Os pontos no gráfico mostram 4040 intervalos de 1 ano para o acumulado de chuva e a variação no estoque total de água (do dia 1º de janeiro de 2003/2004 até hoje). O padrão mostra que mais chuva faz o estoque variar para cima e menos chuva para baixo, como seria de se esperar.
Este e os demais gráficos desta página consideram sempre a capacidade total de armazenamento de água em São Paulo (2,24 trilhões de litros), isto é, a soma dos reservatórios dos Sistemas Cantareira, Alto Tietê, Guarapiranga, Cotia, Rio Grande e Rio Claro. Quer explorar os dados?
A região de chuva acumulada de 1.400 mm a 1.600 mm ao ano concentra a maioria dos pontos observados de 2003 para cá. É para esse padrão usual de chuvas que o sistema foi projetado. Nessa região, o sistema opera sem grandes desvios de seu equilíbrio: máximo de 15% para cima ou para baixo em um ano. Por usar como referência a variação em 1 ano, esse modo de ver os dados elimina a oscilação sazonal de chuvas e destaca as variações climáticas de maior amplitude. Ver padrões ano a ano.
Uma segunda camada de informação no mesmo gráfico são as zonas de risco. A zona vermelha é delimitada pelo estoque atual de água em %. Todos os pontos dentro dessa área (com frequência indicada à direita) representam, portanto, situações que se repetidas levarão ao colapso do sistema em menos de 1 ano. A zona amarela mostra a incidência de casos que se repetidos levarão à diminuição do estoque. Só haverá recuperação efetiva do sistema se ocorrerem novos pontos acima da faixa amarela.
Para contextualizar o momento atual e dar uma ideia de tendência, pontos interligados em azul destacam a leitura adicionada hoje (acumulado de chuva e variação entre hoje e mesmo dia do ano passado) e as leituras de 30, 60 e 90 atrás (em tons progressivamente mais claros).
Discussão a partir de um modelo simples
O ajuste de um modelo linear aos casos observados mostra que existe uma razoável correlação entre o acumulado de chuva e a variação no estoque hídrico, como o esperado.
Ao mesmo tempo, fica clara a grande dispersão de comportamento do sistema, especialmente na faixa de chuvas entre 1.400 mm e 1.500 mm. Acima de 1.600 mm há dois caminhos bem separados, o inferior corresponde ao perído entre 2009 e 2010 quando os reservatórios ficaram cheios e não foi possível estocar a chuva excedente.
Além de uma gestão deliberadamente mais ou menos eficiente da água disponível, podem contribuir para as flutuações observadas as variações combinadas no consumo, nas perdas e na efetividade da captação de água. Entretanto, não há dados para examinarmos separadamente o efeito de cada uma dessas variáveis.
Simulação 1: Efeito do aumento do estoque de água
Nesta simulação foi hipoteticamente incluído no sistema de abastecimento a reserva adicional da represa Billings, com volume de 998 bilhões de litros (já descontados o braço “potável” do reservatório Rio Grande).
Aumentar o estoque disponível não muda o ponto de equilíbrio, mas altera a inclinação da reta que representa a relação entre a chuva e a variação no estoque. A diferença de inclinação entre a linha azul (simulada) e a vermelha (real) mostra o efeito da ampliação do estoque.
Se a Billings não fosse hoje um depósito gigante de esgotos, poderíamos estar fora da situação crítica. Entretanto, vale enfatizar que o simples aumento de estoque não é capaz de evitar indefinidamente a escassez se a quantidade de chuva persistir abaixo do ponto de equilíbrio.
Simulação 2: Efeito da melhoria na eficiência
O único modo de manter o estoque estável quando as chuvas se tornam mais escassas é mudar a ‘curva de eficiência’ do sistema. Em outras palavras, é preciso consumir menos e se adaptar a uma menor entrada de água no sistema.
A linha azul no gráfico ao lado indica o eixo ao redor do qual os pontos precisariam flutuar para que o sistema se equilibrasse com uma oferta anual de 1.200 mm de chuva.
A melhoria da eficiência pode ser alcançada por redução no consumo, redução nas perdas e melhoria na tecnologia de captação de água (por exemplo pela recuperação das matas ciliares e nascentes em torno dos mananciais).
Se persistir a situação desenhada de 2013 a 2015, com chuvas em torno de 1.000 mm será necessário atingir uma curva de eficiência que está muito distante do que já se conseguiu praticar, acima mesmo dos melhores casos já observados.
Com o equilíbrio de “projeto” em torno de 1.500 mm, a conta é mais ou menos assim: a Sabesp perde 500 mm (33% da água distribuída), a população consume 1.000 mm. Para chegar rapidamente ao equilíbrio em 1.000 mm, o consumo deveria ser de 500 mm, uma vez que as perdas não poderão ser rapidamente evitadas e acontecem antes do consumo.
Se 1/3 da água distribuída não fosse sistematicamente perdida não haveria crise. Os 500 mm de chuva disperdiçados anualmente pela precariedade do sistema de distribução não fazem falta quando chove 1.500 mm, mas com 1.000 mm cada litro jogado fora de um lado é um litro que terá de ser economizado do outro.
Simulação 3: Eficiência corrente e economia necessária
Para estimar a eficiência corrente são usadas as últimas 120 observações do comportamento do sistema.
A curva de eficiência corrente permite estimar o ponto de equilíbrio atual do sistema (ponto vermelho em destaque).
O ponto azul indica a última observação do acumulado anual de chuvas. A diferença entre os dois mede o tamanho do desequilíbrio.
Apenas para estancar a perda de água do sistema, é preciso reduzir em 49% o fluxo de retirada. Como esse fluxo inclui todas as perdas, se depender apenas da redução no consumo, a economia precisa ser de 66% se as perdas forem de 33%, ou de 56% se as perdas forem de 17%.
Parece incrível que a eficiência do sistema esteja tão baixa em meio a uma crise tão grave. A tentativa de contenção no consumo está aumentando o consumo? Volumes menores e mais rasos evaporam mais? As pessoas ainda não perceberam a tamanho do desastre?
Supondo que novos estoques de água não serão incorporados no curto prazo, o prognóstico sobre se e quando a água vai acabar depende da quantidade de chuva e da eficiência do sistema.
O gráfico mostra quantos dias restam de água em função do acumulado de chuva, considerando duas curvas de eficiência: a média e a corrente (estimada a partir dos últimos 120 dias).
O ponto em destaque considera a observação mais recente de chuva acumulada no ano e mostra quantos dias restam de água se persistirem as condições atuais de chuva e de eficiência.
O prognóstico é uma referência que varia de acordo com as novas observações e não tem probabilidade definida. Trata-se de uma projeção para melhor visualizar as condições necessárias para escapar do colapso.
Porém, há duas importantes limitações nesses dados que podem distorcer a interpretação da realidade: 1) a Sabesp usa somente porcentagens para se referir a reservatórios com volumes totais muito diferentes; 2) a entrada de novos volumes não altera a base-de-cálculo sobre o qual essa porcentagem é medida.
Por isso, foi necessário corrigir as porcentagens da série de dados original em relação ao volume total atual, uma vez que os volumes que não eram acessíveis se tornaram acessíveis e, convenhamos, sempre estiveram lá nas represas. A série corrigida pode ser obtida aqui. Ela contém uma coluna adicional com os dados dos volumes reais (em bilhões de litros: hm3)
Além disso, decidimos tratar os dados de forma consolidada, como se toda a água estivesse em um único grande reservatório. A série de dados usada para gerar os gráficos desta página contém apenas a soma ponderada do estoque (%) e da chuva (mm) diários e também está disponível.
As correções realizadas eliminam os picos causados pelas entradas dos volumes mortos e permitem ver com mais clareza o padrão de queda do estoque em 2014.
Padrões ano a ano
Média e quartis do estoque durante o ano
Sobre este estudo
Preocupado com a escassez de água, comecei a estudar o problema ao final de 2014. Busquei uma abordagem concisa e consistente de apresentar os dados, dando destaque para as três variáveis que realmente importam: a chuva, o estoque total e a eficiência do sistema. O site entrou no ar em 16 de janeiro de 2015. Todos os dias, os modelos e os gráficos são refeitos com as novas informações.
Espero que esta página ajude a informar a real dimensão da crise da água em São Paulo e estimule mais ações para o seu enfrentamento.
by Megan Gannon, News Editor | January 22, 2015 01:25pm ET
A gigantic mushroom cloud billowed over Nagasaki, Japan, when an atomic bomb was dropped on the city in 1945.
Credit: U.S. National Archives
The world is “3 minutes” from doomsday.
That’s the grim outlook from board members of The Bulletin of the Atomic Scientists. Frustrated with a lack of international action to address climate change and shrink nuclear arsenals, they decided today (Jan. 22) to push the minute hand of their iconic “Doomsday Clock” to 11:57 p.m.
It’s the first time the clock hands have moved in three years; since 2012, the clock had been fixed at 5 minutes to symbolic doom, midnight. [End of the World? Top Doomsday Fears]
The Bulletin of the Atomic Scientists doesn’t use the clock to make any real doomsday predictions. Rather, the clock is a visual metaphor to warn the public about how close the world is to a potentially civilization-ending catastrophe. Each year, the magazine’s board analyzes threats to humanity’s survival to decide where the Doomsday Clock’s hands should be set.
Experts on the board said they felt a sense of urgency this year because of the world’s ongoing addiction to fossil fuels, procrastination with enacting laws to cut greenhouse gas emissions and slow efforts to get rid of nuclear weapons.
“We are not saying it is too late to take action but the window for action is closing rapidly,” Kennette Benedict, executive director of The Bulletin of the Atomic Scientists, said in a news conference this morning in Washington, D.C. “We move the clock hand today to inspire action.”
For instance, if nothing is done to reduce the amount of heat-trapping gasses, such as carbon dioxide, in the atmosphere, Earth could be 5 to 15 degrees Fahrenheit (3 to 8 degrees Celsius) warmer by the end of century, said Sivan Kartha, a senior scientist at the Stockholm Environment Institute.
Some people might not feel alarmed when they see those numbers; they might normally experience that kind of temperature swing in the course of a single day, Kartha said. But, he said a temperature increase of that magnitude was enough to bring the world out of the last ice age, and it will be enough to “radically transform” the Earth’s surface in the future.
Sharon Squassoni, another board member and director of the Proliferation Prevention Program at the Center for Strategic and International Studies, said nuclear disarmament efforts have “ground to a halt” and many nations are expanding, not scaling back, their nuclear capabilities. Russia is upgrading its nuclear program, India plans to expand its nuclear submarine fleet, and Pakistan has reportedly started operating a third plutonium reactor, Squassoni said.
She said the United States has good rhetoric on nuclear nonproliferation, but at the same time is in the midst of a $335 billion overhaul of its nuclear program. (That figure seems to come from a Congressional Budget Office report from December 2013.)
“The risk from nuclear weapons is not that someone is going to press the button, but the existence of these weapons costs a lot of time, effort and money to keep them secure,” Squassoni said, adding that there have been troubling safety discrepancies reported in recent years at power plants.
The Bulletin of the Atomic Scientists was founded in 1945 by scientists who created the atomic bomb as part of the Manhattan Project and wanted to raise awareness about the dangers of nuclear technology. The Doomsday Clock first appeared on a cover of the magazine in 1947, with its hands set at 11:53 p.m.
The clock’s hands shifted quite a bit over the following seven decades. They were closest to midnight in 1953, set at 11:58 p.m., after both the United States and the Soviet Union conducted their first tests of the hydrogen bomb. The clock’s hands were pushed all the way back to 11:43 p.m., 17 minutes to midnight, in December 1991, after the world’s superpowers signed the Strategic Arms Reduction Treaty, which at the time, seemed like a promising move toward nuclear disarmament.
Promessa de campanha do governador Geraldo Alckmin (PSDB), a falta de água em São Paulo é uma realidade há meses em diversos pontos do Estado. Na semana passada, ele admitiu que há sim racionamento (diante da repercussão, tentou voltar atrás), algo que a população – sobretudo a dos bairros mais carentes – já sabia. O que também já se sabe é que, sim, a água vai mesmo acabar. Se não chegar a zerar, terá níveis baixíssimos que afetarão a vida de todos, a partir de março.
Os especialistas ouvidos pelo Brasil Post viram com bons olhos o fato de que o governo paulista, com atraso, reconheceu o racionamento. Também aprovaram a aplicação de multa contra aqueles que consomem muita água – embora a medida, tardia, devesse ser uma política sempre presente, e não para ‘apagar incêndios’ como agora. Contudo, o cenário que se colocará com a chegada do período de estiagem, entre o fim de março e começo de abril, se estendendo até outubro, vai requerer novos hábitos, seja dos gestores ou da população.
“Quando acabar a água serão interrompidas atividades que não são consideradas essenciais, com cortes para o comércio, para a indústria e o fechamento de locais com muito uso de água, como shoppings, escolas e universidades”, analisou o professor Antonio Carlos Zuffo, especialista na área de recursos hídricos na Unicamp. Parece exagerado, mas não é. Segundo o jornal O Estado de S. Paulo desta quarta-feira (21), os seis mananciais que abastecem 20 milhões de pessoas na Grande São Paulo têm registrado déficit de 2,5 bilhões de litros por dia em pleno período no qual deveriam encher para suprir os meses de seca.
Já em 2002, a Saneas, revista da Associação dos Engenheiros da Companhia de Saneamento Básico do Estado de São Paulo (AESabesp), publicava um texto no qual apontava “uma inegável situação de estresse hídrico”, a qual podia “ter um final trágico, com previsões de escassez crônica em 15 anos”. A Agência Nacional de Águas (ANA) apontava, na outorga de uso do Sistema Cantareirade 2004, que era preciso diminuir a dependência desse sistema. Em plena crise, na tentativa de renovação em 2014, havia uma tentativa de aumentar, e não diminuir, o uso do Cantareira. Ou seja, algo impraticável e ignorando as previsões. Não, a culpa não é de São Pedro.
“Hoje a situação é muito pior que no ano passado. Em janeiro de 2014 tínhamos 27,2% positivos no Cantareira, hoje temos 23,5% negativos. Ou seja, consumimos 50% do volume nesse período. Mantida a média de consumo, a água acaba no fim de março. É preciso lembrar que janeiro é o mês com maior incidência de chuva em SP, seguido por dezembro. No mês passado, choveu 25% a menos do que a média. Esse mês só choveu 22%, 23% da média. A equação é simples: não vai ter água para todo mundo”, completou Zuffo.
Informação e transparência
Para a ambientalista Malu Ribeiro, da ONG SOS Mata Atlântica, a demora em admitir o óbvio por parte das autoridades trouxe mais prejuízos do que benefícios ao longo dos últimos 13 meses. “A sociedade precisa ter a noção clara da gravidade dessa crise. Quando as autoridades passam certa confiança, como era o caso do governo Alckmin, a tendência é que não se alerte da forma necessária e as pessoas se mantenham em uma situação confortável. Muita gente não acredita na proporção dessa crise, muito se agravou e agora é preciso cautela”, avaliou.
As mudanças na Secretaria de Recursos Hídricos e na presidência da Companhia de Saneamento Básico do Estado de São Paulo (Sabesp), com as entradas de Benedito Braga e Jerson Kelman, respectivamente, também foram benéficas, já que colocam em posições estratégicas dois especialistas no tema. Entretanto, isso não basta. A necessidade de discutir a gestão da água sob o âmbito estratégico, algo muito teórico e pouco prático no Brasil, é vista como fundamental em tempos de crise.
“Há ainda muita ocupação em áreas de mananciais, por exemplo. Então vemos que o comportamento, apesar da crise não ser nova, não mudou. Veja em Itu, onde eu moro, onde a crise foi muito pior e, agora que choveu um pouco, as pessoas acham que não precisam mais poupar, que tudo voltou ao normal. O combate ao desperdício deve ser permanente e temos de ter prevenção. É preciso doer no bolso, por isso a multa deve ser permanente”, disse Malu.
“A falta de informação resultou em uma insegurança, sem informar à população sobre o seu papel na crise. A ONU já apontava que a década entre 2010 e 2020 seria da água, e não por acaso, mas no Brasil há uma timidez nesse sentido. É preciso mudar essa cultura de abundância que se tem no Sudeste e desenvolver um plano estratégico, com mais poder aos comitês de bacia. É absurdo o desperdício de água na agricultura, e isso não é discutido. É hora de acordar”, completou a ambientalista.
‘Água cara’ veio para ficar
De acordo com os especialistas, a crise da água expõe também um cenário já esperado, já que a Terra passa por ciclos alternados entre seca e chuvas a cada 30 anos. O atual, iniciado em 2010 e que segue até 2040, será recheado de períodos de seca em regiões populosas, quadro a se inverter apenas daqui a 25 anos. Assim, é preciso mudar hábitos, antes de mais nada. Mesmo em tempos de calor excessivo, há quem ainda não tenha se dado conta disso.
“Muita gente se vê alheia ao problema e, com o calor, acaba correndo para compras piscininhas e usa a água para o lazer. O Carnaval que está chegando também ajuda a tirar o cidadão comum do foco, como ocorreu durante as eleições. Isso não é mais possível. Há a responsabilidade dos gestores, mas também é preciso que o cidadão se atente ao seu papel, sob pena de termos novas ‘cidades mortas’, como no Vale do Paraíba ou no Vale do Jequitinhonha, onde os recursos naturais foram exauridos”, afirmou Malu.
E que ninguém se anime com a promessa da Sabesp de que ainda há uma terceira cota de 41 bilhões de litros do volume morto do Cantareira, cujo uso deve ser solicitado pelo governo paulista junto à ANA nos próximos dias. “Sabemos que 45% do Cantareira que não é captado é volume morto. A terceira cota restante não é toda ela captável. Teríamos com ela mais uns 10%, suficiente só para mais algumas semanas”, comentou Zuffo.
Medidas sugeridas ao longo da crise, o reuso da água e a dessalinização são medidas caras e que dependem de outros aspectos para serem implementadas – e, com o possível racionamento de energia elétrica, podem não sair do papel. Ou seja, não são a solução a curto prazo. O uso de mais água de represas como a Billings (com sua notória poluição) também dependem de obras – outro entrave para quem gostaria de não ver a falta de água por dias seguidos se tornar uma realidade por meses a fio. Sem chuva, só há um caminho a seguir.
“Há uma variabilidade cíclica natural, que nada tem a ver com o aquecimento global, mas não temos engenharia para resolver a questão no curto prazo. Temos é que ter inteligência para nos adaptar e reduzir de 250 litros para 150 litros, ou ainda menos, o consumo de água por cada pessoa. Há países europeus em que o uso não passa de 60 litros/pessoa. É preciso usar menos e tratar a água de maneira que ela possa ser reutilizada. Tudo depende de tecnologia e novos hábitos”, concluiu Zuffo.
Rignot was a co-author of the “holy shit moment” paper from last spring, showing that large areas of the West Antarctic Ice sheet are now in “irreversible decline”.
That news made for one of my most harrowing videos of the last year, which you can, and should view if you have not – below the fold.
I’m keeping these clips from our interviews minimally edited – I want the raw video to speak for itself to current readers, and to historians, who will undoubtedly understand all too well why we were peeling our jaws off the floor after this one.
Apostamos em cinco coisas que tendem a aparecer neste ano
19/01/2015 | 06h01
Foto: SpaceX/Youtube
Em 2014, a ciência conseguiu pousar em um cometa, descobriu que estava errada sobre a evolução genética das aves, revelou os maiores fósseis da história. Miguel Nicolelis apresentou seu exoesqueletona Copa do Mundo, o satélite brasileiro CBERS-4, em parceria com a China, foi ao espaço com sucesso, um brasileiro trouxe a principal medalha da matemáticapara casa.
Mas e em 2015, o que veremos? Apostamos em cinco coisas que poderão aparecer neste ano.
Foguetes reusáveis
Se queremos colonizar Marte, não adianta passagem só de ida. Esses foguetes, capazes de ir e voltar, são a promessa para transformar o futuro das viagens espaciais. Veremos se a empresa SpaceX, que já está nessa, consegue.
Robôs em casa
Os japoneses da Softbank começam a vender, em fevereiro, um robô humanoide chamado Pepper. Ele usa inteligência artificial para reconhecer o humor do dono e fala quatro línguas. Apesar de ser mais um ajudante do que um cara que faz, logo logo aprenderá novas funções.
Universo invisível
O Grande Colisor de Hádronsvai voltar a funcionar em março e terá potência duas vezes maior de quebrar partículas. Uma das possibilidades é que ele ajude a descobrir novas superpartículas que, talvez, componham a matéria escura. Seria o primeiro novo estado da matéria descoberto em um século.
Cura para o ebola
Depois da crise de 2014, pode ser que as vacinas para o ebola comecem a funcionar e salvem muitas vidas na África. Vale o mesmo para a aids. O HIV está cercado, esperamos que a ciência finalmente o vença neste ano.
Discussões climáticas
2014 foi um dos mais quentes da história e, do jeito que a coisa vai, 2015 seguirá a mesma trilha. Em dezembro, o mundo vai discutir um acordo para tentar reverter o grau de emissões de gases em Paris. São medidas para ser implementadas a partir de 2020. Que sejam sensatos nossos líderes.
Na primeira reunião de 2015 do Grupo de Trabalho em Previsão Climática Sazonal do Ministério da Ciência, Tecnologia e Inovação, pesquisadores alertam que haverá chuvas abaixo da média no Norte e Nordeste e acima da média no Sul do País
Chuvas abaixo da média na região Semiárida do Nordeste e na região Norte do Brasil, com possibilidade de queimadas e incêndios em Roraima, e continuidade de precipitação acima da média na região Sul. Essas são as tendências climáticas para os próximos três meses (fevereiro, março e abril). Elas foram apresentadas nesta sexta-feira (16) na primeira reunião de 2015 do Grupo de Trabalho em Previsão Climática Sazonal (GTPCS) do Ministério da Ciência, Tecnologia e Inovação (MCTI).
Paulo Nobre, pesquisador do Instituto Nacional de Pesquisas Espaciais (Inpe/MCTI), atribuiu os resultados da avaliação do grupo à continuidade do fenômeno El Niño. “Temos uma condição sazonal dessas três regiões onde é possível hoje cientificamente e tecnologicamente fazer essas previsões”, afirmou o especialista que conduziu as atividades do primeiro encontro do GTPCS.
Participam do grupo de trabalho, instituído pelo MCTI em novembro de 2013, as principais lideranças na área de previsão climática no País. A cada mês os especialistas se reúnem para traçar prognósticos para o trimestre seguinte. O objetivo é dar subsídios aos tomadores de decisões sobre o cenário climático que se aproxima.
O secretário de Políticas e Programas de Pesquisa e Desenvolvimento do MCTI, Carlos Nobre, alertou que a previsão climática para o próximo trimestre inspira atenção. “O Brasil está vivendo um momento de diferentes extremos climáticos em diferentes partes do país com impactos na economia e na sociedade”, destacou o secretário que também coordena do GTPCS. “As informações geradas pelo grupo de trabalho alimentam imediatamente ministérios e a presidência da República para que sejam tomadas as medidas necessárias.”
Na abertura do encontro, que aconteceu pela primeira vez em Brasília, o ministro da Ciência, Tecnologia e Inovação, Aldo Rebelo, enfatizou a importância de haver previsão climática de curto prazo. “O trabalho dos pesquisadores do GTPCS já contribuiu no ano passado para reduzir os danos da seca no Nordeste e das enchentes em Rondônia”, exemplificou.
Participam do grupo pesquisadores do Centro de Previsão de Tempo e Estudos Climáticos (CPTEC) do Inpe; do Centro de Ciência do Sistema Terrestre (CCST); do Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden/MCTI); e do Instituto Nacional de Pesquisas da Amazônia (Inpa/MCTI). A cada reunião um dos membros conduzirá as atividades. Nesta sexta, o meteorologista Paulo Nobre, pesquisador do Inpe, coordenou os trabalhos.
Para outras regiões do país não há previsibilidade climática, a exemplo do Sudeste. “O Nordeste, por exemplo, é a região com maior previsibilidade sazonal porque tem a dependência do Oceano e um tempo de variação bem lento. Na região Sudeste, o que causa chuva são as frentes frias que tem um tempo de previsibilidade de uma semana, no máximo duas”, explica Paulo Nobre, pesquisador do Inpe. No limite do conhecimento científico o que se pode afirmar é que as chuvas continuarão abaixo da média neste período.
Acesse aqui o relatório completo emitido pelo GTPCS.
Diante da crise da água em São Paulo, o coordenador geral da Rede Nossa São Paulo e do Programa Cidades Sustentáveis faz um apelo às autoridades e aos cidadãos para que assumam as devidas responsabilidades. Confira:
A cidade de São Paulo está diante de uma catástrofe social, econômica e ambiental sem precedentes. O nível do sistema Cantareira está em cerca de 6% e segue baixando por volta de 0,1% ao dia. O que significa que, em aproximadamente 60 dias, o sistema pode secar COMPLETAMENTE!
O presidente da Sabesp declarou que o sistema pode ZERAR em março ou, na melhor das hipóteses, em junho deste ano. E NÃO HÁ UM PLANO B em curto prazo. Isto significa que seis milhões de pessoas ficarão praticamente SEM UMA GOTA DE ÁGUA ou com enorme escassez. Não é que haverá apenas racionamento ou restrição. Poderá haver ZERO de água, NEM UMA GOTA.
Você já se deu conta do que isto significa em termos sociais, econômicos (milhares de estabelecimentos inviabilizados e enorme desemprego) e ambientais? Você já se deu conta de que no primeiro momento a catástrofe atingirá os mais vulneráveis (pobres, crianças e idosos) e depois todos nós?
O que nos espanta é a passividade da sociedade e das autoridades diante da iminência desta monumental catástrofe. Todas as medidas tomadas pelas autoridades e o comportamento da sociedade são absolutamente insuficientes para enfrentar este verdadeiro cataclismo.
Parece que estamos todos anestesiados e impotentes para agir, para reagir, para pressionar, para alertar, para se mobilizar em torno de propostas e, principalmente, em ações e planos de emergência de curto prazo e políticas e comportamentos que levem a uma drástica transformação da nossa relação com o meio ambiente e os recursos hídricos.
Há uma unanimidade de que esta é uma crise de LONGUÍSSIMA DURAÇÃO por termos deixado, permitido, que se chegasse a esta dramática situação. Agora, o que mais parece é que estamos acomodados e tranquilos num Titanic sem nos dar conta do iceberg que está se aproximando.
Nosso intuito, nosso apelo, nosso objetivo com este alarme é conclamar as autoridades, os formadores de opinião, as lideranças e os cidadãos a se conscientizarem urgentemente da gravíssima situação que vive a cidade, da dimensão da catástrofe que se aproxima a passos largos.
Precisamos parar de nos enganar. É fundamental que haja uma grande mobilização de todos para que se tomem ações e medidas à altura da dramática situação que vivemos. Deixar de lado rivalidades e interesses políticos, eleitorais, desavenças ideológicas. Não faltam conhecimentos, não faltam ideias, não faltam propostas (o Conselho da Cidade de São Paulo aprovou um grande conjunto delas). Mas faltam mobilização e liderança para enfrentar este imenso desafio.
Todos precisamos assumir nossa responsabilidade à altura do nosso poder, de nossa competência e de nossa consciência. O tempo está se esgotando a cada dia.
* Oded Grajew é empresário, coordenador da secretaria executiva da Rede Nossa São Paulo, presidente emérito do Instituto Ethos e idealizador do Fórum Social Mundial.
Updated below | Through three-plus decades of reporting, I’ve been seeking ways to better mesh humanity’s infinite aspirations with life on a finite planet. (Do this Google search — “infinite aspirations” “finite planet” Revkin – to get the idea. Also read the 2002 special issue of Science Times titled “Managing Planet Earth.”)
So I was naturally drawn to a research effort that surfaced in 2009 defining a “safe operating space for humanity” by estimating a set of nine “planetary boundaries” for vital-sign-style parameters like levels of greenhouse gases, flows of nitrogen and phosphorus and loss of biodiversity.
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A diagram from a 2009 analysis of “planetary boundaries” showed humans were already hitting limits (red denotes danger zones).Credit Stockholm Resilience Center
The same was true for a related “Great Acceleration” dashboard showing humanity’s growth spurt (the graphs below), created by the International Geosphere-Biosphere Program.
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A graphic illustrating how human social and economic trends, resource appetites and environmental impacts have surged since 1950.Credit International Geosphere-Biosphere Program
Who would want to drive a car without gauges tracking engine heat, speed and fuel levels? I use that artwork in all my talks.
In a prepared statement, a co-author of the acceleration analysis, Lisa Deutsch, a senior lecturer at the Stockholm Resilience Center, saw little that was encouraging:
Of all the socio-economic trends only construction of new large dams seems to show any sign of the bending of the curves – or a slowing of the Great Acceleration. Only one Earth System trend indicates a curve that may be the result of intentional human intervention – the success story of ozone depletion. The leveling off of marine fisheries capture since the 1980s is unfortunately not due to marine stewardship, but to overfishing.
The paper is behind a paywall, but the Stockholm Resilience Center, which has led this work, has summarized the results, including the authors’ conclusion that we’re in the danger zone on four of the nine boundaries: climate change, loss of biosphere integrity, land-system change and alteration of biogeochemical cycles (for the nutrients phosphorus and nitrogen).
Their work has been a valuable prod to the community of scientists and policy analysts aiming to smooth the human journey, resulting in strings of additional studies. Some followup work has supported the concept, and even broadened it, as with a 2011 proposal by Kate Raworth of the aid group Oxfam to add social-justice boundaries, as well: “A Safe and Just Space for Humanity – Can We Live Within the Doughnut?”
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In 2011, Kate Raworth at the aid group Oxfam proposed a framework for safe and just human advancement illustrated as a doughnut-shaped zone.Credit Oxfam
But others have convincingly challenged many of the boundaries and also questioned their usefulness, given how both impacts of, and decisions about, human activities like fertilizing fields or tapping aquifers are inherently local — not planetary in scale. (You’ll hear from some critics below.)
I hope the public (and policy makers) will realize this is not a right-wrong, win-lose science debate. A complex planet dominated by a complicated young species will never be managed neatly. All of us, including environmental scientists, will continue to learn and adjust.
I was encouraged, for instance, to see the new iteration of the boundaries analysis take a much more refined view of danger zones, including more of an emphasis on the deep level of uncertainty in many areas:
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A diagram from a paper defining “planetary boundaries” for human activities shows areas of greatest risk in red.Credit Science
The authors, led by Will Steffen of Australian National University and Johan Rockström of the Stockholm Resilience Center, have tried to refine how they approach risks related to disrupting ecosystems – not simply pointing to lost biological diversity but instead devising a measure of general “biosphere integrity.”
That measure, and the growing human influence on the climate through the buildup of long-lived greenhouse gases are the main source of concern, they wrote:
Two core boundaries – climate change and biosphere integrity – have been identified, each of which has the potential on its own to drive the Earth System into a new state should they be substantially and persistently transgressed.
But the bottom line has a very retro feel, adding up to the kind of ominous, but generalized warnings that many environmental scientists and other scholars began giving with the “Limits to Growth” analysis in 1972. Here’s a cornerstone passage from the paper, reprising a longstanding view that the environmental conditions of the Holocene – the equable span since the end of the last ice age – is ideal:
The precautionary principle suggests that human societies would be unwise to drive the Earth System substantially away from a Holocene-like condition. A continuing trajectory away from the Holocene could lead, with an uncomfortably high probability, to a very different state of the Earth System, one that is likely to be much less hospitable to the development of human societies.
I sent the Science paper to a batch of environmental researchers who have been constructive critics of the Boundaries work. Four of them wrote a group response, posted below, which includes this total rejection of the idea that the Holocene is somehow special:
[M]ost species evolved before the Holocene and the contemporary ecosystems that sustain humanity are agroecosystems, urban ecosystems and other human-altered ecosystems….
Steffen et al (2015) revise the “planetary boundaries framework” initially proposed in 2009 as the “safe limits” for human alteration of Earth processes (Rockstrom et al 2009). Limiting human harm to environments is a major challenge and we applaud all efforts to increase the public utility of global-change science. Yet the planetary boundaries (PB) framework – in its original form and as revised by Steffen et al – obscures rather than clarifies the environmental and sustainability challenges faced by humanity this century.
Steffen et al concede that “not all Earth system processes included in the PB have singular thresholds at the global/continental/ocean basin level.” Such processes include biosphere integrity (see Brook et al 2013), biogeochemical flows, freshwater use, and land-system change. “Nevertheless,” they continue, “it is important that boundaries be established for these processes.” Why? Where a global threshold is unknown or lacking, there is no scientifically robust way of specifying such a boundary – determining a limit along a continuum of environmental change becomes a matter of guesswork or speculation (see e.g. Bass 2009; Nordhaus et al 2012). For instance, the land-system boundary for temperate forest is set at 50% of forest cover remaining. There is no robust justification for why this boundary should not be 40%, or 70%, or some other level.
While the stated objective of the PB framework is to “guide human societies” away from a state of the Earth system that is “less hospitable to the development of human societies”, it offers little scientific evidence to support the connection between the global state of specific Earth system processes and human well-being. Instead, the Holocene environment (the most recent 10,000 years) is assumed to be ideal. Yet most species evolved before the Holocene and the contemporary ecosystems that sustain humanity are agroecosystems, urban ecosystems and other human-altered ecosystems that in themselves represent some of the most important global and local environmental changes that characterize the Anthropocene. Contrary to the authors’ claim that the Holocene is the “only state of the planet that we know for certain can support contemporary human societies,” the human-altered ecosystems of the Anthropocene represent the only state of the planet that we know for certain can support contemporary civilization.
Human alteration of environments produces multiple effects, some advantageous to societies, such as enhanced food production, and some detrimental, like environmental pollution with toxic chemicals, excess nutrients and carbon emissions from fossil fuels, and the loss of wildlife and their habitats. The key to better environmental outcomes is not in ending human alteration of environments but in anticipating and mitigating their negative consequences. These decisions and trade-offs should be guided by robust evidence, with global-change science investigating the connections and tradeoffs between the state of the environment and human well-being in the context of the local setting, rather than by framing and reframing environmental challenges in terms of untestable assumptions about the virtues of past environments.
Even without specifying exact global boundaries, global metrics can be highly misleading for policy. For example, with nitrogen, where the majority of human emissions come from synthetic fertilizers, the real-world challenge is to apply just the right amount of nitrogen to optimize crop yields while minimizing nitrogen losses that harm aquatic ecosystems. Reducing fertilizer application in Africa might seem beneficial globally, yet the result in this region would be even poorer crop yields without any notable reduction in nitrogen pollution; Africa’s fertilizer use is already suboptimal for crop yields. What can look like a good or a bad thing globally can prove exactly the opposite when viewed regionally and locally. What use is a global indicator for a local issue? As in real estate, location is everything.
Finally, and most importantly, the planetary boundaries are burdened not only with major uncertainties and weak scientific theory – they are also politically problematic. Real world environmental challenges like nitrogen pollution, freshwater consumption and land-use change are ultimately a matter of politics, in the sense that there are losers and winners, and solutions have to be negotiated among many stakeholders. The idea of a scientific expert group determining top-down global limits on these activities and processes ignores these inevitable trade-offs and seems to preclude democratic resolution of these questions. It has been argued that (Steffen et al 2011):
Ultimately, there will need to be an institution (or institutions) operating, with authority, above the level of individual countries to ensure that the planetary boundaries are respected. In effect, such an institution, acting on behalf of humanity as a whole, would be the ultimate arbiter of the myriad trade-offs that need to be managed as nations and groups of people jockey for economic and social advantage. It would, in essence, become the global referee on the planetary playing field.
Here the planetary boundaries framework reaches its logical conclusion with a political scenario that is as unlikely as it is unpalatable. There is no ultimate global authority to rule over humanity or the environment. Science has a tremendously important role to play in guiding environmental management, not as a decider, but as a resource for deliberative, evidence-based decision making by the public, policy makers, and interest groups on the challenges, trade-offs and possible courses of action in negotiating the environmental challenges of societal development (DeFries et al 2012). Proposing that science itself can define the global environmental limits of human development is simultaneously unrealistic, hubristic, and a strategy doomed to fail.
Update, 9:40 p.m.| Will Steffen, the lead author of the updated Planetary Boundaries analysis, sent this reply to Ellis and co-authors tonight:
Response to Ellis et al. on planetary boundaries
Of course we welcome constructive debate on and criticism of the planetary boundaries (PB) update paper. However, the comments of Ellis et al. appear to be more of a knee-jerk reaction to the original 2009 paper than a careful analysis of the present paper. In fact, one wonders if they have even read the paper, including the Supplementary Online Material (SOM) where much methodological detail is provided.
One criticism seems to be based on a rather bizarre conflation of a state of the Earth System with (i) the time when individual biological species evolved, and (ii) the nature and distribution of human-altered terrestrial ecosystems. This makes no sense from an Earth System science perspective. The state of the Earth System (a single system at the planetary level) also involves the oceans, the atmosphere, the cryosphere and very important processes like the surface energy balance and the flows and transformation of elements. It is the state of this single complex system, which provides the planetary life support system for humanity, that the PB framework is concerned with, not with fragmentary bits of it in isolation.
In particular, the PB framework is based on the fact – and I emphasise the word “fact” – that the relatively stable Holocene state of the Earth System (the past approximately 11,700 years) is the only state of the System that has allowed the development of agriculture, urban settlements and complex human societies. Some argue that humanity can now survive, and even thrive, in a rapidly destabilizing planetary environment, but that is a belief system based on supreme technological optimism, and is not a reasoned scientifically informed judgment. Also, Ellis et al. seem to conflate human alteration of terrestrial environments with human alteration of the fundamental state of the Earth System as a whole. These are two vastly different things.
The criticisms show further misunderstanding of the nature of complex systems like the Earth System and how they operate. For example, Ellis et al. claim that a process is not important unless it has a threshold. Even a cursory understanding of the carbon cycle, for example, shows that this is nonsense. Neither the terrestrial nor the marine carbon sinks have known large-scale thesholds yet they are exceedingly important for the functioning of the climate system, which does indeed have known large-scale thresholds such as the melting of the Greenland ice sheet. Sure, it is more challenging to define boundaries for processes that are very important for the resilience of the Earth System but don’t have large-scale thresholds, but it is not impossible. The zone of uncertainty tends to be larger for these boundaries, but as scientific understanding improves, this zone will narrow.
An important misrepresentation of our paper is the assertion that we are somehow suggesting that fertilizer application in Africa be reduced. Nothing could be further from the truth. In fact, if Ellis et al had taken the time to read the SOM, the excellent paper by Carpenter and Bennett (2011) on the P boundary, the equally excellent paper by de Vries et al. (2013) on the N boundary, and the paper by Steffen and Stafford Smith (2013) on the distribution and equity issues for many of the PBs, including N and P, they wouldn’t have made such a misrepresentation.
Finally, the Steffen et al. (2011) paper seems to have triggered yet another misrepresentation. The paragraph of the paper quoted by Ellis et al. is based on contributions from two of the authors who are experts in institutions and governance issues, and does not come from the natural science community. Nowhere in the paragraph quoted, nor in the Steffen et al. (2011) paper as a whole, is there the proposal for a “a scientific expert group determining top-down global limits…”. The paragraph reprinted by Ellis et al. doesn’t mention scientists at all. That is a complete misrepresentation of our work.
We reiterate that we very much welcome careful and constructive critiques of the PB update paper, preferably in the peer-reviewed literature. In fact, such critiques of the 2009 PB paper were very helpful in developing the 2015 paper. Knee-jerk reactions in the blogosphere make for interesting reading, but they are far less useful in advancing the science.
Update, Jan. 16, 2:09 p.m. | Johan Rockström and Katherine Richardson, authors of the boundaries analysis, sent these additional reactions to the Ellis et al. critique:
We are honored that Erle Ellis, Barry Brook, Linus Blomqvist and Ruth DeFries (Ellis et al.) show such strong interest in our Planetary Boundaries research. The 2015 science update draws upon the over 60 scientific articles that have been published specifically scrutinizing different aspects of the Planetary Boundaries framework (amongst them the contributions by all these four researchers), and the most recent advancements in Earth System science. This new paper scientifically addresses and clarifies all of the natural science related aspects of Ellis et al.’s critique. It can also be noted that Ellis et al.’s critique simply echoes the standpoints regarding Planetary Boundaries research that the same group (Blomqvist et al., 2012) brought forward in 2012. Now, as then, their criticisms seem largely to be based on misunderstandings and their own viewpoints:
(1) We have never argued that there are planetary scale tipping points for all Planetary Boundary processes. Furthermore, there does not need to be a tipping point for these processes and systems in order for them to function as key regulators of the stability of the Earth system. A good example here is the carbon sink in the biosphere (approximately 4.5 Gt/year) which has doubled over the past 50 years in response to human emissions of CO2 and, thus, provides a good example of Earth resilience at play;
(2) Establishing the Planetary Boundaries, i.e. identifying Earth System scale boundaries for environmental processes that regulate the stability of the planet, does not (of course) contradict or replace the need for local action, transparency and democratic processes. Our society has long accepted the need for local – and to some extent regional- environmental management. Scientific evidence has now accumulated that indicates a further need for management of some environmental challenges at the global level. Many years of multi-lateral climate negotiation indicate a recognized need for global management of the CO2 emissions that occur locally. Our Planetary Boundaries research identifies that there are also other processes critical to the functioning of the Earth System that are so impacted by human activities that they, too, demand management at the global level. Ours is a positive – not a doomsday – message. It will come as no surprise to any reader that there are environmental challenges associated with all of the 9 Earth System functions we examine. Through our research, we offer a framework that can be useful in developing management at a global level.
It is important to emphasize that Ellis et al. associate socio-political attributes to our work that do not exist. The Science paper published today (16th January 2015), is a natural science update and advancement of the planetary boundaries framework. It makes no attempt to enter the (very important) social science realm of equity, institutions or global governance. The implications attributed to the PB framework must, then, reflect Ellis et al.’s own normative values. Furthermore, Ellis et al. argue that the “key to better environmental outcomes is not ending human alteration” but “anticipating and mitigating the negative consequences” of human environmental perturbation. While Planetary Boundaries research does not dictate how societies should use the insights it provides, “anticipating negative consequences” is at the absolute core of our approach!
Regarding Earth system tipping points. As Will Steffen points out in his earlier response, it would have been scientifically more correct for Ellis et al. to refer not only to their own assessment of uncertainties regarding a potential biosphere tipping point but also to the response to their article by Terry Hughes et al. (2014). These researchers presented the current state of empirical evidence concerning changes in interactions and feedbacks and how they can (in several cases do!) trigger tipping points at ecosystem and biome scale, and that such non-linear dynamics at local to regional scale can add up to impacts at the Earth system scale.
A different worldview. The Ellis et al. critique appears not to be a scientific criticism per se but rather is based on their own interpretation of differences in worldview. They do not substantively put in question the stability of the Earth system as a basis for human development– see Will Steffen’s response. Thus, it appears that we and Ellis et al. are in agreement here. Of course species and ecosystems have evolved prior to the Holocene but only in the stable environment of the Holocene have humans been able to exploit the Earth system at scale (e.g., by inventing agriculture as a response to a stable hydro-climate in the Holocene).
Ellis et al. argue that the only constructive avenue is to “investigate the connections and trade-offs between the state of the environment and human well-being in the context of the local setting..:”. This is clearly not aligned with current scientific evidence. In the Anthropocene, there is robust evidence showing that we need to address global environmental change at the global level, as well as at the regional, national and local contexts, and in particular understanding cross-scale interactions between them.
On global governance. It seems hardly surprising, given the Ellis et al.’s misunderstanding of the Planetary Boundaries framework that their interpretation of the implications of operationalizing the framework rests also on misunderstandings. They claim the Planetary Boundaries framework translates to an “ultimate global authority to rule over humanity”. No one would argue that the current multi-lateral climate negotiations are an attempt to establish “ultimate global authority over humanity” and this is certainly never been suggested by the Planetary Boundaries research. In essence, the Planetary Boundary analysis simply identifies Earth System processes that – in the same manner as climate – regulate the stability of the Earth System, and if impacted too far by human activities potentially can disrupt the functioning of the Earth System. The Planetary Boundaries is, then, nothing more than a natural sciences contribution to an important societal discussion and which presents evidence which can support the definition of Planetary Boundaries to safeguard a stable and resilient Earth system. How this then translates to governance is another issue entirely and important social science contributions have addressed these (Galaz et al 2012). As our research shows, there is natural science evidence that global management of some environmental challenges is necessary. From the social science literature (Biermann et al., 2012) as well as from real world policy making, we see that such global scale regulation is possible to construct in a democratic manner and does establish a safe operating space, e.g. the Montreal protocol, a global agreement to address one of the identified planetary boundaries and which, to our knowledge, is never referred to as a “global authority ruling over humanity”. As noted above, the UNFCCC process is also fundamentally concerned with establishing the global “rules of the game” by which society can continue to develop within a climate planetary boundary. The Aichi targets (within the UN Convention on Biological Diversity) of setting aside marine and terrestrial areas for conservation are also good examples of the political translation of a science based concern over global loss of biodiversity. The coming SDG (Sustainable Development Goals) framework includes a proposed set of four goals (oceans, climate, biodiversity and freshwater), which is a de-facto example of applying planetary boundary thinking to create a global framework for safeguarding a stable environment on the planet for societies and communities across the world. We find it interesting – and encouraging – that societies and the world community are already developing management tools within several “planetary boundary domains”. In all cases, this is happening in good democratic order and building upon bottom-up processes and informed by science. This ought to be reassuring for Ellis et al. who portray implementation of Planetary Boundary thinking as a dark force of planetary rule.
* * *
[Reaction]
The Limits of Planetary Boundaries 2.0 (Brave New Climate)
Today a new paper appeared in the journal Science, called “Planetary boundaries: Guiding human development on a changing planet“, which attempts to refine and clarify the concept. It states that four of nine planetary boundaries have been crossed, re-imagines the biodiversity boundary as one of ‘biodiversity integrity’, and introduces the concept of ‘novel entities’. A popular summary in the Washington Post can be read here. On the invitation of New York Times “Dot Earth” reporter Andy Revkin, my colleagues and I have written a short response, which I reproduce below. The full Dot Earth article can be read here.
Steffen et al (2015) revise the “planetary boundaries framework” initially proposed in 2009 as the “safe limits” for human alteration of Earth processes(Rockstrom et al 2009). Limiting human harm to environments is a major challenge and we applaud all efforts to increase the public utility of global-change science. Yet the planetary boundaries (PB) framework – in its original form and as revised by Steffen et al – obscures rather than clarifies the environmental and sustainability challenges faced by humanity this century.
Steffen et al concede that “not all Earth system processes included in the PB have singular thresholds at the global/continental/ocean basin level.” Such processes include biosphere integrity (see Brook et al 2013), biogeochemical flows, freshwater use, and land-system change. “Nevertheless,” they continue, “it is important that boundaries be established for these processes.” Why? Where a global threshold is unknown or lacking, there is no scientifically robust way of specifying such a boundary – determining a limit along a continuum of environmental change becomes a matter of guesswork or speculation (see e.g. Bass 2009;Nordhaus et al 2012). For instance, the land-system boundary for temperate forest is set at 50% of forest cover remaining. There is no robust justification for why this boundary should not be 40%, or 70%, or some other level.
While the stated objective of the PB framework is to “guide human societies” away from a state of the Earth system that is “less hospitable to the development of human societies”, it offers little scientific evidence to support the connection between the global state of specific Earth system processes and human well-being. Instead, the Holocene environment (the most recent 10,000 years) is assumed to be ideal. Yet most species evolved before the Holocene and the contemporary ecosystems that sustain humanity are agroecosystems, urban ecosystems and other human-altered ecosystems that in themselves represent some of the most important global and local environmental changes that characterize the Anthropocene. Contrary to the authors’ claim that the Holocene is the “only state of the planet that we know for certain can support contemporary human societies,” the human-altered ecosystems of the Anthropocene represent the only state of the planet that we know for certain can support contemporary civilization.
Human alteration of environments produces multiple effects, some advantageous to societies, such as enhanced food production, and some detrimental, like environmental pollution with toxic chemicals, excess nutrients and carbon emissions from fossil fuels, and the loss of wildlife and their habitats. The key to better environmental outcomes is not in ending human alteration of environments but in anticipating and mitigating their negative consequences. These decisions and trade-offs should be guided by robust evidence, with global-change science investigating the connections and tradeoffs between the state of the environment and human well-being in the context of the local setting, rather than by framing and reframing environmental challenges in terms of untestable assumptions about the virtues of past environments.
Even without specifying exact global boundaries, global metrics can be highly misleading for policy. For example, with nitrogen, where the majority of human emissions come from synthetic fertilizers, the real-world challenge is to apply just the right amount of nitrogen to optimize crop yields while minimizing nitrogen losses that harm aquatic ecosystems. Reducing fertilizer application in Africa might seem beneficial globally, yet the result in this region would be even poorer crop yields without any notable reduction in nitrogen pollution; Africa’s fertilizer use is already suboptimal for crop yields. What can look like a good or a bad thing globally can prove exactly the opposite when viewed regionally and locally. What use is a global indicator for a local issue? As in real estate, location is everything.
Finally, and most importantly, the planetary boundaries are burdened not only with major uncertainties and weak scientific theory – they are also politically problematic. Real world environmental challenges like nitrogen pollution, freshwater consumption and land-use change are ultimately a matter of politics, in the sense that there are losers and winners, and solutions have to be negotiated among many stakeholders. The idea of a scientific expert group determining top-down global limits on these activities and processes ignores these inevitable trade-offs and seems to preclude democratic resolution of these questions. It has been argued that (Steffen et al 2011):
Ultimately, there will need to be an institution (or institutions) operating, with authority, above the level of individual countries to ensure that the planetary boundaries are respected. In effect, such an institution, acting on behalf of humanity as a whole, would be the ultimate arbiter of the myriad trade-offs that need to be managed as nations and groups of people jockey for economic and social advantage. It would, in essence, become the global referee on the planetary playing field.
Here the planetary boundaries framework reaches its logical conclusion with a political scenario that is as unlikely as it is unpalatable. There is no ultimate global authority to rule over humanity or the environment. Science has a tremendously important role to play in guiding environmental management, not as a decider, but as a resource for deliberative, evidence-based decision making by the public, policy makers, and interest groups on the challenges, trade-offs and possible courses of action in negotiating the environmental challenges of societal development (DeFries et al 2012). Proposing that science itself can define the global environmental limits of human development is simultaneously unrealistic, hubristic, and a strategy doomed to fail.
As tempestades que têm desabado sobre a cidade de São Paulo desde o fim de dezembro derrubaram árvores e postes, mas não serviram para abastecer as represas do Cantareira, prolongando a crise da água. Cientistas, porém, afirmam que isso é compreensível e era até esperado.
O problema que leva à essa situação paradoxal passa por uma espécie de pane que acontece pelo segundo verão consecutivo no sistema que os meteorologistas chamam de ZCAS (Zona de Convergência do Atlântico Sul). Trata-se de uma banda de nuvens que se estende desde o oeste da Amazônia até Mato Grosso, Minas Gerais, São Paulo e segue até alto mar.
“O sistema, que favoreceria as chuvas na região central do Brasil como um todo, não está atuando como deveria”, diz Anna Bárbara de Melo, do CPTEC (Centro de Previsão de Tempo e Estudos Climáticos), ligado ao Instituto Nacional de Pesquisas Espaciais.
Em dezembro, a ZCAS entrou em ação, mas no lugar “errado”. “O sistema ocorreu, só que favorecendo a região sul da Bahia e o Tocantins”, diz a pesquisadora. “Todo o estado de Minas, em dezembro, teve menos precipitação que o normal, com exceção de algumas áreas no norte.”
Segundo o climatologista Tércio Ambrizzi, da USP, o fenômeno pode estar relacionado à mudança climática.
“O fato de a atmosfera estar mais aquecida tem gerado uma variabilidade climática maior, enfatizando os eventos extremos”, diz o climatologista. “Em 2010 e 2011, nós estávamos enfrentando as inundações e mortes ocorridas nos deslizamentos do Rio de Janeiro”, conta Ambrizzi.
“Naquele ano o Cantareira estava com mais de 100% da capacidade, vertendo água e prejudicando algumas cidades. Três anos depois, passamos para um extremo seco com chuvas abaixo da média.”
CAPITAL
Mas, se falta chuva na Cantareira, por que tanta água na capital?
Isso se explica por um outro fenômeno, tipicamente relacionado às chuvas de verão: as ilhas de calor.
Em grandes concentrações urbanas, sem vegetação, o pouco de umidade que existe sobre essas áreas tende a subir em função do calor, até atingir temperaturas mais baixas e se condensar. Isso cria nuvens com uma extensão horizontal relativamente pequena, mas uma extensão vertical grande, com bastante água. A chuva então cai numa região específica, com muita violência, explica Ambrizzi. Em geral, tais tempestades ocorrem no início da noite.
Essas fortes descargas, concentradas em horários limitados, não chegaram nem a trazer um volume médio histórico de água nem mesmo para a capital.
Na primeira metade de janeiro, a estação meteorológica do Mirante de Santana, na zona norte de São Paulo, registrou 71 mm de chuva acumulada, quando a média histórica era de 130 mm. No Cantareira, mais ao norte, a situação é pior, com apenas 60 mm de chuva tendo ocorrido até agora, menos da metade do que se esperava. O nível do reservatório caiu de 7,2% para 6,2%, numa época do ano em que costuma subir.
Algumas das chuvas de verão estimuladas pela mancha urbana de São Paulo poderiam até ter contribuído para elevar o nível de algumas represas do sistema Cantareira, mas aí surge o terceiro problema. Segundo hidrólogos, o solo da maior parte das represas já estava tão seco, castigado pelo sol, que boa parte da água foi simplesmente absorvida pela terra, sem causar nenhuma elevação no nível dos reservatórios.
Esse “efeito esponja”, diz Ambrizzi, pode ter anulado qualquer benefício que chuvas de verão tenham trazido para as represas do Cantareira mais próximas da capital.
Summary: In the midst of the California rainy season, scientists are embarking on a field campaign designed to improve the understanding of the natural and human-caused phenomena that determine when and how the state gets its precipitation. They will do so by studying atmospheric rivers, meteorological events that include the famous rainmaker known as the Pineapple Express.
An atmospheric river reaches the San Francisco Bay Area, Dec. 11, 2014. Credit: University of Wisconsin
In the midst of the California rainy season, scientists are embarking on a field campaign designed to improve the understanding of the natural and human-caused phenomena that determine when and how the state gets its precipitation. They will do so by studying atmospheric rivers, meteorological events that include the famous rainmaker known as the Pineapple Express.
CalWater 2015 is an interagency, interdisciplinary field campaign starting January 14, 2015. CalWater 2015 will entail four research aircraft flying through major storms while a ship outfitted with additional instruments cruises below. The research team includes scientists from Scripps Institution of Oceanography at UC San Diego, the Department of Energy’s Pacific Northwest National Laboratory, NOAA, and NASA and uses resources from the DOE’s Atmospheric Radiation Measurement (ARM) Climate Research Facility — a national scientific user facility.
The study will help provide a better understanding of how California gets its rain and snow, how human activities are influencing precipitation, and how the new science provides potential to inform water management decisions relating to drought and flood.
“After several years in the making by an interdisciplinary science team, and through support from multiple agencies, the CalWater 2015 field campaign is set to observe the key conditions offshore and over California like has never been possible before,” said Scripps climate researcher Marty Ralph, a CalWater lead investigator. “These data will ultimately help develop better climate projections for water and will help test the potential of using existing reservoirs in new ways based on atmospheric river forecasts.”
Like land-based rivers, atmospheric rivers carry massive amounts of moisture long distances — in California’s case, from the tropics to the U.S. West Coast. When an atmospheric river hits the coast, it releases its moisture as precipitation. How much and whether it falls as rain or snow depends on aerosols — tiny particles made of dust, sea salt, volatile molecules, and pollution.
The researchers will examine the strength of atmospheric rivers, which produce up to 50 percent of California’s precipitation and can transport 10-20 times the flow of the Mississippi River. They will also explore how to predict when and where atmospheric rivers will hit land, as well as the role of ocean evaporation and how the ocean changes after a river passes.
“Climate and weather models have a hard time getting precipitation right,” said Ralph. “In fact, the big precipitation events that are so important for water supply and can cause flooding, mostly due to atmospheric rivers, are some of the most difficult to predict with useful accuracy. The severe California drought is essentially a result of a dearth of atmospheric rivers, while, conversely, the risk of Katrina-like damages for California due to severe ARs has also been quantified in previous research.”
For the next month or more, instrument teams will gather data from the NOAA research vessel Ronald H. Brown and two NOAA, one DOE, and one NASA research aircraft with a coordinated implementation strategy when weather forecasters see atmospheric rivers developing in the Pacific Ocean off the coast of California. NASA will also provide remote sensing data for the project.
“Improving our understanding of atmospheric rivers will help us produce better forecasts of where they will hit and when, and how much rain and snow they will deliver,” said Allen White, NOAA research meteorologist and CalWater 2015 mission scientist. “Better forecasts will give communities the environmental intelligence needed to respond to droughts and floods.”
Most research flights will originate at McClellan Airfield in Sacramento. Ground-based instruments in Bodega Bay, Calif., and scattered throughout the state will also collect data on natural and human contributions to the atmosphere such as dust and pollution. This data-gathering campaign follows the 2009-2011 CalWater1 field campaign, which yielded new insights into how precipitation processes in the Sierra Nevada can be influenced by different sources of aerosols that seed the clouds.
“This will be an extremely important study in advancing our overall understanding of aerosol impacts on clouds and precipitation,” said Kimberly Prather, a CalWater lead investigator and Distinguished Chair in Atmospheric Chemistry with appointments at Scripps Oceanography and the Department of Chemistry and Biochemistry at UC San Diego. “It will build upon findings from CalWater1, adding multiple aircraft to directly probe how aerosols from different sources, local, ocean, as well as those from other continents, are influencing clouds and precipitation processes over California.”
“We are collecting this data to improve computer models of rain that represent many complex processes and their interactions with the environment,” said PNNL’s Leung. “Atmospheric rivers contribute most of the heavy rains along the coast and mountains in the West. We want to capture those events better in our climate models used to project changes in extreme events in the future.”
Prather’s group showed during CalWater1 that aerosols can have competing effects, depending on their source. Intercontinental mineral dust and biological particles possibly from the ocean corresponded to events with more precipitation, while aerosols produced by local air pollution correlated with less precipitation.
The CalWater 2015 campaign is comprised of two interdependent efforts. Major investments in facilities include aircraft, ship time, and sensors by NOAA. Marty Ralph, Kim Prather, and Dan Cayan from Scripps, and Chris Fairall, Ryan Spackman, and Allen White of NOAA lead CalWater-2. The DOE-funded ARM Cloud Aerosol Precipitation Experiment (ACAPEX) is led by Ruby Leung from PNNL. NSF and NASA have also provided major support for aspects of CalWater, leveraging the NOAA and DOE investments.
POSTED ON JANUARY 15, 2015 AT 11:05 AM UPDATED: JANUARY 15, 2015 AT 1:50 PM
A Sri Lankan man throws his bait as he fishes in Colombo, Sri Lanka, Monday, July 1, 2013.
CREDIT: AP PHOTO/ERANGA JAYAWARDENA
A new study from scientists at Harvard and Rutgers Universities has been sweepingtheinternet, and for good reason: it shows, quite alarmingly, that the planet’s seas have been rising much faster than we thought.
The research can be confusing on its face. At first glance, it shows that scientists have actually been overstating the rate of sea level rise for the first 90 years of the 20th century. Instead of rising about six inches over that period of time, the Harvard and Rutgers scientists discovered that the sea actually only rose by about five inches. That’s a big overstatement — a two quadrillion gallon overstatement, in fact — enough to fill three billion Olympic-size swimming pools, the New York Times reported.
But here’s the thing. If the sea wasn’t rising as steadily as we believed from 1900 to 1990, that means that it has been rising much more quickly than we thought from 1990 to the present day. In other words, we used to think the rate of acceleration of sea level rise in the last 25 years was only a little worse compared to the past — now that we know the rate used to be much slower, we know that it’s much worse.
This chart shows as estimate of global sea level side from four different analyses, shown in red, blue, purple, and black. Shaded regions show uncertainty.
CREDIT: NATURE
“What this paper shows is that the sea-level acceleration over the past century has been greater than had been estimated by others,” lead writer Eric Morrow said in a statement. “It’s a larger problem than we initially thought.”
Specifically, previous research had stated the seas rose about two-thirds of an inch per decade between 1900 and 1990. But with the new study, that rate was recalculated to less than half an inch a decade. Both old and new research say that since 1990, the ocean has been rising at about 1.2 inches a decade, meaning the gap is much wider than previously thought.
Most scientists believe that the main driver of sea level rise is the thermal expansion of warming oceans and the melting of the world’s ice sheets and mountain glaciers, two phenomena driven by global warming. Antarctica, for example, is losing land ice at an accelerating rate. In December, scientists discovered that a West Antarctic ice sheet roughly the size of Texas is losing the amount of ice equivalent to Mount Everest every two years, representing a melt rate that has tripled over the last decade.
The common skeptic argument is that while Antarctica is losing land ice, it is actually gaining sea ice. While that’s true, sea ice melt does not affect sea level rise. It’s like an ice cube in a glass — if it melts, nothing happens. Up north in the Arctic, however, the loss of sea ice is just as important to look at, because when it melts, more sunlight is absorbed by the oceans. In Antarctica, sea ice melt is less of a problem for ocean warmth.
In addition, tropical glaciers in the Andes Mountains are melting, threatening freshwater supplies in South America. Some scientists have also predicted that the Greenland Ice Sheet — which covers about 80 percent of the massive country — is approaching a “tipping point” that could also have “huge implications” for global sea levels and ocean carbon dioxide absorption.
“We know the sea level is changing for a variety of reasons,” study co-author Carling Hay said. “There are ongoing effects due to the last ice age, heating and expansion of the ocean due to global warming, changes in ocean circulation, and present-day melting of land-ice, all of which result in unique patterns of sea-level change.”
All that may seem pretty grim, but there is a least one good thing to come out of the research — a new and hopefully more accurate method for measuring sea level rise. Before this study, scientists estimated global sea level by essentially dropping long yard sticks into different points of the ocean, and then averaging out the measurements to see if the ocean rose or fell.
For this study, Morrow and Hay attempted to use the data from how individual ice sheets contribute to global sea-level rise, and how ocean circulation is changing to inform their measurements. If the method proves to be better, it could serve to, as the New York Times put it, “increase scientists’ confidence that they understand precisely why the ocean is rising — and therefore shore up their ability to project future increases.”
Summary: The year 2014 ranks as Earth’s warmest since 1880, according to two separate analyses by NASA and National Oceanic and Atmospheric Administration (NOAA) scientists. The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, according to an analysis of surface temperature measurements.
This color-coded map displays global temperature anomaly data from 2014. Credit: NASA’s Goddard Space Flight Center
The year 2014 ranks as Earth’s warmest since 1880, according to two separate analyses by NASA and National Oceanic and Atmospheric Administration (NOAA) scientists.
The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, according to an analysis of surface temperature measurements by scientists at NASA’s Goddard Institute of Space Studies (GISS) in New York.
In an independent analysis of the raw data, also released Friday, NOAA scientists also found 2014 to be the warmest on record.
“NASA is at the forefront of the scientific investigation of the dynamics of the Earth’s climate on a global scale,” said John Grunsfeld, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “The observed long-term warming trend and the ranking of 2014 as the warmest year on record reinforces the importance for NASA to study Earth as a complete system, and particularly to understand the role and impacts of human activity.”
Since 1880, Earth’s average surface temperature has warmed by about 1.4 degrees Fahrenheit (0.8 degrees Celsius), a trend that is largely driven by the increase in carbon dioxide and other human emissions into the planet’s atmosphere. The majority of that warming has occurred in the past three decades.
“This is the latest in a series of warm years, in a series of warm decades. While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases,” said GISS Director Gavin Schmidt.
While 2014 temperatures continue the planet’s long-term warming trend, scientists still expect to see year-to-year fluctuations in average global temperature caused by phenomena such as El Niño or La Niña. These phenomena warm or cool the tropical Pacific and are thought to have played a role in the flattening of the long-term warming trend over the past 15 years. However, 2014’s record warmth occurred during an El Niño-neutral year.
“NOAA provides decision makers with timely and trusted science-based information about our changing world,” said Richard Spinrad, NOAA chief scientist. “As we monitor changes in our climate, demand for the environmental intelligence NOAA provides is only growing. It’s critical that we continue to work with our partners, like NASA, to observe these changes and to provide the information communities need to build resiliency.”
Regional differences in temperature are more strongly affected by weather dynamics than the global mean. For example, in the U.S. in 2014, parts of the Midwest and East Coast were unusually cool, while Alaska and three western states — California, Arizona and Nevada — experienced their warmest year on record, according to NOAA.
The GISS analysis incorporates surface temperature measurements from 6,300 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations. This raw data is analyzed using an algorithm that takes into account the varied spacing of temperature stations around the globe and urban heating effects that could skew the calculation. The result is an estimate of the global average temperature difference from a baseline period of 1951 to 1980.
NOAA scientists used much of the same raw temperature data, but a different baseline period. They also employ their own methods to estimate global temperatures.
GISS is a NASA laboratory managed by the Earth Sciences Division of the agency’s Goddard Space Flight Center, in Greenbelt, Maryland. The laboratory is affiliated with Columbia University’s Earth Institute and School of Engineering and Applied Science in New York.
NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites, as well as airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.
The data set of 2014 surface temperature measurements is available at:
2014 was 0.69°C (1.24°F) above the 20th century average of 14.1°C, making it the hottest year on record since NOAA’s National Climatic Data Center began taking measurements in 1880. The record surpassed the previous hottest year record, shared by 2005 and 2010, by 0.04°C (0.07°F). As the Earth heats up, new temperature records are increasingly common, but 2014’s record-breaking global temperature—which represents the average of land and ocean surface temperatures—is especially remarkable given that 2014 saw little influence from El Niño warming and was an ENSO-neutral year. Here is some important context on how the 2014 temperature record reaffirms long-term, human-caused global warming trends; how recent warming is tied to extreme weather patterns; and how analysts use global temperature datasets to assess the state of the climate. Top points to note include:
In 2014, the U.S. saw unprecedented levels of simultaneous extreme heat in the West and cooler than average temperatures in the East, with both trends linked to global warming.
2014’s heat record is alarming in the absence of a full El Niño-Southern Oscillation (ENSO) and provides yet more evidence that that human-caused warming is now the dominant force driving changes in global temperature trends.
Global warming is not only on the rise but is fueling extreme weather and unprecedented patterns of extreme temperature anomalies.
Sea surface temperatures in particular are reaching record highs, driving extreme atmospheric patterns that cause heavy rainfall and floods in some countries and droughts in others.
Three of the four major groups that track combined ocean and land surface global temperatures—NOAA, NASA, and the JMA— have confirmed that 2014 was the hottest year on record, even with biases that underestimate warming in the ocean and Arctic.
Record Heat Supports Long-Term Warming Trend
Climate change linked to unusual temperature trends in the U.S.
Human-caused warming in 2014 trumped the ENSO signal.
February 1985 was the last month where global temperature fell below the 20th century monthly average, making December 2014 the 358th consecutive month where global land and ocean surface temperature was above average. Each of the last three decades has been much warmer than the decade before. In the 1990s, every year was warmer than the average of the previous decade, and the 2000s were warmer still. Now, according to NOAA, thirteen out of fifteen of the hottest years on record occurred since 2000, and the two exceptions (1997 and 1998) were strong El Niño years. In 2014, six out of 12 months tied or topped previous monthly global temperature records.
The combination of human-caused warming and year-to-year natural variation has generally determined which years set new temperature records. Prior to 2014, 2010 and 2005 tied for the hottest year on record, both of which were El Niño years. This makes sense because, in addition to long-term warming due to an increase in atmospheric greenhouse gases, the ENSO can bump global temperatures up or down for one to several years at a time. During El Niño events, some of the heat that gets stored in the oceans spreads out and gets released back into the atmosphere, causing large-scale atmospheric circulation changes and an increase in global temperature. La Niña periods, on the other hand, are characterized by cooler than average temperatures.
What makes 2014 especially remarkable is that it set a new global temperature record during an ENSO-neutral year. From January-February 2014, sea surface temperatures were mostly below average across the eastern equatorial Pacific. By the fall, temperatures were above average, leading to speculation about the onset of an El Niño event. Scientists in the U.S. have three criteria, each of which must be met to officially declare the start of an El Niño. Conditions in the fall of 2014 met the first two criteria (that monthly sea surface temperature anomalies exceed 0.5°C and last across several seasons), but not the final criterion (observance of an atmospheric response associated with more rain over the central Pacific and less rain over Indonesia).
Global annual average temperature anomalies (relative to the 1961-1990 average) for 1950-2013 based on an average of the three data sets from NASA, NOAA and the UK Met Office. Coloring indicates whether a year was classified as an El Niño year (red), an ENSO neutral year (grey) or a La Niña year (blue).
This means 2014 was the hottest year on record without the added boost from a full-fledged El Niño event, and it will have been even warmer than recent years with moderate ENSO contributions (2010 and 2005). Moreover, this implies that the amount of warming due to human activity is enough to trump the natural year-to-year variation associated with the ENSO cycle. With NOAA holding there is a 50-60 percent chance of a noteworthy El Niño event developing in early 2015, there’s a good chance 2015 will be even hotter, making for two record-setting years in a row. What’s more, as more heat is pumped into the ocean, climate models project a doubling in the frequency of extreme El Niño events in the future.
Record ocean surface temperatures driving 2014’s heat demonstrate the ocean’s role as an important heat sink and are linked to unusual atmospheric patterns.
Global average sea surface temperature (which is a conservative and incomplete cross-section of the ocean) has shown an alarming trend in 2014. From MaythroughNovember, each month set a new record for global sea surface temperature anomaly (or departure from average), with June also setting a new record for the highest departure from average for any month. The record was short-lived, however, as June’s temperatures were quickly surpassed first in August and then again in September. A study analyzing the record ocean surface warming in 2014 finds that unusually warm surface temperatures in the North Pacific were largely responsible. While it is still too soon to know for sure, this could indicate the start of a new trend where the massive amount of heat being absorbed by the ocean is making its way to the surface, and getting reflected in surface temperatures.
Oceanic warming is especially worrisome because it has broad and complex impacts on the global climate system. Most immediately, the ocean is connected to the atmosphere—the two systems work together to move heat and freshwater across latitudes to maintain a balanced climate. This is known as ocean-atmospheric coupling. Climate scientists are actively researching how changes in ocean and atmospheric heat content impact circulation patterns, in particular how changes in circulation affect the weather patterns that steer storms. For example, one recent analysis found that ocean warming might cause atmospheric precipitation bands to shift toward the poles, causing an increase in the intensity and frequency of extreme precipitation events at middle and high latitudes as well as a reduction in the same near the equator. Already, we are starting to experience patterns consistent with this kind of analysis.
Recent observational data has indicated a slowing in the rate of ocean surface warming relative to other climate variables, which scientists have pinned to cool-surface La Niña episodes in the equatorial Pacific. However, it is important to remember that different regions of the ocean heat up differently, and global observational data often underreports changes in regions that are difficult to measure (such as around the poles or in the deep oceans). The deep oceans in particular are responsible for absorbing much of the excess heat. Deep ocean circulation patterns carry sun-warmed tropical waters into the higher latitudes where they sink and flow back towards the Equator, acting as a kind of buffer to climate change by slowing the rate of surface warming. In addition, research shows that three major ocean basins—the Equatorial Pacific, North Atlantic, and Southern Ocean—are important areas of ocean heat uptake and that observational data often fails to capture the full extent of actual warming in these regions. Despite the limitations associated with measuring changes in ocean heat content, however, we are still seeing record-breaking heat in the oceans.
Warmer World Linked To More Extreme Weather
Unusual jet stream patterns, linked to warming in the Arctic and warmer sea surface temperatures in the Pacific, drove extreme drought in the western U.S. and chills in the East.
Temperatures in the U.S. throughout 2014 were exceptional, marked by simultaneous record heat in the West and cooler than average temperatures in the East. While it may seem strange for global warming to sometimes be accompanied by colder winters, recent studies hold that warming in the Arctic and in the western Pacific Ocean has led to changes in the jet stream, which can result in volatile weather patterns and unusually persistent periods of extreme weather in the mid-northern latitudes. The avenues through which warming influences the jet stream represent a new and still emerging facet of climate science.
Throughout 2013 and 2014, the jet stream frequently dipped from the Arctic to the south, creating a persistent dipole—or two opposed atmospheric pressure systems—with the Western U.S. receiving warm, high-pressure air from the Pacific, and the Eastern U.S. receiving Arctic air carried by the sunken jet stream.
Arguably the most severe outgrowth of this recent trend in the U.S. has been the historic 2012-2014 California drought (which forecasters predict will continue into 2015). The state began 2014 with its lowest Sierra snowpack recording—12 percent—in more than 50 years of record keeping. In August, California set a new U.S. Drought Monitor record with 58.4 percent of the state in the worst drought category, known as “exceptional drought.” The dry conditions along the West Coast also fueled a severe wildfire season. On August 2, California Governor Jerry Brown declared a state of emergency due to the ongoing drought, fires and deteriorating air quality throughout the state. Meanwhile, Oregon and Washington topped the nation in total number of acres burned, with Washington experiencing its largest wildfire ever recorded.
The horizontal line marks the precipitation level of the 2000 – 2004 drought, the worst of the past 800 years up to 2012. Droughts of this intensity are predicted to be the new normal by 2030, and will be considered an outlier of extreme wetness by 2100
By contrast, the Central and Eastern U.S. experienced unusually persistent cold temperatures throughout 2014. The winter of 2013-2014 was among the coldest on record for the Great Lakes, and Minnesota, Wisconsin, Michigan, Illinois, and Indiana each had winter temperatures that ranked among the ten coldest on record. Ice coverage over the Great Lakes peaked at 92.2 percent on March 6, the second highest measurement on record. The summer was also cooler than average for the region, which led into an unseasonably frigid fall.
Several U.S. locations experienced their coldest Novembers on record due to a procession of cold fronts tapping air from the Arctic. At the start, the Arctic outbreak was largely the product of the extra-tropical remnant of Typhoon Nuri from the Pacific. The system was the most powerful storm to ever move over the Bering Sea, gaining strength from warmer than average ocean and atmospheric conditions. Due to its strength, the storm caused the jet stream to sink southward bringing Arctic conditions to the United States. As a result, North America snow cover reached a record extent for mid-November—15.35 million square kilometers—crushing the old record from 1985 by over two million square kilometers. On November 16, temperatures were warmer in Alaska (significantly in some cases) than in many Central and Eastern U.S. states. Arctic temperatures ran up to 40 degrees above average (with Fairbanks, Alaska blowing away old temperature records by almost two degrees), while the Central and Eastern U.S. experienced record snowfall and temperatures up to 40 degrees below average.
The weather forecast across the United States from November 16 through November 20
Taken together, 2014 has witnessed a record-setting split in the U.S. between regions of simultaneous hot and cold temperatures. According to Scott Robeson, a climate scientist at Indiana University Bloomington, these hot and cold extremes are important. Robeson recently authored a studyon warm and cold anomalies in the northern hemisphere and found, “Average temperatures don’t tell us everything we need to know about climate change. Arguably, these cold extremes and warm extremes are the most important factors for human society.” Robeson notes that temperatures in the Northern Hemisphere are considerably more volatile than in the South, where there is less land mass to add complexity to weather systems. The extreme weather observed in 2014 in the U.S. has many layers of complexity, with ocean and Arctic temperatures influencing circulation patterns, and agrowingbodyofscientificevidence suggests global warming may be the common denominator.
Internationally, 2014 saw record heat and drought in some countries, but cold spells and flooding in others. As in the U.S., many of these trends are associated with unusual ocean-atmospheric circulation patterns with likely connections to climate change.
Perturbations in the jet stream have wide ranging climate impacts that vary depending on geographical region. One recent analysis finds a connection between a wavy jet stream pattern—with greater dips from north to south—and increases in the probabilities of heat waves in western North America and central Asia; cold outbreaks in eastern North America; droughts in central North America, Europe and central Asia; and wet spells in western Asia.
Just as most of the weather in the western U.S. is below the jet stream and connected to the Pacific, most of the weather in Europe rides in under the jet stream from the Atlantic. While the jet stream has been unusually far north in the Pacific, bringing high temperatures and drought to the western U.S., the jet stream has been unusually far south across the Atlantic. As a result, the UK was hit by an exceptional run of winter storms and an intense polar vortex at the start of 2014, with rainfall amounts, storm intensities, wave heights, and other extreme weather trends at or near record levels. Related damages from December 23, 2013 – March 1, 2014 added up to $1.5 billion. Global warming has doubled the risk of extreme conditions, as warmer temperatures and melting ice in the Arctic cause the jet stream to push cold air southwards.
In January and February, an exceptional dry spell hit Southeast Asia, with the worst impacts—including water shortages, wildfires, crop failure, and increased incidence of infectious disease—felt in Singapore, Malaysia, Indonesia, and Thailand. Singapore suffered its longest dry spell on record between January 13 and February 8, which caused extensive damage to rice crops and fish stocks at several offshore farms. Dengue hotspots in Malaysia experienced a four-fold increase in infections to about 14,000 compared with the same period last year.
Continuous, heavy rainfall in May resulted in some of the worst flooding ever recorded in Southeast Europe, mainly Serbia, Bosnia and Herzegovina (BiH), and Croatia. Three months’ worth of rain fell in only three days, making it the heaviest rainfall in BiH since records began in 1894. On May 15, the Serbian Government declared a state of emergency for its entire territory. The storm caused $4.5 billion in damage.
May also saw the Eastern Pacific’s strongest May hurricane on record, Hurricane Amanda, which peaked as a top-end Category 4 hurricane with 155 mph winds. The impressive hurricane was linked to record sea surface temperatures, which measured 0.59°C above the 20th century average of 16.3°C, the highest temperature anomaly on record for May. In July in the Western Pacific, Typhoon Rammasun became the strongest typhoon to hit China’s Hainan Province in 21 years, surprising forecasters as it gained more strength than anticipated. Like Amanda, wind speeds topped out around 155 mph. The typhoon remained very strong as it made landfall, leading to extreme rainfall and flooding in China that caused $7.2 billion in damage. Global warming is expected to increase the rainfall from tropical cyclones.
In Australia, 2014 was the third hottest year on record (with 2013 being the hottest) and was characterized by frequent periods of abnormally warm weather that contributed to huge bushfires in Victoria and South Australia. According to Dr. Karl Braganza, manager of the Bureau of Meteorology’s climate monitoring section, Australia is seeing “reoccurring heat waves, long durations of heat but very little cold weather.” A report by Australia’s Climate Council finds that the frequency and severity of bushfires is getting worse in the southern state of New South Wales each year due to “record-breaking heat and hotter weather over the long term.”
Following the wettest January to August on record, the UK experienced its driest September since records began in 1910, receiving 19.4mm of rain, or 20 percent of the expected average. Monthly temperatures in the UK were also significantly above average. One recent study finds that human-caused global warming has increased the chances of extremely hot summers in parts of Europe tenfold. The UK Met Office is currently researching how jet stream variations and changes to atmospheric circulation may be increasing the risk of patterns that slow the movement of weather systems, allowing heat waves to develop and intensify.
Understanding the Global Surface Temperature Datasets
Three of the major global temperature datasets that combine both ocean and atmospheric temperatures have declared 2014 the hottest year on record.
The 10 warmest years on record according to the NOAA and NASA datasets.
The four most highly cited combined SST and land temperature datasets are NOAA’s MLOST, NASA’s GISTEMP, the UK’s HadCRUT, and the JMA’s CLIMAT. While HadCRUT has yet to confirm, NOAA, NASA and the JMA—using independent data and analysis—have decalred 2014 the hottest year on record. The Japanese Meteorological Agency (JMA) was one of the first agencies to report 2014’s heat record in a preliminary analysis and found that 2014’s global temperature was 0.63°C above average. NOAA’s data holds that 2014’s temperature was 0.69°C above average, and NASA that it was 0.68°C above average.
Satellites that measure temperatures in the lower atmosphere, or troposphere, did not rank 2014 as a record year, but the troposphere is only one region where excess heat gets stored.
Because satellite datasets measure the atmosphere, and not the climate system as a whole, it is inaccurate to compare satellite temperature averages with combined land and SST averages. Combined land and SST datasets are based on instrumental readings taken on site in the ocean and atmosphere, while satellite records focus on the troposphere and infer temperatures at various levels using measurements of radiance (the intensity of radiation passing through a point in a given direction). Both types of datasets improve our understanding of the rate at which the Earth is warming and how the climate system as a whole distributes heat. But because the two types of datasets vary in terms of their scope, it is perfectly possible for the atmospheric temperature average, as measured by satellites, not to set a new record, while the global combined land and SST average does.
This was the case in 2014. The two most widely cited satellite records are the University of Alabama in Huntsville (UAH) and the privately owned Remote Sensing Systems (RSS) datasets. According to the RSS data, 2014’s annual average temperature in the lower troposphere was the sixth warmest on record, or 0.26°C above the long-term average. The UAH data has not yet been confirmed, but will likely reaffirm the RSS finding. This is to be expected, however, in a year where record ocean heat was the dominant driver of observed warming.
Temperature analyses provide an important health gauge for the planet.
The instrumental temperature record—based on readings from ships and buoys that measure sea-surface temperature (SST) as well as land-based weather stations—has provided vital information about the Earth’s climate over the last century and beyond. To reconstruct global temperatures, each agency divides the Earth’s surface into latitude-longitude grid boxes that are used to integrate in situ (“on site”) temperature measurements from around the globe.
The three most highly cited combined SST and land temperature datasets are NOAA’s MLOST, NASA’s GISTEMP, and the UK’s HadCRUT. All three datasets report global average temperature as an anomaly, or departure from average, relative to a reference period. This is because absolute temperatures can vary (depending on factors like elevation), whereas anomalies allow for more meaningful comparisons between locations and accurate calculations of temperature trends. HadCRUT uses the most recent reference period to calculate anomalies, 1961-1990, followed by GISTEMP’s 1951-1980 period. MLOST, on the other hand, uses the 20th century, 1901-2000, as its reference period to establish a longer-term average.
Global Land and Ocean Temperature Anomalies, January-December
While the concept of these datasets is fairly simple, their construction is challenging due to difficulties in obtaining data; documenting and accounting for changes in instrumentation and observing practices; addressing changes in station location and local land use; understanding random measurement errors; and deciding where and how to fill in missing data in space and time. Each group has approached the above challenges somewhat differently. The final datasets differ in their spatial coverage, spatial resolution, starting year, and degree of interpolation (a method of constructing missing data points based on surrounding, discrete points). For this reason, NOAA, NASA, and UK Met Office global temperature anomalies vary subtly.
Global temperature data often underestimates the amount of warming due to coverage bias.
Analyzing temperature observations at a global scale often comes at the cost of not including important spatial detail. This challenge—known as coverage bias—is something all three of the major global temperature datasets struggle with and attempt to reconcile.
NOAA’s Merged Land-Ocean Surface Temperature Analysis (MLOST) uses land surface air temperatures taken from the Global Historical Climatology Network (GHCN) dataset and ocean temperatures from the Extended Reconstructed Sea Surface Temperature (ERSST) dataset, and combines these into a comprehensive global surface temperature dataset. The comprehensive dataset spans from 1880 to the present at monthly resolution on a 5×5 degree latitude-longitude grid. MLOST uses interpolation, but areas without enough data—mainly at the poles, over Africa, and at the center of the Atlantic and Pacific Oceans—are masked in the data analysis to prevent any overreliance on reconstructions that are based on too little data.
NASA Goddard’s Global Surface Temperature Analysis (GISTEMP) also uses GHCN data from 1880 to the present, but GISTEMP has some important differences from NOAA’s MLOST. While GISTEMP has a more focused spatial resolution, with a 2×2 grid, and better coverage at the poles due to the inclusion of data from Antarctic “READER” stations, it only provides data in terms of temperature anomalies. All three of the major global datasets report global temperatures as anomalies to make comparison and computation easier, but GISTEMP is unique in that it works solely with anomaly data from the outset. NOAA and HadCRUT have absolute temperature data from which they derive regional anomalies. As for HadCRUT, it is unique in that it incorporates many additional sources beyond GHCN and is the only global analysis that does not use interpolation. It also has more spatial coverage gaps than MLOST and GISTEMP and a tendency to significantly underreport warming, primarily due to a lack of temperature data at the Arctic, which is warming much fasterthan other regions.
Chuvas devem continuar abaixo da média em 2015, diz Cemaden (G1)
Ano deve ser influenciado por eventos extremos de 2014, diz especialista
Se o ano passado foi um período de condições climáticas extremas no Brasil, entre elas a seca em diversas regiões, a situação em 2015 pode piorar. Esta é a avaliação feita pelo Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden) em Cachoeira Paulista (SP), que já prevê chuvas abaixo da média novamente.
De acordo com o meteorologista do Cemaden, Marcelo Seluchi, neste verão choveu pouco mais da metade do normal para o período. O órgão é uma das extensões do Instituto Nacional de Pesquisas Espaciais (Inpe) para estudos e alertas de desastres naturais. “Comparado com o ano passado, a situação de 2015 pode piorar nas metrópoles em várias regiões do Brasil e no Vale do Paraíba”, afirma.
Cantareira pode secar em julho, prevê centro de monitoramento (O Globo)
Governador Alckmin diz que foi mal interpretado ao falar sobre racionamento
O Sistema Cantareira, responsável por abastecer 6,5 milhões de pessoas na Grande São Paulo, pode secar em julho, caso o consumo de água na Região Metropolitana continue o mesmo e a chuva mantenha o ritmo observado nos últimos meses. A projeção foi feita pelo Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden), ligado ao Ministério da Ciência e Tecnologia.
Combinação de seca e calor extremo agrava crise do Cantareira (Estadão)
Dados oficiais mostram que nos primeiros 15 dias do ano o sistema recebeu 35% menos água do que a média de janeiro passado, enquanto as temperaturas máximas na capital batem recordes
Apontada pelo governo Geraldo Alckmin (PSDB) como a causa da crise hídrica paulista no início de 2014, a combinação de seca severa nos mananciais e calor extremo na capital está ainda mais crítica em 2015. Dados oficiais mostram que nos primeiros 15 dias do ano o Sistema Cantareira recebeu 35% menos água do que a média de janeiro passado, enquanto as temperaturas máximas na cidade estão batendo o recorde registrado no mesmo período do ano anterior.
Novo estudo indica que nível do mar subiu apenas 1,2 mm entre 1900 e 1990; avaliações antigas diziam que elevação foi de 1,8mm
Do início do século 20 até a década passada, o nível dos oceanos subiu em ritmo 30% maior do que se imaginava, de acordo com um estudo realizado por pesquisadores da Universidade de Harvard (Estados Unidos).
Afirmação foi feita pela assessora sênior para a América Latina e o Caribe da instituição financeira; Karin Kemper afirmou também que aumento do nível dos mares pode ter impacto no Rio de Janeiro.
A assessora regional sênior do Banco Mundial para a América Latina e o Caribe, Karin Kemper, disse, em entrevista à Rádio ONU, que se a temperatura global continuar aumentando, a seca no nordeste do Brasil pode piorar.
“Sabemos que o nordeste sempre sofreu com as secas, mas poderia ter uma frequência mais intensa ou poderia ter secas mais prolongadas. Sabemos que isso tem efeitos econômicos tanto para a população do interior, mas também podemos imaginar que, por exemplo, as cidades grandes do nordeste podem sofrer mais impactos por insegurança hídrica.”
Investimentos
Citando o relatório lançado pelo Banco Mundial na semana passada, Kemper disse ainda que os impactos do aumento da temperatura serão maiores sobre as populações mais pobres, mais vulneráveis, mulheres, crianças, como também grupos indígenas.
A assessora para a América Latina e o Caribe alertou que investimentos que poderiam ser feitos em outros setores vão acabar sendo destinados para combater os efeitos climáticos.
“Se houver um aumento do nível dos mares, por exemplo, o cálculo que temos no relatório para o Rio de Janeiro varia de uma alta de, no mínimo, 62 cm até 1 metro, no máximo. Isso significa que se precisa fazer investimentos nas cidades costeiras. Esse dinheiro poderia ser utilizado em outras coisas como em hospitais, escolas e outros setores de desenvolvimento.”
O relatório do Banco Mundial disse que um novo padrão climático global pode reduzir em 70% a produção de soja no Brasil e a de trigo em 60%.
O documento mostra dois cenários futuros prevendo as consequências de aumentos médios da temperatura global de 2 e 4 graus centígrados, até 2050. Os especialistas calculam que os danos causados por enchentes costeiras devem chegar a US$ 22 bilhões, o equivalente a mais de R$ 56 bilhões.
Source: National Oceanic and Atmospheric Administration
Summary: Natural oceanic and atmospheric patterns are the primary drivers behind California’s ongoing drought. A high pressure ridge off the West Coast (typical of historic droughts) prevailed for three winters, blocking important wet season storms, with ocean surface temperature patterns making such a ridge much more likely.
Folsom Lake. Top photo taken in 2011, bottom taken in 2014. Credit: CA Dept. of Water Resources
According to a new NOAA-sponsored study, natural oceanic and atmospheric patterns are the primary drivers behind California’s ongoing drought. A high pressure ridge off the West Coast (typical of historic droughts) prevailed for three winters, blocking important wet season storms, with ocean surface temperature patterns making such a ridge much more likely. Typically, the winter season in California provides the state with a majority of its annual snow and rainfall that replenish water supplies for communities and ecosystems.
Further studies on these oceanic conditions and their effect on California’s climate may lead to advances in drought early warning that can help water managers and major industries better prepare for lengthy dry spells in the future.
“It’s important to note that California’s drought, while extreme, is not an uncommon occurrence for the state. In fact, multi-year droughts appear regularly in the state’s climate record, and it’s a safe bet that a similar event will happen again. Thus, preparedness is key,” said Richard Seager, report lead author and professor with Columbia University’s Lamont Doherty Earth Observatory.
This report builds on earlier studies, published in September in the Bulletin of the American Meteorological Society, which found no conclusive evidence linking human-caused climate change and the California drought. The current study notes that the atmospheric ridge over the North Pacific, which has resulted in decreased rain and snowfall since 2011, is almost opposite to what models project to result from human-induced climate change. The report illustrates that mid-winter precipitation is actually projected to increase due to human-induced climate change over most of the state, though warming temperatures may sap much of those benefits for water resources overall, while only spring precipitation is projected to decrease.
The report makes clear that to provide improved drought forecasts for California, scientists will need to fully understand the links between sea surface temperature variations and winter precipitation over the state, discover how these ocean variations are generated, and better characterize their predictability.
This report contributes to a growing field of science-climate attribution-where teams of scientists aim to identify the sources of observed climate and weather patterns.
“There is immense value in examining the causes of this drought from multiple scientific viewpoints,” said Marty Hoerling, report co-author and researcher with NOAA’s Earth System Research Laboratory. “It’s paramount that we use our collective ability to provide communities and businesses with the environmental intelligence they need to make decisions concerning water resources, which are becoming increasingly strained.”
Summary: A new study has found early warning signals of a reorganization of the Atlantic ocean’s circulation which could have a profound impact on the global climate system.
A new study by researchers at the University of Exeter has found early warning signals of a reorganisation of the Atlantic ocean’s circulation which could have a profound impact on the global climate system.
The research, published today in the journal Nature Communications, used a simulation from a highly complex model to analyse the Atlantic Meridional Overturning Circulation (AMOC), an important component of the Earth’s climate system.
It showed that early warning signals are present up to 250 years before it collapses, suggesting that scientists could monitor the real world overturning circulation for the same signals.
The AMOC is like a conveyor belt in the ocean, driven by the salinity and temperature of the water. The system transports heat energy from the tropics and Southern Hemisphere to the North Atlantic, where it is transferred to the atmosphere.
Experiments suggest that if the AMOC is ‘switched off’ by extra freshwater entering the North Atlantic, surface air temperature in the North Atlantic region would cool by around 1-3°C, with enhanced cooling of up to 8°C in the worst affected regions.
The collapse would also encourage drought in the Sahel — the area just south of the Sahara desert — and dynamic changes in sea level of up to 80cm along the coasts of Europe and North America.
“We found that natural fluctuations in the circulation were getting longer-lived as the collapse was approached, a phenomenon known as critical slowing down,” said lead author Chris Boulton.
“We don’t know how close we are to a collapse of the circulation, but a real world early warning could help us prevent it, or at least prepare for the consequences” adds co-author Professor Tim Lenton.
The study is the most realistic simulation of the climate system in which this type of early warning signal has been tested.
“The best early warning signals in the model world are in places where major efforts are going into monitoring the circulation in the real world — so these efforts could have unexpected added value’ adds Professor Lenton.
Journal Reference:
Chris A. Boulton, Lesley C. Allison, Timothy M. Lenton. Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model. Nature Communications, 2014; 5: 5752 DOI: 10.1038/ncomms6752
Summary: The global average temperature over land and ocean surfaces for January to October 2014 was the highest on record, according to the U.S. National Oceanic and Atmospheric Administration. It said October was the hottest since records began in 1880.
The global average temperature over land and ocean surfaces for January to October 2014 was the highest on record, according to NOAA. October was the hottest since records began in 1880. Credit: NOAA
The global average temperature over land and ocean surfaces for January to October 2014 was the highest on record, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). It said October was the hottest since records began in 1880.
NOAA said the combined global land and ocean average surface temperature for the January-October period was 0.68°C (1.22°F) above the 20th century average of 14.1°C (57.4°F). For October, it was 0.74°C (1.33°F) above the 20th century average of 14.0°C (57.1°F).
The high October temperature was driven by warmth across the globe over both the land and ocean surfaces and was fairly evenly distributed between the Northern and Southern Hemispheres. The Southern Hemisphere had its hottest October on record and the Northern Hemisphere its third warmest.
October marked the third consecutive month and fifth of the past six with a record high global temperature for its respective month (July was fourth highest).
The Tokyo Climate Center, which is a WMO Regional Climate Centre, also reported that October was the hottest on record. The record was also confirmed by data from NASA’s Goddard Institute for Space Studies.
WMO uses a combination of datasets to compile its annual Statement on the Status of the Global Climate. Additional information is drawn from the ERA-Interim reanalysis-based data set maintained by the European Centre for Medium-Range Weather Forecasts.
Agência FAPESP – Para conseguir prever com precisão eventos extremos, como tempestades, ou simular cenários de impactos das mudanças climáticas, é preciso avançar no conhecimento dos processos físicos que ocorrem no interior das nuvens e descobrir a variação de fatores como o tamanho das gotas de chuva, a proporção das camadas de água e de gelo e o funcionamento das descargas elétricas.
Com esse objetivo, uma série de campanhas para coleta de dados foi realizada entre 2010 e 2014 em seis cidades brasileiras – Alcântara (MA), Fortaleza (CE), Belém (PA), São José dos Campos (SP), Santa Maria (RS) e Manaus (AM) – no âmbito de um Projeto Temático FAPESP coordenado por Luiz Augusto Toledo Machado, do Instituto Nacional de Pesquisas Espaciais (Inpe). Essas campanhas contaram com a participação de pesquisadores da Universidade de São Paulo (USP) e de diversas faculdades de Meteorologia no Brasil, que sediaram os experimentos.
Os principais resultados da iniciativa, conhecida como “Projeto Chuva”, foram descritos em um artigo de capa do Bulletin of the American Meteorological Society, revista de grande impacto na área de meteorologia.
Segundo Machado, as regiões escolhidas para a pesquisa de campo representam os diferentes regimes de precipitação existentes no Brasil. “É importante fazer essa caracterização regional para que os modelos matemáticos possam fazer previsões em alta resolução, ou seja, em escala de poucos quilômetros”, disse o pesquisador.
Um conjunto comum de instrumentos – que inclui radares de nuvens de dupla polarização – foi usado nos diferentes sítios de forma que as medidas pudessem ser comparadas e parametrizadas para modelagem.
O radar de dupla polarização, em conjunto com outros instrumentos, envia ondas horizontais e verticais que, por reflexão, indicam o formato dos cristais de gelo e das gotas de chuva, ajudando a elucidar a composição das nuvens e os mecanismos de formação e intensificação das descargas elétricas durante as tempestades. Também foram coletados dados como temperatura, umidade e composição de aerossóis.
Além disso, experimentos adicionais distintos foram realizados em cada uma das seis cidades. No caso de Alcântara, onde a coleta de dados ocorreu em março de 2010, o experimento teve como foco o desenvolvimento de algoritmos de estimativa de precipitação para o satélite internacional Global Precipitation Measurement (GPM) – lançado em fevereiro de 2014 pela Nasa (a agência espacial americana) e pela Agência Japonesa de Exploração Aeroespacial (Jaxa).
“Naquela região, o grande desafio é conseguir estimar a precipitação das chamadas nuvens quentes, que não têm cristais de gelo em seu interior. Elas são comuns na região do semiárido nordestino”, explicou Machado.
Por não abrigarem gelo, a chuva dessas nuvens passa despercebida pelos sensores de micro-ondas que equipam os satélites usados normalmente para medir a precipitação, resultando em dados imprecisos.
As medições de nuvens quentes feitas por radar em Alcântara, comparadas com as medições feitas por satélite, indicaram que os valores de volume de água estavam subestimados em mais de 50%.
Em Fortaleza, onde a coleta foi feita em abril de 2011, foi testado em parceria com a Defesa Civil um sistema de previsão de tempestades em tempo real e de acesso aberto chamado Sistema de Observação de Tempo Severo (SOS Chuva).
“Usamos os dados que estavam sendo coletados pelos radares e os colocamos em tempo real dentro de um sistema de informações geográficas. Dessa forma, é possível fazer previsões para as próximas duas horas. E saber onde chove forte no momento, onde tem relâmpago e como a situação vai se modificar em 20 ou 30 minutos. Também acrescentamos um mapa de alagamento, que permite prever as regiões que podem ficar alagadas caso a água suba um metro, por exemplo”, contou Machado.
A experiência foi tão bem-sucedida, contou o pesquisador, que a equipe decidiu repeti-la nas campanhas realizadas posteriormente. “O SOS Chuva contribui para diminuir a vulnerabilidade da população a eventos extremos do clima, pois oferece informações não apenas para os agentes da Defesa Civil como também para os cidadãos”, disse.
Em junho de 2011 foi realizada a campanha de coleta de dados em Belém, onde os pesquisadores usaram uma rede de instrumentos de GPS para estimar a quantidade de água na atmosfera. Os resultados devem ser publicados em breve. Também foram lançados balões meteorológicos capazes de voar durante 10 horas e coletar dados da atmosfera. “O objetivo era entender o fluxo de vapor d’água que vem do Oceano Atlântico que forma a chuva na Amazônia”, contou Machado.
Entre novembro de 2011 e março de 2012, foi realizada a campanha de São José dos Campos, cujo foco era estudar os relâmpagos e a eletricidade atmosférica. Para isso, foi utilizado um conjunto de redes de detecção de descargas elétricas em parceria com a Agência de Pesquisas Oceânicas e Atmosféricas (NOAA), dos Estados Unidos, e a Agência Europeia de Satélites Meteorológicos (Eumetsat).
“Foram coletados dados para desenvolver os algoritmos dos sensores de descarga elétrica dos satélites geoestacionários de terceira geração, que ainda serão lançados pela NOAA e pela Eumetsat nesta década. Outro objetivo era entender como a nuvem vai se modificando antes que ocorra a primeira descarga elétrica, de forma a prever a ocorrência de raios”, contou Machado.
Em Santa Maria, entre novembro e dezembro de 2012, foram testados, em parceria com pesquisadores argentinos, modelos matemáticos de previsão de eventos extremos. Segundo Machado, a região que abrange o sul do Brasil e o norte da Argentina que ocorrem as tempestades mais severas do mundo.
“Os resultados mostraram que os modelos ainda não são precisos o suficiente para prever com eficácia a ocorrência desses eventos extremos. Em 2017, faremos um novo experimento semelhante, chamado Relâmpago, no norte da Argentina”, contou Machado.
GOAmazon
As duas operações intensivas de coleta de dados realizadas em Manaus – a primeira entre fevereiro e março de 2014 e a segunda entre setembro e outubro do mesmo ano – ainda não haviam ocorrido quando o artigo foi submetido à publicação.
Ao comentar as principais diferenças encontradas nas diversas regiões brasileiras, Machado destaca que as regiões Sul e Sudeste são as que apresentam gotas de chuva de tamanhos maiores e uma camada mista, na qual há água no estado líquido e sólido, mais desenvolvida. Essa é, segundo o pesquisador, a principal razão da maior incidência de descargas elétricas nesses locais.
Já as nuvens da Amazônia apresentam a camada de gelo no topo – acima de 20 quilômetros de altura – mais bem desenvolvida que a de outras regiões. As regiões litorâneas, como Alcântara e Fortaleza, apresentam em maior quantidade as chamadas nuvens quentes, nas quais quase não há descargas elétricas.
“Foi o primeiro recenseamento de nuvens feito no Brasil. Essas informações servirão de base para testar e desenvolver modelos capazes de descrever em detalhes a formação de nuvens, com alta resolução espacial e temporal”, concluiu o pesquisador.
A falta d’água se alastrou pelo país, sintoma das mudanças climáticas e do desmatamento na Amazônia, cada vez mais debilitada. Nos aproximamos de um futuro desértico e a culpa é toda nossa
por Camila Almeida
Novembro 2014
Em 2014, não choveu. Pelo menos não quanto deveria. Os índices de chuvas apresentam déficit, os reservatórios minguaram a percentuais críticos, a nascente do Rio São Francisco secou pela primeira vez na história. Esses eventos extremos estavam previstos pelos estudiosos das mudanças climáticas, causadas quase exclusivamente pela atividade humana, especialmente pela queima de combustíveis fósseis. Mas outro fator está agravando esse quadro: o desmatamento. A Amazônia é a responsável por manter úmido todo o continente, e sua depredação influencia diretamente no clima.
A floresta funciona como uma fábrica de chuvas. Por cima das nossas cabeças, há imensos rios seguindo seu curso, levando nuvens carregadas por onde passam. São os rios voadores, que começaram a ser estudados em 2006, numa parceria entre o aviador francês Gérard Moss e o engenheiro agrônomo Antonio Donato Nobre, do Instituto Nacional de Pesquisas Espaciais (INPE). Sobrevoando a Amazônia, eles descobriram todo o seu potencial de bombeamento de água e traçaram o curso que os rios voadores seguem pelo País. Esta capacidade da floresta de exportar umidade é um dos cinco segredos da floresta, poeticamente explicados no relatório O Futuro Climático da Amazônia, publicado recentemente por Nobre.
Nossa água vem da Amazônia
Entenda o processo de transpiração da floresta e a formação das nuvens sobre ela. Ao lado, conheça o percurso dos rios voadores e como eles levam chuvas por todo o continente.
O fluxo dos rios voadores é mais intenso no verão, estação em que chove na maior parte do País. Isso acontece graças à inclinação da Terra nesta época do ano, que favorece a entrada dos ventos marítimos na América do Sul. Mas há mais uma vantagem geográfica que garante esse circuito: a Cordilheira dos Andes, localizada a oeste da floresta. O imenso paredão faz com que os ventos não passem direto e deixem o resto do Brasil sem umidade. De acordo
com o físico Philip Fearnside, do Instituto Nacional de Pesquisas da Amazônia (INPA), é no
começo do ano que os rios voadores reabastecem as fontes de água e reservatórios brasileiros. Ao se chocarem contra a Serra da Mantiqueira e da Canastra, no Sudeste, enchem a nascente de vários rios importantes, como o São Francisco. “Esta região é a caixa dágua do Brasil”, avalia Fearnside. “Se não chover na época em que tem que chover, os reservatórios
não serão recarregados ao longo do ano”, completa. Esse tem sido o drama em 2014.
Desmatamento que vai, volta
Poder contar com a maior floresta tropical do mundo, inclusive em relação aos recursos hídricos, é um privilégio. Pouquíssimo valorizado. Nos últimos 40 anos, derrubamos 42 bilhões de árvores. Além disso, devido às queimadas, existe mais de 1 milhão de km² de floresta morta, degradada. O que não se imaginava é que uma revanche em forma de seca chegaria tão rápido. “Hoje, estamos vivendo a reciprocidade da inconsequência”, atesta Nobre. Há mais de 20 anos, estudos alertavam para esse perigo. Em 1991, o climatologista Carlos Nobre, irmão de Antonio e também do INPE, comandou uma simulação para avaliar os impactos no clima da mudança do uso da terra. Constataram que, se a floresta fosse substituída por plantações ou pastagens, a temperatura média da superfície aumentaria cerca de 2,5 ºC, a evapotranspiração das plantas diminuiria 30% e as chuvas cairiam 20%. Também se previa uma ampliação das estações secas na área amazônica. Hoje, com quase metade da floresta original danificada, tais efeitos parecem ter vindo à tona.
“O desmatamento zero é para ontem. Chegamos a níveis climáticos críticos. Precisamos começar a replantar o que já perdemos”, aponta Antonio Nobre. Apesar da urgência, as perspectivas não são animadoras. Só na região amazônica, há mais de 40 projetos do Programa de Aceleração do Crescimento do Governo Federal só no quesito geração de energia. São usinas, barragens e outras medidas que causam inundações e corte de árvores e que afetam diretamente populações indígenas. Os projetos de estradas também são preocupantes. A recuperação da Rodovia Manaus-Porto Velho (BR-319), abandonada desde a década de 1980 por falta de manuntenção, também consta no PAC. De acordo com Philip Fearnside, o projeto é um risco para a Amazônia. “Uma estrada valoriza demais a terra, e especulação gera desmatamento e favorece a grilagem”, explica. O mesmo acontece com a Rodovia Santarém-Cuiabá (BR-163), com mais de 1.700 km de extensão.
“A estrada vai ser recuperada para facilitar o transporte da soja produzida no Mato Grosso”, aponta Fearnside, sobre uma das áreas amazônicas que mais sofrem com o agronegócio. “A terra valoriza tanto que pecuaristas estão vendendo suas terras para produtores de soja do Sul. Por sua vez, isso tem aumentado muito o desmatamento no Pará, com a liberação de terrenos para a criação de gado desses pecuaristas”, critica o especialista. Ele também destaca o fortalecimento da bancada ruralista no Congresso, após as eleições deste ano.
Desmatamento e degradação:
Clima em crise
Neste verão, os rios voadores não avançaram sobre o Sudeste; tampouco as frentes frias. A ilha de calor instalada sobre a região, característica de uma urbanização extrema, cria bloqueios que afastam as chuvas. Por isso, a água esborrou na borda dessa bolha quente, gerando chuvas acima da média no Sul e países vizinhos. Hoje, há registros de seca em todos os Estados brasileiros. Em alguns deles, a seca é “excepcional”, ainda mais grave do que a “extrema”. O quadro já era grave no ano passado, quando o Nordeste viveu a pior seca dos últimos 50 anos, inserindo o Brasil no mapa de eventos climáticos extremos, da Organização Mundial de Meteorologia.
De acordo com o físico especialista em ciências atmosféricas Alexandre Araújo Costa, da Universidade Estadual do Ceará, o agravamento de secas e das cheias está relacionado ao aumento da temperatura na atmosfera. Aquecida, ela se expande, fazendo com que seja necessário reunir mais vapor dágua para formar nuvens. “Esse processo demanda mais tempo, portanto tende a prolongar os períodos de estiagem. Por outro lado, as nuvens se formam a partir de uma quantidade maior de vapor dágua, fazendo com que os eventos de precipitações se tornem mais intensos. Um planeta mais quente é um planeta de extremos”, explica.
Para a filósofa e ecologista Déborah Danowski, que lançou recentemente o livro Há mundo por vir? Ensaio sobre os medos e os fins, com seu marido e antropólogo Eduardo Viveiros de Castro, entramos num caminho sem volta. “A crise climática não pode mais ser evitada. Se cortássemos agora as emissões de CO₂, a Terra ainda iria se aquecer aproximadamente 1 ºC. Isso porque já jogamos no ar uma quantidade tão grande, que muito dele ainda nem foi absorvido”, aponta. O que não quer dizer que não haja muito o que fazer. Para ela, o primeiro passo é repensar os modelos econômicos de crescimento e consumo. “O que nos cabe é tentar mitigar as causas que levam ao aprofundamento das mudanças climáticas e, ao mesmo tempo, nos adaptar à vida em um mundo mais difícil ecologicamente.”
Estamos todos ilhados
Seja pelo excesso de calor ou pelas enchentes. Mais filosoficamente: não temos saída para o clima. Os eventos extremos parecem estar se tornando uma realidade no Brasil.
Em novo relatório sobre mudanças climáticas, instituição prevê grave impacto na agricultura. No Brasil, a produção de soja pode ser reduzida em 70% até 2050
As mudanças climáticas podem levar a retrocessos nos esforços para derrotar a pobreza extrema em todo o mundo, advertiu o Banco Mundial neste domingo 23, ao divulgar um relatório sobre os impactos do aquecimento global.
No documento, intitulado Reduzam o calor: enfrentando a nova normalidade climática (em tradução livre), o banco afirma que elevações bruscas de temperatura devem reduzir profundamente a produtividade nas lavouras e o abastecimento de água em muitas áreas.
O relatório, que foca em impactos regionais específicos do aquecimento global, prevê efeitos no Brasil. Um aumento de até 2 °C na temperatura média em relação aos tempos pré-industriais levaria a uma redução da produção agrícola do país – de até 70% para a soja e 50% para o trigo em 2050, diz o documento.
O Banco Mundial estima que, em 2050, a temperatura média seja 1,5 °C mais alta do que a registrada na era pré-industrial, com base no impacto das emissões de gases de efeito estufa do passado e atualmente.
“Sem uma ação forte e rápida, o aquecimento poderia exceder 1,5 °C ou 2 °C, e o impacto decorrente poderia piorar significativamente a pobreza intra e intergeracional em várias regiões do mundo”, diz o relatório.
Quanto ao nível do mar, o documento afirma que este continuará subindo por séculos, visto que as grandes capas de gelo da Groenlândia e da Antártica vêm derretendo lentamente. Se as temperaturas se mantiverem nos níveis atuais, os mares subirão 2,3 metros nos próximos 2 mil anos, aponta o estudo.
Entre outros efeitos citados, cidades andinas estariam ameaçadas pelo derretimento de geleiras, e comunidades do Caribe e da costa ocidental da Índia poderiam ver diminuir seus suprimentos de peixes. Na Macedônia, o cultivo de milho, trigo e uva seria reduzido em 50 %.
Ações urgentes
Sem ações coordenadas, o perigo é que o aumento da temperatura média global chegue a 4 °C até o fim do século, um cenário descrito pelo Banco Mundial como “um mundo assustador de aumento de riscos e instabilidade global”.
“Acabar com a pobreza, aumentar a prosperidade global e reduzir a desigualdade no mundo, o que já é difícil, vai ser muito mais difícil com um aquecimento de 2 °C, disse o presidente do Banco Mundial, Jim Yong Kim. “Mas com [um aumento de] 4 °C, há sérias dúvidas de que essas metas possam ser alcançadas.”
Os piores efeitos do aquecimento global poderiam ser evitados através da redução das emissões de gases de efeito estufa, reitera o relatório.
Representantes de quase 200 países se reunirão em breve para a próxima Conferência Mundial do Clima. Realizado no Peru entre os dias 1º e 12 de dezembro, o evento tem como objetivo a definição das bases de um acordo global de limitações de emissões de gases do efeito estufa. Espera-se que o acordo seja firmado em Paris em 2015.
NM/afp/rtr
* Publicado originalmente pela Deutsche Welle e retirado do site Carta Capital.
Uma (in)certa antropologia 
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