É possível manipular o clima? Geoengineering could bring severe drought to the tropics, research shows. Climate science: can geoengineering save the world? /The Guardian

"Mostrámos que uma das principais técnicas da geoengenharia pode causar efeitos secundários não intencionais numa larga faixa do planeta", efeitos até agora ignorados nas investigações, sublinha."

"Um outro estudo, divulgado anteontem pelo site Science 2.0, mostra que, em geral, os cidadãos norte-americanos condenam os métodos de geoengenharia para controlar o ambiente."

É possível manipular o clima. A CIA já está a estudar

Por Joana Azevedo Viana

publicado em 15 Jan 2014 in (jornal) i online

Estudos sobre alegada teoria da conspiração relacionada com técnicas de manipulação do clima alertam para "efeitos secundários não intencionais"

Quando a tempestade tropical Katrina ganhou força e se transformou num furacão que varreu o Sul dos Estados Unidos, com ventos de mais de 280 quilómetros por hora, em 2005, os crentes na conspiração desdobraram-se em análises de como o furacão foi artificialmente criado para atingir Nova Orleães.

Thomas Bearden, tenente-coronel na reforma, acusou a Rússia e os seus "métodos à KGB" de estar por trás do plano maquiavélico; segundo o americano, os russos têm estado, desde 1976, a usar uma arma secreta da era soviética para controlar o clima e destronar os inimigos em perigosos jogos de geoestratégia.

Outros acusaram a máfia japonesa, a Yakuza, que em 1989, dizem, terá pedido emprestada essa arma à Rússia para destruir plataformas de exploração petrolífera nas costas dos EUA. Outros defenderam que foi um "efeito secundário" de planos da própria administração americana para controlar o tempo e assim controlar as mentes dos seus cidadãos.

Terá sido portanto com alguma surpresa que os assíduos críticos de teorias da conspiração como estas receberam há alguns meses a notícia de que a geoengenharia está agora a ser investigada com fundos da CIA.

Em Julho, a "Mother Jones" anunciou que a agência secreta norte-americana acabava de dar 630 mil dólares à Academia Nacional de Ciências (NAS) para financiar um projecto de 21 meses sobre o uso da engenharia do clima para alterar o ambiente no planeta e reduzir o aquecimento global.

O estudo foi anunciado no site da NAS como "o primeiro a ser financiado pela comunidade de serviços secretos dos EUA". À revista, William Kearney, porta-voz da academia, confirmou que a expressão fazia referência à CIA. A agência, contudo, não confirmou nem desmentiu a notícia, nem uma outra a dar conta de que, em 2012, terá encerrado o seu centro de estudos sobre alterações climáticas após sofrer pressões dos republicanos no Congresso que dizem que a CIA não deve intrometer-se no assunto.

"É natural que a agência trabalhe com cientistas para melhor entender um tema como as alterações climáticas, o fenómeno e as suas implicações na segurança nacional [dos EUA]", foi a única declaração feita à revista sobre o assunto por Edward Price, porta-voz da secreta.

O aparente interesse de grandes potências em alterar o clima na Terra não é novo. Durante a guerra do Vietname, a Força Aérea americana terá usado pela primeira vez técnicas de manipulação climática como instrumento de táctica militar, libertando nas nuvens partículas químicas para criar chuvas artificiais que transformassem o trilho de Ho Chi Minh num lamaçal, para assim obter uma vantagem estratégica.

Entre 1962 e 1983, terá havido engenheiros com pretensões semelhantes no Projecto Fúria da Tempestade, liderado pela Marinha norte-americana e pelo Departamento do Comércio para enfraquecer ciclones tropicais. Mais recentemente, o Gabinete de Modificação da Meteorologia da China foi acusado de aplicar este processo de "sementeira em nuvens" para assegurar que só choveria longe dos estádios onde os Jogos Olímpicos de 2008 tiveram lugar.

"ACTORES SOLITÁRIOS" Apesar de no passado as tentativas de manipular o clima terem sido recebidas em tom jocoso pela comunidade científica, o facto de técnicas como a sementeira em nuvens estarem a ser aplicadas tem gerado questões sérias entre os cientistas.

Desde o início do ano, algumas revistas especializadas e jornais como o "The Guardian" têm dado uma atenção sem precedentes à ideia controversa da geoengenharia, citando vários riscos inerentes ao processo. Para David Keith, investigador da Universidade de Harvard e defensor assertivo dos métodos para controlar o aquecimento global, "[a geoengenharia] é fundamentalmente exequível, relativamente barata e parece reduzir os riscos de alterações climáticas de forma significativa". Mas esse optimismo vem com ressalvas. "Isto acarreta riscos, entre eles efeitos secundários não intencionais imprevisíveis", diz Keith.

"E toda esta questão dos actores solitários?", questiona Ken Caldeira, cientista da NAS. "Devemos preocupar-nos com o facto de a China agir unilateralmente? É só conversa fiada ou o governo dos EUA deve preparar-se para isso?"

A dita "questão dos actores solitários" não envolve só países. Pelo menos um indivíduo, Russ George, terá já tentado modificar o clima. O ex-director da Planktos, empresa americana que de-senvolve tecnologias para combater o aquecimento global, terá fertilizado com ferro o oceano Pacífico, na costa canadiana, para forçar um aumento de plâncton que absorva mais dióxido de carbono - libertado na atmosfera a um ritmo e em quantidades cada vez maiores.

Em 2010, a BBC entrevistou um militar russo que diz fazer uso destas técnicas há anos para impedir que chova em importantes feriados nacionais. "Usamos uma máquina especial que cospe iodeto de prata, gelo seco ou cimento para as nuvens ou então abrimos uma escotilha [no avião] e um homem atira sementes para as nuvens manualmente", explicou então Alexander Akimenkov, piloto da Força Aérea russa.

De acordo com o artigo, não é só o governo russo que semeia nuvens para não colher tempestades. Há já empresas privadas no país que, por 6 mil dólares à hora, garantem que o casamento de um cliente, ou outro evento privado, é soalheiro até ao fim.

"O RISCO NÃO É SÓ COMEÇAR" Os cientistas avisam agora que os riscos vêm não só desta falta de controlo de como, quem e onde são usadas técnicas de geoengenharia, mas também do simples facto de estarem a ser aplicadas.

Segundo um estudo publicado pela revista científica "Environmental Research Letters" a 8 de Janeiro, os trópicos vão ser afectados por secas graves se a geoengenharia continuar a ser aplicada como penso rápido no combate às alterações climáticas.

"Há muitas questões de governação - quem controla o termóstato da Terra - porque o impacto da geoengenharia não vai ser uniforme em todo o planeta", diz Andrew Charlton-Perez, cientista da Universidade de Reading e membro da equipa de investigação.

Através de modelos recriados em computador, os cientistas confirmaram que a aplicação da técnica de injectar sulfatos em grande escala nas nuvens consegue reduzir o aumento da temperatura, mas que tal poderá provocar, em situações extremas, uma quebra de um terço da pluviosidade na América do Sul, na Ásia e em África. As consequentes secas, dizem os investigadores, afectarão milhares de milhões de pessoas e as já frágeis florestas tropicais, que funcionam como filtros imensos de carbono.

"Os investigadores escolheram um cenário climático grave, portanto não devemos ficar surpreendidos por qualquer técnica de geoengenharia ou para reverter os efeitos [da anterior] tenha impacto sério e desigual", diz Matthew Watson, da Universidade de Bristol e defensor de mais investigação antes de se aplicarem medidas destas. "Continua a ser verdade que a única via garantida [para salvar o planeta] é reduzir os níveis recorde de gases com efeito de estufa que continuamos a injectar na atmosfera. É vital que os cientistas continuem a investigar a geoengenharia, mas nenhum governo sério em relação às alterações climáticas deve olhar para ela como um penso rápido."

O cenário "grave" estudado prevê que, se os níveis de dióxido de carbono quadruplicarem na atmosfera e não houver intervenção, as temperaturas globais vão subir em média 4 graus Celsius, acima dos 2 considerados perigosos pelos governos mundiais. Já se esse aumento da temperatura for combatido pela geoengenharia, será possível desacelerar e até reduzir para níveis nulos o aquecimento global.

Na simulação computorizada, os cientistas injectaram 60 toneladas de dióxido de enxofre por ano na estratosfera, o equivalente a cinco erupções vulcânicas, cada uma medida pela escala da erupção do monte Pinatubo, nas Filipinas, que em 1991 reduziu 0,5 graus a temperatura global nos dois anos seguintes.

Através desta libertação de dióxido de enxofre, similar à dos vulcões quando entram em erupção, os cientistas apuraram que as partículas na estratosfera não só absorvem parte do calor vindo do Sol mas também a energia térmica libertada pela superfície terrestre.

"O aquecimento funciona como estabilizador da parte da atmosfera em que vivemos, reduzindo a ressurgência de ar. Nos trópicos a maior parte da chuva vem da movimentação rápida do ar, portanto [o método de geoengenharia] funciona como redutor de precipitação", explica Charlton-Perez.

Se a hipótese se confirmar, a queda na precipitação nos trópicos pode chegar aos 30%, com impacto adverso e significativo sobre as populações e o ambiente. "Iríamos assistir a mudanças tão bruscas que as pessoas teriam muito pouco tempo para se adaptar", diz o co-autor do estudo. "Mostrámos que uma das principais técnicas da geoengenharia pode causar efeitos secundários não intencionais numa larga faixa do planeta", efeitos até agora ignorados nas investigações, sublinha.

Um outro estudo, divulgado anteontem pelo site Science 2.0, mostra que, em geral, os cidadãos norte-americanos condenam os métodos de geoengenharia para controlar o ambiente. "Foi um resultado surpreendente num padrão muito claro", explica Malcolm Wright, professor da Universidade de Massey e autor do estudo. "Intervenções como pôr espelhos no espaço ou partículas na estratosfera não são bem recebidas. Processos mais naturais como a iluminação de nuvens acolhem menos objecções, mas ao que o público reage melhor é à criação de biochar (carvão vegetal para bloquear o CO 2) ou à captura directa de carbono do ar."

Geoengineering could bring severe drought to the tropics, research shows

Study models impact on global rainfall when artificial volcanic eruptions are created in a bid to reverse climate change

Damian Carrington

theguardian.com, Wednesday 8 January 2014 / http://www.theguardian.com/environment/2014/jan/08/geoengineering-drought-tropics-climate-change-volcano

Reversing climate change via huge artificial volcanic eruptions could bring severe droughts to large regions of the tropics, according to new scientific research.

The controversial idea of geoengineering – deliberately changing the Earth's climate – is being seriously discussed as a last-ditch way of avoiding dangerous global warming if efforts to slash greenhouse gas emissions fail.

But the new work shows that a leading contender – pumping sulphate particles into the stratosphere to block sunlight – could have side-effects just as serious as the effects of warming itself. Furthermore, the impacts would be different around the world, raising the prospect of conflicts between nations that might benefit and those suffering more damage.

"There are a lot of issues regarding governance – who controls the thermostat – because the impacts of geoengineering will not be uniform everywhere," said Dr Andrew Charlton-Perez, at the University of Reading and a member of the research team.

The study, published in the journal Environmental Research Letters, is the first to convincingly model what happens to rainfall if sulphates were deployed on a huge scale.

While the computer models showed that big temperature rises could be completely avoided, it also showed cuts in rain of up to one-third in South America, Asia and Africa. The consequent droughts would affect billions of people and also fragile tropical rainforests that act as a major store of carbon. "We would see changes happening so quickly that there would be little time for people to adapt," said Charlton-Perez.

Another member of the research team, Professor Ellie Highwood, said: "On the evidence of this research, stratospheric aerosol geoengineering is not providing world leaders with any easy answers to the problem of climate change."

The study considered what would happen if carbon dioxide levels quadrupled in the atmosphere – the sort of extreme situation in which geoengineering might be seriously considered. Without intervention, temperatures rose by 4C, far above the 2C level considered dangerous by the world's governments.

But the temperature rise was reduced to zero if a massive geoengineering effort took place. The 60m tonnes of sulphur dioxide pumped into the stratosphere each year in the simulation is equivalent to five volcanic eruptions, each on the scale of Mount Pinatubo, the huge 1991 eruption in the Philippines that cut global temperatures by about 0.5C in the following year or two.

The sulphate particles in the model not only reflected incoming sunlight, cutting temperatures, but also absorbed heat rising up from the Earth's surface. This reduced the temperature difference between the lower and upper atmosphere, which is the engine that drives cloud formation and rainfall. The reduction in rainfall seen in the geoengineering model was as big as the increase in rainfall projected if global warming was unabated.

Dr Matthew Watson, a researcher at the University of Bristol and advocate of further research into geoengineering, said: "The researchers chose an extreme climate scenario so we should not be surprised if that, and any geoengineering attempt to counter it, had severe and uneven impacts."

He added: "It remains the case that our only guaranteed way forward is to reduce the record levels of greenhouse gases we continue to pump into the atmosphere. It's vital that scientists continue researching geoengineering; but no government serious about climate change should see it as a quick fix."

Climate science: can geoengineering save the world?

Climate professors Mike Hulme and David Keith go head to head over whether climate engineering could provide a solution to climate change

Geoengineering. It's not the sexiest sounding topic, but a small group of scientists say it just might be able to save the world.

The basic idea behind geonengineering (or climate engineering) is that humans can artificially moderate the Earth's climate allowing us to control temperature, thereby avoiding the negative impacts of climate change. There are a number of methods suggested to achieve this scientific wizardry, including placing huge reflectors in space or using aerosols to reduce the amount of carbon in the air.

It's a hugely controversial theory. One of the main counter-arguments is that promoting a manmade solution to climate change will lead to inertia around other efforts to reduce human impact. But the popularity of geoengineering is on the rise among some scientists and even received a nod from the IPCC in its recent climate change report.

In a fast-flowing and sometimes heated head-to-head climate professors David Keith and Mike Hulme set out the for and against. Keith, a geoengineering advocate, doesn't believe that this science is a solve-all but says "it could significantly reduce climate impacts to vulnerable people and ecosystems over the next half century." While Hulme sets out his stall in no uncertain terms: "Solar climate engineering is a flawed idea seeking an illusory solution to the wrong problem".

Enjoy the debate and do add your comments at the end.

David Keith: Gordon McKay professor of applied physics (SEAS) and professor of public policy at Harvard Kennedy School

David Keith

Deliberately adding one pollutant to temporarily counter another is a brutally ugly technical fix, yet that is the essence of the suggestion that sulphur be injected into the stratosphere to limit the damage caused by the carbon we've pumped into the air.

I take solar geoengineering seriously because evidence from atmospheric physics, climate models, and observations strongly suggest that it could significantly reduce climate impacts to vulnerable people and ecosystems over the next half century.

The strongest arguments against solar geoengineering seem to be the fear that it is a partial fix that will encourage us to slacken our efforts to cut carbon emissions. This is moral confusion. It is our responsibility to limit the impact that our cheap energy has on our grandchildren independently of the choices we make about temporary solar geoengineering.

Were we faced with a one-time choice between making a total commitment to a geoengineering programme to offset all warming and abandoning geoengineering forever, I would choose abandonment. But this is not the choice we face. Our choice is between the status quo—with almost no organised research on the subject—and commitment to a serious research program that will develop the capability to geoengineer, improve understanding of the technology's risks and benefits, and open up the research community to dilute the geo-clique. Given this choice, I choose research; and if that research supports geoengineering's early promise, I would then choose gradual deployment.

Mike Hulme: professor of climate and culture in the School of Social Science & Public Policy at King's College London

Mike Hulme

David, your ambition to significantly reduce future climate impacts is one of course we can share along with many others. But I am mystified by your faith that solar climate engineering is an effective way of achieving this. More direct and assured methods would be to invest in climate adaptation measures—a short-term gain—and to invest in new clean energy technologies—a long-term gain.

My main argument against solar engineering is not the moral hazard argument you refer to. It is twofold. First, all evidence to date—from computer simulations and from the analogies of explosive volcanic eruptions—is that deliberately injecting sulphur into the stratosphere will further destabilise regional climates. It may reduce globally-averaged warming, but that it not what causes climate damage. It is regional weather that does that—droughts in the US, floods in Pakistan, typhoons in Philippines. Solar climate engineering in short is a zero-sum game: some will win, some will lose.

Which leads me to my second argument. The technology is ungovernable. Even the gradual deployment you propose will have repercussions for all nations, all peoples and all species. All of these affected agents therefore need representation in any decisions made and over any regulatory bodies established. But given the lamentable state in which the conventional UN climate negotiations linger on, I find it hard to envisage any scenario in which the world's nations will agree to a thermostat in the sky.

Solar climate engineering is a flawed idea seeking an illusory solution to the wrong problem.

DK - You are correct that climate impacts are ultimately felt at the local scale as changes in soil moisture, precipitation or similar quantities. No one feels the global average temperature. Precisely because of this concern my group has studied regional responses to geoengineering.

In the first quantitative look at the effectiveness of solar geoengineering we found—to our surprise—that it can reduce changes in both temperature and precipitation on a region-by-region basis. This work has now been replicated by much larger study using a whole set of climate models led by Alan Robock one of the more skeptical scientist working on the topic, and they got the same result. While there are claims in the popular press that it will "destabilise regional climates"—presumably meaning that it will increase local variability—I know of no scientific paper that backs this up.

I have no faith in geoengineering. I have some faith in empirical science and reasoned argument. It's true that we don't have mechanisms for legitimate governance of this technology. Indeed in the worse case this technology could lead to large-scale conflict. This exactly why I and others have started efforts to engage policy makers from around the world to begin working on the problem.

MH - David, The point here is how much faith we can place in climate models to discern these types of regional changes. As the recent report from the UN's Intergovernmental Panel on Climate Change has shown, at sub-continental scales state-of-the-art climate models do not robustly simulate the effects of greenhouse gas accumulation on climate.

What you are claiming then is that we can rely upon these same models to be able to ascertain accurately the additional effects of sulphur loading of the stratosphere. Frankly, I would not bet a dollar on such results, let alone the fate of millions.

You may say that this is exactly why we need more research—bigger and better climate models. I've been around the climate research scene long enough to remember 30 years of such claims. Are we to wait another 30 years? What we can be sure about is that once additional pollutants are injected into the skies, the real climate will not behave like the model climate at scales that matter for people.

As for getting political scientists to research new governance mechanisms for the global thermostat - you again place more faith in human rationality than I. We have had more than 20 years of a real-world experiment into global climate governance: it's called the UN Framework Convention on Climate Change. It's hardly been a roaring success! You must be a supreme optimist to then expect a novel system of global governance can be invented and sustained over the time periods necessary for solar climate engineering to be effective.

DK: You made a very strong claim that geoengineering is zero-sum. If true, I would oppose any further work on the technology. I responded that results from all climate models strongly suggest that this is not the case. Your response was to dismiss climate models. Assume for the moment that climate models tell us nothing about regional climate response, on what then do you base your claim that solar geoengineering is zero sum - that is, that is just shuffles winners and losers?

When climate skeptics rubbish models I defend science by agreeing if all we had was complex models I too would be a doubter; but, I then argue, that we base our conclusions on a breath of evidence from basic physics and a vast range of observations to simple—auditable—models as well as the full-blow three dimensional climate models. Models of atmospheric circulation and aerosols developed for earth make good predictions of the climates of other planets. This is a triumph of science.

The same science that shows us that carbon dioxide will change the climate shows that scattering a bit more sunlight will reduce that climate change. How you do you accept one and reject the other?

On the other points: I am not exited by an endless round of climate model improvements nor do it think that political scientist will solve this. We need less theory and more empiricism.

MH: David, I agree that we need less theory and more empiricism. This is one of the reasons why I am skeptical that climate models are able to reveal confidently what will happen to regional climates—especially precipitation—once sulphur is pumped into the stratosphere.

I don't dismiss climate models, but I discriminate between what they are good for and what they are less good for. Having spent nearly half of my professional life studying their ability to simulate regional and local rainfall—by comparing simulations against observations, empiricism if you will—I have little faith in their skill at the regional and local scales.

But let's assume for a moment that climate models were reliable at these scales. Another argument against intentional solar climate engineering is that it will introduce another reason for antagonism between nations. There are those who claim that their models are good enough to precisely attribute specific local meteorological extremes—and ensuing human damages—to greenhouse gas emissions. There will be nations who will want to claim that any damaging weather extreme following sulphur injection was aerosol-caused rather than natural- or greenhouse gas-caused. The potential for liability and counter-liability claims between nations is endless.

I am against solar climate engineering not because some violation of nature's integrity - the argument used by some. I am against it because my reading of scientific evidence and of collective human governance capabilities suggests to me that the risks of implementation greatly outweigh any benefits. There are surer ways of reducing the dangers of climate change.

David Keith and Mike Hulme will be debating "The Case For and Against Climate Engineering" on Monday December 2 between 17:00 and 18:30 at the Oxford Martin School. Entry is free and open to the public. Registration is not required. The debate will be webcast live. To join in the conversation tweet using #geoengineering and direct questions to the speakers @oxmartinschool