terça-feira, 21 de novembro de 2017
Por Eric Holthaus
In a remote region of Antarctica known as Pine Island Bay, 2,500 miles from the tip of South America, two glaciers hold human civilization hostage.
Stretching across a frozen plain more than 150 miles long, these glaciers, named Pine Island and Thwaites, have marched steadily for millennia toward the Amundsen Sea, part of the vast Southern Ocean. Further inland, the glaciers widen into a two-mile-thick reserve of ice covering an area the size of Texas.
There’s no doubt this ice will melt as the world warms. The vital question is when.
The glaciers of Pine Island Bay are two of the largest and fastest-melting in Antarctica. (A Rolling Stone feature earlier this year dubbed Thwaites “The Doomsday Glacier.”) Together, they act as a plug holding back enough ice to pour 11 feet of sea-level rise into the world’s oceans — an amount that would submerge every coastal city on the planet. For that reason, finding out how fast these glaciers will collapse is one of the most important scientific questions in the world today.
To figure that out, scientists have been looking back to the end of the last ice age, about 11,000 years ago, when global temperatures stood at roughly their current levels. The bad news? There’s growing evidence that the Pine Island Bay glaciers collapsed rapidly back then, flooding the world’s coastlines — partially the result of something called “marine ice-cliff instability.”
The ocean floor gets deeper toward the center of this part of Antarctica, so each new iceberg that breaks away exposes taller and taller cliffs. Ice gets so heavy that these taller cliffs can’t support their own weight. Once they start to crumble, the destruction would be unstoppable.
“Ice is only so strong, so it will collapse if these cliffs reach a certain height,” explains Kristin Poinar, a glaciologist at NASA’s Goddard Space Flight Center. “We need to know how fast it’s going to happen.”
In the past few years, scientists have identified marine ice-cliff instability as a feedback loop that could kickstart the disintegration of the entire West Antarctic ice sheet this century — much more quickly than previously thought.
Minute-by-minute, huge skyscraper-sized shards of ice cliffs would crumble into the sea, as tall as the Statue of Liberty and as deep underwater as the height of the Empire State Building. The result: a global catastrophe the likes of which we’ve never seen.
Ice comes in many forms, with different consequences when it melts. Floating ice, like the kind that covers the Arctic Ocean in wintertime and comprises ice shelves, doesn’t raise sea levels. (Think of a melting ice cube, which won’t cause a drink to spill over.)
Land-based ice, on the other hand, is much more troublesome. When it falls into the ocean, it adds to the overall volume of liquid in the seas. Thus, sea-level rise.
Antarctica is a giant landmass — about half the size of Africa — and the ice that covers it averages more than a mile thick. Before human burning of fossil fuels triggered global warming, the continent’s ice was in relative balance: The snows in the interior of the continent roughly matched the icebergs that broke away from glaciers at its edges.
Now, as carbon dioxide traps more heat in the atmosphere and warms the planet, the scales have tipped.
A wholesale collapse of Pine Island and Thwaites would set off a catastrophe. Giant icebergs would stream away from Antarctica like a parade of frozen soldiers. All over the world, high tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees.
All this could play out in a mere 20 to 50 years — much too quickly for humanity to adapt.
“With marine ice cliff instability, sea-level rise for the next century is potentially much larger than we thought it might be five or 10 years ago,” Poinar says.
A lot of this newfound concern is driven by the research of two climatologists: Rob DeConto at the University of Massachusetts-Amherst and David Pollard at Penn State University. A study they published last year was the first to incorporate the latest understanding of marine ice-cliff instability into a continent-scale model of Antarctica.
Their results drove estimates for how high the seas could rise this century sharply higher. “Antarctic model raises prospect of unstoppable ice collapse,” read the headline in the scientific journal Nature, a publication not known for hyperbole.
Instead of a three-foot increase in ocean levels by the end of the century, six feet was more likely, according to DeConto and Pollard’s findings. But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, their study showed.
Three feet of sea-level rise would be bad, leading to more frequent flooding of U.S. cities such as New Orleans, Houston, New York, and Miami. Pacific Island nations, like the Marshall Islands, would lose most of their territory. Unfortunately, it now seems like three feet is possible only under the rosiest of scenarios.
At six feet, though, around 12 million people in the United States would be displaced, and the world’s most vulnerable megacities, like Shanghai, Mumbai, and Ho Chi Minh City, could be wiped off the map.
At 11 feet, land currently inhabited by hundreds of millions of people worldwide would wind up underwater. South Florida would be largely uninhabitable; floods on the scale of Hurricane Sandy would strike twice a month in New York and New Jersey, as the tug of the moon alone would be enough to send tidewaters into homes and buildings.
DeConto and Pollard’s breakthrough came from trying to match observations of ancient sea levels at shorelines around the world with current ice sheet behavior.
Around 3 million years ago, when global temperatures were about as warm as they’re expected to be later this century, oceans were dozens of feet higher than today.
Previous models suggested that it would take hundreds or thousands of years for sea-level rise of that magnitude to occur. But once they accounted for marine ice-cliff instability, DeConto and Pollard’s model pointed toward a catastrophe if the world maintains a “business as usual” path — meaning we don’t dramatically reduce carbon emissions.
Rapid cuts in greenhouse gases, however, showed Antarctica remaining almost completely intact for hundreds of years.
Pollard and DeConto are the first to admit that their model is still crude, but its results have pushed the entire scientific community into emergency mode.
“It could happen faster or slower, I don’t think we really know yet,” says Jeremy Bassis, a leading ice sheet scientist at the University of Michigan. “But it’s within the realm of possibility, and that’s kind of a scary thing.”
Scientists used to think that ice sheets could take millennia to respond to changing climates. These are, after all, mile-thick chunks of ice.
The new evidence, though, says that once a certain temperature threshold is reached, ice shelves of glaciers that extend into the sea, like those near Pine Island Bay, will begin to melt from both above and below, weakening their structure and hastening their demise, and paving the way for ice-cliff instability to kick in.
In a new study out last month in the journal Nature, a team of scientists from Cambridge and Sweden point to evidence from thousands of scratches left by ancient icebergs on the ocean floor, indicating that Pine Island’s glaciers shattered in a relatively short amount of time at the end of the last ice age.
The only place in the world where you can see ice-cliff instability in action today is at Jakobshavn glacier in Greenland, one of the fastest-collapsing glaciers in the world. DeConto says that to construct their model, they took the collapse rate of Jakobshavn, cut it in half to be extra conservative, then applied it to Thwaites and Pine Island.
But there’s reason to think Thwaites and Pine Island could go even faster than Jakobshavn.
Right now, there’s a floating ice shelf protecting the two glaciers, helping to hold back the flow of ice into the sea. But recent examples from other regions, like the rapidly collapsing Larsen B ice shelf on the Antarctic Peninsula, show that once ice shelves break apart as a result of warming, their parent glaciers start to flow faster toward the sea, an effect that can weaken the stability of ice further inland, too.
“If you remove the ice shelf, there’s a potential that not just ice-cliff instabilities will start occurring, but a process called marine ice-sheet instabilities,” says Matthew Wise, a polar scientist at the University of Cambridge.
This signals the possible rapid destabilization of the entire West Antarctic ice sheet in this century. “Once the stresses exceed the strength of the ice,” Wise says, “it just falls off.”
And, it’s not just Pine Island Bay. On our current course, other glaciers around Antarctica will be similarly vulnerable. And then there’s Greenland, which could contribute as much as 20 feet of sea-level rise if it melts.
Next to a meteor strike, rapid sea-level rise from collapsing ice cliffs is one of the quickest ways our world can remake itself. This is about as fast as climate change gets.
Still, some scientists aren’t fully convinced the alarm is warranted. Ted Scambos, lead scientist at the National Snow and Ice Data Center in Colorado, says the new research by Wise and his colleagues, which identified ice-cliff instabilities in Pine Island Bay 11,000 years ago, is “tantalizing evidence.” But he says that research doesn’t establish how quickly it happened.
“There’s a whole lot more to understand if we’re going to use this mechanism to predict how far Thwaites glacier and the other glaciers are going to retreat,” he says. “The question boils down to, what are the brakes on this process?”
Scambos thinks it is unlikely that Thwaites or Pine Island would collapse all at once. For one thing, if rapid collapse did happen, it would produce a pile of icebergs that could act like a temporary ice shelf, slowing down the rate of retreat.
Despite the differences of opinion, however, there’s growing agreement within the scientific community that we need to do much more to determine the risk of rapid sea-level rise. In 2015, the U.S. and U.K. governments began to plan a rare and urgent joint research program to study Thwaites glacier. Called “How much, how fast?,” the effort is set to begin early next year and run for five years.
Seeing the two governments pooling their resources is “really a sign of the importance of research like this,” NASA’s Poinar says.
Given what’s at stake, the research program at Thwaites isn’t enough, but it might be the most researchers can get. “Realistically, it’s probably all that can be done in the next five years in the current funding environment,” says Pollard.
He’s referring, of course, to the Trump administration’s disregard for science and adequate scientific funding; the White House’s 2018 budget proposal includes the first-ever cut to the National Science Foundation, which typically funds research in Antarctica.
“It would be sensible to put a huge effort into this, from my perspective,” Pollard says. Structural engineers need to study Antarctica’s key glaciers as though they were analyzing a building, he says, probing for weak spots and understanding how exactly they might fail. “If you vastly increase the research now, [the cost] would still be trivial compared to the losses that might happen.”
Bassis, the ice sheet scientist at the University of Michigan, first described the theoretical process of marine ice-cliff instability in research published only a few years ago.
He’s 40 years old, but his field has already changed enormously over the course of his career. In 2002, when Bassis was conducting his PhD research in a different region of Antarctica, he was shocked to return to his base camp and learn that the Larsen B ice shelf had vanished practically overnight.
“Every revision to our understanding has said that ice sheets can change faster than we thought,” he says. “We didn’t predict that Pine Island was going to retreat, we didn’t predict that Larsen B was going to disintegrate. We tend to look at these things after they’ve happened.”
There’s a recurring theme throughout these scientists’ findings in Antarctica: What we do now will determine how quickly Pine Island and Thwaites collapse. A fast transition away from fossil fuels in the next few decades could be enough to put off rapid sea-level rise for centuries. That’s a decision worth countless trillions of dollars and millions of lives.
“The range of outcomes,” Bassis says, “is really going to depend on choices that people make.”
terça-feira, 14 de novembro de 2017
Os Paradise Papers são um conjunto de 13,4 milhões de documentos eletrónicos confidenciais de natureza fiscal que foram enviados ao jornal alemão Süddeutsche Zeitung. O jornal os compartilhou com o Consórcio Internacional de Jornalistas Investigativos, e alguns detalhes foram divulgados em 5 de novembro de 2017. Wikipédia
quinta-feira, 9 de novembro de 2017
Com o seu documentário de 2006, Uma Verdade Inconveniente, Al Gore, o antigo vice-presidente dos Estados Unidos, garantiu a atenção do público para a ameaça das alterações climáticas. Este julho, estreia nos cinemas An Inconvenient Sequel. Gore, 69 anos, diz que a fasquia está mais elevada, mas as soluções são mais claras.
Quais acha serem os mal-entendidos do público relativamente às alterações climáticas?
Penso que a grande maioria das pessoas entende que as alterações climáticas são um desafio extremamente importante, que os seres humanos são responsáveis por isso e que temos de agir rapidamente e de forma decisiva para conseguir resolver o assunto. Os argumentos mais persuasivos vieram da Mãe Natureza. Os eventos meteorológicos extremos são cada vez mais frequentes e severos, e é cada vez mais difícil ignorar o que está a acontecer. E mesmo aqueles que não querem utilizar as palavras “ aquecimento global” ou “crise climática” estão a encontrar maneiras de dizer, “sim, temos de mudar para energia solar, eólica, baterias, carros elétricos e por aí a diante”. Temos tanto em risco.
Porque surgiram divergências políticas tão acutilantes sobre as alterações climáticas?
Há um antigo ditado popular no Tennessee que diz: “se vires uma tartaruga no cimo do poste de uma vedação, podes ter a certeza de que não chegou ali sozinha”. Uma maioria determinada – com apoio financeiro ativo de alguns dos grandes poluidores de carbono – atrasou o progresso durante uns tempos. Utilizaram o poder dos lobbies e ameaças de financiar opositores, utilizaram as mesmas técnicas que já vimos utilizar no passado pelas grandes tabaqueiras para criar falsas dúvidas. Todos nós somos vulneráveis ao que os psicólogos chamam “negação”: se alguma coisa é desconfortável, é mais fácil afastá-la, é mais fácil não nos envolvermos. Mas a solução é ouvir e aproximarmo-nos das pessoas a partir de onde elas estão.
Disse publicamente que a saída do Acordo de Paris sobre as mudanças climáticas preconizada pela Administração Trump era uma “ação irresponsável e indefensável.” Qual é o caminho agora?
Mesmo que Trump consiga eliminar medidas que ajudem os EUA a reduzir as emissões, os desenvolvimentos no mercado — como a queda continuada do custo da eletricidade renovável — fazem com que os EUA possam atingir os objetivos definidos para os EUA no Acordo de Paris não obstante as ações de Trump. A Califórnia e Nova Iorque estão a progredir mais rapidamente do que o exigido pelo Plano de Energia Limpa. E há um número crescente de cidades que está a progredir ainda mais rapidamente. Além disso, a comunidade empresarial está muito à frente da comunidade política e muitas empresas orientadas para o consumo estão a prometer usar energia 100% renovável.
E o papel da China?
A China está a evoluir de forma bastante impressionante. Este é o quarto ano em que regista uma redução de emissões de dióxido de carbono e o terceiro em que apresenta uma queda no uso de carvão. No final deste ano, vai implementar um teto para as emissões e um plano de comércio. É líder mundial no fabrico de painéis solares e de turbinas eólicas, comboios rápidos e redes elétricas inteligentes. A China mostrou uma liderança forte neste tema.
O documentário Uma Verdade Inconveniente teve uma enorme ressonância em 2006 e ajudou a que se atingisse um momento de viragem no que respeita à sensibilização para as mudanças climáticas. Porque acha que isto aconteceu?
Dou grande parte do mérito a David Guggenheim, realizador do filme. Sinto-me envergonhado ao admitir que não achava que fazer o filme fosse boa ideia. Não acreditava que fosse possível transformar uma apresentação de diapositivos num filme. Mas ele convenceu-me e fez um trabalho fantástico.
O primeiro filme juntava partes de uma série de estudos científicos que mostravam que era preciso tomar medidas para parar o aquecimento global de responsabilidade humana, pelo que se tratou de uma feliz confluência de acontecimentos. Mas, depois, os grandes poluidores de carbono congregaram-se e começaram a aplicar muito mais dinheiro em campanhas de negação das mudanças climáticas e em argumentos pseudocientíficos falsos e, ajudados pelas contribuições e pelo dinheiro de grupos de pressão, conseguiram travar os progressos. Mais recentemente, voltamos a tomar as rédeas da iniciativa.
Qual é o seu objetivo neste novo filme, An Inconvenient Sequel?
O meu principal objetivo é contribuir para a dinâmica atual. Cem por cento dos proveitos do filme, e do livro, que estamos a fazer serão destinados à formação de mais ativistas do clima. Foi também o que aconteceu com o primeiro filme.
No novo filme, uma cena muito forte mostra o Al Gore a visitar a cidade conservadora de Georgetown, no Texas, onde o presidente da câmara republicano, Dale Ross, tem vindo a encetar esforços para que a cidade dependa de energia 100 por cento renovável. Parece que se deu muito bem com Ross. Como é que isso aconteceu?
A ligação foi estabelecida do ponto de vista humano, apesar de pertencermos a partidos diferentes. Ele é contabilista certificado, pelo que consegue perceber claramente o dinheiro que os cidadãos da cidade a que preside poderiam poupar se desse o arrojado passo de usar eletricidade 100% renovável. Esta oportunidade de poupar o dinheiro das pessoas e, ao mesmo tempo, reduzir a poluição está a ficar disponível em todo o mundo.
Qual é o segredo para trabalhar com pessoas que podem não concordar consigo em muitos aspetos?
Bem, é preciso ouvir as pessoas e falar com elas tendo em conta aquilo que pensam naquele momento. Acho que à medida que fui envelhecendo fui aprendendo a fazê-lo um pouco melhor. A Mãe Natureza é uma grande aliada quando tentamos convencer as pessoas sobre a seriedade de tudo isto, mas o mercado também o é.
No novo filme, diz que considera as recentes contrariedades na causa climática um fracasso pessoal. Pode explicar-nos porquê?
Houve momentos em que pensei que poderia ter feito mais. Se nos dedicamos a algo e não vemos o objetivo a concretizar-se, temos a tentação de pensar que talvez tenhamos falhado. Em alguns momentos mais sombrios da última década, não consegui deixar de pensar que estávamos a perder esta batalha. Não é o que penso neste momento. Acredito que vamos vencer esta luta.
Alguns ambientalistas dizem que é o mensageiro errado na causa do clima devido à sua filiação e história partidária, tal como Hillary Clinton pode ter sido a mensageira errada em novembro último. Dizem que o Al Gore afasta muitas pessoas. O que tem a dizer sobre isso?
A ciência social refuta esse argumento. O que fez crescer o negacionismo climático foi a grande recessão de 2008 e as despesas cada vez maiores dos partidários do negacionismo. Recentemente, verificou-se um regresso aos níveis de apoio público à ação sobre a crise climática que se registaram depois do lançamento de Uma Verdade Inconveniente.
O que é que o assusta mais no futuro?
Embora estejamos a vencer esta luta, não o estamos a fazer tão rapidamente quanto necessário. A acumulação continuada de poluição humana causadora de aquecimento global vem aumentar os danos que irão repercutir-se no futuro. Algumas das mudanças não são recuperáveis. Não podemos simplesmente ligar o interruptor e reverter o derretimento dos grandes mantos de gelo.
O que lhe dá esperança para o futuro?
Há muitas pessoas pelo mundo a trabalhar sobre esse assunto e isso deixa-me muito otimista. Seria uma grande ajuda ter políticas e leis que acelerassem a nossa resposta. Mas as forças dos mercados estão a trabalhar a nosso favor. A energia solar, a energia eólica e outras energias estão a ficar cada vez mais baratas e melhores. Mais cidades e empresas se estão a converter às energias 100% renováveis. Acredito que não há nada que possa deter a revolução da sustentabilidade.
quarta-feira, 8 de novembro de 2017
Millions of new iPhones will be sold this month. What really happens to the millions that get thrown out?
This fall, iPhone 8s and Xs are hitting shelves across North America, setting in motion that most time-honored of rituals — the smartphone funeral.
Around 1.5 billion phones are sold a year, which means about as many get the heave-ho. With little ceremony, we shove them into drawers or pack them away into boxes.
Occasionally, we might just throw them away. We feel sheepish about it, and for good reason: Once trashed, they end up in landfills, leaching toxic chemicals into the soil. In fact, electronics account for up to 70 percent of landfills’ toxic waste.
To avoid this guilt, we try to take our phones — not to mention all those broken printers, dead Fitbits and cracked iPads — to recycling centers. Driving away after such a drop-off feels good: We did the responsible, eco-friendly thing.
But what happens to these devices after we leave? The answer is complicated and, in most cases, far from eco-friendly. Welcome to the murky world of e-waste “recycling,” a.k.a. the sordid afterlife of your smartphone.
The myth of e-waste “recycling”
If the recycler is a reputable organization, it first checks to see whether your electronics can be refurbished and reused. If so, they’ll be scrubbed of data (hopefully) and either donated or resold on the secondary market. Devices that won’t sell in the U.S. are typically shipped to distributors in South America or Asia. (Remember the Motorola Razr? Long after its popularity faded, there was a booming market for it in Latin America.)
Only when it’s cheaper for companies to reuse component parts — rather than manufacturing from scratch — will our old phones truly meet a better fate.
If the electronics are past the point of no return, they’re sent to recycling plants and put through powerful, all-purpose shredders. Metal components are then shipped to one of a handful of registered smelters, where they’re melted down. A few precious metals from the circuit boards, including gold and palladium, are recovered from the molten liquid, but the vast majority of materials are left to burn, releasing chloride, mercury and other vapors into the atmosphere.
But smelting is still a “good” option, if only because the alternatives are far worse. For nearly every above-board recycler, there’s a corresponding organization that makes money by collecting e-waste, packing it into shipping containers and selling it through a shadowy network of middlemen to scrapyards in countries such as China, India, Ghana and Pakistan.
The environmental cost of such a transaction is high — but the human cost is higher. Walk the streets of e-graveyards like Agbobloshie in West Africa or similar sites in Asia or another part of the developing world, and you’ll see hundreds, if not thousands, of microentrepreneurs, essentially cooking printed circuit boards to extract the metals within. From experience, I can say that the smell in the air is dizzying, and sticks in your nostrils and throat for days.
In the process, these workers are exposed to nickel, cadmium and mercury, among other toxic fumes, which leak into the surrounding air, ground and drinking water. This can lead to a wide variety of serious, sometimes life-threatening health problems, including cancers and birth defects.
Searching for a better afterlife for our smartphones
Environmental and human costs aside, there’s another glaring problem with how we currently treat end-of-life electronics. When we toss our gadgets in the trash, the gold in the circuit board goes with them. Though the amounts in any one phone are minute, the aggregate adds up: It’s estimated that the gold in the world’s e-waste equals as much as 11 percent of the total amount mined each year — literally millions of pounds of gold chucked in the garbage.
In response to these concerns, some manufacturers and retailers are starting to take steps in the right direction. Apple, Samsung, Best Buy and Amazon incentivize consumers to return old devices in exchange for cash or gift cards. (Hand over a non-cracked iPhone 6, for example, and you’ll get $145.) Yet one of the big obstacles remains technology. The trace amounts of minerals inside a typical phone simply don’t justify the enormous expense of extraction.
Our best hope lies in a much bigger shift in perspective: Having manufacturers design expressly with reusability in mind. This cradle-to-cradle approach to production is a cornerstone of the circular economy movement. Apple and other companies, for instance, have come under pressure to make screens, batteries and other components easier to replace and upgrade. “Fair trade phones,” with modular components, are still a novelty but gaining a foothold. A loftier goal: Smartphones that separate into component parts at the touch of a button, freeing up materials to reenter the supply chain.
The tipping point, as is often the case, will come down to economics. Only when it’s cheaper for companies to reuse component parts — rather than manufacturing from scratch—will our old phones truly meet a better fate. In the meantime, nearly 100 million pounds of toxic e-waste is generated each year. As a new wave of iPhones (not to mention Galaxies and Huaweis) floods the market, it’s time we found a way to let our old phones rest in peace, once and for all.
Peter Holgate is a circular-economy thought leader and the founder of Ronin8 Technologies. Reach him @peterjholgate