torna-se destrutiva e insuportável, e a consequência já se faz sentir no clima como falência múltipla de órgãos. Apesar disso, creio que ainda temos uma pequena chance de evitar o pior se, como humanidade, dermos apoio irrestrito para a busca da verdade.
Precisamos de uma operação Lava Jato no campo, e a ciência tem todas as ferramentas para apoiar esse esforço de sobrevivência.
Strains of E. coli resistant to one antibiotic can protect other bacteria growing nearby
Date:
May 16, 2016
Source:
Massachusetts Institute of Technology
Summary:
Researchers have found that two strains of E. coli bacteria, each resistant to one antibiotic, can protect each other in an environment where both drugs are present.
Mutualism, a phenomenon in which different species benefit from their interactions with each other, can help bacteria form drug-resistant communities. Pictured is an artist’s interpretation of mutualism among bacteria. Credit: Jose-Luis Olivares/MIT
A new study from MIT finds that two strains of bacteria that are each resistant to one antibiotic can protect each other in an environment containing both drugs.
The findings demonstrate that mutualism, a phenomenon in which different species benefit from their interactions with each other, can help bacteria form drug-resistant communities. This is the first experimental demonstration in microbes of a type of mutualism known as cross-protection, which is more commonly seen in larger animals.
The researchers focused on two strains of E. coli, one resistant to ampicillin and the other resistant to chloramphenicol. These bacteria and many others defend themselves from antibiotics by producing enzymes that break down the antibiotics. As a side effect, this also protects cells that don’t produce those enzymes, by removing the antibiotic from the environment.
“Any time that you’re breaking down an antibiotic, there’s this potential for cross-protection,” says Jeff Gore, the Latham Family Career Development Associate Professor of Physics and the senior author of the study, which appears in the Proceedings of the National Academy of Sciences the week of May 16.
The MIT team found that, indeed, both strains could survive in an environment where both antibiotics were present, even though each was only resistant to one of the drugs. This type of situation is likely also found in the natural world, especially in soil where many strains of bacteria live together.
“Each of them is making different toxins and each of them is resistant to different toxins,” Gore says. “A lot of antibiotics are produced by microbes as part of the combat that is taking place between microorganisms in the soil.”
Gore and co-first authors Eugene Yurtsev and Arolyn Conwill, both MIT graduate students, also found that the populations of the two strains oscillate over time. Population oscillations are common in predator-prey interactions but rare in mutualistic interactions such as the cross-protection seen in this study.
Throughout their experiments, the researchers diluted the bacterial population each day by transferring about 1 percent of the population to a new test tube, to which new antibiotics were added. They found that while the total size of the bacterial population remained about the same, there were large oscillations in the relative percentages of each strain, which varied by nearly 1,000 percent over a period of about three days.
For example, if the ampicillin-resistant strain was more abundant in the beginning of a cycle, it rapidly deactivated ampicillin in the environment, allowing the chloramphenicol-resistant strain to begin growing. The ampicillin-resistant strain only began growing once the other strain had expanded enough to deactivate most of the chloramphenicol, at which point the chloramphenicol-resistant strain had already overtaken the ampicillin-resistant strain.
“The mutualism exhibits oscillations because the strain that is more abundant at the beginning of a growth cycle might end up less abundant at the end of that cycle,” Gore says.
At lower antibiotic concentrations, the bacterial population can survive in this oscillating pattern indefinitely, but at higher drug concentrations, the oscillations destabilize the population, and it eventually collapses.
Gore suspects that similar population oscillations may also be seen in natural environments such as the human gut, as bacteria exit the body along with bowel movements, or in soil as bacteria are washed away by rainfall.
Gore’s lab is now looking at this type of mutualism in bacteria living in the gut of the worm C. elegans. The researchers are also studying how these types of population oscillations can become synchronized over large geographic areas, and how migration between populations influences this synchronization.
Journal Reference:
Saurabh R. Gandhi, Eugene Anatoly Yurtsev, Kirill S. Korolev, and Jeff Gore. Range expansions transition from pulled to pushed waves as growth becomes more cooperative in an experimental microbial population. PNAS, 2016 DOI: 10.1073/pnas.1521056113
Increases in carbon uptake by southeast US forests in response to tropical cyclone activity alone exceed carbon emissions by American vehicles each year.
Date:
May 2, 2016
Source:
Duke University
Summary:
New research reveals that the increase in forest photosynthesis and growth made possible by tropical cyclones in the southeastern United States captures hundreds of times more carbon than is released by all vehicles in the US in a given year.
This map shows the total increase of photosynthesis and carbon uptake by forests caused by all hurricanes in 2004. The dotted gray lines represent the paths of the individual storms. Credit: Lauren Lowman, Duke University
While hurricanes are a constant source of worry for residents of the southeastern United States, new research suggests that they have a major upside — counteracting global warming.
Previous research from Duke environmental engineer Ana Barros demonstrated that the regular landfall of tropical cyclones is vital to the region’s water supply and can help mitigate droughts.
Now, a new study from Barros reveals that the increase in forest photosynthesis and growth made possible by tropical cyclones in the southeastern United States captures hundreds of times more carbon than is released by all vehicles in the U.S. in a given year.
The study was published online on April 20, 2016, in the Journal of Geophysical Research — Biogeosciences.
“Our results show that, while hurricanes can cause flooding and destroy city infrastructure, there are two sides to the story,” said Barros, the James L. Meriam Professor of Civil and Environmental Engineering at Duke University. “The other side is that hurricanes recharge the aquifers and have an enormous impact on photosynthesis and taking up carbon from the atmosphere.”
In the study, Lauren Lowman, a doctoral student in Barros’s laboratory, used a hydrological computer model to simulate the ecological impacts of tropical cyclones from 2004-2007. The earlier years of that time period had a high number of tropical cyclone landfall events, while the latter years experienced relatively few.
By comparing those disparate years to simulations of a year without tropical cyclone events, Lowman was able to calculate the effect tropical cyclones have on the rates of photosynthesis and carbon uptake in forests of the southeastern United States.
“It’s easy to make general statements about how much of an impact something like additional rainfall can have on the environment,” said Lowman. “But we really wanted to quantify the amount of carbon uptake that you can relate to tropical cyclones.”
According to Barros and Lowman, it is difficult to predict what effects climate change will have on the region’s future. Even if the number of tropical cyclones that form in the Atlantic increases, that doesn’t guarantee that the number making landfall will also rise. And long-term forecasts for the region’s temperature and rainfall currently show less change than normal year-to-year variability.
But no matter what the future brings, one thing is clear — the regularity and number of tropical cyclones making landfall will continue to be vital.
“There are a lot of regional effects competing with large worldwide changes that make it very hard to predict what climate change will bring to the southeastern United States,” said Barros. “If droughts do become worse and we don’t have these regular tropical cyclones, the impact will be very negative. And regardless of climate change, our results are yet one more very good reason to protect these vast forests.”
This research was funded in part by the National Science Foundation Coupled Human and Natural Systems Program (CNH-1313799) and an earlier grant from the National Oceanic and Atmospheric Administration (NA08OAR4310701).
Journal Reference:
Lauren E. L. Lowman, Ana P. Barros. Interplay of Drought and Tropical Cyclone Activity in SE US Gross Primary Productivity. Journal of Geophysical Research: Biogeosciences, 2016; DOI: 10.1002/2015JG003279
Robert Fletcher is an associate professor at the Sociology of Development and Change Group at Wageningen University in the Netherlands. His most recent book is Romancing the Wild: Cultural Dimensions of Ecotourism (2014).
Bram Büscher is a professor and Chair at the Sociology of Development and Change Group at Wageningen University in the Netherlands. His most recent book is Transforming the Frontier: Peace Parks and the Politics of Neoliberal Conservation in Southern Africa (2013).
A member of the military-style Special Ranger Patrol talks to a suspected rhino poacher on 7 November 2014 at the Kruger National Park, South Africa. Photo by James Oatway/Sunday Times/Getty
Edward O Wilson is one of the world’s most revered, reviled and referenced conservation biologists. In his new book (and Aeon essay) Half-Earth, he comes out with all guns blazing, proclaiming the terrible fate of biodiversity, the need for radical conservation, and humanity’s centrality in both. His basic message is simple: desperate times call for desperate measures, ‘only by setting aside half the planet in reserve, or more, can we save the living part of the environment and achieve the stabilisation required for our own survival’. Asserting that ‘humanity’ behaves like a destructive juggernaut, Wilson is deeply concerned that the current ‘sixth extinction’ is destroying many species before scientists have even been able to identify them.
Turning half of the Earth into a series of nature parks is a grand utopian vision for conservation, perhaps even a hyperbolic one, yet Wilson seems deadly serious about it. Some environmental thinkers have been arguing the exact opposite, namely that conservation should give up its infatuation with parks and focus on ‘mixing’ people and nature in mutually conducive ways. Wilson defends a traditional view that nature needs more protection, and attacks them for being ‘unconcerned with what the consequences will be if their beliefs are played out’. As social scientists who study the impact of international conservation on peoples around the world, we would argue that it is Wilson himself who has fallen into this trap: the world he imagines in Half-Earth would be a profoundly inhumane one if ever his beliefs were ‘played out’.
The ‘nature needs half’ idea is not entirely new – it is an extreme version of a more widespread ‘land sparing’ conservation strategy. This is not about setting aside half the Earth as a whole but expanding the world’s current network of protected areas to create a patchwork grid encompassing at least half the world’s surface (and the ocean) and hence ‘about 85 per cent’ of remaining biodiversity. The plan is staggering in scale: protected areas, according to the International Union for the Conservation of Nature, currently incorporate around 10-15 per cent of the Earth’s terrain, so would need to more than triple in extent.
Wilson identifies a number of causes of the current ecological crisis, but is particularly concerned by overpopulation. ‘Our population,’ he argues, ‘is too large for safety and comfort… Earth’s more than 7 billion people are collectively ravenous consumers of all the planet’s inadequate bounty.’ But can we talk about the whole of humanity in such generalised terms? In reality, the world is riven by dramatic inequality, and different segments of humanity have vastly different impacts on the world’s environments. The blame for our ecological problems therefore cannot be spread across some notion of a generalised ‘humanity’.
Although Wilson is careful to qualify that it is the combination ofpopulation growth and ‘per-capita consumption’ that causes environmental degradation, he is particularly concerned about places he identifies as the remaining high-fertility problem spots – ‘Patagonia, the Middle East, Pakistan, and Afghanistan, plus all of sub-Saharan Africa exclusive of South Africa’. These are countries with some of the world’s lowest incomes. Paradoxically, then, it is those consuming the least that are considered the greatest problem. ‘Overpopulation’, it seems, is the same racialised bogeyman as ever, and the poor the greatest threat to an environmentally-sound future.
Wilson’s Half-Earth vision is offered as an explicit counterpoint to so-called ‘new’ or ‘Anthropocene’ conservationists, who are loosely organised around the controversial Breakthrough Institute. For Wilson, these ‘Anthropocene ideologists’ have given up on nature altogether. In her book, Rambunctious Garden (2011), Emma Marris characteristically argues that there is no wilderness left on the Earth, which is everywhere completely transformed by the human presence. According to Anthropocene thinking, we are in charge of the Earth and must manage it closely whether we like it or not. Wilson disagrees, insisting that ‘areas of wilderness… are real entities’. He contends that an area need not be ‘pristine’ or uninhabited to be wilderness, and ‘[w]ildernesses have often contained sparse populations of people, especially those indigenous for centuries or millennia, without losing their essential character’.
Research across the globe has shown that many protected areas once contained not merely ‘sparse’ inhabitants but often quite dense populations – clearly incompatible with the US Wilderness Act’s classic definition of wilderness as an area ‘where man himself is a visitor who does not remain’. Most existing ‘wilderness’ parks have required the removal or severe restriction of human beings within their bounds. Indeed, one of Wilson’s models for conservation success – Gorongosa National Park in Mozambique – sidelined local people despite their unified opposition. In his book Conservation Refugees (2009), Mark Dowie estimates that 20-50 million people have been displaced by previous waves of protected-area creation. To extend protected areas to half of the Earth’s surface would require a relocation of human populations on a scale that could dwarf all previous conservation refugee crises.
Would these people include Montana cattle ranchers? Or Australian wheat growers? Or Florida retirees? The answer, most likely, is no, for the burden of conservation has never been shared equitably across the world. Those who both take the blame and pay the greatest cost of environmental degradation are, almost always, those who do not have power to influence either their own governments or international politics. It is the hill tribes of Thailand, the pastoralists of Tanzania, and the forest peoples of Indonesia who are invariably expected to relocate, often at gunpoint, as Dowie and many scholars, including Dan Brockington in his book Fortress Conservation (2002), have demonstrated.
How will human society withstand the shock of removing so much land and ocean from food-growing and other uses? Wilson criticises the Anthropocene worldview’s faith that technological innovation can solve environmental problems or find substitutes for depleted resources, but he simultaneously promotes his own techno-fix in a vision of ‘intensified economic evolution’ in which ‘the free market, and the way it is increasingly shaped by high technology’ will solve the problem seemingly automatically. According to Wilson, ‘products that win competition today… are those that cost less to manufacture and advertise, need less frequent repair and replacement, and give highest performance with a minimum amount of energy’. He thus invokes a biological version of Adam Smith’s invisible hand in maintaining that ‘[j]ust as natural selection drives organic evolution by competition among genes to produce more copies of themselves per unit cost in the next generation, raising benefit-to-cost of production drives the evolution of the economy’ and asserting, without any evidence, that ‘[a]lmost all of the competition in a free market, other than in military technology, raises the average quality of life’.
Remarkably, this utopian optimism about technology and the workings of the free market leads Wilson to converge on a position rather like that of the Anthropocene conservationists he so dislikes, advocating a vision of ‘decoupling economic activity from material and environmental throughputs’ in order to create sustainable livelihoods for a population herded into urban areas to free space for self-willed nature. The Breakthrough Institute has recently promoted its own, quite similar, manifesto for land sparing and decoupling to increase terrain for conservation.
In this vision, science and technology can compensate for some of humanity’s status as the world’s ‘most destructive species’. And at the pinnacle of science stands (conservation) biology, according to Wilson. He argues: ‘If people are to live long and healthy lives in the sustainable Eden of our dreams, and our minds are to break free and dwell in the far more interesting universe of reason triumphant over superstition, it will be through advances in biology.’ How exactly humans are to ‘break free’ is not explained and is, in fact, impossible according to Wilson himself, given ‘the Darwinian propensity in our brain’s machinery to favour short-term decisions over long-range planning’. As far as Wilson is concerned, any worldview that does not favour protected-area expansion as the highest goal is by definition an irrational one. In this way, the world’s poor are blamed not only for overpopulating biodiversity hotspots but also for succumbing to the ‘religious belief and inept philosophical thought’ standing in the way of environmental Enlightenment.
Let us finish by making a broader point, drawing on Wilson’s approving quotation of Alexander von Humboldt, the 19th-century German naturalist who claimed that ‘the most dangerous worldview is the worldview of those who have not viewed the world’. In viewing the world, we also construct it, and the world Wilson’s offers us in Half-Earth is a truly bizarre one. For all his zeal, (misplaced) righteousness and passion, his vision is disturbing and dangerous, and would have profoundly negative ‘consequences if played out’. It would entail forcibly herding a drastically reduced human population into increasingly crowded urban areas to be managed in oppressively technocratic ways. How such a global programme of conservation Lebensraum would be accomplished is left to the reader’s imagination. We therefore hope readers will not take Wilson’s proposal seriously. Addressing biodiversity loss and other environmental problems must proceed by confronting the world’s obscene inequality, not by blaming the poor and trusting the ‘free market’ to save them.
Half-Earth (AEON)
29 February, 2016
Half of the Earth’s surface and seas must be dedicated to the conservation of nature, or humanity will have no future
The Serengeti National Park. Photo by Medford Taylor/National Geographic
Edward O Wilson is a professor emeritus in entomology at Harvard. Half-Earth concludes Wilson’s trilogy begun by The Social Conquest of Earth and The Meaning of Human Existence, a National Book Award finalist.
Unstanched haemorrhaging has only one end in all biological systems: death for an organism, extinction for a species. Researchers who study the trajectory of biodiversity loss are alarmed that, within the century, an exponentially rising extinction rate might easily wipe out most of the species still surviving at the present time.
The crucial factor in the life and death of species is the amount of suitable habitat left to them. When, for example, 90 per cent of the area is removed, the number that can persist sustainably will descend to about a half. Such is the actual condition of many of the most species-rich localities around the world, including Madagascar, the Mediterranean perimeter, parts of continental southwestern Asia, Polynesia, and many of the islands of the Philippines and the West Indies. If 10 per cent of the remaining natural habitat were then also removed – a team of lumbermen might do it in a month – most or all of the surviving resident species would disappear.
Today, every sovereign nation in the world has a protected-area system of some kind. All together the reserves number about 161,000 on land and 6,500 over marine waters. According to the World Database on Protected Areas, a joint project of the United Nations Environmental Program and the International Union for Conservation of Nature, they occupied by 2015 a little less than 15 per cent of Earth’s land area and 2.8 per cent of Earth’s ocean area. The coverage is increasing gradually. This trend is encouraging. To have reached the existing level is a tribute to those who have led and participated in the global conservation effort.
But is the level enough to halt the acceleration of species extinction? Unfortunately, it is in fact nowhere close to enough. The declining world of biodiversity cannot be saved by the piecemeal operations in current use alone. The extinction rate our behaviour is now imposing on the rest of life, and seems destined to continue, is more correctly viewed as the equivalent of a Chicxulub-sized asteroid strike played out over several human generations.
The only hope for the species still living is a human effort commensurate with the magnitude of the problem. The ongoing mass extinction of species, and with it the extinction of genes and ecosystems, ranks with pandemics, world war, and climate change as among the deadliest threats that humanity has imposed on itself. To those who feel content to let the Anthropocene evolve toward whatever destiny it mindlessly drifts, I say please take time to reconsider. To those who are steering the growth of reserves worldwide, let me make an earnest request: don’t stop, just aim a lot higher.
I see just one way to make this 11th-hour save: committing half of the planet’s surface to nature to save the immensity of life-forms that compose it. Why one-half? Why not one-quarter or one-third? Because large plots, whether they already stand or can be created from corridors connecting smaller plots, harbour many more ecosystems and the species composing them at a sustainable level. As reserves grow in size, the diversity of life surviving within them also grows. As reserves are reduced in area, the diversity within them declines to a mathematically predictable degree swiftly – often immediately and, for a large fraction, forever. A biogeographic scan of Earth’s principal habitats shows that a full representation of its ecosystems and the vast majority of its species can be saved within half the planet’s surface. At one-half and above, life on Earth enters the safe zone. Within half, existing calculations from existing ecosystems indicate that more than 80 per cent of the species would be stabilised.
There is a second, psychological argument for protecting half of Earth. The current conservation movement has not been able to go the distance because it is a process. It targets the most endangered habitats and species and works forward from there. Knowing that the conservation window is closing fast, it strives to add increasing amounts of protected space, faster and faster, saving as much as time and opportunity will allow.
The key is the ecological footprint, defined as the amount of space required to meet the needs of an average person
Half-Earth is different. It is a goal. People understand and prefer goals. They need a victory, not just news that progress is being made. It is human nature to yearn for finality, something achieved by which their anxieties and fears are put to rest.
The Half-Earth solution does not mean dividing the planet into hemispheric halves or any other large pieces the size of continents or nation-states. Nor does it require changing ownership of any of the pieces, but instead only the stipulation that they be allowed to exist unharmed. It does, on the other hand, mean setting aside the largest reserves possible for nature, hence for the millions of other species still alive.
The key to saving one-half of the planet is the ecological footprint, defined as the amount of space required to meet all of the needs of an average person. It comprises the land used for habitation, fresh water, food production and delivery, personal transportation, communication, governance, other public functions, medical support, burial, and entertainment. In the same way the ecological footprint is scattered in pieces around the world, so are Earth’s surviving wildlands on the land and in the sea. The pieces range in size from the major desert and forest wildernesses to pockets of restored habitats as small as a few hectares.
But, you may ask, doesn’t a rising population and per-capita consumption doom the Half-Earth prospect? In this aspect of its biology, humanity appears to have won a throw of the demographic dice. Its population growth has begun to decelerate autonomously, without pressure one way or the other from law or custom. In every country where women have gained some degree of social and financial independence, their average fertility has dropped by a corresponding amount through individual personal choice.
There won’t be an immediate drop in the total world population. An overshoot still exists due to the longevity of the more numerous offspring of earlier, more fertile generations. There also remain high-fertility countries, with an average of more than three surviving children born to each woman, thus higher than the 2.1 children per woman that yields zero population growth. Even as it decelerates toward zero growth, population will reach between 9.6 billion and 12.3 billion, up from the 7.2 billion existing in 2014. That is a heavy burden for an already overpopulated planet to bear, but unless women worldwide switch back from the negative population trend of fewer than 2.1 children per woman, a turn downward in the early 22nd century is inevitable.
And what of per-capita consumption? The footprint will evolve, not to claim more and more space, as you might at first suppose, but less. The reason lies in the evolution of the free market system, and the way it is increasingly shaped by high technology. The products that win are those that cost less to manufacture and advertise, need less frequent repair and replacement, and give highest performance with a minimum amount of energy. Just as natural selection drives organic evolution by competition among genes to produce more copies of themselves per unit cost in the next generation, raising benefit-to-cost of production drives the evolution of the economy. Teleconferencing, online purchase and trade, ebook personal libraries, access on the Internet to all literature and scientific data, online diagnosis and medical practice, food production per hectare sharply raised by indoor vertical gardens with LED lighting, genetically engineered crops and microorganisms, long-distance business conferences and social visits by life-sized images, and not least the best available education in the world free online to anyone, anytime, and anywhere. All of these amenities will yield more and better results with less per-capita material and energy, and thereby will reduce the size of the ecological footprint.
In viewing the future this way, I wish to suggest a means to achieve almost free enjoyment of the world’s best places in the biosphere that I and my fellow naturalists have identified. The cost-benefit ratio would be extremely small. It requires only a thousand or so high-resolution cameras that broadcast live around the clock from sites within reserves. People would still visit any reserve in the world physically, but they could also travel there virtually and in continuing real time with no more than a few keystrokes in their homes, schools, and lecture halls. Perhaps a Serengeti water hole at dawn? Or a teeming Amazon canopy? There would also be available streaming video of summer daytime on the coast in the shallow offshore waters of Antarctica, and cameras that continuously travel through the great coral triangle of Indonesia and New Guinea. With species identifications and brief expert commentaries unobtrusively added, the adventure would be forever changing, and safe.
The spearhead of this intensive economic evolution, with its hope for biodiversity, is contained in the linkage of biology, nanotechnology, and robotics. Two ongoing enterprises within it, the creation of artificial life and artificial minds, seem destined to preoccupy a large part of science and high technology for the rest of the present century.
The creation of artificial life forms is already a reality. On 20 May 2010, a team of researchers at the J Craig Venter Institute in California announced the second genesis of life, this time by human rather than divine command. They had built live cells from the ground up. With simple chemical reagents off the shelf, they assembled the entire genetic code of a bacterial species, Mycoplasma mycoides, a double helix of 1.08 million DNA base pairs. During the process they modified the code sequence slightly, implanting a statement made by the late theoretical physicist Richard Feynman, ‘What I cannot create, I do not understand,’ in order to detect daughters of the altered mother cells in future tests.
If our minds are to break free and dwell in the far more interesting universe of reason triumphant over superstition, it will be through advances in biology
The textbook example of elementary artificial selection of the past 10 millennia is the transformation of teosinte, a species of wild grass with three races in Mexico and Central America, into maize (corn). The food found in the ancestor was a meagre packet of hard kernels. Over centuries of selective breeding it was altered into its modern form. Today maize, after further selection and widespread hybridisation of inbred strains that display ‘hybrid vigour’ is the principal food of hundreds of millions.
The first decade of the present century thus saw the beginning of the next new major phase of genetic modification beyond hybridisation: artificial selection and even direct substitution in single organisms of one gene for another. If we use the trajectory of progress in molecular biology during the previous half century as a historical guide, it appears inevitable that scientists will begin routinely to build cells of wide variety from the ground up, then induce them to multiply into synthetic tissues, organs, and eventually entire independent organisms of considerable complexity.
If people are to live long and healthy lives in the sustainable Eden of our dreams, and our minds are to break free and dwell in the far more interesting universe of reason triumphant over superstition, it will be through advances in biology. The goal is practicable because scientists, being scientists, live with one uncompromising mandate: press discovery to the limit. There has already emerged a term for the manufacture of organisms and parts of organisms: synthetic biology. Its potential benefits, easily visualised as spreading through medicine and agriculture, are limited only by imagination. Synthetic biology will also bring onto centre stage the microbe-based increase of food and energy.
Each passing year sees advances in artificial intelligence and their multitudinous applications – advances that would have been thought distantly futuristic a decade earlier. Robots roll over the surface of Mars. They travel around boulders and up and down slopes while photographing, measuring minutiae of topography, analysing the chemical composition of soil and rocks, and scrutinising everything for signs of life.
In the early period of the digital revolution, innovators relied on machine design of computers without reference to the human brain, much as the earliest aeronautical engineers used mechanical principles and intuition to design aircraft instead of imitating the flight of birds. But with the swift growth of both fields, one-on-one comparisons are multiplying. The alliance of computer technology and brain science has given birth to whole brain emulation as one of the ultimate goals of science.
From the time of the ancient human-destined line of amphibians, then reptiles, then mammals, the neural pathways of every part of the brain were repeatedly altered by natural selection to adapt the organism to the environment in which it lived. Step-by-step, from the Paleozoic amphibians to the Cenozoic primates, the ancient centres were augmented by newer centres, chiefly in the growing cortex, that added to learning ability. All things being equal, the ability of organisms to function through seasons and across different habitats gave them an edge in the constant struggle to survive and reproduce.
Little wonder, then, that neurobiologists have found the human brain to be densely sprinkled with partially independent centres of unconscious operations, along with all of the operators of rational thought. Located through the cortex in what might look at first like random arrays are the headquarters of process variously for numbers, attention, face-recognition, meanings, reading, sounds, fears, values, and error detection. Decisions tend to be made by the brute force of unconscious choice in these centres prior to conscious comprehension.
Next in evolution came consciousness, a function of the human brain that, among other things, reduces an immense stream of sense data to a small set of carefully selected bite-size symbols. The sampled information can then be routed to another processing stage, allowing us to perform what are fully controlled chains of operations, much like a serial computer. This broadcasting function of consciousness is essential. In humans, it is greatly enhanced by language, which lets us distribute our conscious thoughts across the social network.
What has brain science to do with biodiversity? At first, human nature evolved along a zigzag path as a continually changing ensemble of genetic traits while the biosphere continue to evolve on its own. But the explosive growth of digital technology transformed every aspect of our lives and changed our self-perception, bringing the ‘bnr’ industries (biology, nanotechnology, robotics) to the forefront of the modern economy. These three have the potential either to favour biodiversity or to destroy it.
I believe they will favour it, by moving the economy away from fossil fuels to energy sources that are clean and sustainable, by radically improving agriculture with new crop species and ways to grow them, and by reducing the need or even the desire for distant travel. All are primary goals of the digital revolution. Through them the size of the ecological footprint will also be reduced. The average person can expect to enjoy a longer, healthier life of high quality yet with less energy extraction and raw demand put on the land and sea. If we are lucky (and smart), world population will peak at a little more than 10 billion people by the end of the century followed by the ecological footprint soon thereafter. The reason is that we are thinking organisms trying to understand how the world works. We will come awake.
Silicon Valley dreamers of a digitised humanity have failed to give much thought at all to the biosphere
That process is already under way, albeit still far too slowly – with the end in sight in the 23rd century. We and the rest of life with us are in the middle of a bottleneck of rising population, shrinking resources, and disappearing species. As its stewards we need to think of our species as being in a race to save the living environment. The primary goal is to make it through the bottleneck to a better, less perilous existence while carrying through as much of the rest of life as possible. If global biodiversity is given space and security, most of the large fraction of species now endangered will regain sustainability on their own. Furthermore, advances made in synthetic biology, artificial intelligence, whole brain emulation, and other similar, mathematically based disciplines can be imported to create an authentic, predictive science of ecology. In it, the interrelations of species will be explored as fervently as we now search through our own bodies for health and longevity. It is often said that the human brain is the most complex system known to us in the universe. That is incorrect. The most complex is the individual natural ecosystem, and the collectivity of ecosystems comprising Earth’s species-level biodiversity. Each species of plant, animal, fungus, and microorganism is guided by sophisticated decision devices. Each is intricately programmed in its own way to pass with precision through its respective life cycle. It is instructed on when to grow, when to mate, when to disperse, and when to shy away from enemies. Even the single-celled Escherichia coli, living in the bacterial paradise of our intestines, moves toward food and away from toxins by spinning its tail cilium one way, then the other way, in response to chemosensory molecules within its microscopic body.
How minds and decision-making devices evolve, and how they interact with ecosystems is a vast area of biology that remains mostly uncharted – and still even undreamed by those scientists who devote their lives to it. The analytic techniques coming to bear on neuroscience, on Big Data theory, on simulations with robot avatars, and on other comparable enterprises will find applications in biodiversity studies. They are ecology’s sister disciplines.
It is past time to broaden the discussion of the human future and connect it to the rest of life. The Silicon Valley dreamers of a digitised humanity have not done that, not yet. They have failed to give much thought at all to the biosphere. With the human condition changing so swiftly, we are losing or degrading to uselessness ever more quickly the millions of species that have run the world independently of us and free of cost. If humanity continues its suicidal ways to change the global climate, eliminate ecosystems, and exhaust Earth’s natural resources, our species will very soon find itself forced into making a choice, this time engaging the conscious part of our brain. It is as follows: shall we be existential conservatives, keeping our genetically-based human nature while tapering off the activities inimical to ourselves and the rest of the biosphere? Or shall we use our new technology to accommodate the changes important solely to our own species, while letting the rest of life slip away? We have only a short time to decide.
The beautiful world our species inherited took the biosphere 3.8 billion years to build. The intricacy of its species we know only in part, and the way they work together to create a sustainable balance we have only recently begun to grasp. Like it or not, and prepared or not, we are the mind and stewards of the living world. Our own ultimate future depends upon that understanding. We have come a very long way through the barbaric period in which we still live, and now I believe we’ve learned enough to adopt a transcendent moral precept concerning the rest of life.
Poluentes chegam a 200 km ao norte e ao sul da foz do rio Doce, atingem unidades de conservação, alteram equilíbrio ecológico e se acumulam no assoalho marinho
Poluição à vista: os resíduos que vazaram do reservatório de Mariana formam mancha acastanhada na foz do rio Doce.
Em janeiro deste ano, ao sobrevoarem o litoral do Espírito Santo e do sul da Bahia, biólogos, oceanógrafos e técnicos de órgãos ambientais do governo federal reconheceram os borrões escuros na superfície do mar formados pelo acúmulo de resíduos metálicos que vazaram do reservatório da mineradora Samarco em Mariana, Minas Gerais, em novembro de 2015. A mancha de resíduos, também chamada de pluma, aproximava-se do arquipélago de Abrolhos, uma das principais reservas de vida silvestre marinha da costa brasileira.
Os borrões não eram apenas os indesejados resquícios da extração de minério de ferro de Minas Gerais, mas uma de suas consequências, como se verificou logo depois. Em meio às manchas verde-escuro havia colônias de algas e outros organismos marinhos microscópicos – o fitoplâncton – com dezenas de quilômetros de extensão, muito maiores que as observadas nos anos anteriores, de acordo com as análises de pesquisadores da Universidade Federal do Espírito Santo (Ufes).
Outra peculiaridade é que os organismos cresciam e se multiplicavam rapidamente, em decorrência do excesso de ferro dos rejeitos da mineradora de Mariana que se espalham pelo mar a partir da foz do rio Doce, onde chegaram no final de novembro. Desde então, levados continuamente ao mar pelo rio, os resíduos formam uma mancha móvel que oscila ao longo de 200 quilômetros (km) ao norte e ao sul da foz do rio Doce, que alterou o equilíbrio marinho, como indicado pela massa de fitoplâncton, e atingiu pelo menos três unidades de conservação de organismos marinhos.
“As manchas de fitoplâncton são comuns no verão, mas não desse modo”, explica Alex Bastos, professor de oceanografia da Ufes, no final de fevereiro. Análises preliminares indicaram que as colônias de algas são constituídas por organismos que se formam e morrem em poucos dias, mais rapidamente que o habitual. A decomposição acelerada dos organismos consome oxigênio da água do mar, com consequências imprevisíveis sobre as comunidades de organismos marinhos.
Além disso, a diversidade de espécies havia sido reduzida quase à metade. Camilo Dias Júnior, com sua equipe de oceanografia da Ufes, encontrou no máximo 40 espécies de fitoplâncton por amostra analisada; antes da chegada dos resíduos os pesquisadores reconheciam de 50 a 70 espécies. A hipótese dos pesquisadores e técnicos é de que já poderia ter ocorrido uma seleção de variedades mais adaptadas ao excesso de ferro trazido com a descarga dos resíduos no mar.
Nos sobrevoos do litoral do Espírito Santo e da Bahia, Claudio Dupas, coordenador do Núcleo de Geoprocessamento e Monitoramento Ambiental da Superintendência do Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (Ibama) em São Paulo, observou muitos barcos de pesca próximos às manchas de fitoplâncton na foz do rio Doce. Atraídos pela abundância de alimento, o grande número de peixes chamou a atenção dos pescadores.
Com base nas análises preliminares da qualidade de água e na observação do cenário, a equipe do Ibama elaborou um relatório técnico alertando sobre alterações na qualidade da água, prejudicada com a descarga de resíduos no mar. Com base no documento e no princípio da precaução – para evitar que a população seja prejudicada pelo consumo de peixes contaminados –, no dia 22 de fevereiro um juiz federal de Vitória proibiu por tempo indeterminado a pesca na região da foz do rio Doce. “Assim que saiu a decisão do juiz, o superintendente do Ibama em Vitória, Guanadir Gonçalves, pediu-me para fazer um mapa com a delimitação da área de proibição, que foi para a internet e para os celulares dos fiscais em campo no mesmo dia”, diz Dupas.
Desde janeiro os movimentos da mancha de resíduos podem ser acompanhados por meio de mapas gerados pelo Ibama a partir de imagens de satélites no site governancapelodoce.com.br, mantido pela Samarco. Já o site siscom.ibama.gov.br/mariana contém imagens de satélite de alta resolução de antes e depois do incidente, da barragem à foz. Os mapas indicam que os resíduos já chegaram a 50 km ao sul de Vitória, capital do Espírito Santo, e atingiram três unidades de conservação do ambiente marinho, o Refúgio de Vida Silvestre de Santa Cruz, a Área de Proteção Ambiental (APA) Costa das Algas e uma das principais áreas de desova da tartaruga-cabeçuda (Caretta caretta), uma faixa de 37 km de praias conhecida como Reserva Biológica Comboios. “Ainda não é possível avaliar o impacto sobre o ambiente, a vida dos organismos marinhos e dos moradores da região”, diz Dupas.
Desde que vazou da barragem de Fundão, em 5 de novembro, até chegar ao mar, a enorme massa de resíduos da extração de minério de ferro causou uma transformação profunda. Destruiu casas e matas às margens do rio Doce, provocando a morte de 18 pessoas e de toneladas de peixes e outros organismos aquáticos. A bióloga Flávia Bottino participou das expedições do Grupo Independente para Análise do Impacto Ambiental (Giaia) ao longo do rio Doce em novembro e observou uma intensa turbidez da água, que dificultava a penetração da luz e a sobrevivência dos organismos. Os biólogos encontraram camarões de água doce que sobreviveram ao desastre, mas os organismos bentônicos, que viviam no fundo do rio, tinham sido soterrados.
Limites incertos
A alta concentração de partículas sólidas que absorvem calor pode ter causado o aumento da temperatura da água para cerca de 30º Celsius. “A água do rio estava quente”, ela notou. As análises das amostras de água coletadas em dezembro ao longo de um trecho de cerca de 800 km do rio, realizadas nas unidades das universidades de São Paulo (USP) em Ribeirão Preto, Federal de São Carlos (UFSCar) em São Carlos e Sorocaba, Estadual Paulista (Unesp) em São Vicente, e na de Brasília (UnB), indicaram concentrações elevadas de manganês, ferro, arsênio e chumbo. As chuvas podem agravar a situação ao lavar as margens dos rios, cobertas de resíduos, e transportá-los ao mar.
Por meio de coletas realizadas com o navio Vital de Oliveira Moura, da Marinha, a equipe da Ufes verificou que 25 km a leste da foz do Rio Doce os resíduos formam uma camada de 1 a 2 centímetros sobre a lama do fundo do mar, a 25 metros de profundidade. “Está havendo um acúmulo rápido do rejeito no assoalho marinho”, diz Bastos, da Ufes, com base em coletas realizadas desde novembro, logo após o rompimento da barragem (ver Pesquisa FAPESP no 239). “Nem nas maiores cheias o acúmulo de sedimentos no rio no fundo do mar foi tão alto.”
No início de fevereiro, em uma reunião dos pesquisadores da Ufes com representantes do Ibama, Instituto Estadual do Meio Ambiente (Iema) e Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), Bastos comentou que a concentração de ferro no fundo do mar havia aumentado 20 vezes, em comparação com os níveis de antes do acidente, a de alumínio 10 vezes e a de cromo e manganês, cinco. Outro professor da Ufes, Renato Rodrigues Neto, observou que a vazão do rio passou de 300 metros cúbicos por segundo (m³/s), antes do rompimento da barragem, para cerca de 4.000 m³/s, aumentando a quantidade de lama com resíduos metálicos despejada no mar.
As imagens de satélite indicam que os resíduos metálicos podem ter chegado até o arquipélago de Abrolhos no início de janeiro, embora, ressalta Dupas, ainda não seja possível diferenciar os sedimentos vindos do rio Doce, a cerca de 200 km de distância, dos do rio Caravelas, que deságua na região. Segundo ele, os resultados das análises em andamento devem ser anunciados em abril.
Vários estudos em outras áreas marinhas têm indicado que os resíduos industriais podem ir muito além dos lugares onde foram produzidos, misturar-se com os sedimentos do fundo do mar, aflorando se revolvidos por redes de pesca, ou ser absorvidos por organismos marinhos. Uma equipe do Instituto Oceanográfico (IO) da USP identificou metais pesados (chumbo, cobre e zinco) e compostos orgânicos derivados de petróleo produzidos na zona industrial de Santos e do polo industrial de Cubatão, a 15 km do mar, misturados com a lama do assoalho marinho a uma profundidade de 100 metros e a uma distância de 200 km da costa. Não se pensava que a poluição gerada em terra pudesse chegar tão longe.
Condições ambientais
As conclusões ajudam a pensar o que poderia se passar no litoral do Espírito Santo e dos estados vizinhos, à medida que a lama da mineradora se espalha. “Os eventos, a rigor, não têm conexão à primeira vista”, disse Michel Mahiques, professor de oceanografia do IO-USP que coordenou os estudos em Santos. O vazamento da Samarco em Mariana foi um fenômeno agudo, com uma descarga intensa de resíduos, enquanto Santos e outros, como a baía da Guanabara, são casos crônicos, de décadas de liberação contínua de poluentes. “O fato comum”, ele diz, “é que existem porções do fundo marinho nas quais as condições ambientais permitem a deposição de materiais gerados pela atividade humana, ainda que a grandes distâncias”.
Em um estudo anterior no litoral de Santos, seu grupo identificou isótopos de césio 137 originários de explosões atômicas ou de usinas nucleares, nas quais esse tipo de material é gerado. “O césio foi transportado pela atmosfera e aderiu a partículas muito pequenas do fundo do mar”, conta. “Podemos chamar esses casos de teleconexões, em que um evento em um determinado ponto do planeta pode afetar regiões muito distantes.” Segundo ele, os casos clássicos são os acidentes das usinas nucleares de Chernobyl em 1986 e de Fukushima em 2011.
“Precisamos lançar outro olhar para o potencial de acumulação de material no meio marinho”, comenta Mahiques. Seus estudos indicaram que os poluentes se acumulam principalmente nos cinturões de lama, faixas em geral com 3 a 4 km de largura e dezenas de quilômetros de extensão, na chamada plataforma continental, sobre estruturas antigas de relevo. “Há um efeito a distância. Os sedimentos permanecem em pontos bem distantes da origem. Duzentos quilômetros foi o limite a que chegamos, mas ainda não sabemos se poderiam ir mais longe.” Mahiques argumenta que dois conceitos básicos sobre o funcionamento da plataforma continental deveriam ser revistos. O primeiro é que a quantidade de materiais do continente que chega ao mar seria pequena. O segundo é que os ambientes costeiros retêm a sujeira. “A quantidade não é pequena, nem os estuários são um filtro perfeito dos resíduos gerados no continente.”
Os pesquisadores analisaram 21 amostras de sedimentos coletadas em 2005 e outras, mais recentes, reunidas por meio do navio oceanográfico Alpha Crucis. Os resultados indicaram que os níveis de chumbo, zinco e cobre a 100 metros de profundidade a mais de 100 km da costa eram próximos aos encontrados na baía de Santos, embora mais baixos que os limites mais altos do estuário santista, um ambiente próximo à terra que mistura água de rios e do mar. No estuário, a concentração de chumbo no sedimento marinho variava de 9 miligramas por quilograma (mg/kg) em áreas não contaminadas a 59 mg/kg em amostras do fundo do porto, indicando um aumento de cinco a 10 vezes em comparação com os valores anteriores ao processo de industrialização. Os autores desse trabalho afirmaram que os poluentes industriais misturados com a lama no fundo do mar poderiam facilmente voltar à circulação, como resultado de movimentos intensos da água ou de atividade humana como a dragagem para a ampliação de portos ou a pesca com redes pesadas que revolvem o fundo do mar.
Estudos anteriores de pesquisadores do IO-USP já haviam mostrado que a descarga contínua de esgotos domésticos e de poluentes industriais na baía de Santos era provavelmente uma das causas da reduzida diversidade de organismos marinhos na região, em comparação com áreas menos poluídas.
Em paralelo, uma equipe da Unesp em São Vicente encontrou níveis acima dos permitidos em lei de quatro metais pesados – cádmio, cobre, chumbo e mercúrio – em amostras de água, sedimento e em caranguejos-uçá dos manguezais dos municípios de Cubatão, Bertioga, Iguape, São Vicente e Cananeia. Nas regiões com maior concentração desses metais, os caranguejos apresentavam uma proporção maior de células com alterações genéticas associadas à ocorrência de malformações (verPesquisa FAPESP no 225). Estudo de uma equipe da Universidade Federal do Rio Grande publicado em novembro de 2015 associou a contaminação por metal como possível causa da fibropapilomatose, uma doença específica de tartarugas marinhas, caracterizada pela formação de tumores benignos sobre a pele, em tartarugas-verde (Chelonia mydas) de Ubatuba, SP, já que os animais examinados apresentavam um nível acima do normal de cobre, ferro e chumbo, em comparação com animais saudáveis.
“Quando pensarmos em legislação e políticas públicas, para fazer uma projeção do impacto de eventuais acidentes ambientais, temos de olhar mais longe e rever o conceito de área de influência, já que o efeito pode ser muito maior do que o imaginado”, disse Mahiques. Bastos, da Ufes, observou que os danos ambientais podem ser intensos em consequência de pequenas alterações na concentração de metais na água do mar, mesmo que os limites ainda estejam abaixo dos máximos estabelecidos pela legislação ambiental.
The claim that Eskimo languages have many words for different types of snow is well known among the public, but it has been greatly exaggerated and is therefore often dismissed by scholars of language. However, a new study published in PLOS ONE supports the general idea behind the original claim.
The claim that Eskimo languages have many words for different types of snow is well known among the public, but it has been greatly exaggerated and is therefore often dismissed by scholars of language.
However, a new study published in PLOS ONE supports the general idea behind the original claim. Carnegie Mellon University and University of California, Berkeley researchers found that languages that use the same word for snow and ice tend to be spoken in warmer climates, reflecting lower communicative need to talk about snow and ice.
“We wanted to broaden the investigation past Eskimo languages and look at how different languages carve up the world into words and meanings,” said Charles Kemp, associate professor of psychology in CMU’s Dietrich College of Humanities and Social Sciences.
For the study, Kemp, and UC Berkeley’s Terry Regier and Alexandra Carstensen analyzed the connection between local climates, patterns of language use and word(s) for snow and ice across nearly 300 languages. They drew on multiple sources of data including library reference works, Twitter and large digital collections of linguistic and meteorological data.
The results revealed a connection between temperature and snow and ice terminology, suggesting that local environmental needs leave an imprint on languages. For example, English originated in a relatively cool climate and has distinct words for snow and ice. In contrast, the Hawaiian language is spoken in a warmer climate and uses the same word for snow and for ice. These cases support the claim that languages are adapted to the local communicative needs of their speakers — the same idea that lies behind the overstated claim about Eskimo words for snow. The study finds support for this idea across language families and geographic areas.
“These findings don’t resolve the debate about Eskimo words for snow, but we think our question reflects the spirit of the initial snow claims — that languages reflect the needs of their speakers,” said Carstensen, a psychology graduate student at UC Berkeley.
The researchers suggest that in the past, excessive focus on the specific example of Eskimo words for snow may have obscured the more general principle behind it.
Carstensen added, “Here, we deliberately asked a somewhat different question about a broader set of languages.”
The study also connects with previous work that explores how the sounds and structures of language are shaped in part by a need for efficiency in communication.
“We think our study reveals the same basic principle at work, modulated by local communicative need,” said Regier, professor of linguistics and cognitive science at UC Berkeley.
O geógrafo Adam Wilson e o ecologista Walter Jetz observaram as nuvens para saber a vida que existe sob elas. Os dois cientistas usaram imagens de satélites tiradas duas vezes ao dia durante os últimos 15 anos para criar um atlas das nuvens e relacionaram esse mapa com a biodiversidade do planeta, desenhando desde os limites dos grandes biomas (paisagens bioclimáticas) até a distribuição geográfica das diferentes espécies.
Suspensas lá em cima, as nuvens são um elemento fundamental da climatologia. Sua presença anuncia umidade, chuvas, água para as plantas, bosques e florestas, explosão de vida… Por outro lado, sua ausência caracteriza paisagens mais secas e desoladas, seja nos desertos ou no interior da Antártida. Foi essa conexão entre clima e biodiversidade que levou Wilson, professor da Universidade de Buffalo, e Jetz, pesquisador de Yale (ambas nos EUA), a buscar uma forma de detectar os padrões e dinâmica globais das nuvens mais eficiente do que os sistemas atuais.
Encontraram a solução nas fotografias da Terra tiradas há anos pela NASA. Concretamente, eles usaram os dados acumulados pela missão MODIS, siglas do espectroradiômetro de imagens de resolução média, um instrumento científico que vai a bordo de dois satélites chamados Terra e Aqua. O primeiro foi colocado em órbita em 1999, o segundo, quatro anos depois. Os dois circundam o planeta em uma órbita de polo a polo tirando fotografias sincronizadas para que Terra sobrevoe o equador de manhã e Aqua o faça pela tarde em sentido oposto. A cada dois dias fotografam todo o planeta em alta resolução.
As regiões equatoriais são as de maior concentração anual de nuvens e menor variação mensal
Com esse alcance global e uma resolução de até menos de um quilômetro, os dois pesquisadores criaram seu atlas das nuvens. Em sua versão online é possível observar a frequência anual de nebulosidade, entendida como a porcentagem de dias com mais nuvens do que claros, em cada latitude. Também se observa a variação mensal, por estação e anual.
Em um primeiro olhar (ver fotografia), é possível observar uma correlação entre a latitude e padrões de nebulosidade. Dessa forma, a América equatorial, a bacia do rio Congo na África e o sudeste da Ásia são as regiões com mais nuvens do planeta, até 80% dos dias são nublados. Mesmo que as espécies que habitam esses grandes biomas possam ser diferentes, são ecossistemas que possuem diversas características em comum.
O mapa permite observar também a variação inter-anual. Enquanto as selvas equatoriais apresentam poucas variações que nunca superam 5% de um mês ao outro, os biomas monçônicos da Índia e o sahel africano são os que sofrem maiores diferenças entre os meses nublados e os claros, o que corresponde à temporada de chuvas e a temporada seca.
“Quando visualizamos os dados, destacou-se a claridade com a qual pudemos ver os muitos e diferentes biomas da Terra tendo por base a frequência e o momento dos dias nublados dos últimos 15 anos”, diz Wilson. “Quando passamos de um ecossistema a outro, essas transições mostram-se muito claramente e o melhor é que esses dados permitem observar diretamente esses padrões com uma resolução de um quilômetro”, acrescenta.
O mapa mostra a distribuição das nuvens desde 1999. Em negro as áreas com maior nebulosidade anual. As diferentes cores e sua intensidade mostram as variações mensais. Adam Wilson
Essa resolução é uma das maiores contribuições da pesquisa. Pode ser óbvio que a bacia do Congo tenha muitos dias com nuvens, mas com as imagens de satélites é possível observar as diferenças locais, entre a margem norte e sul de um rio e as encostas leste e oeste de uma montanha, por exemplo. Era possível conseguir esse grau de detalhamento nas áreas mais desenvolvidas do planeta, mas não nas menos, que são exatamente as que possuem maior riqueza biológica.
Até agora, os estudos sobre biodiversidade eram baseados na observação direta dos pesquisadores (e, portanto, muito parcial) e as extrapolações de outros sistemas de coleta de dados. Um dos maiores são as estações meteorológicas que, com seus dados de umidade, vento, precipitações, desenham a paisagem climática nas quais vivem as diferentes espécies. Mas a rede de estações também não é suficientemente compacta, de modo que os cientistas precisam interpolar a partir de dados às vezes muito locais e dispersos.
O atlas das nuvens indicou a distribuição geográfica da protea real (sua flor na imagem), um arbusto da faixa de clima mediterrâneo da África do Sul. Adam Wilson
“Compreender os padrões espaciais da biodiversidade é fundamental se queremos tomar decisões balizadas sobre como proteger as espécies e gerir a biodiversidade e seus muitos serviços para o futuro”, diz Jetz. Mas acrescenta: “para as regiões que possuem mais diversidade biológica, existe uma escassez real de dados dos locais”.
Esse estudo original, publicado na PLoS Biology, mostra também a íntima e frágil relação entre as nuvens e os chamados bosques nublados. É que essas selvas com a presença constante ou pelo menos regular de nuvens baixas como nevoeiro também não escapam à detecção dos satélites. Essas regiões são ricas em endemismos, de modo que a alteração dos padrões de nebulosidade pela ação humana e a mudança climática pode ter consequências catastróficas.
Os pesquisadores, que não pretendem substituir os modelos existentes, mas acrescentar mais uma camada de conhecimento, quiseram comprovar a validade de seu atlas das nuvens para indicar não só os limites de um determinado ecossistema, mas a distribuição geográfica de duas espécies. Uma é o pequeno trepatroncos montano, um pássaro das selvas montanhosas do norte da América do Sul. A outra é a protea real, um arbusto da região de clima mediterrâneo da África do Sul. Nos dois casos, o que viram nas nuvens foi mais preciso do que os dados oferecidos pelos modelos baseados em registros de precipitações e temperatura.
(Ian Hatton et al, Science Advances, 2021)
(Ian Hatton et al, Science Advances, 2021)
Poluição à vista: os resíduos que vazaram do reservatório de Mariana formam mancha acastanhada na foz do rio Doce.
Uma (in)certa antropologia 
Você precisa fazer login para comentar.