Arquivo mensal: novembro 2015
Isabelle Stengers’ new book available open access
Isabelle Stengers’ new book, In Catastrophic Times, is available for free as a .pdf download at this site. Here is a description of the book (which you can also buy in hard copy as well following the link above):
There has been an epochal shift: the possibility of a global climate crisis is now upon us. Pollution, the poison of pesticides, the exhaustion of natural resources, falling water tables, growing social inequalities – these are all problems that can no longer be treated separately. The effects of global warming have a cumulative impact, and it is not a matter of a crisis that will “pass” before everything goes back to “normal.”
Our governments are totally incapable of dealing with the situation. Economic warfare obliges them to stick to the goal of irresponsible, even criminal, economic growth, whatever the cost. It is no surprise that people were so struck…
Ver o post original 32 mais palavras
Ancient viral molecules essential for human development (Science Daily)
Date: November 23, 2015
Source: Stanford University Medical Center
Summary: Genetic material from ancient viral infections is critical to human development, according to researchers.
Genetic material from ancient viral infections is critical to human development, according to researchers at the Stanford University School of Medicine.
They’ve identified several noncoding RNA molecules of viral origins that are necessary for a fertilized human egg to acquire the ability in early development to become all the cells and tissues of the body. Blocking the production of this RNA molecule stops development in its tracks, they found.
The discovery comes on the heels of a Stanford study earlier this year showing that early human embryos are packed full of what appear to be viral particles arising from similar left-behind genetic material.
“We’re starting to accumulate evidence that these viral sequences, which originally may have threatened the survival of our species, were co-opted by our genomes for their own benefit,” said Vittorio Sebastiano, PhD, an assistant professor of obstetrics and gynecology. “In this manner, they may even have contributed species-specific characteristics and fundamental cell processes, even in humans.”
Sebastiano is a co-lead and co-senior author of the study, which will be published online Nov. 23 in Nature Genetics. Postdoctoral scholar Jens Durruthy-Durruthy, PhD, is the other lead author. The other senior author of the paper is Renee Reijo Pera, PhD, a former professor of obstetrics and gynecology at Stanford who is now on the faculty of Montana State University.
Sebastiano and his colleagues were interested in learning how cells become pluripotent, or able to become any tissue in the body. A human egg becomes pluripotent after fertilization, for example. And scientists have learned how to induce other, fully developed human cells to become pluripotent by exposing them to proteins known to be present in the very early human embryo. But the nitty-gritty molecular details of this transformative process are not well understood in either case.
An ancient infection
The researchers knew that a type of RNA molecules called long-intergenic noncoding, or lincRNAs, have been implicated in many important biological processes, including the acquisition of pluripotency. These molecules are made from DNA in the genome, but they don’t go on to make proteins. Instead they function as RNA molecules to affect the expression of other genes.
Sebastiano and Durruthy-Durruthy used recently developed RNA sequencing techniques to examine which lincRNAs are highly expressed in human embryonic stem cells. Previously, this type of analysis was stymied by the fact that many of the molecules contain highly similar, very repetitive regions that are difficult to sequence accurately.
They identified more than 2,000 previously unknown RNA sequences, and found that 146 are specifically expressed in embryonic stem cells. They homed in on the 23 most highly expressed sequences, which they termed HPAT1-23, for further study. Thirteen of these, they found, were made up almost entirely of genetic material left behind after an eons-ago infection by a virus called HERV-H.
HERV-H is what’s known as a retrovirus. These viruses spread by inserting their genetic material into the genome of an infected cell. In this way, the virus can use the cell’s protein-making machinery to generate viral proteins for assembly into a new viral particle. That particle then goes on to infect other cells. If the infected cell is a sperm or an egg, the retroviral sequence can also be passed to future generations.
HIV is one common retrovirus that currently causes disease in humans. But our genomes are also littered with sequences left behind from long-ago retroviral infections. Unlike HIV, which can go on to infect new cells, these retroviral sequences are thought to be relatively inert; millions of years of evolution and accumulated mutations mean that few maintain the capacity to give instructions for functional proteins.
After identifying HPAT1-23 in embryonic stem cells, Sebastiano and his colleagues studied their expression in human blastocysts — the hollow clump of cells that arises from the egg in the first days after fertilization. They found that HPAT2, HPAT3 and HPAT5 were expressed only in the inner cell mass of the blastocyst, which becomes the developing fetus. Blocking their expression in one cell of a two-celled embryo stopped the affected cell from contributing to the embryo’s inner cell mass. Further studies showed that the expression of the three genes is also required for efficient reprogramming of adult cells into induced pluripotent stem cells.
Sequences found only in primates
“This is the first time that these virally derived RNA molecules have been shown to be directly involved with and necessary for vital steps of human development,” Sebastiano said. “What’s really interesting is that these sequences are found only in primates, raising the possibility that their function may have contributed to unique characteristics that distinguish humans from other animals.”
The researchers are continuing their studies of all the HPAT molecules. They’ve learned that HPAT-5 specifically affects pluripotency by interacting with and sequestering members of another family of RNAs involved in pluripotency called let-7.
“Previously retroviral elements were considered to be a class that all functioned in basically the same way,” said Durruthy-Durruthy. “Now we’re learning that they function as individual elements with very specific and important roles in our cells. It’s fascinating to imagine how, during the course of evolution, primates began to recycle these viral leftovers into something that’s beneficial and necessary to our development.”
- Jens Durruthy-Durruthy, Vittorio Sebastiano, Mark Wossidlo, Diana Cepeda, Jun Cui, Edward J Grow, Jonathan Davila, Moritz Mall, Wing H Wong, Joanna Wysocka, Kin Fai Au, Renee A Reijo Pera. The primate-specific noncoding RNA HPAT5 regulates pluripotency during human preimplantation development and nuclear reprogramming. Nature Genetics, 2015; DOI: 10.1038/ng.3449
Army ants’ ‘living’ bridges span collective intelligence, ‘swarm’ robotics (Science Daily)
Date: November 24, 2015
Source: Princeton University
Summary: Researchers report for the first time that the ‘living’ bridges army ants of the species Eciton hamatum build with their bodies are more sophisticated than scientists knew. The ants automatically assemble with a level of collective intelligence that could provide new insights into animal behavior and even help in the development of intuitive robots that can cooperate as a group.
Without any orders or direction, individuals from the rank and file instinctively stretch across the opening, clinging to one another as their comrades-in-arms swarm across their bodies. But this is no force of superhumans. They are army ants of the species Eciton hamatum, which form “living” bridges across breaks and gaps in the forest floor that allow their famously large raiding swarms to travel efficiently.
Researchers from Princeton University and the New Jersey Institute of Technology (NJIT) report for the first time that these structures are more sophisticated than scientists knew. The ants exhibit a level of collective intelligence that could provide new insights into animal behavior and even help in the development of intuitive robots that can cooperate as a group, the researchers said.
Ants of E. hamatum automatically form living bridges without any oversight from a “lead” ant, the researchers report in the journal Proceedings of the National Academy of the Sciences. The action of each individual coalesces into a group unit that can adapt to the terrain and also operates by a clear cost-benefit ratio. The ants will create a path over an open space up to the point when too many workers are being diverted from collecting food and prey.
“These ants are performing a collective computation. At the level of the entire colony, they’re saying they can afford this many ants locked up in this bridge, but no more than that,” said co-first author Matthew Lutz, a graduate student in Princeton’s Department of Ecology and Evolutionary Biology.
“There’s no single ant overseeing the decision, they’re making that calculation as a colony,” Lutz said. “Thinking about this cost-benefit framework might be a new insight that can be applied to other animal structures that people haven’t thought of before.”
The research could help explain how large groups of animals balance cost and benefit, about which little is known, said co-author Iain Couzin, a Princeton visiting senior research scholar in ecology and evolutionary biology, and director of the Max Planck Institute for Ornithology and chair of biodiversity and collective behavior at the University of Konstanz in Germany.
Previous studies have shown that single creatures use “rules of thumb” to weigh cost-and-benefit, said Couzin, who also is Lutz’s graduate adviser. This new work shows that in large groups these same individual guidelines can eventually coordinate group-wide, he said — the ants acted as a unit although each ant only knew its immediate circumstances.
“They don’t know how many other ants are in the bridge, or what the overall traffic situation is. They only know about their local connections to others, and the sense of ants moving over their bodies,” Couzin said. “Yet, they have evolved simple rules that allow them to keep reconfiguring until, collectively, they have made a structure of an appropriate size for the prevailing conditions.
“Finding out how sightless ants can achieve such feats certainly could change the way we think of self-configuring structures in nature — and those made by man,” he said.
Ant-colony behavior has been the basis of algorithms related to telecommunications and vehicle routing, among other areas, explained co-first author Chris Reid, a postdoctoral research associate at the University of Sydney who conducted the work while at NJIT. Ants exemplify “swarm intelligence,” in which individual-level interactions produce coordinated group behavior. E. hamatum crossings assemble when the ants detect congestion along their raiding trail, and disassemble when normal traffic has resumed.
Previously, scientists thought that ant bridges were static structures — their appearance over large gaps that ants clearly could not cross in midair was somewhat of a mystery, Reid said. The researchers found, however, that the ants, when confronted with an open space, start from the narrowest point of the expanse and work toward the widest point, expanding the bridge as they go to shorten the distance their compatriots must travel to get around the expanse.
“The amazing thing is that a very elegant solution to a colony-level problem arises from the individual interactions of a swarm of simple worker ants, each with only local information,” Reid said. “By extracting the rules used by individual ants about whether to initiate, join or leave a living structure, we could program swarms of simple robots to build bridges and other structures by connecting to each other.
“These robot bridges would exhibit the beneficial properties we observe in the ant bridges, such as adaptability to local conditions, real-time optimization of shape and position, and rapid construction and deconstruction without the need for external building materials,” Reid continued. “Such a swarm of robots would be especially useful in dangerous and unpredictable conditions, such as natural disaster zones.”
Radhika Nagpal, a professor of computer science at Harvard University who studies robotics and self-organizing biological systems, said that the findings reveal that there is “something much more fundamental about how complex structures are assembled and adapted in nature, and that it is not through a supervisor or planner making decisions.”
Individual ants adjusted to one another’s choices to create a successful structure, despite the fact that each ant didn’t necessarily know everything about the size of the gap or the traffic flow, said Nagpal, who is familiar with the research but was not involved in it.
“The goal wasn’t known ahead of time, but ‘emerged’ as the collective continually adapted its solution to the environmental factors,” she said. “The study really opens your eyes to new ways of thinking about collective power, and has tremendous potential as a way to think about engineering systems that are more adaptive and able to solve complex cost-benefit ratios at the network level just through peer-to-peer interactions.”
She compared the ant bridges to human-made bridges that automatically widened to accommodate heavy vehicle traffic or a growing population. While self-assembling road bridges may be a ways off, the example illustrates the potential that technologies built with the same self-assembling capabilities seen in E. hamatum could have.
“There’s a deep interest in creating robots that don’t just rely on themselves, but can exploit the group to do more — and self-assembly is the ultimate in doing more,” Nagpal said. “If you could have small simple robots that were able to navigate complex spaces, but could self-assemble into larger structures — bridges, towers, pulling chains, rafts — when they face something they individually did not have the ability to do, that’s a huge increase in power in what robots would be capable of.”
The spaces E. hamatum bridges are not dramatic by human standards — small rifts in the leaf cover, or between the ends of two sticks. Bridges will be the length of 10 to 20 ants, which is only a few centimeters, Lutz said. That said, E. hamatum swarms form several bridges during the course of a day, which can see the back-and-forth of thousands of ants.
“The bridges are something that happen numerous times every day. They’re creating bridges to optimize their traffic flow and maximize their time,” Lutz said.
“When you’re moving hundreds of thousands of ants, creating a little shortcut can save a lot of energy,” he said. “This is such a unique behavior. You have other types of ants forming structures out of their bodies, but it’s not such a huge part of their lives and daily behavior.”
The research also included Scott Powell, an army-ant expert and assistant professor of biology at George Washington University; Albert Kao, a postdoctoral fellow at Harvard who received his doctorate in ecology and evolutionary biology from Princeton in 2015; and Simon Garnier, an assistant professor of biological sciences at NJIT who studies swarm intelligence and was once a postdoctoral researcher in Couzin’s lab at Princeton.
To conduct their field experiments, Lutz and Reid constructed a 1.5-foot-tall apparatus with ramps on both sides and adjustable arms in the center with which they could adjust the size of the gap. They then inserted the apparatus into active E. hamatum raiding trails that they found in the forests of Barro Colorado Island, Panama. Because ants follow one another’s chemical scent, Lutz and Reid used sticks and leaves from the ants’ trail to get them to reform their column across the device.
Lutz and Reid observed how the ants formed bridges across gaps that were set at angles of 12, 20, 40 and 60 degrees. They gauged how much travel-distance the ants saved with their bridge versus the surface area (in centimeters squared) of the bridge itself. Twelve-degree angles shaved off the most distance (around 11 centimeters) while taking up the fewest workers. Sixty-degree angles had the highest cost-to-benefit ratio. Interestingly, the ants were willing to expend members for 20-degree angles, forming bridges up to 8 centimeters squared to decrease their travel time by almost 12 centimeters, indicating that the loss in manpower was worth the distance saved.
Lutz said that future research based on this work might compare these findings to the living bridges of another army ant species, E. burchellii, to determine if the same principles are in action.
The paper, “Army ants dynamically adjust living bridges in response to a cost-benefit trade-off,” was published Nov. 23 by Proceedings of the National Academy of Sciences. The work was supported by the National Science Foundation (grant nos. PHY-0848755, IOS0-1355061 and EAGER IOS-1251585); the Army Research Office (grant nos. W911NG-11-1-0385 and W911NF-14-1-0431); and the Human Frontier Science Program (grant no. RGP0065/2012).
- Chris R. Reid, Matthew J. Lutz, Scott Powell, Albert B. Kao, Iain D. Couzin, Simon Garnier. Army ants dynamically adjust living bridges in response to a cost–benefit trade-off. Proceedings of the National Academy of Sciences, 2015; 201512241 DOI: 10.1073/pnas.1512241112
Congresso pode votar projetos que fragilizam proteção ambiental a desastres como o de Mariana (ISA)
JC 5309, 25 de novembro de 2015
Proposta de “rito sumário” para licenciamento ambiental de empreendimentos “estratégicos” do governo pode ser votada nesta quarta (25/11). Novo Código de Mineração também pode ser votado nas próximas semanas sem garantir proteção ao meio ambiente e populações afetadas pela atividade minerária
Uma comissão do Senado pode votar, na tarde desta quarta (25/11), um projeto que fragiliza o principal instrumento para evitar desastres ambientais, o licenciamento ambiental. A Câmara também pode apreciar, nas próximas semanas, o novo Código de Mineração, que promete estimular como nunca a atividade no País, mas não traz salvaguardas que protejam efetivamente o meio ambiente e populações afetadas.
As duas votações podem acontecer poucos dias depois do rompimento de uma barragem de rejeitos de mineração da empresa Samarco, que destruiu o distrito de Bento Rodrigues, em Mariana (MG), afetou dezenas de outros municípios entre Minas Gerais e Espírito Santo, lançou uma onda de lama ao longo do Rio Doce, praticamente destruindo seus ecossistemas, e agora deverá causar impactos ambientais graves na costa capixaba, naquela que já é considerada a maior tragédia ambiental do País. Denúncias dão conta de que o licenciamento ambiental da barragem deveria ter sido mais rigoroso. A Samarco pertence à Vale e à mineradora anglo-australiana BHP Billiton.
Por enquanto, já foram registradas 12 mortes e 11 pessoas continuam desaparecidas. A onda de lama interrompeu o fornecimento de água de pelos menos 500 mil pessoas entre os dois estados. Ainda não se sabe toda a extensão dos danos, mas os custos de reparação devem passar do patamar de bilhões de reais. Não há previsão para a recuperação dos ecossistemas ao longo do rio.
A proposta que pode ser votada nesta quarta é o Projeto de Lei do Senado (PLS) 654/2015, de autoria do senador Romero Jucá (PMDB-RR). Ele cria um “rito sumário” para o licenciamento ambiental de empreendimentos que sejam considerados “estratégicos” pelo Poder Executivo federal ou estadual, por meio de decreto. A proposta estabelece uma licença ambiental única a ser concedida em torno de oito meses, sem previsão de audiências públicas. Poderiam ser classificados como “estratégicos” empreendimentos como extração de minério, estradas, ferrovias, aeroportos, hidrelétricas, portos e linhas de comunicação.
A tendência é que, se aprovado o projeto, teriam um licenciamento acelerado obras complexas com grandes impactos, justamente aquelas que especialistas e organizações da sociedade civil consideram que necessitam de processos de licenciamento mais cautelosos e eficazes.
“É um completo contrassenso que o Senado possa aprovar um projeto que pretende reduzir drasticamente a prevenção de danos socioambientais como os ocorridos após o rompimento da barragem da Samarco”, critica Maurício Guetta, advogado do ISA. “O caso de Mariana, a exemplo de outros tantos, deveria servir de lição para que o Congresso e o Poder Executivo aprimore o licenciamento ambiental, evitando a ocorrência de danos irreparáveis. Flexibilizá-lo será prejudicial a todos: meio ambiente, populações afetadas, governos e o próprio empresariado.”
O relator da matéria é o senador Blairo Maggi (PR-MT). O projeto está na Comissão Especial de Desenvolvimento Nacional em caráter terminativo, ou seja, se aprovado segue diretamente para a Câmara sem passar pelo plenário do Senado. Os parlamentares podem, porém, aprovar um recurso para levar a proposta ao plenário. Essa comissão recebeu as propostas da chamada “Agenda Brasil”, iniciativa do presidente do Senado, Renan Calheiros (PMDB-AL), que supostamente visaria a enfrentar a crise econômica.
As assessorias do líder do governo no Senado, Delcídio Amaral (PT-S), e de Maggi responderam que os parlamentares não poderiam conceder entrevistas até o fechamento desta reportagem.
Código de Mineração
O presidente da Câmara, Eduardo Cunha (PMDB-RJ), manifestou, há alguns dias, a intenção de levar o Projeto de Lei 37/2011, o novo Código de Mineração, diretamente ao plenário, atalhando sua tramitação (saiba mais). O parecer sobre a proposta ainda não foi oficialmente apresentado e discutido pelos deputados na Comissão Especial que o analisava.
Sob a justificativa de simplificar e liberalizar a burocracia relacionada à mineração, o relator, deputado Leonardo Quintão (PMDB-MG), apresentou um parecer preliminar que aprofunda retrocessos para o meio ambiente e os direitos de comunidades indígenas e tradicionais impactadas pela atividade. Segundo Quintão, esse relatório teria sido elaborado junto com técnicos do Ministério de Minas e Energia e teria apoio do Planalto (leia mais). A assessoria do líder do governo na Câmara, José Guimarães (PT-CE), informou que ele só vai se pronunciar sobre o projeto quando for apresentado um relatório final.
Quintão vem argumentando que sua proposta não reforça salvaguardas ambientais, sociais e trabalhistas porque já há legislações específicas que as garantiriam. Ele também afirma que o parecer assegura recursos para as comunidades afetadas por meio de verbas que serão destinadas aos municípios que abrigam empreendimentos de mineração. Sem explicitar e detalhar formas de compensação e proteção socioambientais, no entanto, o relatório não garante os direitos de populações específicas diretamente atingidas.
Depois do desastre de Mariana, ao invés de adiar a votação de seu parecer para reavaliá-la, Quintão vem empenhando esforços para acelerar a tramitação da matéria. O deputado limitou-se a prometer algumas mudanças em seu relatório. O site do parlamentar afirma que ele irá incluir na proposta um “seguro antidanos” obrigatório para “cobrir prejuízos ao meio ambiente, às pessoas, à infraestrutura urbana e à economia local em caso de catástrofes”. Também promete estabelecer a exigência de que as mineradoras apresentem planos para o tratamento de resíduos de barragem que permitam sua reutilização.
Para Maurício Guetta, essas medidas são insuficientes e deixam de contemplar ações preventivas para evitar tragédias como a de Mariana. “Faz mais de dois anos que cobramos do relator alterações substanciais no texto, para que sejam incluídas medidas de prevenção de danos decorrentes das atividades minerárias e para que sejam garantidos os direitos das populações afetadas e dos trabalhadores. Mesmo após o desastre de Mariana, ele continua a ignorar as demandas apresentadas”, denuncia Guetta.
Gut microbes signal to the brain when they’re full (Science Daily)
Date: November 24, 2015
- Source: Cell Press
Summary: Don’t have room for dessert? The bacteria in your gut may be telling you something. Twenty minutes after a meal, gut microbes produce proteins that can suppress food intake in animals, reports a study. The researchers also show how these proteins injected into mice and rats act on the brain reducing appetite, suggesting that gut bacteria may help control when and how much we eat.
Don’t have room for dessert? The bacteria in your gut may be telling you something. Twenty minutes after a meal, gut microbes produce proteins that can suppress food intake in animals, reports a study published November 24 in Cell Metabolism. The researchers also show how these proteins injected into mice and rats act on the brain reducing appetite, suggesting that gut bacteria may help control when and how much we eat.
The new evidence coexists with current models of appetite control, which involve hormones from the gut signalling to brain circuits when we’re hungry or done eating. The bacterial proteins–produced by mutualistic E. coli after they’ve been satiated–were found for the first time to influence the release of gut-brain signals (e.g., GLP-1 and PYY) as well as activate appetite-regulated neurons in the brain.
“There are so many studies now that look at microbiota composition in different pathological conditions but they do not explore the mechanisms behind these associations,” says senior study author Sergueï Fetissov of Rouen University and INSERM’s Nutrition, Gut & Brain Laboratory in France. “Our study shows that bacterial proteins from E. coli can be involved in the same molecular pathways that are used by the body to signal satiety, and now we need to know how an altered gut microbiome can affect this physiology.”
Mealtime brings an influx of nutrients to the bacteria in your gut. In response, they divide and replace any members lost in the development of stool. The study raises an interesting theory: since gut microbes depend on us for a place to live, it is to their advantage for populations to remain stable. It would make sense, then, if they had a way to communicate to the host when they’re not full, promoting host to ingest nutrients again.
In the laboratory, Fetissov and colleagues found that after 20 minutes of consuming nutrients and expanding numbers, E. coli bacteria from the gut produce different kinds of proteins than they did before their feeding. The 20 minute mark seemed to coincide with the amount of time it takes for a person to begin feeling full or tired after a meal. Excited over this discovery, the researcher began to profile the bacterial proteins pre- and post-feeding.
They saw that injection of small doses of the bacterial proteins produced after feeding reduced food intake in both hungry and free-fed rats and mice. Further analysis revealed that “full” bacterial proteins stimulated the release of peptide YY, a hormone associated with satiety, while “hungry” bacterial hormones did not. The opposite was true for glucagon-like peptide-1 (GLP-1), a hormone known to simulate insulin release.
The investigators next developed an assay that could detect the presence of one of the “full” bacterial proteins, called ClpB in animal blood. Although blood levels of the protein in mice and rats detected 20 minutes after meal consumption did not change, it correlated with ClpB DNA production in the gut, suggesting that it may link gut bacterial composition with the host control of appetite. The researchers also found that ClpB increased firing of neurons that reduce appetite. The role of other E.coli proteins in hunger and satiation, as well as how proteins from other species of bacteria may contribute, is still unknown.
“We now think bacteria physiologically participate in appetite regulation immediately after nutrient provision by multiplying and stimulating the release of satiety hormones from the gut,” Fetisov says. “In addition, we believe gut microbiota produce proteins that can be present in the blood longer term and modulate pathways in the brain.”
- Jonathan Breton, Naouel Tennoune, Nicolas Lucas, Marie Francois, Romain Legrand, Justine Jacquemot, Alexis Goichon, Charlène Guérin, Johann Peltier, Martine Pestel-Caron, Philippe Chan, David Vaudry, Jean-Claude do Rego, Fabienne Liénard, Luc Pénicaud, Xavier Fioramonti, Ivor S. Ebenezer, Tomas Hökfelt, Pierre Déchelotte, Sergueï O. Fetissov. Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth. Cell Metabolism, 2015; DOI: 10.1016/j.cmet.2015.10.017
Pecuária é responsável por 15% dos gases do efeito estufa (O Globo)
Renato Grandelle, 24/11/2015
Desmatamento na Região de Xapuri no Acre – Gustavo Stephan/ 05-12-2013
RIO— Parte expressiva da liberação de carbono na atmosfera fica bem longe da fumaça liberada por usinas ou carros. Um novo estudo do Chatham House, o Real Instituto de Relações Internacionais do Reino Unido, indica que cerca de 15% dos poluentes que levam ao aquecimento global são provenientes da pecuária — seja pelo metano da digestão e estrume dos animais, ou pela produção de culturas para alimentação. De acordo com o relatório “Mudanças climáticas, mudanças na alimentação”, reduzir a quantidade de carne no prato é fundamental para assegurar que a temperatura global não avance mais do que 2 graus Celsius neste século.
O planeta, porém, ignora a recomendação. Estima-se que, com o aumento da classe média nos países em desenvolvimento — especialmente na China e no Brasil —, o consumo de carne crescerá até 76% nos próximos 35 anos.
Mudar a alimentação pode cortar pela metade os custos das futuras medidas contra o aquecimento global. E o clima não será a única área favorecida pela nova dieta. Coautora do estudo, Laura Wellesley ressalta que conter o consumo exagerado de carne também traz benefícios imediatos à saúde.
— Não estamos sugerindo que todo mundo deve se tornar vegetariano. A carne, consumida com moderação, pode fazer parte de uma dieta saudável para o indivíduo e o meio ambiente — ressalta. — De acordo com a Escola de Medicina de Harvard, a porção diária não deve ultrapassar 70 gramas, que é um hambúrguer de tamanho médio. Se nada for feito para nos limitarmos a este valor, os padrões alimentares atuais serão incompatíveis com o aumento de temperatura de apenas 2 graus Celsius.
DIETA SAUDÁVEL FORA DA COP-21
Atualmente, o consumo dos brasileiros é de duas vezes e meia a quantidade diária recomendada; nos EUA, é de três vezes mais. Um estudo divulgado em outubro pela Organização Mundial de Saúde alertou que a ingestão exagerada de carnes vermelhas e processadas pode levar à ocorrência de doenças não transmissíveis, principalmente o câncer.
— Mudanças de alimentação devem estar no topo da lista das discussões na Conferência do Clima de Paris (COP-21). É uma estratégia rápida e econômica para conter as emissões de gases-estufa — avalia Laura.
Ainda assim, o debate sobre a dieta mundial deve ficar fora da mesa de negociações da COP-21. Para os pesquisadores do Chatham House, os governos temem que campanhas reivindicando limitações ao consumo de carne desagradem a opinião pública e a indústria de alimentos.
Desde o início do ano, cerca de 150 países apresentaram à ONU metas voluntárias para cortar a emissão de gases de efeito estufa. A diminuição do consumo de carne não foi mencionada em nenhum projeto.
— Como são cautelosos em assumir um risco, os governos têm favorecido a inércia e permanecem em silêncio sobre a questão das dietas sustentáveis — lamenta Laura. — As pesquisas revelam que inicialmente muitas pessoas não gostam da ideia de comer menos carne, e por isso são resistentes à ideia de intervenção do poder público. No entanto, depois que são informadas sobre a relação entre dieta e clima, a maioria recomenda que o governo promova intervenções e forneça orientações e incentivos para a mudança na alimentação.
No Brasil, diz o levantamento, a população sente orgulho da pecuária, mas demonstra preocupação com sua potencial expansão desordenada para a Floresta Amazônica. A pecuária é uma das atividades econômicas mais importantes do país — representa 6,8% do PIB —, mas também corresponde a uma das mais ineficientes do mundo, já que é baseada na prática extensiva. Os lucros estão no tamanho da área usada, e não na eficiência produtiva. No Cerrado há, em média, apenas 1 boi por hectare — estima-se que é possível triplicar esta ocupação sem qualquer comprometimento dos rendimentos do setor.
A força econômica da pecuária e o hábito do consumo exagerado de carne — a “tradição do churrasco de fim de semana”, como destaca o Chatham House — são os maiores obstáculos para que o governo federal desenvolva projetos que promovam a alimentação saudável e, ao mesmo tempo, aumente o alerta da população contra as mudanças climáticas. O brasileiro é conhecido como um dos povos mais preocupados no mundo com o aquecimento global, mas nunca foi informado sobre sua ligação com mudanças na dieta.
Climate policy: Democracy is not an inconvenience (Nature)
NATURE | COMMENT
22 September 2015
Climate scientists are tiring of governance that does not lead to action. But democracy must not be weakened in the fight against global warming, warns Nico Stehr.
Illustration by David Parkins
There are many threats to democracy in the modern era. Not least is the risk posed by the widespread public feeling that politicians are not listening. Such discontent can be seen in the political far right: the Tea Party movement in the United States, the UK Independence Party, the Pegida (Patriotic Europeans Against the Islamization of the West) demonstrators in Germany, and the National Front in France.
More surprisingly, a similar impatience with the political elite is now also present in the scientific community. Researchers are increasingly concerned that no one is listening to their diagnosis of the dangers of human-induced climate change and its long-lasting consequences, despite the robust scientific consensus. As governments continue to fail to take appropriate political action, democracy begins to look to some like an inconvenient form of governance. There is a tendency to want to take decisions out of the hands of politicians and the public, and, given the ‘exceptional circumstances’, put the decisions into the hands of scientists themselves.
This scientific disenchantment with democracy has slipped under the radar of many social scientists and commentators. Attention is urgently needed: the solution to the intractable ‘wicked problem’ of global warming is to enhance democracy, not jettison it.
Voices of discontent
Democratic nations seem to have failed us in the climate arena so far. The past decade’s climate summits in Copenhagen, Cancun, Durban and Warsaw were political washouts. Expectations for the next meeting in Paris this December are low.
Academics increasingly point to democracy as a reason for failure. NASA climate researcher James Hansen was quoted in 2009 in The Guardian as saying: “the democratic process doesn’t quite seem to be working”1. In a special issue of the journal Environmental Politics in 2010, political scientist Mark Beeson argued2 that forms of ‘good’ authoritarianism “may become not only justifiable, but essential for the survival of humanity in anything approaching a civilised form”. The title of an opinion piece published earlier this year in The Conversation, an online magazine funded by universities, sums up the issue: ‘Hidden crisis of liberal democracy creates climate change paralysis’ (see go.nature.com/pqgysr).
The depiction of contemporary democracies as ill-equipped to deal with climate change comes from a range of considerations. These include a deep-seated pessimism about the psychological make-up of humans; the disinclination of people to mobilize on issues that seem far removed; and the presumed lack of intellectual competence of people to grasp complex issues. On top of these there is the presumed scientific illiteracy of most politicians and the electorate; the inability of governments locked into short-term voting cycles to address long-term problems; the influence of vested interests on political agendas; the addiction to fossil fuels; and the feeling among the climate-science community that its message falls on the deaf ears of politicians.
“It is dangerous to blindly believe that science and scientists alone can tell us what to do.”
Such views can be heard from the highest ranks of climate science. Hans Joachim Schellnhuber, founding director of the Potsdam Institute for Climate Impact Research and chair of the German Advisory Council on Global Change, said of the inaction in a 2011 interview with German newspaper Der Spiegel: “comfort and ignorance are the biggest flaws of human character. This is a potentially deadly mix”.
What, then, is the alternative? The solution hinted at by many people leans towards a technocracy, in which decisions are made by those with technical knowledge. This can be seen in a shift in the statements of some co-authors of Intergovernmental Panel on Climate Change reports, who are moving away from a purely advisory role towards policy prescription (see, for example, ref. 3).
We must be careful what we wish for. Nations that have followed the path of ‘authoritarian modernization’, such as China and Russia, cannot claim to have a record of environmental accomplishments. In the past two or three years, China’s system has made it a global leader in renewables (it accounts for more than one-quarter of the planet’s investment in such energies4). Despite this, it is struggling to meet ambitious environmental targets and will continue to lead the world for some time in greenhouse-gas emissions. As Chinese citizens become wealthier and more educated, they will surely push for more democratic inclusion in environmental policymaking.
Broad-based support for environmental concerns and subsequent regulations came about in open democratic argument on the value of nature for humanity. Democracies learn from mistakes; autocracies lack flexibility and adaptability5. Democratic nations have forged the most effective international agreements, such as the Montreal Protocol against ozone-depleting substances.
Impatient scientists often privilege hegemonic players such as world powers, states, transnational organizations, and multinational corporations. They tend to prefer sweeping policies of global mitigation over messier approaches of local adaptation; for them, global knowledge triumphs over local know-how. But societal trends are going in the opposite direction. The ability of large institutions to impose their will on citizens is declining. People are mobilizing around local concerns and efforts6.
The pessimistic assessment of the ability of democratic governance to cope with and control exceptional circumstances is linked to an optimistic assessment of the potential of large-scale social and economic planning. The uncertainties of social, political and economic events are treated as minor obstacles that can be overcome easily by implementing policies that experts prescribe. But humanity’s capacity to plan ahead effectively is limited. The centralized social and economic planning concept, widely discussed decades ago, has rightly fallen into disrepute7.
The argument for an authoritarian political approach concentrates on a single effect that governance ought to achieve: a reduction of greenhouse-gas emissions. By focusing on that goal, rather than on the economic and social conditions that go hand-in-hand with it, climate policies are reduced to scientific or technical issues. But these are not the sole considerations. Environmental concerns are tightly entangled with other political, economic and cultural issues that both broaden the questions at hand and open up different ways of approaching it. Scientific knowledge is neither immediately performative nor persuasive.
There is but one political system that is able to rationally and legitimately cope with the divergent political interests affected by climate change and that is democracy. Only a democratic system can sensitively attend to the conflicts within and among nations and communities, decide between different policies, and generally advance the aspirations of different segments of the population. The ultimate and urgent challenge is that of enhancing democracy, for example by reducing social inequality8.
If not, the threat to civilization will be much more than just changes to our physical environment. The erosion of democracy is an unnecessary suppression of social complexity and rights.
The philosopher Friedrich Hayek, who led the debate against social and economic planning in the mid-twentieth century9, noted a paradox that applies today. As science advances, it tends to strengthen the idea that we should “aim at more deliberate and comprehensive control of all human activities”. Hayek pessimistically added: “It is for this reason that those intoxicated by the advance of knowledge so often become the enemies of freedom”10. We should heed his warning. It is dangerous to blindly believe that science and scientists alone can tell us what to do.
- Nature 525, 449–450 (24 September 2015) dos:10.1038/525449a
- The Guardian (18 March 2009). ‘Leading climate scientist: “democratic process isn’t working”’
- Environ. Politics 19, 276–294 (2010).
- PLoS ONE http://dx.doi.org/10.1371/journal.pone.0081648 (2013). et al.
- Renewables 2015 Global Status Report ( , 2015). .
- The Confidence Trap: A History of Democracy in Crisis from World War I to the Present (Princeton Univ. Press, 2013).
- Information, Power and Democracy, Liberty is a Daughter of Knowledge (Cambridge Univ. Press, 2015).
- Debating Governance: Authority, Steering, and Democracy (Oxford Univ. Press, 2000).
- The Society of Equals (Harvard Univ. Press, 2013).
- Nature 148, 580–584 (1941).
- The Constitution of Liberty (Routledge, 1960).
Você precisa fazer login para comentar.