Quanto mais específicos e precisos forem os dados atmosféricos coletados na área observada, mais precisa será a probabilidade.
29 de abril de 2023
Se você é daqueles que não sai de casa sem antes conferir a previsão do tempo, certamente já se perguntou por que a porcentagem de chuva oferecida pela maioria dos serviços de meteorologia nem sempre corresponde ao que você vê pela janela.
Outros, tendo indagado um pouco mais sobre o assunto, podem ter dito que o que o percentual representa é a área do território em que vai chover durante um determinado período de tempo (por exemplo, “das 9h às 12h”).
E para colocar mais lenha na fogueira, você deve ter visto alguns vídeos do TikTok explicando que o que a porcentagem reflete é a certeza dos meteorologistas de que vai chover em uma determinada área, com base em medições de fatores como temperatura, pressão atmosférica e velocidade do vento.
Diante de explicações tão variadas e distintas para algo que parece ser tão simples, a BBC News Mundo, serviço de notícias em espanhol da BBC, resolveu buscar uma explicação mais exata para o que aquele número representa —e percebeu que, de certa forma, todo mundo tem razão.
Probabilidade de precipitação
Para poder estabelecer o que essa porcentagem realmente significa, vamos começar revisando a definição dada pelo Serviço Meteorológico dos EUA:
“A probabilidade de precipitação representa simplesmente a probabilidade estatística de que haja 0,01 polegadas [0,25 mm] ou mais de precipitação [seja chuva, neve ou granizo] em uma determinada área dentro do período de tempo especificado.”
A porcentagem leva em consideração diferentes fatores para expressar em um valor estatístico a probabilidade de ocorrer precipitação em um determinado ponto.
“Vejamos um exemplo do que essa probabilidade significa”, diz o serviço meteorológico em sua definição.
“Se a previsão para um determinado distrito diz que há 40% de probabilidade de chuva para esta tarde, isso significa que há 40% de chance de chover em algum lugar do distrito entre meio-dia e 18h”, acrescenta.
Com base nessa definição, quanto mais específicos e precisos forem os dados atmosféricos coletados na área observada, mais preciso será o percentual de probabilidade.
Isso explica por que os dados fornecidos por diferentes serviços meteorológicos variam (embora não muito).
Duas medições, mesmo resultado
Para poder fazer uma previsão, um analista meteorológico multiplica dois fatores: a certeza que tem de que um sistema de precipitação vai se formar ou se aproximar, calculado por meio de medições atmosféricas, pela extensão —área física— que se espera que tal precipitação tenha no território analisado.
A esse resultado, basta mover duas casas decimais, e a probabilidade de precipitação é obtida.
Isso indica que é possível chegar à mesma porcentagem de precipitação tendo valores diferentes para cada fator.
Para ver essa ideia na prática, vamos voltar ao nosso exemplo do distrito com 40% de probabilidade de precipitação: se um analista tivesse 80% de certeza de que vai chover naquele distrito (medindo a velocidade do vento, a temperatura do ar, a umidade etc.), mas só espera que o sistema de precipitação cubra 50% da área, ele dirá que há uma “probabilidade de 40% de chuva” durante esse período de tempo.
Por outro lado, se outro analista estimasse que a precipitação iria cobrir 100% da área analisada, mas só tivesse 40% de certeza de que essa precipitação iria atingir o distrito, ele obteria o mesmo resultado: “40% de probabilidade de chuva em qualquer ponto do distrito durante esse período de tempo.”
Pequenas variações entre os sistemas
Cada meteorologista terá seus próprios modelos de medição e coleta de dados para calcular a probabilidade de precipitação nos locais que analisa —e alguns serão mais precisos que outros.
O importante é identificar o quão precisos são os métodos de coleta de dados atmosféricos que cada serviço possui na área específica em que você se encontra, algo que pode ser feito comparando-os e analisando qual deles se adequa melhor à realidade que você observa pela janela.
E, claro, não se pode esquecer que, por se basear em modelos probabilísticos, a meteorologia está longe de ser infalível.
Se você confiar apenas na previsão do tempo, é inevitável que um dia, por melhor que seja o sistema que usa, você saia de casa sem guarda-chuva com base na previsão do aplicativo —e seja pego na rua por um temporal.
Technologically speaking, we live in a time of plenty. Today, I can ask a chatbot to render TheCanterbury Tales as if written by Taylor Swift or to help me write a factually inaccurate autobiography. With three swipes, I can summon almost everyone listed in my phone and see their confused faces via an impromptu video chat. My life is a gluttonous smorgasbord of information, and I am on the all-you-can-eat plan. But there is one specific corner where technological advances haven’t kept up: weather apps.
Weather forecasts are always a game of prediction and probabilities, but these apps seem to fail more often than they should. At best, they perform about as well as meteorologists, but some of the most popular ones fare much worse. The cult favorite Dark Sky, for example, which shut down earlier this year and was rolled into the Apple Weather app, accurately predicted the high temperature in my zip code only 39 percent of the time, according to ForecastAdvisor, which evaluates online weather providers. The Weather Channel’s app, by comparison, comes in at 83 percent. The Apple app, although not rated by ForecastAdvisor, has a reputation for off-the-mark forecasts and has been consistently criticized for presenting faulty radar screens, mixing up precipitation totals, or, as it did last week, breaking altogether. Dozens of times, the Apple Weather app has lulled me into a false sense of security, leaving me wet and betrayed after a run, bike ride, or round of golf.
People love to complain about weather forecasts, dating back to when local-news meteorologists were the primary source for those planning their morning commutes. But the apps have produced a new level of frustration, at least judging by hundreds of crankytweets over the past decade. Nearly two decades into the smartphone era—when anyone can theoretically harness the power of government weather data and dissect dozens of complex, real-time charts and models—we are still getting caught in the rain.
Weather apps are not all the same. There are tens of thousands of them, from the simply designed Apple Weather to the expensive, complex, data-rich Windy.App. But all of these forecasts are working off of similar data, which are pulled from places such as the National Oceanic and Atmospheric Administration (NOAA) and the European Centre for Medium-Range Weather Forecasts. Traditional meteorologists interpret these models based on their training as well as their gut instinct and past regional weather patterns, and different weather apps and services tend to use their own secret sauce of algorithms to divine their predictions. On an average day, you’re probably going to see a similar forecast from app to app and on television. But when it comes to how people feel about weather apps, these edge cases—which usually take place during severe weather events—are what stick in a person’s mind. “Eighty percent of the year, a weather app is going to work fine,” Matt Lanza, a forecaster who runs Houston’s Space City Weather, told me. “But it’s that 20 percent where people get burned that’s a problem.”
No people on the planet have a more tortured and conflicted relationship with weather apps than those who interpret forecasting models for a living. “My wife is married to a meteorologist, and she will straight up question me if her favorite weather app says something different than my forecast,” Lanza told me. “That’s how ingrained these services have become in most peoples’ lives.” The basic issue with weather apps, he argues, is that many of them remove a crucial component of a good, reliable forecast: a human interpreter who can relay caveats about models or offer a range of outcomes instead of a definitive forecast.
Lanza explained the human touch of a meteorologist using the example of a so-called high-resolution forecasting model that can predict only 18 hours out. It is generally quite good, he told me, at predicting rain and thunderstorms—“but every so often it runs too hot and over-indexes the chances of a bad storm.” This model, if left to its own devices, will project showers and thunderstorms blanketing the region for hours when, in reality, the storm might only cause 30 minutes of rain in an isolated area of the mapped region. “The problem is when you take the model data and push it directly into the app with no human interpretation,” he said. “Because you’re not going to get nuance from these apps at all. And that can mean a difference between a chance of rain all day and it’s going to rain all day.”
But even this explanation has caveats; all weather apps are different, and their forecasts have varying levels of sophistication. Some pipe model data right in, whereas others are curated using artificial intelligence. Peter Neilley, the Weather Channel’s director of weather forecasting sciences and technologies, said in an email that the company’s app incorporates “billions of weather data points,” adding that “our expert team of meteorologists does oversee and correct the process as needed.”
Weather apps might be less reliable for another reason too. When it comes to predicting severe weather such as snow, small changes in atmospheric moisture—the type of change an experienced forecaster might notice—can cause huge variances in precipitation outcomes. An app with no human curation might choose to average the model’s range of outcomes, producing a forecast that doesn’t reflect the dynamic situation on the ground. Or consider cities with microclimates: “Today, in Chicago, the lakefront will sit in the lower 40s, and the suburbs will be 50-plus degrees,” Greg Dutra, a meteorologist at ABC 7 Chicago, told me. “Often, the difference is even more stark—20-degree swings over just miles.” These sometimes subtle temperature disparities can mean very different forecasts for people living in the same region—something that one-size-fits-all weather apps don’t always pick up.
Naturally, meteorologists think that what they do is superior to forecasting by algorithm alone, but even weather-app creators told me that the challenges are real. “It’s impossible for a weather-data provider to be accurate everywhere in the world,” Brian Mueller, the founder of the app Carrot Weather, told me. His solution to the problem of app-based imprecision is to give users more ability to choose what they see when they open Carrot, letting them customize what specific weather information the app surfaces as well as what data sources the app will draw from. Mueller said that he learned from Dark Sky’s success how important beautiful, detailed radar maps were—both as a source of weather data and for entertainment purposes. In fact, meteorology seems to be only part of the allure when it comes to building a beloved weather app. Carrot has a pleasant design interface, with bright colors and Easter eggs scattered throughout, such as geography challenges based off of its weather maps. He’s also hooked Carrot up to ChatGPT to allow people to chat with the app’s fictional personality.
But what if these detailed models and dizzying maps, in the hands of weather rubes like myself, are the real problem? “The general public has access to more weather information than ever, and I’d posit that that’s a bad thing,” Chris Misenis, a weather-forecasting consultant in North Carolina who goes by the name “Weather Moose,” told me. “You can go to PivotalWeather.com right now and pull up just about any model simulation you want.” He argues that these data are fine to look at if you know how to interpret them, but for people who aren’t trained to analyze them, they are at best worthless and at worst dangerous.
In fact, forecasts are better than ever, Andrew Blum, a journalist and the author of the book The Weather Machine: A Journey Inside the Forecast, told me. “But arguably, we are less prepared to understand,” he said, “and act upon that improvement—and a forecast is only as good as our ability to make decisions with it.” Indeed, even academic research around weather apps suggests that apps fail worst when they give users a false sense of certainty around forecasting. A 2016 paper for the Royal Meteorological Society argued that “the current way of conveying forecasts in the most common apps is guilty of ‘immodesty’ (‘not admitting that sometimes predictions may fail’) and ‘impoverishment’ (‘not addressing the broader context in which forecasts … are made’).”
The conflicted relationship that people have with weather apps may simply be a manifestation of the information overload that dominates all facets of modern life. These products grant anyone with a phone access to an overwhelming amount of information that can be wildly complex. Greg Dutra shared one such public high-resolution model from the NOAA with me that was full of indecipherable links to jargony terms such as “0-2 km max vertical vorticity.” Weather apps seem to respond mostly to this fire hose of data in two ways: By boiling them down to a reductive “partly sunny” icon, or by bombarding the user with information they might not need or understand. At its worst, a modern weather app seems to flatter people, entrusting them to do their own research even if they’re not equipped. I’m not too proud to admit that some of the fun of toying around with Dark Sky’s beautiful radar or Windy.App’s endless array of models is the feeling of role-playing as a meteorologist. But the truth is that I don’t really know what I’m looking at.
What people seem to be looking for in a weather app is something they can justify blindly trusting and letting into their lives—after all, it’s often the first thing you check when you roll over in bed in the morning. According to the 56,400 ratings of Carrot in Apple’s App Store, its die-hard fans find the app entertaining and even endearing. “Love my psychotic, yet surprisingly accurate weather app,” one five-star review reads. Although many people need reliable forecasting, true loyalty comes from a weather app that makes people feel good when they open it.
Our weather-app ambivalence is a strange pull between feeling grateful for instant access to information and simultaneously navigating a sense of guilt and confusion about how the experience is also, somehow, dissatisfying—a bit like staring down Netflix’s endless library and feeling as if there’s nothing to watch. Weather apps aren’t getting worse. In fact they’re only getting more advanced, inputting more and more data and offering them to us to consume. Which, of course, might be why they feel worse.
Segundo o Cemaden, que é um órgão federal, a Defesa Civil estadual foi alertada sobre a ocorrência de chuvas fortes na região e o alto risco de desastres em uma reunião online na manhã de sexta (17). A vila do Sahy, o ponto em que mais pessoas morreram, foi citada como uma área de alto risco para deslizamento.
Em nota, a Defesa Civil diz que emitiu alertas preventivos à população desde que foi informada da previsão de fortes chuvas.
“Nós alertamos e avisamos a Defesa Civil na sexta, foram quase 48 horas antes de o desastre acontecer. Seguimos o protocolo que é estabelecido, alertando a Defesa Civil estadual para que ela se organizasse com os municípios”, disse Osvaldo Moraes, presidente do Cemaden.
O Cemaden é ligado ao Ministério da Ciência, Tecnologia e Inovação. O centro é responsável por monitorar índices meteorológicos e geológicos e alertar, caso necessário, os órgãos de prevenção.
Moraes diz que, ainda na quinta-feira (16), um boletim meteorológico já indicava as fortes chuvas na região. Esse boletim foi repassado para a Defesa Civil do estado.
Depois desse primeiro alerta, o Cemaden se reuniu com um representante da Defesa Civil estadual na sexta de manhã. “Nós emitimos boletins diários, o de quinta já indicava o risco. Mas o de sexta-feira aumentou o nível de alerta para essa região.”
A Defesa Civil disse que enviou 14 alertas de mensagem de texto (SMS) para mais de 34 mil celulares cadastrados na região do litoral norte. O órgão informou ainda que começou a articular ações as defesas civis municipais na quinta-feira quando recebeu a previsão de fortes chuvas na região.
“Os primeiros avisos divulgados pela Defesa Civil do Estado, que ocorreram ainda de forma preventiva, foram publicados por volta das 15 horas de quinta-feira, nas redes sociais da Defesa Civil e do Governo com informações sobre o volume de chuvas estimado para o período, bem como as medidas de segurança que poderiam ser adotadas pela população em áreas de risco”, diz a nota.
O órgão disse ainda que à 00h52 de sexta, ao acompanhar imagens de radares e satélites, enviou a primeira mensagem de SMS com o alerta.
Nas redes sociais da Defesa Civil, a primeira mensagem de alertas para chuvas fortes no sábado foi feita às 12h22. A mensagem, no entanto, não fala sobre os riscos de desmoronamento.
Durante a noite, outros alertas foram postados pelo órgão e nenhum deles faz menção ao risco de desmoronamento de terra. Foi só às 19h49 uma mensagem recomendou que as pessoas deixassem o local se precisassem.
Para os especialistas, a proporção do desastre e o elevado número de vítimas mostram que apenas a estratégia de envio de SMS aos moradores não é eficiente. Além de não ser possível saber se as pessoas viram os alertas, não havia um plano ou orientação sobre o que fazer na situação.
“Você cria um sistema de aviso, as pessoas podem até receber a mensagem, mas não sabem o que fazer com aquela informação. Não há uma orientação para onde devem ir, quando sair de casa, o que levar”, diz Eduardo Mario Mendiondo, coordenador científico do Ceped (Centro de Estudos e Pesquisas sobre Desastres) da USP.
Para ele, a estratégias devem pensar também criação de rotas de fugas em áreas de risco e na orientação aos moradores. “A população precisa saber qual o risco está correndo e como se proteger. É injusto depois dizer que eles não queriam sair de casa, eles não tinham orientação correta do que fazer.”
Segundo ele, em diversas cidades do país, como Petrópolis e Salvador, o alerta ocorre por uma sirene.
“Você garante que todo mundo vai ouvir a qualquer momento do dia. É o instrumento mais antigo, mas que funciona. Uma sirene dá o recado claro do risco iminente”, diz.
Para Fernando Rocha Nogueira, coordenador do LabGRIS (Laboratório Gestão de Riscos) da UFABC, as autoridade brasileiras assistem de forma inerte aos desastres que ocorrem no país. Segundo ele, o Brasil conta com bons sistemas de monitoramento, mas não desenvolve estratégias para proteger a população.
“Temos um problema grave de comunicação no país. Tinha o mapeamento de que iria chover muito, que havia um alto risco e não se deu a atenção devida. Milhares de pessoas desceram para o litoral, ignorando a previsão. Nós não temos conscientização do risco, nós vivemos um negacionismo das informações climáticas”, diz.
Como foram os avisos
Quinta-feira (16) Boletim do Cemaden alerta para a ocorrência de chuvas fortes e volumosas no litoral paulista durante o Carnaval
Sexta-feira (17) Em reunião virtual, o Cemaden faz alerta sobre a previsão de chuvas fortes e o risco de deslizamentos de terra para integrantes da Defesa Civil do estado. A vila do Sahy estava entre as áreas apontadas como de maior risco
12h22: Defesa Civil do Estado avisa nas redes sociais que a chuva estava se espalhando pela região de Ubatuba e Caraguatatuba. “Tem vento e raios. Atinge municípios vizinhos. Tenha cuidado nas próximas horas”, diz a mensagem
18h33: Uma nova mensagem da Defesa Civil é postada alertando para chuva persistente na região.
19h49: Outra mensagem é postada pela Defesa Civil diz que a “chuva está se espalhando” pelo Litoral Norte e pede para que as pessoas “tenham cuidado nas próximas horas”
23h13: A Defesa Civil alerta que a chuva persiste na região e recomenda “não enfrente alagamentos. Fique atento a inclinação de muros e a rachaduras. Se precisar saia do local”
03h15: O órgão volta a alerta sobre a chuva forte e persistente no litoral norte e diz “não enfrente alagamentos. Fique atento a inclinação de muros e a rachaduras. Se precisar saia do local.”
Como consequência do temporal, 48 pessoas morreram, sendo 47 em São Sebastião e uma em Ubatuba, conforme os dados desta quarta (22).
Segundo o professor Eduardo Mario Mendiondo, coordenador científico do Ceped (Centro de Educação e Pesquisa de Desastres) da USP, os modelos atuais de previsão utilizam parâmetros atmosféricos calibrados por condições históricas e precisam ser atualizados.
“O clima está mudando, com maior magnitude e com maior frequência de ocorrência de extremos. Os modelos precisam ser atualizados de forma constante, em escala global e em regiões específicas, com microclima e dinâmicas peculiares, como é o caso da Serra do Mar e da Baixada Santista”, afirma Mendiondo.
O professor chama atenção para falta de investimentos públicos. Segundo ele, o governo precisa reforçar o quadro de servidores e investir em novas ferramentas para Cemaden (Centro Nacional de Monitoramento e Alertas de Desastres Naturais), Inpe (Instituto Nacional de Pesquisas Espaciais) e Inmet (Instituto Nacional de Meteorologia).
“Falta aumentar em 20 vezes o potencial de supercomputadores atuais em território nacional, falta contratar até 20 vezes o número servidores de manutenção e operação de supercomputadores e falta contratar até em dez vezes o número atual de técnicos operadores”, afirma o professor da USP.
Para suprir tais necessidades, Mendiondo estima que é necessário investimentos de R$ 25 bilhões por ano. “Isto para converter essas novas evidências científicas, melhorando as previsões, seguindo exemplos como Japão, Europa e Estados Unidos.”
O meteorologista Mamedes Luiz Melo afirma que o volume de chuva foi agravado pela ação do ciclone extratropical associado a uma frente fria que passou pelo Sul do país e por São Paulo. “A tecnologia vinha alertando, mas estamos lidando com algo móvel na atmosfera”, afirma Melo.
A Defesa Civil diz, em nota, que os boletins especiais e de aviso de risco meteorológicos são emitidos com base em simulações numéricas de previsão do tempo. “Tais limiares baseiam-se no histórico da chuva da região em que a chuva acumulada representa risco para transtornos, como deslizamentos, desabamentos, alagamentos, enchentes e ocorrências relacionadas a raios e ventos”, disse a Defesa Civil.
As projeções do Inmet, que emite alertas sobre riscos de deslizamentos para órgãos públicos, previram volumes de chuva menores do que um modelo usado pela empresa de meteorologia MetSul.
O modelo da empresa, chamado WRF, apontou que algumas áreas poderiam ter chuva acima de 600 mm em alguns pontos do terreno, o que acabou se confirmando. As previsões mais graves do instituto federal falavam em chuvas no patamar de 400 mm.
A previsão do Inmet para a chuva no litoral norte utilizou seis modelos numéricos diferentes. O instituto também usa o WRF, mas com uma resolução menor do que a da MetSul. Ou seja, a empresa conseguiu fazer os cálculos a partir de detalhes mais precisos do relevo do que o órgão público.
“O WRF tem se mostrado uma ferramenta muito importante na identificação de eventos extremos de chuva”, diz a meteorologista Estael Sias, da MetSul. “É importante assinalar que o modelo WRF é meramente uma ferramenta de trabalho, um produto, e não a previsão, e que o prognóstico final divulgado ao público e clientes leva em conta outros modelos e também a experiência do meteorologista para eventos extremos.”
Segundo o meteorologista Franco Nadal Villela, da equipe do Inmet em São Paulo, a resolução não é o fator mais decisivo na previsão de chuvas. Ele diz que os modelos usados pelo instituto deram conta de prever que o temporal em São Sebastião seria muito grave, embora não tenham chegado ao valor de 600 mm.
“Há modelos de menor resolução que pontualmente previram menos precipitação”, diz Villela. “As previsões modeladas estavam prevendo bem este evento e as variações na quantificação de precipitação [volume de chuva por hora] são mais uma das varáveis que ponderamos para emitir alertas.”
A Folha enviou perguntas através de email ao Inpe, que coordena o Centro de Previsão de Tempo e Estudos Climáticos (Cptec), mas não obteve resposta até a publicação deste texto.
Para José Marengo, climatologista e coordenador do Cemaden, defende mudanças [sic]. Ele explica que o modelo de previsão do tempo divide a região em áreas de até 200 quilômetros quadrados. Com isso, não é possível prever a quantidade de chuva aproximada em toda a região.
“O Brasil não está preparado tecnologicamente. É como se dividisse o Brasil em caixas grandes de 200 quilômetros quadrados, por isso há distorções dentro da mesma região. Pode ter áreas em que chove menos e outras que superaram os 600 milímetros, a modelagem não é perfeita”, afirma Marengo.
Ele também alerta para a falta de novas tecnologias. “O supercomputador do Inpe, o Tupã, que resolve as equações matemáticas em alta velocidade, é de 2010 e considerado obsoleto”, afirma o climatologista.
O professor Pedro Côrtes, do Instituto de Energia e Ambiente da USP, concorda que é área precise de mais recursos, mas pondera que as previsões dos órgãos do governo foram suficientes para apontar que uma tempestade grave se aproximava.
“A espera pelo investimento não pode postergar a solução do problema, as previsões já funcionam.”
Plastic has become an obvious pollutant over recent decades, choking turtles and seabirds, clogging up our landfills and waterways. But in just the past few years, a less obvious problem has emerged. Researchers are starting to get concerned about how tiny bits of plastic in the air, lofted into the skies from seafoam bubbles or spinning tires on the highway, might potentially change our future climate.
“Here’s something that people just didn’t think about — another aspect of plastic pollution,” says environmental analytical chemist Denise Mitrano of ETH Zürich University, in Switzerland, who co-wrote an article last November highlighting what researchers know — and don’t yet know — about how plastics can change clouds, potentially altering temperature and rainfall patterns.
Clouds form when water or ice condenses on “seeds” in the air: usually tiny particles of dust, salt, sand, soot, or other material thrown up by burning fossil fuels, forest fires, cooking, or volcanoes. There are plenty of these fine particles, or aerosols, in the skies — a lot more since the Industrial Revolution — and they affect everything from the quality of the air we breathe, to the color of sunsets, to the number and type of clouds in our skies.
Until recently, when chemists thought of the gunk in our air, plastics did not leap to mind. Concentrations were low, they thought, and plastic is often designed to be water repellent for applications like bags or clothing, which presumably made them unlikely to seed cloud droplets. But in recent years, studies have confirmed not only that microscopic pieces of plastic can seed clouds — sometimes powerfully — but they also travel thousands of miles from their source. And there are a lot more particles in the air than scientists originally thought. All this has opened researchers’ eyes to their potential contribution to atmospheric murk — and, possibly, to future climate change.
“The people who invented plastics all those decades ago, who were very proud of inventions that transformed society in many ways — I doubt they envisaged that plastics were going to end up floating around in the atmosphere and potentially influencing the global climate system,” says Laura Revell, an atmospheric scientist at the University of Canterbury in New Zealand. “We are still learning what the impacts are for humans, ecosystems, and climate. But certainly, from what we know so far, it doesn’t look good.”
Global annual production of plastics has skyrocketed from 2 million tons in 1950 to more than 450 million tons today. And despite growing concerns about this waste accumulating in the environment, production is ramping up rather than slowing down — some oil companies are building up their plastic production capacity as the demand for fossil fuel declines. To date, more than 9 billion tons of plastic has been produced, and about half of it has gone to landfills or been otherwise discarded. Some project that by 2025, 11 billion tons of plastic will have accumulated in the environment.
Plastic has been found in soils, water, crops, and on the ocean floor. And in recent years, several studies have suggested that microplastics (pieces less than 5 millimeters in length) and nanoplastics (smaller than approximately 1,000 nanometers) were being transported long distances through the air. In 2019, for example, researchers found microplastics in the Pyrenees that had arrived via rain or snowfall. In 2020, Janice Brahney of Utah State University and four co-authors published a high-profile Science paper revealing high amounts of plastic in federally protected areas of the United States. Brahney had found the plastic by accident; she had been looking for phosphorus, but was surprised by all the colorful bits of gunk in her ground-based filters. Her study led to a slew of headlines warning, “It’s raining plastic.”
Brahney’s extensive U.S. dataset also opened the door for modelers to figure out where, exactly, all this plastic was coming from. “It’s a really beautiful data set,” says Cornell University’s Natalie Mahowald, who did the modeling work.
Mahowald took the plastic concentrations Brahney had cataloged and mapped them against atmospheric patterns and known sources of plastics, including roads, agricultural dust, and oceans. On roadways, tires and brakes hurl microplastics into the air. Plastic winds up in agricultural dust, notes Mahowald, in part from plastics used on farm fields and in part because people toss fleece clothing into washing machines: The wastewater flows to treatment plants that separate solids from liquids, and about half the resulting biosolids get sent to farms for use as fertilizer. As for the ocean, Mahowald says, big globs of plastic in places like the Pacific Gyre degrade into microscopic pieces, which then float to the surface and are whipped up into the air by chopping waters and bursting air bubbles.
Mahowald’s model concluded that over the western U.S., 84 percent of microplastics were coming from roads, 5 percent from agricultural dust, and 11 percent from the oceans. Plastic is so lightweight that even chunks tens of micrometers across — the width of a human hair — can be lofted and blown great distances. The model revealed that some of this plastic was found thousands of miles from its presumed source. The smaller the pieces, the longer they can stay aloft.
While individual bits of plastic may stay in the air for only hours, days, or weeks, there’s so much being kicked up so consistently that there’s always some in the air: enough that plastic bits are now also found in human lungs. “We’re definitely breathing them right now,” says Mahowald.
Working out exactly how much plastic is in our skies is extremely difficult. Most of these studies are done by painstakingly teasing bits of plastic out of filters and examining them under a microscope to get an estimate of shape and color, then using spectroscopic techniques to confirm their source material. The smaller the pieces, the harder they are to identify. Studies can also be plagued by contamination: Walking into a lab wearing a fleece sweater, for example, can skew results with shedding plastic microfibers.
Nearly a dozen studies have shown airborne microplastic concentrations ranging from between 0.01 particles per cubic meter over the western Pacific Ocean to several thousand particles per cubic meter in London and Beijing. The cities showing higher levels are probably genuinely more polluted, says Revell, but it’s also true that those studies used a more-sensitive technique that could identify smaller bits of plastic (under 10 micrometers in size). The other studies would have missed such smaller pieces, which made up about half the plastic found in the London and Beijing studies.
Plastic bits are now found in human lungs. “We’re definitely breathing them right now,” says Mahowald.
Concentrations of airborne nanoplastics are understood even less. The numbers floating around today, says atmospheric chemist Zamin Kanji, Mitrano’s colleague at ETH Zürich, are likely to be “significantly underestimated.”
For now, the proportion of plastics to total airborne aerosols is tiny, so plastics aren’t contributing much to aerosol climate impacts, says Mahowald. Even in London and Beijing, plastic may account for only a millionth of the total aerosols. But plastic production, and the accumulation of plastic in the environment, keeps going up. Says Mahowald, “It’s only going to get worse.”
That’s especially true in less polluted regions — like over the oceans of the Southern Hemisphere, Kanji says. Since plastic can likely travel farther than other, denser aerosols, it could become a dominant airborne pollutant in more pristine areas. Brahney and Mahowald’s paper concludes that plastic currently makes up less than 1 percent of anthropogenic aerosols landing on the ground but they could, “alarmingly,” make up more than 50 percent of the aerosols landing on some parts of the ocean downwind from plastic sources.
Exactly how aerosols affect climate has been a critical sticking point in climate models, and many of the details are still unknown. Different aerosols can change the climate by either reflecting or absorbing sunlight, which can depend, in part, on their color. Black soot, for example, tends to have a warming effect, while salt reflects and cools. Aerosols can land on the ground and change the albedo, or reflectivity, of ice and snow.
Aerosols also affect cloud formation: Different bits and pieces can seed more and smaller droplets of water or ice, making for different types of clouds at different elevations that last for different amounts of time. High-altitude, thin, icy clouds tend to warm the Earth’s surface like a blanket, while low-altitude, bright and fluffy clouds tend to reflect sunlight and cool the Earth.
Though tiny, aerosols have an oversized influence on climate. The murk of anthropogenic aerosols in the sky has, overall, had a dramatic cooling effect since the Industrial Revolution (without them, global warming would be 30 to 50 percent greater than it is today). And they have more sway on extreme weather than greenhouse gases do: A world warmed by removing aerosols would have more floods and droughts, for example, than a world warmed the same amount by CO2.
Revell and her colleagues took a stab at trying to model how microplastics might affect temperature by either reflecting or absorbing sunlight, a calculation of what’s known as “radiative forcing.” For simplicity’s sake, they assumed that plastic is always clear, even though that’s not true (and darker material tends to absorb more sunlight), and that the global concentration is uniformly one particle per cubic meter, which is on the order of 1,000 times lower than concentrations measured in, say, London.
With those assumptions, Revell found that plastic’s direct impact on radiative forcing is “so small as to be insignificant.” But, importantly, if concentrations reach 100 particles per cubic meter (which they already have in many spots), plastics could have about the same magnitude of radiative forcing as some aerosols already included in Intergovernmental Panel on Climate Change assessments. In other words, plastics become noteworthy. But whether they would warm, or cool, the Earth is unknown.
Though tiny, aerosols have an oversized influence on climate.
Aerosols often have a greater impact on the climate through their influence on clouds. Pristine plastic beads, Kanji notes, repel water and so are unlikely to affect clouds. But plastic can “age” in a matter of hours, says Kanji, during its transit to the sky: It can be abraded, or it can accumulate salt from the ocean and other chemicals from the atmosphere, all of which can make the particles more water-loving. Plastic pieces can also contain nooks and crannies, which aid in the formation of ice.
In the lab, Kanji’s student Omar Girlanda has run preliminary tests showing that under such battered conditions, plastic pieces can be potent cloudmakers. “Some of them are as good as mineral dust particles,” says Kanji, “which is the most well-known, effective ice nucleus out there.”
Kanji says skies heavily polluted with plastic will probably make both more high-altitude ice clouds, which tend to warm the Earth’s surface, and more low-altitude water clouds, which tend to cool the Earth. Which effect will dominate is unknown. “It doesn’t make sense to model it at the moment, given the poor estimates we have of [atmospheric] plastic,” says Kanji. Plastic could also affect precipitation patterns: In general, Kanji says, clouds that are more polluted tend to last longer before bursting into rain than do less polluted clouds, and then they rain more heavily.
Revell and her colleagues are now whittling down the assumptions in their paper, working out more detailed calculations for more realistic estimates of plastic concentrations, colors, and sizes. “All we know is that the problem is not going to go away anytime soon,” she says. “These plastics are incredibly long lived. They’re breaking down, and they’re going to be forming new microplastics for centuries. We just don’t know how big the problem is that we’ve committed ourselves to.”
Nicola Jones is a freelance journalist based in Pemberton, British Columbia. Her work can be found in Nature, Scientific American, Globe and Mail, and New Scientist.
Cadê os trabalhos do Cacique Cobra Coral para o carnaval carioca, prefeito? /Foto: Reprodução G1/Marcelo Brandt
A frequência de Eduardo Paes no Centro de Operações Rio (COR) tem aumentado nas últimas semanas. O prefeito tem até um quartinho no prédio da Cidade Nova, como mostrou em vídeo, nessa segunda (13/02), para casos emergenciais, o que acontece bem pouco, já que ele não dorme.
No entanto, cariocas e turistas estão preocupados com a previsão de chuva forte para os dias de carnaval e já estão pedindo que Paes contrate os serviços da Fundação Cacique Cobra Coral, quer dizer, da médium Adelaide Scritori, que diz incorporar o espírito que espanta as águas e cujo trabalho funcionou no réveillon. Supõe-se!
Nas redes, comentários como “essa chuvarada constante no Rio me faz acreditar que o Cacique Cobra Coral já até recebeu o Pix do carnaval. Seria a única explicação para esse sofrimento atual. Estamos nos sacrificando em prol de um bem maior”, “Dudu, pague o Cacique Cobra Coral imediatamente!”, “acompanhando com preocupação a previsão do tempo para os dias de carnaval. Pensando em fazer uma vaquinha e contratar o Cacique Cobra Coral pra garantir sol até a Quarta-Feira de Cinzas” e assim vai.
Além do réveillon, a fundação também fez um trabalho para a posse de Lula em Brasília, já que a previsão do dia 1º de janeiro era de chuva. Mas a fundação não está vinculada a nenhum grupo político ou ideológico, tanto que também fez serviços na posse de Bolsonaro, em 2019. Hoje, a fundação atende clientes em 17 países de 4 continentes, com histórias de sucesso.
Em duas décadas, região Norte foi a única que chegou ao patamar de equilíbrio racial; Centro-Oeste teve maior avanço
Douglas Gavras, Patrick Fuentes e Cristina Sano
19 de novembro de 2022
Concluindo um mestrado em comunicação na UFBA (Universidade Federal da Bahia), Mariana Gomes, 24, é de uma família que foi transformada pela educação. Seu avô deixou o interior da Bahia para se tornar médico, o que estimulou a geração seguinte a ter um diploma superior e, em seguida, a geração dos netos.
Cotista, ela teve a possibilidade de dividir as cadeiras da graduação com outros alunos negros. “A minha geração já tem a referência da universidade como possibilidade real de manter esse processo de ascensão e conquistar direitos básicos.”
Agora, além de ver a necessidade de manter e aprimorar as políticas de acesso ao ensino superior, ela quer pensar no dia seguinte. “É preciso que mais pretos e pardos percebam a educação como possibilidade de resguardar direitos e avançar em oportunidades de trabalho e autonomia.”
Apesar de avanços no aumento da diversidade no ensino superior, mantido o ritmo atual, o Brasil deve levar quase 116 anos para que pretos e pardos tenham acesso às mesmas oportunidades que os brancos, de acordo com a mais recente edição do Ifer (Índice Folha de Equilíbrio Racial).
Enquanto políticas, como o sistema de cotas raciais, ajudaram a melhorar o indicador de equilíbrio racial para a educação —e ainda assim, a diferença em relação aos brancos só deve ser superada em 34 anos— a redução da desigualdade de renda e longevidade decepciona.
Quando considerada a renda, o tempo necessário até o equilíbrio é de 406 anos. No caso da sobrevida ou longevidade, a maior parte dos estados do país está em relativo equilíbrio racial, mas os indicadores têm piorado rumo ao desequilíbrio, segundo o Ifer.
O índice é uma ferramenta cuja metodologia foi elaborada no ano passado pelos pesquisadores do Insper Sergio Firpo, Michael França —ambos colunistas da Folha— e Alysson Portella.
Seus componentes são ensino superior completo, sobrevida e presença no topo da pirâmide de renda, tendo como base a Pnad (Pesquisa Nacional por Amostra de Domicílios), do IBGE (Instituto Brasileiro de Geografia e Estatística). Ao longo deste mês, outras reportagens irão detalhar o que ocorreu com esses itens.
O resultado é um indicador que varia de -1 a 1. Quanto mais próximo de -1, maior é a representação dos brancos em relação aos negros; já o valor muito perto de 1 aponta um cenário hipotético, em que a população negra teria mais representação.
Além disso, quanto mais próximo de zero estiver o número, mais perto o indicador vai estar do equilíbrio racial, considerando-se a população de referência.
Para estimar o tempo que falta até chegar o equilíbrio, é feito um cálculo usando a linha temporal dos dados e considerando a tendência linear que mais se aproxima do que ocorreu no período. Essa tendência, então, é extrapolada para o futuro, para que saiba em quanto tempo se chegará a zero.
MELHORA DA DESIGUALDADE É TÍMIDA, APONTAM NÚMEROS
Na versão mais recente do índice, os pesquisadores compararam os indicadores por um período de 2001 a 2021 e concluíram que a redução do desequilíbrio racial no país caminhou de forma modesta.
Em duas décadas, o indicador geral melhorou 0,071 ponto, indo de -0,389 para -0,318, apontando ainda a maior representação de brancos ante negros.
Nesse período, a região Norte foi a única do país que conseguiu atingir o patamar de equilíbrio racial relativo, que varia de 0,2 a -0,2. Nos estados ao norte, o indicador geral do Ifer passou de -0,301 para -0,196 ponto.
“São sociedades mais pobres também, com pouco espaço para ter uma desigualdade muito visível. Há uma certa homogeneidade, inclusive racial, na carência. São economias com crescimento e renda menores”, diz Firpo, que também é colunista da Folha.
Ainda assim, a maior queda se deu no Centro-Oeste, com uma melhora de 0,133 ponto, indo de -0,378 para -0,245.
Na outra ponta, nas regiões mais ricas do país, a desigualdade é bem mais forte: o Sudeste teve o pior indicador em 2021, de -0,383 ponto (já era o lanterninha em 2001, com -0,411); no Sul, passou de -0,308 em 2001 para -0,253 em 2021.
Das 27 unidades da Federação, 22 melhoraram, 4 pioraram (Ceará, Santa Catarina, São Paulo e Sergipe) e 1 ficou estagnada (Espírito Santo). No caso dos estados, como a base amostral para algumas UFs é muito pequena, optou-se por utilizar as médias móveis de três anos, e a série vai de 2004 a 2021.
Quando se olha para os dados gerais do país, a pequena melhora foi impulsionada pelo indicador que aponta o acesso ao ensino superior, com uma melhora de 0,223 ponto, ao passar de -0,598 para -0,375.
“O Brasil ainda não dá acesso à elite para os negros. Isso tem se reduzido, mas em uma velocidade muito pequena, o que deixa claro o quanto é necessário aumentar o número de políticas públicas integradoras”, diz Firpo.
Ele avalia que o reflexo da redução da desigualdade só deve começar a aparecer com mais clareza nos demais indicadores após maiores investimentos em qualificação profissional.
“Facilitar o acesso à universidade pública é uma demanda histórica e importante, mas a forma mais eficiente de reduzir a desigualdade de oportunidades é integrar negros e brancos, ricos e pobres desde cedo, fazer com que a parcela mais excluída da população conviva com pessoas que vão ampliar sua possibilidade de acesso a um conjunto de oportunidades lá na frente”, diz.
No mesmo intervalo de tempo, o indicador nacional de renda melhorou apenas 0,068 ponto, de -0,516 para -0,448 ponto.
Nesse caso, o cálculo da renda considera a proporção de pretos e pardos que alcançam ou ultrapassam a renda (incluindo salários e demais rendimentos) que separa os brancos 10% mais ricos dos demais 90%, além de seu peso populacional.
Já os dados de sobrevida —apesar de seguirem no patamar de equilíbrio entre negros e brancos, na maioria dos casos— apontam uma piora: era de -0,052, em 2001, e foi para -0,130 duas décadas mais tarde.
O cálculo do componente de sobrevida no Ifer é semelhante ao que é feito para o indicador de renda: extrai-se o grupo de brancos 10% mais idosos e calcula-se a idade que o separa dos demais 90%.
O destaque negativo também é o Sudeste, onde o índice de Sobrevida passou de -0,104 para -0,202, saindo do nível de equilíbrio para o de maior representatividade branca.
AVANÇO DE LONGEVIDADE E RENDA DEMANDA INVESTIMENTOS
Mesmo celebrando os avanços em parte dos indicadores, os especialistas ouvidos pela reportagem destacam a necessidade de políticas públicas direcionadas para o combate ao racismo, tanto no mercado de trabalho quanto na rede pública de atendimento, para que os demais indicadores também avancem.
“Não basta que apenas a educação melhore, cada um dos componentes possui o mesmo peso e deveria ser observado de forma consistente por políticas públicas de redução da desigualdade”, diz França, que também é colunista da Folha.
Ele também destaca que a piora do índice de sobrevida no período, que caminha para o desequilíbrio, pode indicar a diferença no acesso a planos de saúde privados, um fator em que a população branca sempre leva vantagem, e a falta de investimentos adequados no SUS (Sistema Único de Saúde).
“Já para o componente da renda é preciso começar a discutir mais seriamente as barreiras que existem para os negros. Ampliamos o acesso ao ensino superior, mas isso ainda não se reflete em melhores postos no mercado de trabalho”, complementa.
Além de educação, saúde e renda, fatores como privilégios ligados a cor de pele e estrutura familiar economicamente saudável ajudam a explicar a queda tímida no desequilíbrio entre negros e brancos”, diz Portella. “Chegar aos 10% mais privilegiados no Brasil é difícil. Em um país tão desigual, muitas vezes os pequenos ganhos não são suficientes para colocar [os negros] no topo.”
Sobre as diferenças regionais, ele acrescenta que locais com maior concentração de renda, como o Sudeste, possuem obstáculos adicionais para a população negra, dado o privilégio econômico dos brancos.
“Pessoas realmente ricas contam com redes de contatos que desempenham um papel muito importante [na ascensão social]. Então, para um negro da periferia vai ser muito difícil acessar uma rede que vai te permitir entrar nesse grupo; já uma pessoa branca fica mais fácil se manter lá”, diz.
“A população [negra] também acaba sendo mais vulnerável aos ciclos da economia e às decisões do governo”, avalia Marcelo Paixão, economista e professor da Universidade do Texas. Segundo ele, apesar de melhoras simbólicas e materiais no desequilíbrio entre brancos e negros no Brasil, momentos de crise econômica ou de alta na inflação, tendem a afetar mais pessoas negras.
Para Paixão, a desigualdade passa por ciclos, no qual pode diminuir e se agravar em diferentes períodos históricos. No entanto, a falta de estrutura familiar mais organizada, as dificuldades no acesso ao mercado de trabalho formal e à Previdência são maiores para os negros.
“Equidade é dar ferramentas específicas a grupos que tiveram uma desigualdade de oportunidade na origem. Se você nasce numa família que consegue suprir a ineficiência do setor público, seu filho larga na frente”, diz Carla Beni, economista e professora no MBA da FGV (Fundação Getulio Vargas).
Ela destaca que a discriminação também impende o equilíbrio relativo entre negros e brancos. “A falácia da meritocracia dificulta o aprofundamento do debate e criação de novas políticas para aumentar representatividade da população negra e parda no país”, diz.
Para o economista Mário Theodoro, autor de “A Sociedade Desigual – Racismo e Branquitude na Formação do Brasil”, ainda faltam políticas direcionadas para a redução da desigualdade.
“Um estudo que fiz durante o governo anterior do presidente Lula mostrava a redução da pobreza entre negros e brancos, mas agora é preciso pensar em mecanismos que privilegiam os negros mais pobres. As políticas universais são fundamentais, mas se não forem complementadas pelas políticas de combate ao racismo, o patamar de diferença vai se manter.”
An international team led by Oregon State University researchers says in a report published today that the Earth’s vital signs have reached “code red” and that “humanity is unequivocally facing a climate emergency.”
In the special report, “World Scientists’ Warning of a Climate Emergency 2022,” the authors note that 16 of 35 planetary vital signs they use to track climate change are at record extremes. The report’s authors share new data illustrating the increasing frequency of extreme heat events and heat-related deaths, rising global tree cover loss because of fires, and a greater prevalence of insects and diseases thriving in the warming climate. Food insecurity and malnutrition caused by droughts and other climate-related extreme events in developing countries are increasing the number of climate refugees.
William Ripple, a distinguished professor in the OSU College of Forestry, and postdoctoral researcher Christopher Wolf are the lead authors of the report, and 10 other U.S. and global scientists are co-authors.
“Look at all of these heat waves, fires, floods and massive storms,” Ripple said. “The specter of climate change is at the door and pounding hard.”
“As we can see by the annual surges in climate disasters, we are now in the midst of a major climate crisis, with far worse to come if we keep doing things the way we’ve been doing them,” Wolf said.
“As Earth’s temperatures are creeping up, the frequency or magnitude of some types of climate disasters may actually be leaping up,” said the University of Sydney’s Thomas Newsome, a co-author of the report. “We urge our fellow scientists around the world to speak out on climate change.”
“The Scientist’s Warning” is a documentary by the research team summarizing the report’s results and can be watched online:
A different ‘Big One’ is approaching. Climate change is hastening its arrival.
Aug. 12, 2022
California, where earthquakes, droughts and wildfires have shaped life for generations, also faces the growing threat of another kind of calamity, one whose fury would be felt across the entire state.
This one will come from the sky.
According to new research, it will very likely take shape one winter in the Pacific, near Hawaii. No one knows exactly when, but from the vast expanse of tropical air around the Equator, atmospheric currents will pluck out a long tendril of water vapor and funnel it toward the West Coast.
This vapor plume will be enormous, hundreds of miles wide and more than 1,200 miles long, and seething with ferocious winds. It will be carrying so much water that if you converted it all to liquid, its flow would be about 26 times what the Mississippi River discharges into the Gulf of Mexico at any given moment.
When this torpedo of moisture reaches California, it will crash into the mountains and be forced upward. This will cool its payload of vapor and kick off weeks and waves of rain and snow.
The coming superstorm — really, a rapid procession of what scientists call atmospheric rivers — will be the ultimate test of the dams, levees and bypasses California has built to impound nature’s might.
But in a state where scarcity of water has long been the central fact of existence, global warming is not only worsening droughts and wildfires. Because warmer air can hold more moisture, atmospheric rivers can carry bigger cargoes of precipitation. The infrastructure design standards, hazard maps and disaster response plans that protected California from flooding in the past might soon be out of date.
As humans burn fossil fuels and heat up the planet, we have already increased the chances each year that California will experience a monthlong, statewide megastorm of this severity to roughly 1 in 50, according to a new study published Friday. (The hypothetical storm visualized here is based on computer modeling from this study.)
In the coming decades, if global average temperatures climb by another 1.8 degrees Fahrenheit, or 1 degree Celsius — and current trends suggest they might — then the likelihood of such storms will go up further, to nearly 1 in 30.
At the same time, the risk of megastorms that are rarer but even stronger, with much fiercer downpours, will rise as well.
These are alarming possibilities. But geological evidence suggests the West has been struck by cataclysmic floods several times over the past millennium, and the new study provides the most advanced look yet at how this threat is evolving in the age of human-caused global warming.
The researchers specifically considered hypothetical storms that are extreme but realistic, and which would probably strain California’s flood preparations. According to their findings, powerful storms that once would not have been expected to occur in an average human lifetime are fast becoming ones with significant risks of happening during the span of a home mortgage.
“We got kind of lucky to avoid it in the 20th century,” said Daniel L. Swain, a climate scientist at the University of California, Los Angeles, who prepared the new study with Xingying Huang of the National Center for Atmospheric Research in Boulder, Colo. “I would be very surprised to avoid it occurring in the 21st.”
Unlike a giant earthquake, the other “Big One” threatening California, an atmospheric river superstorm will not sneak up on the state. Forecasters can now spot incoming atmospheric rivers five days to a week in advance, though they don’t always know exactly where they’ll hit or how intense they’ll be.
Using Dr. Huang and Dr. Swain’s findings, California hopes to be ready even earlier. Aided by supercomputers, state officials plan to map out how all that precipitation will work its way through rivers and over land. They will hunt for gaps in evacuation plans and emergency services.
The last time government agencies studied a hypothetical California megaflood, more than a decade ago, they estimated it could cause $725 billion in property damage and economic disruption. That was three times the projected fallout from a severe San Andreas Fault earthquake, and five times the economic damage from Hurricane Katrina, which left much of New Orleans underwater for weeks in 2005.
Dr. Swain and Dr. Huang have handed California a new script for what could be one of its most challenging months in history. Now begin the dress rehearsals.
“Mother Nature has no obligation to wait for us,” said Michael Anderson, California’s state climatologist.
In fact, nature has not been wasting any time testing California’s defenses. And when it comes to risks to the water system, carbon dioxide in the atmosphere is hardly the state’s only foe.
THE ULTIMATE CURVEBALL
On Feb. 12, 2017, almost 190,000 people living north of Sacramento received an urgent order: Get out. Now. Part of the tallest dam in America was verging on collapse.
That day, Ronald Stork was in another part of the state, where he was worrying about precisely this kind of disaster — at a different dam.
Standing with binoculars near California’s New Exchequer Dam, he dreaded what might happen if large amounts of water were ever sent through the dam’s spillways. Mr. Stork, a policy expert with the conservation group Friends of the River, had seen on a previous visit to Exchequer that the nearby earth was fractured and could be easily eroded. If enough water rushed through, it might cause major erosion and destabilize the spillways.
He only learned later that his fears were playing out in real time, 150 miles north. At the Oroville Dam, a 770-foot-tall facility built in the 1960s, water from atmospheric rivers was washing away the soil and rock beneath the dam’s emergency spillway, which is essentially a hillside next to the main chute that acts like an overflow drain in a bathtub. The top of the emergency spillway looked like it might buckle, which would send a wall of water cascading toward the cities below.
Mr. Stork had no idea this was happening until he got home to Sacramento and found his neighbor in a panic. The neighbor’s mother lived downriver from Oroville. She didn’t drive anymore. How was he going to get her out?
Mr. Stork had filed motions and written letters to officials, starting in 2001, about vulnerabilities at Oroville. People were now in danger because nobody had listened. “It was nearly soul crushing,” he said.
“With flood hazard, it’s never the fastball that hits you,” said Nicholas Pinter, an earth scientist at the University of California, Davis. “It’s the curveball that comes from a direction you don’t anticipate. And Oroville was one of those.”
Ronald Stork in his office at Friends of the River in Sacramento.
The spillway of the New Exchequer Dam.
Such perils had lurked at Oroville for so long because California’s Department of Water Resources had been “overconfident and complacent” about its infrastructure, tending to react to problems rather than pre-empt them, independent investigators later wrote in a report. It is not clear this culture is changing, even as the 21st-century climate threatens to test the state’s aging dams in new ways. One recent study estimated that climate change had boosted precipitation from the 2017 storms at Oroville by up to 15 percent.
A year and a half after the crisis, crews were busy rebuilding Oroville’s emergency spillway when the federal hydropower regulator wrote to the state with some unsettling news: The reconstructed emergency spillway will not be big enough to safely handle the “probable maximum flood,” or the largest amount of water that might ever fall there.
Sources: Global Historical Climatology Network, Huang and Swain (2022) Measurements taken from the Oroville weather station and the nearest modeled data point
This is the standard most major hydroelectric projects in the United States have to meet. The idea is that spillways should basically never fail because of excessive rain.
Today, scientists say they believe climate change might be increasing “probable maximum” precipitation levels at many dams. When the Oroville evacuation was ordered in 2017, nowhere near that much water had been flowing through the dam’s emergency spillway.
Yet California officials have downplayed these concerns about the capacity of Oroville’s emergency spillway, which were raised by the Federal Energy Regulatory Commission. Such extreme flows are a “remote” possibility, they argued in a letter last year. Therefore, further upgrades at Oroville aren’t urgently needed.
In a curt reply last month, the commission said this position was “not acceptable.” It gave the state until mid-September to submit a plan for addressing the issue.
The Department of Water Resources told The Times it would continue studying the matter. The Federal Energy Regulatory Commission declined to comment.
“People could die,” Mr. Stork said. “And it bothers the hell out of me.”
WETTER WET YEARS
Donald G. Sullivan was lying in bed one night, early in his career as a scientist, when he realized his data might hold a startling secret.
For his master’s research at the University of California, Berkeley, he had sampled the sediment beneath a remote lake in the Sacramento Valley and was hoping to study the history of vegetation in the area. But a lot of the pollen in his sediment cores didn’t seem to be from nearby. How had it gotten there?
When he X-rayed the cores, he found layers where the sediment was denser. Maybe, he surmised, these layers were filled with sand and silt that had washed in during floods.
It was only late that night that he tried to estimate the ages of the layers. They lined up neatly with other records of West Coast megafloods.
“That’s when it clicked,” said Dr. Sullivan, who is now at the University of Denver.
His findings, from 1982, showed that major floods hadn’t been exceptionally rare occurrences over the past eight centuries. They took place every 100 to 200 years. And in the decades since, advancements in modeling have helped scientists evaluate how quickly the risks are rising because of climate change.
For their new study, which was published in the journal Science Advances, Dr. Huang and Dr. Swain replayed portions of the 20th and 21st centuries using 40 simulations of the global climate. Extreme weather events, by definition, don’t occur very often. So by using computer models to create realistic alternate histories of the past, present and future climate, scientists can study a longer record of events than the real world offers.
Dr. Swain and Dr. Huang looked at all the monthlong California storms that took place during two time segments in the simulations, one in the recent past and the other in a future with high global warming, and chose one of the most intense events from each period. They then used a weather model to produce detailed play-by-plays of where and when the storms dump their water.
Those details matter. There are “so many different factors” that make an atmospheric river deadly or benign, Dr. Huang said.
Xingying Huang of the National Center for Atmospheric Research in Boulder, Colo. Rachel Woolf for The New York Times
The New Don Pedro Dam spillway.
Wes Monier, a hydrologist, with a 1997 photo of water rushing through the New Don Pedro Reservoir spillway.
In the high Sierras, for example, atmospheric rivers today largely bring snow. But higher temperatures are shifting the balance toward rain. Some of this rain can fall on snowpack that accumulated earlier, melting it and sending even more water toward towns and cities below.
Climate change might be affecting atmospheric rivers in other ways, too, said F. Martin Ralph of the Scripps Institution of Oceanography at the University of California, San Diego. How strong their winds are, for instance. Or how long they last: Some storms stall, barraging an area for days on end, while others blow through quickly.
Scientists are also working to improve atmospheric river forecasts, which is no easy task as the West experiences increasingly sharp shifts from very dry conditions to very wet and back again. In October, strong storms broke records in Sacramento and other places. Yet this January through March was the driest in the Sierra Nevada in more than a century.
“My scientific gut says there’s change happening,” Dr. Ralph said. “And we just haven’t quite pinned down how to detect it adequately.”
Better forecasting is already helping California run some of its reservoirs more efficiently, a crucial step toward coping with wetter wet years and drier dry ones.
On the last day of 2016, Wes Monier was looking at forecasts on his iPad and getting a sinking feeling.
Mr. Monier is chief hydrologist for the Turlock Irrigation District, which operates the New Don Pedro Reservoir near Modesto. The Tuolumne River, where the Don Pedro sits, was coming out of its driest four years in a millennium. Now, some terrifying rainfall projections were rolling in.
First, 23.2 inches over the next 16 days. A day later: 28.8 inches. Then 37.1 inches, roughly what the area normally received in a full year.
If Mr. Monier started releasing Don Pedro’s water too quickly, homes and farms downstream would flood. Release too much and he would be accused of squandering water that would be precious come summer.
But the forecasts helped him time his flood releases precisely enough that, after weeks of rain, the water in the dam ended up just shy of capacity. Barely a drop was wasted, although some orchards were flooded, and growers took a financial hit.
The next storm might be even bigger, though. And even the best data and forecasts might not allow Mr. Monier to stop it from causing destruction. “There’s a point there where I can’t do anything,” he said.
How do you protect a place as vast as California from a storm as colossal as that? Two ways, said David Peterson, a veteran engineer. Change where the water goes, or change where the people are. Ideally, both. But neither is easy.
Firebaugh is a quiet, mostly Hispanic city of 8,100 people, one of many small communities that power the Central Valley’s prodigious agricultural economy. Many residents work at nearby facilities that process almonds, pistachios, garlic and tomatoes.
Firebaugh also sits right on the San Joaquin River.
For a sleepless stretch of early 2017, Ben Gallegos, Firebaugh’s city manager, did little but watch the river rise and debate whether to evacuate half the town. Water from winter storms had already turned the town’s cherished rodeo grounds into a swamp. Now it was threatening homes, schools, churches and the wastewater treatment plant. If that flooded, people would be unable to flush their toilets. Raw sewage would flow down the San Joaquin.
Luckily, the river stopped rising. Still, the experience led Mr. Gallegos to apply for tens of millions in funding for new and improved levees around Firebaugh.
Levees change where the water goes, giving rivers more room to swell before they inundate the land. Levee failures in New Orleans were what turned Katrina into an epochal catastrophe, and after that storm, California toughened levee standards in urbanized areas of the Sacramento and San Joaquin Valleys, two major river basins of the Central Valley.
The idea is to keep people out of places where the levees don’t protect against 200-year storms, or those with a 0.5 percent chance of occurring in any year. To account for rising seas and the shifting climate, California requires that levees be recertified as providing this level of defense at least every 20 years.
Firebaugh, Calif., on the San Joaquin River, is home to 8,100 people and helps power the Central Valley’s agricultural economy.
Ben Gallegos, the Firebaugh city manager.
A 6-year-old’s birthday celebration in Firebaugh.
The problem is that once levees are strengthened, the areas behind them often become particularly attractive for development: fancier homes, bigger buildings, more people. The likelihood of a disaster is reduced, but the consequences, should one strike, are increased.
Federal agencies try to stop this by not funding infrastructure projects that induce growth in flood zones. But “it’s almost impossible to generate the local funds to raise that levee if you don’t facilitate some sort of growth behind the levee,” Mr. Peterson said. “You need that economic activity to pay for the project,” he said. “It puts you in a Catch-22.”
A project to provide 200-year protection to the Mossdale Tract, a large area south of Stockton, one of the San Joaquin Valley’s major cities, has been on pause for years because the Army Corps of Engineers fears it would spur growth, said Chris Elias, executive director of the San Joaquin Area Flood Control Agency, which is leading the project. City planners have agreed to freeze development across thousands of acres, but the Corps still hasn’t given its final blessing.
The Corps and state and local agencies will begin studying how best to protect the area this fall, said Tyler M. Stalker, a spokesman for the Corps’s Sacramento District.
The plodding pace of work in the San Joaquin Valley has set people on edge. At a recent public hearing in Stockton on flood risk, Mr. Elias stood up and highlighted some troubling math.
The Department of Water Resources says up to $30 billion in investment is needed over the next 30 years to keep the Central Valley safe. Yet over the past 15 years, the state managed to spend only $3.5 billion.
“We have to find ways to get ahead of the curve,” Mr. Elias said. “We don’t want to have a Katrina 2.0 play out right here in the heart of Stockton.”
As Mr. Elias waits for projects to be approved and budgets to come through, heat and moisture will continue to churn over the Pacific. Government agencies, battling the forces of inertia, indifference and delay, will make plans and update policies. And Stockton and the Central Valley, which runs through the heart of California, will count down the days and years until the inevitable storm.
The Sacramento-San Joaquin Delta near Stockton, Calif.
The megastorm simulation is based on the “ARkHist” storm modeled by Huang and Swain, Science Advances (2022), a hypothetical statewide, 30-day atmospheric river storm sequence over California with an approximately 2 percent likelihood of occurring each year in the present climate. Data was generated using the Weather Research and Forecasting model and global climate simulations from the Community Earth System Model Large Ensemble.
The chart of precipitation at Oroville compares cumulative rainfall at the Oroville weather station before the 2017 crisis with cumulative rainfall at the closest data point in ARkHist.
The rainfall visualization compares observed hourly rainfall in December 2016 from the Los Angeles Downtown weather station with rainfall at the closest data point in a hypothetical future megastorm, the ARkFuture scenario in Huang and Swain (2022). This storm would be a rare but plausible event in the second half of the 21st century if nations continue on a path of high greenhouse-gas emissions.
The 3D rainfall visualization and augmented reality effect by Nia Adurogbola, Jeffrey Gray, Evan Grothjan, Lydia Jessup, Max Lauter, Daniel Mangosing, Noah Pisner, James Surdam and Raymond Zhong.
Photo editing by Matt McCann.
Produced by Sarah Graham, Claire O’Neill, Jesse Pesta and Nadja Popovich.
Giant rainstorms have ravaged California before. Times journalists combined data, graphics and old-fashioned reporting to explore what the next big one might look like.
Aug. 25, 2022
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Not long ago, when I heard that California officials were embarking on an ambitious, multiyear effort to study one of the worst natural disasters in the state’s history, I knew there would be a lot of interesting material to cover. There was just one wrinkle: The disaster hadn’t happened yet — it still hasn’t.
The California water authorities wanted to examine a much bigger and more powerful version of the rainstorms the state often gets in winter. The milder ones replenish water supplies. But the strong ones cause devastating flooding and debris flows. And the really strong ones, like those that have hit the Pacific Coast several times over the past millennium, can erase whole landscapes, turning valleys and plains into lakes.
As global warming increases the likelihood and the intensity of severe storms, the state’s Department of Water Resources wanted to know: What would a really big (yet plausible) storm look like today? How well would we handle it?
As a climate reporter for The New York Times, I had a pretty good idea of how to tell the first part of the story. The department was starting its study by commissioning two climate scientists to construct a detailed play-by-play of how a monthlong storm might unload its precipitation throughout the state. (And what a lot of precipitation it would be: nearly 16 inches, on average, across California, according to the scientists’ simulations, and much more in mountainous areas.)
All that detail would help operators of dams and other infrastructure pinpoint how much water they might get at specific times and places. It would also allow the graphics wizards at The Times to bring the storm to stunning visual life in our article, which we published this month.
But to make the article more than an academic recounting of a computer-modeling exercise, I knew I had to find ways to ground this future storm strongly in the present. And as I started reporting, I realized this was what a lot of people in the flood-management world were trying to do, too. Unlike traffic congestion, air pollution or even drought, flood risk isn’t in people’s faces most of the time. Forecasters and engineers have to keep reminding them that it’s there.
I realized this wasn’t a story about predicting the future at all. Like a lot of climate stories, it was about how humans and institutions function, or fail to function, when faced with catastrophic possibilities whose arrival date is uncertain.
The near-catastrophe Californians remember most vividly is the 2017 crisis at the Oroville Dam, north of Sacramento. The dam’s emergency spillway nearly collapsed after heavy rainstorms, prompting the evacuation of 188,000 people. The state authorities spent the next few years reinspecting dams and re-evaluating safety needs. Yet I found signs that all this attention might already be starting to fade, even when it came to Oroville itself.
For every example of proactive thinking on flood risks, I found instances where budgets, political exigencies or other complications had gotten in the way. I visited flood-prone communities in the Sacramento-San Joaquin Delta with Kathleen Schaefer, an engineer formerly with the Federal Emergency Management Agency. She helped prepare the last major study of a hypothetical California megastorm, over a decade ago, and she recalled the frosty reception her and her colleagues’ work had received in some official circles.
She described the attitude she encountered this way: “If you can’t do anything about it, if it’s such a big problem, then you don’t want to stick your head out and raise it, because then you’re supposed to do something about it. So it’s better just to be like, ‘Oh, I hope it doesn’t happen on my watch.’”
I also sought out Californians who had suffered the effects of flooding firsthand. One reason the state is so vulnerable is that so many people and their homes and assets are in inundation-prone places. The reasons they stay, despite the dangers, are complex and often deeply personal.
Rudy Mussi has lived through two devastating levee failures near his land, in a part of the Delta called the Jones Tract. Neither experience made him want to go farm somewhere else. He recently invested millions in almond trees.
“Even though there’s risk,” Mr. Mussi told me, “there’s people willing to take that risk.”
Bob Ott grows cherries, almonds and walnuts in the fertile soil along the Tuolumne River. As we drove through his orchards on a rickety golf cart, he showed me where the water had rushed in during the 2017 storms.
Mr. Ott said he knew his land was bound to flood again, whether from a repeat of rains past or from a future megastorm. Still, he would never consider leaving, he said. His family has been farming there for the better part of a century. “This is part of us,” he said.
Fernanda Talarico De Splash, em São Paulo 29/08/2022 04h00
O Rock in Rio está chegando! Depois de três anos, o evento de música voltará a acontecer no Parque Olímpico, Rio de Janeiro. Ao todo, serão sete dias de shows: 2, 3, 4, 8, 9, 10 e 11 de setembro. As apresentações acontecem em diferentes palcos, todos a céu aberto, o que gera uma grande preocupação: será que vai chover?
O Rock in Rio 2022 será a segunda edição seguida do evento que não contará com a parceria da produção com a Fundação Cacique Cobra Coral (FCCC), entidade esotérica que diz controlar o clima.
Ana Avila, meteorologista da Cepagri/Unicamp, afirma a Splash, assim como em 2019, quem for ao evento pode precisar separar o dinheiro da capa de chuva.
Ana explicou que os primeiros três dias de festival devem ter um clima mais seco. “O tempo é bom, ensolarado.” No entanto, a partir do dia 8, pode ser que o público enfrente momentos não tão agradáveis.
“Há a possibilidade de pancadas de chuvas. De fazer sol, mas com pancadas de chuvas. Não tem como cravar se será de dia ou de noite, mas elas podem acontecer.”
“De forma geral, não há nada que possa impedir a atividade ou qualquer evento. O que pode acontecer são pancadas de chuvas. Quanto mais próximos chegarmos dos dias do Rock in Rio, podemos saber melhor as intensidades.”
Se a previsão da especialista se concretizar, os shows de Iron Maiden, Post Malone, Jason Derulo, Dream Theater, Demi Lovato, Justin Bieber e outros que tocam nos primeiros dias de festival, acontecerão em uma noite sem chuva. Porém, os fãs de Guns N’ Roses, Green Day, Billy Idol, Coldplay, Dua Lipa e mais podem acabar se molhando durante as apresentações.
Quanto às temperaturas, Avila explica que nos primeiros dias elas podem variar entre 18ºC e 27ºC e, depois, a partir do dia 8 de setembro, em decorrência de nebulosidade e pancadas de chuvas, elas tendem a diminuir um pouco. “Ou seja, vai continuar calor, não vai haver uma amplitude muito grande. De noite, as mínimas serão de 19ºC e máxima de 22ºC.”
Sem parceria com Fundação Cacique Cobra Coral
Comandada pela médium Adelaide Scritori, que diz incorporar o espírito do Cacique Cobra Coral, entidade capaz de controlar o tempo, a fundação foi uma parceira histórica do Rock in Rio, além de ter mantido diversas colaborações com a prefeitura do Rio de Janeiro desde 2015 para, por exemplo, evitar fortes chuvas nas viradas de ano em Copacabana.
Procurada por Splash, a assessoria do Rock in Rio confirmou que não há mais a parceria com a FCCC. Ela foi questionada sobre o motivo do rompimento, mas até a publicação desta reportagem, não respondeu. A Fundação Cacique Cobra Coral também foi procurada, mas não respondeu nenhuma tentativa de contato.
Segundo reportagem do jornal Extra, Roberto Medina, o empresário responsável pelo evento, se desentendeu com a fundação depois que um grande temporal aconteceu em um dos dias do Rock in Rio de 2015.
À época, um representante da FCCC explicou que a médium se atrasou 30 minutos para chegar ao local do evento pois houve uma confusão com o adesivo do estacionamento. Quando finalmente conseguiram entrar, a chuva já tinha começado.
O mundo vive um inferno astral de ameaças de curto e longo prazo. Em brilhante palestra recente, Tharman Shanmugaratnam, ministro sênior de Singapura, listou cinco riscos que, para ele, configuram uma “longa tempestade perfeita” para o planeta. Neste artigo, discutirei as implicações desse quadro para o Brasil, procurando também identificar as oportunidades disponíveis.
O pano de fundo é conhecido. Ao acordar do sonho do mundo pacífico e integrado do fim da história de Fukuyama, nos deparamos com crescentes tensões, que se manifestam em múltiplas esferas. A mais chocante de todas e primeiro tema da lista de Tharman é a tragédia ucraniana, que configura o rompimento de uma governança global que garantia a soberania e a integridade territorial de todas as nações.
A esse retorno da Guerra Fria original, de natureza ideológica (modificada) e militar, se soma a Guerra Fria.2 entre os Estados Unidos e a China, também ideológica, mas muito mais complexa em suas frentes de disputa.
O embate entre os dois gigantes caracteriza um período de ausência de uma liderança global hegemônica que, como bem diagnosticou Charles P. Kindleberger, tende a ser muito instável. Do ponto de vista econômico, as duas guerras frias forçosamente demandam um importante repensar de alianças e relações de produção e comércio globais.
Para o Brasil, será necessário retornar à política externa tradicional do Itamaraty, voltada para a busca do interesse nacional através de boas relações viabilizadas pelo nosso histórico apego a princípios universais e pela nossa natural vocação multilateral. Nos cabe primeiramente e o quanto antes uma defesa inequívoca da integridade de todas as nações. Temos também que zelar pela manutenção de relações mutuamente benéficas com a maior parte dos países.
Em seu segundo grande tema, o autor discute o perigo de uma prolongada estagflação. O epicentro do problema encontra-se nos Estados Unidos, onde uma economia superaquecida por políticas expansionistas vem sendo atingida pelos choques de oferta da pandemia e das guerras frias. Para o Brasil, o risco maior advém da real possibilidade de o banco central americano ter de elevar os juros bem além do que os mercados já antecipam. Nos faria lembrar da frase “quando o Norte espirra, o Sul pega pneumonia”.
Um cenário alternativo, também nada reconfortante, seria uma queda ainda maior das Bolsas, acompanhada de um novo colapso nos preços dos imóveis, hoje acima em termos reais dos níveis da bolha que estourou em 2008.
Do lado de cá, o quadro é ainda mais complicado do que nos Estados Unidos, pois mesmo em recessão a inflação atingiu dois dígitos. Não é difícil imaginar uma tempestade perfeita para o Brasil, onde desafios externos e internos se reforçam. O próximo presidente terá que conduzir a política econômica com coragem e competência, de preferência com o apoio qualitativo das respostas aos demais desafios, que discuto a seguir.
A ameaça existencial da mudança climática é o terceiro tema do discurso. Aqui o Brasil terá a oportunidade de promover uma guinada verdadeiramente alquímica: trocar uma posição de pária ambiental, decorrente de posturas que aumentaram o desmatamento e o crime organizado, por uma guinada que nos poria em uma posição de liderança global no tema, com consequências extremamente positivas fora e dentro do país.
A criação de um mercado de carbono, como vem sendo discutido no Congresso e prometido pelo Executivo, seria um passo essencial nessa direção. É fundamental que o mercado seja desenhado de forma a permitir a plena inserção do país no mercado global de carbono, alternativa não disponível no momento. Vejo amplo potencial para investimentos no setor, em ambiente de concorrência e plenamente alinhados com o interesse público (estou investindo nessa área).
O elevado risco de novas pandemias vem a seguir. A ciência recomenda todo cuidado com o tema. Aqui também vejo amplo espaço para um cavalo de pau. Será necessário reforçar sob todos os ângulos o SUS, que, com seus 4% do PIB de recursos, precisa urgentemente subir na escala de prioridades dos orçamentos de todas as esferas de governo.
Cabe também incluir nas prioridades da nação mais apoio à pesquisa. Fontes de recursos para tais esforços não faltam, como tenho argumentado aqui. Falta sim transparência orçamentária e vontade política.
Em último lugar na lista, mas não menos importante, são as desigualdades de crescimento e bem-estar dentro dos países e entre eles, os mais ricos em vantagem em ambos os casos. Essa situação vem se agravando com as “tempestades perfeitas” e representa um terreno fértil para populismos e autoritarismos. O Brasil tem muito a fazer nessa área.
Com sucesso nessas frentes, o Brasil se qualificaria para ser relevante na reconstrução de uma governança global ora em frangalhos. As vantagens seriam imensas, pois ajudaria a si próprio em tudo mais. No entanto, sem sucesso, os prejuízos para a população seriam enormes. Um futuro melhor só virá se e quando a nossa democracia não mais estiver ameaçada e um tanto disfuncional.
Dois pagés caiapós de Mato Grosso irão a Roraima no domingo para fazer um ritual de dança da chuva, com o objetivo de tentar acabar com o fogo.
Os dois pagés deverão partir de Colider, no norte do Estado, perto do Pará. A viagem de avião até Boa Vista demora cerca de 5h.
De acordo com o índio caiapó Pitisiaru Metupire, o ritual é secreto e deverá ser feito pelos dois pagés, sozinhos, no meio do mato. Antes de fazer o ritual, os pagés passarão algum tempo no interior da mata “estudando” a situação.
“Não dá para explicar como é, porque o trabalho do pagé é bem diferente do do doutor”, diz Metupire. Segundo o índio, os pagés vão conversar com espíritos dos antepassados que, por sua vez, pedirão aos espíritos da chuva e do trovão que provoquem chuva.
O ritual deverá ser feito na aldeia do Demini, onde há montanhas, consideradas fontes de energia.
“A chuva vai começar e não vai parar mais”, disse Metupire, que é da mesma aldeia dos pagés que irão a Boa Vista. De acordo com ele, os caiapós decidiram ajudar os índios ianomâmis e ofereceram a realização do ritual.
“Eles estão precisando de ajuda e nós vamos lá para tentar resolver o problema”, afirmou Metupire. Depois do ritual, os índios ainda ficarão em Roraima para “estudar” os resultados.
Além dos pagés, o administrador da Funai em Colider, Megaron Txucarramãe, também irá a Boa Vista.
Summary: Drawing on 70 years of historic wind and solar-power data, researchers built an AI model to predict the probability of a network-scale ‘drought,’ when daily production of renewables fell below a target threshold. Under a threshold set at the 30th percentile, when roughly a third of all days are low-production days, the researchers found that Texas could face a daily energy drought for up to four months straight. Batteries would be unable to compensate for a drought of this length, and if the system relied on solar energy alone, the drought could be expected to last twice as long — for eight months.
Renewable energy prices have fallen by more than 70 percent in the last decade, driving more Americans to abandon fossil fuels for greener, less-polluting energy sources. But as wind and solar power continue to make inroads, grid operators may have to plan for large swings in availability.
The warning comes from Upmanu Lall, a professor at Columbia Engineering and the Columbia Climate School who has recently turned his sights from sustainable water use to sustainable renewables in the push toward net-zero carbon emissions.
“Designers of renewable energy systems will need to pay attention to changing wind and solar patterns over weeks, months, and years, the way water managers do,” he said. “You won’t be able to manage variability like this with batteries. You’ll need more capacity.”
In a new modeling study in the journal Patterns, Lall and Columbia PhD student Yash Amonkar, show that solar and wind potential vary widely over days and weeks, not to mention months to years. They focused on Texas, which leads the country in generating electricity from wind power and is the fifth-largest solar producer. Texas also boasts a self-contained grid that’s as big as many countries’, said Lall, making it an ideal laboratory for charting the promise and peril of renewable energy systems.
Drawing on 70 years of historic wind and solar-power data, the researchers built an AI model to predict the probability of a network-scale “drought,” when daily production of renewables fell below a target threshold. Under a threshold set at the 30th percentile, when roughly a third of all days are low-production days, the researchers found that Texas could face a daily energy drought for up to four months straight.
Batteries would be unable to compensate for a drought of this length, said Lall, and if the system relied on solar energy alone, the drought could be expected to last twice as long — for eight months. “These findings suggest that energy planners will have to consider alternate ways of storing or generating electricity, or dramatically increasing the capacity of their renewable systems,” he said.
Anticipating Future ‘Energy’ Droughts — in Texas, and Across the Continental United States
The research began six years ago, when Lall and a former graduate student, David Farnham, examined wind and solar variability at eight U.S. airports, where weather records tend to be longer and more detailed. They wanted to see how much variation could be expected under a hypothetical 100% renewable-energy grid.
The results, which Farnham published in his PhD thesis, weren’t a surprise. Farnham and Lall found that solar and wind potential, like rainfall, is highly variable based on the time of year and the place where wind turbines and solar panels have been sited. Across eight cities, they found that renewable energy potential rose and fell from the long-term average by as much as a third in some seasons.
“We coined the term ‘energy’ droughts since a 10-year cycle with this much variation from the long-term average would be seen as a major drought,” said Lall. “That was the beginning of the energy drought work.”
In the current study, Lall chose to zoom in on Texas, a state well-endowed with both sun and wind. Lall and Amonkar found that persistent renewable energy droughts could last as long as a year even if solar and wind generators were spread across the entire state. The conclusion, Lall said, is that renewables face a storage problem that can only realistically be solved by adding additional capacity or sources of energy.
“In a fully renewable world, we would need to develop nuclear fuel or hydrogen fuel, or carbon recycling, or add much more capacity for generating renewables, if we want to avoid burning fossil fuels,” he said.
In times of low rainfall, water managers keep fresh water flowing through the spigot by tapping municipal reservoirs or underground aquifers. Solar and wind energy systems have no equivalent backup. The batteries used to store excess solar and wind power on exceptionally bright and gusty days hold a charge for only a few hours, and at most, a few days. Hydropower plants provide a potential buffer, said Lall, but not for long enough to carry the system through an extended dry spell of intermittent sun and wind.
“We won’t solve the problem by building a larger network,” he said. “Electric grid operators have a target of 99.99% reliability while water managers strive for 90 percent reliability. You can see what a challenging game this will be for the energy industry, and just how valuable seasonal and longer forecasts could be.”
In the next phase of research, Lall will work with Columbia Engineering professors Vijay Modi and Bolun Xu to see if they can predict both energy droughts and “floods,” when the system generates a surplus of renewables. Armed with these projections, they hope to predict the rise and fall of energy prices.
Yash Amonkar, David J. Farnham, Upmanu Lall. A k-nearest neighbor space-time simulator with applications to large-scale wind and solar power modeling. Patterns, 2022; 3 (3): 100454 DOI: 10.1016/j.patter.2022.100454
We can reduce global temperatures faster than we once thought — if we act now
One of the biggest obstacles to avoiding global climate breakdown is that so many people think there’s nothing we can do about it.
They point out that record-breaking heat waves, fires and storms are already devastating communities and economies throughout the world. And they’ve long been told that temperatures will keep rising for decades to come, no matter how many solar panels replace oil derricks or how many meat-eaters go vegetarian. No wonder they think we’re doomed.
But climate science actually doesn’t say this. To the contrary, the best climate science you’ve probably never heard of suggests that humanity can still limit the damage to a fraction of the worst projections if — and, we admit, this is a big if — governments, businesses and all of us take strong action starting now.
For many years, the scientific rule of thumb was that a sizable amount of temperature rise was locked into the Earth’s climate system. Scientists believed — and told policymakers and journalists, who in turn told the public — that even if humanity hypothetically halted all heat-trapping emissions overnight, carbon dioxide’s long lifetime in the atmosphere, combined with the sluggish thermal properties of the oceans, would nevertheless keep global temperatures rising for 30 to 40 more years. Since shifting to a zero-carbon global economy would take at least a decade or two, temperatures were bound to keep rising for at least another half-century.
But guided by subsequent research, scientists dramatically revised that lag time estimate down to as little as three to five years. That is an enormous difference that carries paradigm-shifting and broadly hopeful implications for how people, especially young people, think and feel about the climate emergency and how societies can respond to it.
This revised science means that if humanity slashes emissions to zero, global temperatures will stop rising almost immediately. To be clear, this is not a get-out-of-jail-free card. Global temperatures will not fall if emissions go to zero, so the planet’s ice will keep melting and sea levels will keep rising. But global temperatures will stop their relentless climb, buying humanity time to devise ways to deal with such unavoidable impacts. In short, we are not irrevocably doomed — or at least we don’t have to be, if we take bold, rapid action.
The science we’re referencing was included — but buried — in the United Nations Intergovernmental Panel on Climate Change’s most recent report, issued in August. Indeed, it was first featured in the IPCC’s landmark 2018 report, “Global warming of 1.5 C.”That report’s key finding — that global emissions must fall by 45 percent by 2030 to avoid catastrophic climate disruption — generated headlines declaring that we had “12 years to save the planet.” That 12-year timeline, and the related concept of a “carbon budget” — the amount of carbon that can be burned while still limiting temperature rise to 1.5 degrees Celsius above preindustrial levels — were both rooted in this revised science. Meanwhile, the public and policy worlds have largely neglected the revised science that enabled these very estimates.
Nonscientists can reasonably ask: What made scientists change their minds? Why should we believe their new estimate of a three-to-five-year lag time if their previous estimate of 30 to 40 years is now known to be incorrect? And does this mean the world still must cut emissions in half by 2030 to avoid climate catastrophe?
The short answer to the last question is yes. Remember, temperatures only stop rising once global emissions fall to zero. Currently, emissions are not falling. Instead, humanity continues to pump approximately 36 billion tons of carbon dioxide a year into the atmosphere. The longer it takes to cut those 36 billion tons to zero, the more temperature rise humanity eventually will face. And as the IPCC’s 2018 report made hauntingly clear, pushing temperatures above 1.5 degrees C would cause unspeakable amounts of human suffering, economic loss and social breakdown — and perhaps trigger genuinely irreversible impacts.
Scientists changed their minds about how much warming is locked in because additional research gave them a much better understanding of how the climate system works. Their initial 30-to-40-year estimates were based on relatively simple computer models that treated the concentration of carbon dioxide in the atmosphere as a “control knob” that determines temperature levels. The long lag in the warming impact is due to the oceans, which continue to warm long after the control knob is turned up. More recent climate models account for the more dynamic nature of carbon emissions. Yes, CO2 pushes temperatures higher, but carbon “sinks,” including forests and in particular the oceans, absorb almost half of the CO2 that is emitted, causing atmospheric CO2 levels to drop, offsetting the delayed warming effect.
Knowing that 30 more years of rising temperatures are not necessarily locked in can be a game-changer for how people, governments and businesses respond to the climate crisis. Understanding that we can still save our civilization if we take strong, fast action can banish the psychological despair that paralyzes people and instead motivate them to get involved. Lifestyle changes can help, but that involvement must also include political engagement. Slashing emissions in half by 2030 demands the fastest possible transition away from today’s fossil-fueled economies in favor of wind, solar and other non-carbon alternatives. That can happen only if governments enact dramatically different policies. If citizens understand that things aren’t hopeless, they can better push elected officials to make such changes.
As important as minimizing temperature rise is to the United States, where last year’s record wildfires in California and the Pacific Northwest illustrated just how deadly climate change can be, it matters most in the highly climate-vulnerable communities throughout the global South. Countless people in Bangladesh, the Philippines, Madagascar, Africa’s Sahel nations, Brazil, Honduras and other low-income countries have already been suffering from climate disasters for decades because their communities tend to be more exposed to climate impacts and have less financial capacity to protect themselves. For millions of people in such countries, limiting temperature rise to 1.5 degrees C is not a scientific abstraction.
The IPCC’s next report, due for release Feb. 28, will address how societies can adapt to the temperature rise now underway and the fires, storms and rising seas it unleashes. If we want a livable future for today’s young people, temperature rise must be kept as close as possible to 1.5 C. The best climate science most people have never heard of says that goal remains within reach. The question is whether enough of us will act on that knowledge in time.
America’s coastline will see sea levels rise in the next 30 years by as much as they did in the entire 20th century, with major Eastern cities hit regularly with costly floods even on sunny days, a government report warns.
By 2050, seas lapping against the U.S. shore will be 10 to 12 inches (0.25 to 0.3 meters) higher, with parts of Louisiana and Texas projected to see waters a foot and a half (0.45 meters) higher, according to a 111-page report issued Tuesday by the National Oceanic and Atmospheric Administration and six other federal agencies.
“Make no mistake: Sea level rise is upon us,” said Nicole LeBoeuf, director of NOAA’s National Ocean Service.
The projected increase is especially alarming given that in the 20th century, seas along the Atlantic coast rose at the fastest clip in 2,000 years.
LeBoeuf warned that the cost will be high, pointing out that much of the American economy and 40% of the population are along the coast.
However, the worst of the long-term sea level rise from the melting of ice sheets in Antarctica and Greenland probably won’t kick in until after 2100, said ocean service oceanographer William Sweet, the report’s lead author.
Warmer water expands, and the melting ice sheets and glaciers adds more water to the worlds oceans.
The report “is the equivalent of NOAA sending a red flag up” about accelerating the rise in sea levels, said University of Wisconsin-Madison geoscientist Andrea Dutton, a specialist in sea level rise who wasn’t part of the federal report. The coastal flooding the U.S. is seeing now “will get taken to a whole new level in just a couple of decades.”
“We can see this freight train coming from more than a mile away,” Dutton said in an email. “The question is whether we continue to let houses slide into the ocean.”
Sea level rises more in some places than others because of sinking land, currents and water from ice melt. The U.S. will get slightly more sea level rise than the global average. And the greatest rise in the U.S. will be on the Gulf and East Coasts, while the West Coast and Hawaii will be hit less than average, Sweet said.
For example, between now and 2060, expect almost 25 inches (0.63 meters) of sea level rise in Galveston, Texas, and just under 2 feet (0.6 meters) in St. Petersburg, Florida, while only 9 inches (0.23 inches) in Seattle and 14 inches (0.36 meters) in Los Angeles, the report said.
While higher seas cause much more damage when storms such as hurricanes hit the coast, they are becoming a problem even on sunny days.
Cities such as Miami Beach, Florida; Annapolis, Maryland; and Norfolk, Virginia, already get a few minor “nuisance” floods a year during high tides, but those will be replaced by several “moderate” floods a year by mid-century, ones that cause property damage, the researchers said.
“It’s going to be areas that haven’t been flooding that are starting to flood,” Sweet said in an interview. “Many of our major metropolitan areas on the East Coast are going to be increasingly at risk.”
The western Gulf of Mexico coast, should get hit the most with the highest sea level rise — 16 to 18 inches (0.4 to 0.45 meters) — by 2050, the report said. And that means more than 10 moderate property-damaging sunny-day floods and one “major” high tide flood event a year.
The eastern Gulf of Mexico should expect 14 to 16 inches (0.35 to 0.4 meters) of sea level rise by 2050 and three moderate sunny-day floods a year. By mid-century, the Southeast coast should get a foot to 14 inches (0.3 to 0.35 meters) of sea level rise and four sunny-day moderate floods a year, while the Northeast coast should get 10 inches to a foot (0.25 to 0.3 meters) of sea level rise and six moderate sunny-day floods a year.
Both the Hawaiian Islands and Southwestern coast should expect 6 to 8 inches (0.15 to 0.2 meters) of sea level rise by mid-century, with the Northwest coast seeing only 4 to 6 inches (0.1 to 0.15 meters). The Pacific coastline will get more than 10 minor nuisance sunny-day floods a year but only about one moderate one a year, with Hawaii getting even less than that.
And that’s just until 2050. The report is projecting an average of about 2 feet of sea level rise in the United States — more in the East, less in the West — by the end of the century.
In Spain, rainfall this winter stands at only a third of the average in recent years
Feb. 14, 2022
In north-western Spain, the sight of roofs emerging from the surface of the water in the Lindoso reservoir is not uncommon at the height of particularly dry summers, but since the lake was first created three decades ago, this winter is the first time the flooded village of Aceredo has been revealed in its entirety.
The decrepit old stone works of the village are an indication of the extent of the severe winter drought impacting Spain and Portugal, which is now devastating crops after more than two months with no rain.
While 10 per cent of Spain has officially been declared as being under “prolonged drought,” large areas outside this categorisation, particularly in the south, also face extreme shortages that could impact the irrigation of crops.
Overall around 50 per cent of all Spanish farms are believed to be at risk due to the record low rainfall which is impacting rain-fed crops including cereals, olives, nuts and vineyards, which could lose 6 per cent to 8 per cent of their production, Spanish farming organisations have warned.
While the government is planning to spend around €570m (£477m) to improve irrigation systems, the lack of rainfall has been blamed on the worsening climate crisis.
Over the last three months of 2021, Spain recorded just 35 per cent of the average rainfall it had during the same period from 1981 to 2010. But there has been almost no rain since then.
Meanwhile in Portugal, 45 per cent of the country is currently experiencing “severe” or “extreme” drought conditions, Portuguese national weather agency IPMA said, with the climate crisis bringing hotter, drier conditions that make agriculture increasingly difficult.
IPMA climatologist Vanda Pires, Portugal told AP the agency had recorded an increase in the frequency of droughts over the past 20 to 30 years, with lower rainfall and higher temperatures.
“It’s part of the context of climate change,” she said.
Scientists estimate that Portugal will see a drop in average annual rainfall of 20 per cent to 40 per cent by the end of the century.
According to the Spain’s national weather agency AEMET, only in 2005 has there been a January with almost no rain in this century.
If there is not significant rain within the next two weeks, emergency subsidies for farmers will be needed, Spanish authorities told AP.
Rubén del Campo, a spokesman for the Spanish weather service, said the below-average rainfall over the last six months was likely to continue for several more weeks, with hopes that spring will bring much-needed rainfall.
Spanish Agriculture Minister Luis Planas said last week the government would take emergency action if it did not rain in two weeks – likely to be financial support measures for farmers to alleviate the loss of crops and revenues.
United Nations (AP) — Drought in the Horn of Africa has killed more than 1.5 million livestock and drastically cut cereal production, “and we are most definitely now sitting on the brink of catastrophe,” a senior official for the U.N. Food and Agriculture Organization said Monday.
Rein Paulsen, FAO’s director of emergencies and resilience who returned from the region Friday, said a “very small window” exists for taking urgent action, and a key is whether the region’s long rains between March and May are good — and whether the agency gets the $130 million it needs until June.
The short rains in the region, which includes parts of Somalia, Ethiopia and Kenya, were supposed to come between October and December but “were extremely poor,” he said. “And this represents the third consecutive failed rainy season with lower average rans, all of which has a severe impact on vulnerable households.”
The result of the drought meant that overall cereal production for the last rainy season in southern Somalia was estimated to be 58% lower than the long-term average, Paulsen said. In agricultural areas in marginal coastal zones in southeastern parts of Kenya, “we’re looking at crop production estimated to be 70% below average,” he said.
In addition, most places for water that have usually been resilient to climate variability have dried up in Kenya, he said during a virtual news conference from Rome.
Paulsen said $130 million in funding is essential now to provide cash for people to buy food until production resumes, to keep livestock alive and to provide drought-resistant seeds for farmers to reap a harvest.
“We have a window to the middle of this year — to June, which is a very time sensitive, narrow window for urgent actions to scale up to prevent a worst-case scenario,” Paulsen said. “Agriculture needs a lot more attention. It’s central to the survival of drought affected communities.”
During his visit to the region, Paulsen said: “We saw both livestock and wildlife carcasses by the side of the road as we were driving. We saw animals dying together with their farmers, and the numbers I think are quite shocking.”
In Kenya alone, 1.4 million livestock died in the final part of last year as a result of drought, and in southern Ethiopia, about 240,000 livestock died as a result of drought, he said.
Paulsen said that “it was quite traumatic driving through communities and seeing farmers tending livestock as they were dying by the side of the roads.”
Livestock are not only crucial to people’s livelihoods, he said, but they provide milk for children, and FAO is focused on providing urgent fodder and water to keep them alive.
The U.N. World Food Program said Feb. 8 that drought has left an estimated 13 million people in the Horn of Africa facing severe hunger amid the driest conditions since 1981. It is seeking $327 million to look after the urgent needs of 4.5 million people over the next six months.
1. More scientists are investigating ways to help people adapt
Over the past half century, thousands of scientists around the world have dedicated their careers to documenting the link between climate change and human activity. A remarkable amount of this work has been done at Columbia’s Lamont-Doherty Earth Observatory, in Palisades, New York. Indeed, one of the founders of modern climate science, the late Columbia geochemist Wally Broecker ’53CC, ’58GSAS, popularized the term “global warming” and first alerted the broader scientific community to the emerging climate crisis in a landmark 1975 paper. He and other Columbia researchers then set about demonstrating that rising global temperatures could not be explained by the earth’s natural long-term climate cycles. For evidence, they relied heavily on Columbia’s world-class collections of tree-ring samples and deep-sea sediment cores, which together provide a unique window into the earth’s climate history.
Today, experts say, the field of climate science is in transition. Having settled the question of whether humans are causing climate change — the evidence is “unequivocal,” according to the UN’s Intergovernmental Panel on Climate Change (IPCC) — many scientists have been branching out into new areas, investigating the myriad ways that global warming is affecting our lives. Columbia scholars from fields as diverse as public health, agriculture, economics, law, political science, urban planning, finance, and engineering are now teaming up with climate scientists to learn how communities can adapt to the immense challenges they are likely to confront.
The University is taking bold steps to support such interdisciplinary thinking. Its new Columbia Climate School, established last year, is designed to serve as a hub for research and education on climate sustainability. Here a new generation of students will be trained to find creative solutions to the climate crisis. Its scholars are asking questions such as: How can communities best protect themselves from rising sea levels and intensifying storm surges, droughts, and heat waves? When extreme weather occurs, what segments of society are most vulnerable? And what types of public policies and ethical principles are needed to ensure fair and equitable adaptation strategies? At the same time, Columbia engineers, physicists, chemists, data scientists, and others are working with entrepreneurs to develop the new technologies that are urgently needed to scale up renewable-energy systems and curb emissions.
“The challenges that we’re facing with climate change are so huge, and so incredibly complex, that we need to bring people together from across the entire University to tackle them,” says Alex Halliday, the founding dean of the Columbia Climate School and the director of the Earth Institute. “Success will mean bringing the resources, knowledge, and capacity of Columbia to the rest of the world and guiding society toward a more sustainable future.”
For climate scientists who have been at the forefront of efforts to document the effects of fossil-fuel emissions on our planet, the shift toward helping people adapt to climate change presents new scientific challenges, as well as the opportunity to translate years of basic research into practical, real-world solutions.
“A lot of climate research has traditionally looked at how the earth’s climate system operates at a global scale and predicted how a given amount of greenhouse-gas emissions will affect global temperatures,” says Adam Sobel, a Columbia applied physicist, mathematician, and climate scientist. “The more urgent questions we face now involve how climate hazards vary across the planet, at local or regional scales, and how those variations translate into specific risks to human society. We also need to learn to communicate climate risks in ways that can facilitate actions to reduce them. This is where climate scientists need to focus more of our energy now, if we’re to maximize the social value of our work.”
2. Big data will enable us to predict extreme weather
Just a few years ago, scientists couldn’t say with any confidence how climate change was affecting storms, floods, droughts, and other extreme weather around the world. But now, armed with unprecedented amounts of real-time and historical weather data, powerful new supercomputers, and a rapidly evolving understanding of how different parts of our climate system interact, researchers are routinely spotting the fingerprints of global warming on our weather.
“Of course, no individual weather event can be attributed solely to climate change, because weather systems are highly dynamic and subject to natural variability,” says Sobel, who studies global warming’s impact on extreme weather. “But data analysis clearly shows that global warming is tilting the scales of nature in a way that is increasing both the frequency and intensity of certain types of events, including heat waves, droughts, and floods.”
According to the World Meteorological Organization, the total number of major weather-related disasters to hit the world annually has increased five-fold since the 1970s. In 2021, the US alone endured eighteen weather-related disasters that caused at least $1 billion in damages. Those included Hurricanes Ida and Nicholas; tropical storms Fred and Elsa; a series of thunderstorms that devastated broad swaths of the Midwest; floods that overwhelmed the coasts of Texas and Louisiana; and a patchwork of wildfires that destroyed parts of California, Oregon, Washington, Idaho, Montana, and Arizona. In 2020, twenty-two $1 billion events struck this country — the most ever.
“The pace and magnitude of the weather disasters we’ve seen over the past couple of years are just bonkers,” says Sobel, who studies the atmospheric dynamics behind hurricanes. (He notes that while hurricanes are growing stronger as a result of climate change, scientists are not yet sure if they are becoming more common.) “Everybody I know who studies this stuff is absolutely stunned by it. When non-scientists ask me what I think about the weather these days, I say, ‘If it makes you worried for the future, it should, because the long-term trend is terrifying.’”
The increasing ferocity of our weather, scientists say, is partly attributable to the fact that warmer air can hold more moisture. This means that more water is evaporating off oceans, lakes, and rivers and accumulating in the sky, resulting in heavier rainstorms. And since hot air also wicks moisture out of soil and vegetation, regions that tend to receive less rainfall, like the American West, North Africa, the Middle East, and Central Asia, are increasingly prone to drought and all its attendant risks. “Climate change is generally making wet areas wetter and dry regions drier,” Sobel says.
But global warming is also altering the earth’s climate system in more profound ways. Columbia glaciologist Marco Tedesco, among others, has found evidence that rising temperatures in the Arctic are weakening the North Atlantic jet stream, a band of westerly winds that influence much of the Northern Hemisphere’s weather. These winds are produced when cold air from the Arctic clashes with warm air coming up from the tropics. But because the Arctic is warming much faster than the rest of the world, the temperature differential between these air flows is diminishing and causing the jet stream to slow down and follow a more wobbly path. As a result, scientists have discovered, storm systems and pockets of hot or cold air that would ordinarily be pushed along quickly by the jet stream are now sometimes hovering over particular locations for days, amplifying their impact. Experts say that the jet stream’s new snail-like pace may explain why a heavy rainstorm parked itself over Zhengzhou, China, for three days last July, dumping an entire year’s worth of precipitation, and why a heat wave that same month brought 120-degree temperatures and killed an estimated 1,400 people in the northwestern US and western Canada.
Many Columbia scientists are pursuing research projects aimed at helping communities prepare for floods, droughts, heat waves, and other threats. Sobel and his colleagues, for example, have been using their knowledge of hurricane dynamics to develop an open-source computer-based risk-assessment model that could help policymakers in coastal cities from New Orleans to Mumbai assess their vulnerability to cyclones as sea levels rise and storms grow stronger. “The goal is to create analytic tools that will reveal how much wind and flood damage would likely occur under different future climate scenarios, as well as the human and economic toll,” says Sobel, whose team has sought input from public-health researchers, urban planners, disaster-management specialists, and civil engineers and is currently collaborating with insurance companies as well as the World Bank, the International Red Cross, and the UN Capital Development Fund. “Few coastal cities have high-quality information of this type, which is necessary for making rational adaptation decisions.”
Radley Horton ’07GSAS, another Columbia climatologist who studies weather extremes; Christian Braneon, a Columbia civil engineer and climate scientist; and Kim Knowlton ’05PH and Thomas Matte, Columbia public-health researchers, are members of the New York City Panel on Climate Change, a scientific advisory body that is helping local officials prepare for increased flooding, temperature spikes, and other climate hazards. New York City has acted decisively to mitigate and adapt to climate change, in part by drawing on the expertise of scientists from Columbia and other local institutions, and its city council recently passed a law requiring municipal agencies to develop a comprehensive long-term plan to protect all neighborhoods against climate threats. The legislation encourages the use of natural measures, like wetland restoration and expansion, to defend against rising sea levels. “There’s a growing emphasis on attending to issues of racial justice as the city develops its adaptation strategies,” says Horton. “In part, that means identifying communities that are most vulnerable to climate impacts because of where they’re located or because they lack resources. We want to make sure that everybody is a part of the resilience conversation and has input about what their neighborhoods need.”
Horton is also conducting basic research that he hopes will inform the development of more geographically targeted climate models. For example, in a series of recent papers on the atmospheric and geographic factors that influence heat waves, he and his team discovered that warm regions located near large bodies of water have become susceptible to heat waves of surprising intensity, accompanied by dangerous humidity. His team has previously shown that in some notoriously hot parts of the world — like northern India, Bangladesh, and the Persian Gulf — the cumulative physiological impact of heat and humidity can approach the upper limits of human tolerance. “We’re talking about conditions in which a perfectly healthy person could actually die of the heat, simply by being outside for several hours, even if they’re resting and drinking plenty of water,” says Horton, explaining that when it is extremely humid, the body loses its ability to sufficiently perspire, which is how it cools itself. Now his team suspects that similarly perilous conditions could in the foreseeable future affect people who live near the Mediterranean, the Black Sea, the Caspian Sea, or even the Great Lakes. “Conditions in these places probably won’t be quite as dangerous as what we’re seeing now in South Asia or the Middle East, but people who are old, sick, or working outside will certainly be at far greater risk than they are today,” Horton says. “And communities will be unprepared, which increases the danger.”
How much worse could the weather get? Over the long term, that will depend on us and how decisively we act to reduce our fossil-fuel emissions. But conditions are likely to continue to deteriorate over the next two to three decades no matter what we do, since the greenhouse gases that we have already added to the atmosphere will take years to dissipate. And the latest IPCC report states that every additional increment of warming will have a larger, more destabilizing impact. Of particular concern, the report cautions, is that in the coming years we are bound to experience many more “compound events,” such as when heat waves and droughts combine to fuel forest fires, or when coastal communities get hit by tropical storms and flooding rivers simultaneously.
“A lot of the extreme weather events that we’ve been experiencing lately are so different from anything we’ve seen that nobody saw them coming,” says Horton, who points out that climate models, which remain our best tool for projecting future climate risks, must constantly be updated with new data as real-world conditions change. “What’s happening now is that the conditions are evolving so rapidly that we’re having to work faster, with larger and more detailed data sets, to keep pace.”
3. The world’s food supply is under threat
“A warmer world could also be a hungry one, even in the rich countries,” writes the Columbia environmental economist Geoffrey Heal in his latest book, Endangered Economies: How the Neglect of Nature Threatens Our Prosperity. “A small temperature rise and a small increase in CO2 concentrations may be good for crops, but beyond a point that we will reach quickly, the productivity of our present crops will drop, possibly sharply.”
Indeed, a number of studies, including several by Columbia scientists, have found that staple crops like corn, rice, wheat, and soybeans are becoming more difficult to cultivate as the planet warms. Wolfram Schlenker, a Columbia economist who studies the impact of climate change on agriculture, has found that corn and soybean plants exposed to temperatures of 90°F or higher for just a few consecutive days will generate much less yield. Consequently, he has estimated that US output of corn and soybeans could decline by 30 to 80 percent this century, depending on how high average temperatures climb.
“This will reduce food availability and push up prices worldwide, since the US is the largest producer and exporter of these commodities,” Schlenker says.
There is also evidence that climate change is reducing the nutritional value of our food. Lewis Ziska, a Columbia professor of environmental health sciences and an expert on plant physiology, has found that as CO2 levels rise, rice plants are producing grains that contain less protein and fewer vitamins and minerals. “Plant biology is all about balance, and when crops suddenly have access to more CO2 but the same amount of soil nutrients, their chemical composition changes,” he says. “The plants look the same, and they may even grow a little bit faster, but they’re not as good for you. They’re carbon-rich and nutrient-poor.” Ziska says that the molecular changes in rice that he has observed are fairly subtle, but he expects that as CO2 levels continue to rise over the next two to three decades, the changes will become more pronounced and have a significant impact on human health. “Wheat, barley, potatoes, and carrots are also losing some of their nutritional value,” he says. “This is going to affect everybody — but especially people in developing countries who depend on grains like wheat and rice for most of their calories.”
Experts also worry that droughts, heat waves, and floods driven by climate change could destroy harvests across entire regions, causing widespread food shortages. A major UN report coauthored by Columbia climate scientist Cynthia Rosenzweig in 2019 described the growing threat of climate-induced hunger, identifying Africa, South America, and Asia as the areas of greatest susceptibility, in part because global warming is accelerating desertification there. Already, some eight hundred million people around the world are chronically undernourished, and that number could grow by 20 percent as a result of climate change in the coming decades, the report found.
In hopes of reversing this trend, Columbia scientists are now spearheading ambitious efforts to improve the food security of some of the world’s most vulnerable populations. For example, at the International Research Institute for Climate and Society (IRI), which is part of the Earth Institute, multidisciplinary teams of climatologists and social scientists are working in Ethiopia, Senegal, Colombia, Guatemala, Bangladesh, and Vietnam to minimize the types of crop losses that often occur when climate change brings more sporadic rainfall. The IRI experts, whose work is supported by Columbia World Projects, are training local meteorologists, agricultural officials, and farmers to use short-term climate-prediction systems to anticipate when an upcoming season’s growing conditions necessitate using drought-resistant or flood-resistant seeds. They can also suggest more favorable planting schedules. To date, they have helped boost crop yields in dozens of small agricultural communities.
“This is a versatile approach that we’re modeling in six nations, with the hope of rolling it out to many others,” says IRI director John Furlow. “Agriculture still dominates the economies of most developing countries, and in order to succeed despite increasingly erratic weather, farmers need to be able to integrate science into their decision-making.”
4. We need to prepare for massive waves of human migration
For thousands of years,the vast majority of the human population has lived in a surprisingly narrow environmental niche, on lands that are fairly close to the equator and offer warm temperatures, ample fresh water, and fertile soils.
But now, suddenly, the environment is changing. The sun’s rays burn hotter, and rainfall is erratic. Some areas are threatened by rising sea levels, and in others the land is turning to dust, forests to kindling. What will people do in the coming years? Will they tough it out and try to adapt, or will they migrate in search of more hospitable territory?
Alex de Sherbinin, a Columbia geographer, is among the first scientists attempting to answer this question empirically. In a series of groundbreaking studies conducted with colleagues at the World Bank, the Potsdam Institute for Climate Impact Research, New York University, Baruch College, and other institutions, he has concluded that enormous waves of human migration will likely occur this century unless governments act quickly to shift their economies away from fossil fuels and thereby slow the pace of global warming. His team’s latest report, published this fall and based on a comprehensive analysis of climatic, demographic, agricultural, and water-use data, predicts that up to 215 million people from Asia, Eastern Europe, Africa, and Latin America — mostly members of agricultural communities, but also some city dwellers on shorelines — will permanently abandon their homes as a result of droughts, crop failures, and sea-level rise by 2050.
“And that’s a conservative estimate,” says de Sherbinin, a senior research scientist at Columbia’s Center for International Earth Science Information Network. “We’re only looking at migration that will occur as the result of the gradual environmental changes occurring where people live, not massive one-time relocations that might be prompted by natural disasters like typhoons or wildfires.”
De Sherbinin and his colleagues do not predict how many climate migrants will ultimately cross international borders in search of greener pastures. Their work to date has focused on anticipating population movements within resource-poor countries in order to help governments develop strategies for preventing exoduses of their own citizens, such as by providing struggling farmers with irrigation systems or crop insurance. They also identify cities that are likely to receive large numbers of new residents from the surrounding countryside, so that local governments can prepare to accommodate them. Among the regions that will see large-scale population movements, the researchers predict, is East Africa, where millions of smallholder farmers will abandon drought-stricken lands and flock to cities like Kampala, Nairobi, and Lilongwe. Similarly, agricultural communities across Latin America, devastated by plummeting corn, bean, and coffee yields, will leave their fields and depart for urban centers. And in Southeast Asia, rice farmers and fishing families in increasingly flood-prone coastal zones like Vietnam’s Mekong Delta, home to twenty-one million people, will retreat inland.
But these migrations, if they do occur, do not necessarily need to be tragic or chaotic affairs, according to de Sherbinin. In fact, he says that with proper planning, and with input from those who are considering moving, it is even possible that large-scale relocations could be organized in ways that ultimately benefit everybody involved, offering families of subsistence farmers who would otherwise face climate-induced food shortages a new start in more fertile locations or in municipalities that offer more education, job training, health care, and other public services.
“Of course, wealthy nations should be doing more to stop climate change and to help people in developing countries adapt to environmental changes, so they have a better chance of thriving where they are,” he says. “But the international community also needs to help poorer countries prepare for these migrations. If and when large numbers of people do find that their lands are no longer habitable, there should be systems in place to help them relocate in ways that work for them, so that they’re not spontaneously fleeing droughts or floods as refugees but are choosing to safely move somewhere they want to go, to a place that’s ready to receive them.”
5. Rising temperatures are already making people sick
One of the deadliest results of climate change, and also one of the most insidious and overlooked, experts say, is the public-health threat posed by rising temperatures and extreme heat.
“Hot weather can trigger changes in the body that have both acute and chronic health consequences,” says Cecilia Sorensen, a Columbia emergency-room physician and public-health researcher. “It actually alters your blood chemistry in ways that make it prone to clotting, which can lead to heart attacks or strokes, and it promotes inflammation, which can contribute to a host of other problems.”
Exposure to severe heat, Sorensen says, has been shown to exacerbate cardiovascular disease, asthma, chronic obstructive pulmonary disease, arthritis, migraines, depression, and anxiety, among other conditions. “So if you live in a hot climate and lack access to air conditioning, or work outdoors, you’re more likely to get sick.”
By destabilizing the natural environment and our relationship to it, climate change is endangering human health in numerous ways. Researchers at Columbia’s Mailman School of Public Health, which launched its innovative Climate and Health Program in 2010, have shown that rising temperatures are making air pollution worse, in part because smog forms faster in warmer weather and because wildfires are spewing enormous amounts of particulate matter into the atmosphere. Global warming is also contributing to food and drinking-water shortages, especially in developing countries. And it is expected to fuel transmission of dengue fever, Lyme disease, West Nile virus, and other diseases by expanding the ranges of mosquitoes and ticks. But experts say that exposure to extreme heat is one of the least understood and fastest growing threats.
“Health-care professionals often fail to notice when heat stress is behind a patient’s chief complaint,” says Sorensen, who directs the Mailman School’s Global Consortium on Climate and Health Education, an initiative launched in 2017 to encourage other schools of public health and medicine to train practitioners to recognize when environmental factors are driving patients’ health problems. “If I’m seeing someone in the ER with neurological symptoms in the middle of a heat wave, for example, I need to quickly figure out whether they’re having a cerebral stroke or a heat stroke, which itself can be fatal if you don’t cool the body down quickly. And then I need to check to see if they’re taking any medications that can cause dehydration or interfere with the body’s ability to cool itself. But these steps aren’t always taken.”
Sorensen says there is evidence to suggest that climate change, in addition to aggravating existing medical conditions, is causing new types of heat-related illnesses to emerge. She points out that tens of thousands of agricultural workers in Central America have died of an enigmatic new kidney ailment that has been dubbed Mesoamerican nephropathy or chronic kidney disease of unknown origin (CKDu), which appears to be the result of persistent heat-induced inflammation. Since CKDu was first observed among sugarcane workers in El Salvador in the 1990s, Sorensen says, it has become endemic in those parts of Central America where heat waves have grown the most ferocious.
“It’s also been spotted among rice farmers in Sri Lanka and laborers in India and Egypt,” says Sorensen, who is collaborating with physicians in Guatemala to develop an occupational-health surveillance system to spot workers who are at risk of developing CKDu. “In total, we think that at least fifty thousand people have died of this condition worldwide.”
Heat waves are now also killing hundreds of Americans each year. Particularly at risk, experts say, are people who live in dense urban neighborhoods that lack trees, open space, reflective rooftops, and other infrastructure that can help dissipate the heat absorbed by asphalt, concrete, and brick. Research has shown that temperatures in such areas can get up to 15°F hotter than in surrounding neighborhoods on summer days. The fact that these so-called “urban heat islands” are inhabited largely by Black and Latino people is now seen as a glaring racial inequity that should be redressed by investing in public-infrastructure projects that would make the neighborhoods cooler and safer.
“It isn’t a coincidence that racially segregated neighborhoods in US cities are much hotter, on average, than adjacent neighborhoods,” says Joan Casey, a Columbia epidemiologist who studies how our natural and built environments influence human health. In fact, in one recent study, Casey and several colleagues showed that urban neighborhoods that lack green space are by and large the same as those that in the 1930s and 1940s were subject to the racist practice known as redlining, in which banks and municipalities designated minority neighborhoods as off-limits for private lending and public investment. “There’s a clear link between that history of institutionalized racism and the subpar public infrastructure we see in these neighborhoods today,” she says.
Extreme heat is hardly the only environmental health hazard faced by residents of historically segregated neighborhoods. Research by Columbia scientists and others has shown that people in these areas are often exposed to dirty air, partly as a result of the large numbers of trucks and buses routed through their streets, and to toxins emanating from industrial sites. But skyrocketing temperatures are exacerbating all of these other health risks, according to Sorensen.
“A big push now among climate scientists and public-health researchers is to gather more street-by-street climate data in major cities so that we know exactly where people are at the greatest risk of heat stress and can more effectively advocate for major infrastructure upgrades in those places,” she says. “In the meantime, there are relatively small things that cities can do now to save lives in the summer — like providing people free air conditioners, opening community cooling centers, and installing more water fountains.”
6. We’re curbing emissions but need to act faster
Since the beginning ofthe industrial revolution, humans have caused the planet to warm 1.1°C (or about 2°F), mainly by burning coal, oil, and gas for energy. Current policies put the world on pace to increase global temperatures by about 2.6°C over pre-industrial levels by the end of the century. But to avoid the most catastrophic consequences of climate change, we must try to limit the warming to 1.5°C, scientists say. This will require that we retool our energy systems, dramatically expanding the use of renewable resources and eliminating nearly all greenhouse-gas emissions by mid-century.
“We’ll have to build the equivalent of the world’s largest solar park every day for the next thirty years to get to net zero by 2050,” says Jason Bordoff, co-dean of the Columbia Climate School. A leading energy-policy expert, Bordoff served on the National Security Council of President Barack Obama ’83CC. “We’ll also have to ramp up global investments in clean energy R&D from about $2 trillion to $5 trillion per year,” he adds, citing research from the International Energy Agency. “The challenge is enormous.”
Over the past few years, momentum for a clean-energy transition has been accelerating. In the early 2000s, global emissions were increasing 3 percent each year. Now they are rising just 1 percent annually, on average, with some projections indicating that they will peak in the mid-2020s and then start to decline. This is the result of a variety of policies that countries have taken to wean themselves off fossil fuels. European nations, for example, have set strict limits on industrial emissions. South Africa, Chile, New Zealand, and Canada have taken significant steps to phase out coal-fired power plants. And the US and China have enacted fuel-efficiency standards and invested in the development of renewable solar, wind, and geothermal energy — which, along with hydropower, account for nearly 30 percent of all electricity production in the world.
“It’s remarkable how efficient renewables have become over the past decade,” says Bordoff, noting that the costs of solar and wind power have dropped by roughly 90 percent and 70 percent, respectively, in that time. “They’re now competing quite favorably against fossil fuels in many places, even without government subsidies.”
But in the race to create a carbon-neutral global economy, Bordoff says, the biggest hurdles are ahead of us. He points out that we currently have no affordable ways to decarbonize industries like shipping, trucking, air travel, and cement and steel production, which require immense amounts of energy that renewables cannot yet provide. “About half of all the emission reductions that we’ll need to achieve between now and 2050 must come from technologies that aren’t yet available at commercial scale,” says Bordoff.
In order to fulfill the potential of solar and wind energy, we must also improve the capacity of electrical grids to store power. “We need new types of batteries capable of storing energy for longer durations, so that it’s available even on days when it isn’t sunny or windy,” he says.
Perhaps the biggest challenge, Bordoff says, will be scaling up renewable technologies quickly enough to meet the growing demand for electricity in developing nations, which may otherwise choose to build more coal- and gas-fueled power plants. “There are large numbers of people around the world today who have almost no access to electricity, and who in the coming years are going to want to enjoy some of the basic conveniences that we often take for granted, like refrigeration, Internet access, and air conditioning,” he says. “Finding sustainable ways to meet their energy needs is a matter of equity and justice.”
Bordoff, who is co-leading the new Climate School alongside geochemist Alex Halliday, environmental geographer Ruth DeFries, and marine geologist Maureen Raymo ’89GSAS, is also the founding director of SIPA’s Center on Global Energy Policy, which supports research aimed at identifying evidence-based, actionable solutions to the world’s energy needs. With more than fifty affiliate scholars, the center has, since its creation in 2013, established itself as an intellectual powerhouse in the field of energy policy, publishing a steady stream of definitive reports on topics such as the future of coal; the potential for newer, safer forms of nuclear energy to help combat climate change; and the geopolitical ramifications of the shift away from fossil fuels. One of the center’s more influential publications, Energizing America, from 2020, provides a detailed roadmap for how the US can assert itself as an international leader in clean-energy systems by injecting more federal money into the development of technologies that could help decarbonize industries like construction, transportation, agriculture, and manufacturing. President Joe Biden’s $1 trillion Infrastructure Investment and Jobs Act, signed into law in November, incorporates many of the report’s recommendations, earmarking tens of billions of dollars for scientific research in these areas.
“When we sat down to work on that project, my colleagues and I asked ourselves: If an incoming administration wanted to go really big on climate, what would it do? How much money would you need, and where exactly would you put it?” Bordoff says. “I think that’s one of our successes.”
Which isn’t to say that Bordoff considers the climate initiatives currently being pursued by the Biden administration to be sufficient to combat global warming. The vast majority of the climate-mitigation measures contained in the administration’s first two major legislative packages — the infrastructure plan and the more ambitious Build Back Better social-spending bill, which was still being debated in Congress when this magazine went to press — are designed to reward businesses and consumers for making more sustainable choices, like switching to renewable energy sources and purchasing electric vehicles. A truly transformative climate initiative, Bordoff says, would also discourage excessive use of fossil fuels. “Ideally, you’d want to put a price on emissions, such as with a carbon tax or a gasoline tax, so that the biggest emitters are forced to internalize the social costs they’re imposing on everyone else,” he says.
Bordoff is a pragmatist, though, and ever mindful of the fact that public policy is only as durable as it is popular. “I think the American people are more divided on this than we sometimes appreciate,” he says. “Support for climate action is growing in the US, but we have to be cognizant of how policy affects everyday people. There would be concern, maybe even outrage, if electric or gas bills suddenly increased. And that would make it much, much harder to gain and keep support during this transition.”
Today, researchers from across the entire University are working together to pursue a multitude of strategies that may help alleviate the climate crisis. Some are developing nanomaterials for use in ultra-efficient solar cells. Others are inventing methods to suck CO2 out of the air and pump it underground, where it will eventually turn into chalk. Bordoff gets particularly excited when describing the work of engineers at the Columbia Electrochemical Energy Center who are designing powerful new batteries to store solar and wind power. “This is a team of more than a dozen people who are the top battery experts in the world,” he says. “Not only are they developing technologies to create long-duration batteries, but they’re looking for ways to produce them without having to rely on critical minerals like cobalt and lithium, which are in short supply.”
In his own work, Bordoff has recently been exploring the geopolitical ramifications of the energy transition, with an eye toward helping policymakers navigate the shifting international power dynamics that are likely to occur as attention tilts away from fossil fuels in favor of other natural resources.
But he believes the best ideas will come from the next generation of young people, who, like the students in the Climate School’s inaugural class this year, are demanding a better future. “When I see the growing sense of urgency around the world, especially among the younger demographics, it gives me hope,” he says. “The pressure for change is building. Our climate policies don’t go far enough yet, so something is eventually going to have to give — and I don’t think it’s going to be the will and determination of the young people. Sooner or later, they’re going to help push through the more stringent policies that we need. The question is whether it will be in time.”
Tradição acontece desde 1887 em pequena cidade da Pensilvânia
Na manhã desta quarta (2), a marmota Phil viu a sua própria sombra e voltou para a sua toca. Segundo a tradição americana do Dia da Marmota, o movimento do animal significa que o frio continuará por mais seis semanas nos Estados Unidos.
Se Phil não tivesse visto a própria sombra, significaria que o calor da primavera estaria a caminho.
A previsão feita pela marmota é uma tradição que acontece desde 1887, sempre no dia 2 de fevereiro, na pequena cidade de Punxsutawney, na Pensilvânia. Após uma edição virtual em 2021 por causa da pandemia, neste ano o evento reuniu milhares de pessoas.
O roedor —que é substituído e rebatizado a cada vez que um animal titular morre— acertou 50% das vezes nos últimos dez anos —ou seja, índice de acerto igual ao de uma previsão aleatória, segundo o Noaa (Centros Nacionais de Informação Ambiental, na sigla em inglês),
O evento do Dia da Marmota foi retratado na comédia “Feitiço do Tempo“, de 1993, no qual um repórter de TV, vivido por Bill Murray, fica “preso” neste dia e é obrigado a reviver a mesma data inúmeras vezes, em sequência. Com isso, Dia da Marmota passou a ser uma forma de se referir à sensação de que os dias se repetem, situação comum na pandemia.
Researchers are exploring whether building massive berms or unfurling underwater curtains could hold back the warm waters degrading ice sheets.
January 14, 2022
In December, researchers reported that huge and growing cracks have formed in the eastern ice shelf of the Thwaites Glacier, a Florida-size mass of ice that stretches 75 miles across western Antarctica.
They warned that the floating tongue of the glacier—which acts as a brace to prop up the Thwaites—could snap off into the ocean in as little as five years. That could trigger a chain reaction as more and more towering cliffs of ice are exposed and then fracture and collapse.
A complete loss of the so-called doomsday glacier could raise ocean levels by two feet—or as much as 10 feet if the collapse drags down surrounding glaciers with it, according to scientists with the International Thwaites Glacier Collaboration. Either way, it would flood coastal cities around the world, threatening tens of millions of people.
All of which raises an urgent question: Is there anything we could do to stop it?
Even if the world immediately halted the greenhouse-gas emissions driving climate change and warming the waters beneath the ice shelf, that wouldn’t do anything to thicken and restabilize the Thwaites’s critical buttress, says John Moore, a glaciologist and professor at the Arctic Centre at the University of Lapland in Finland.
“So the only way of preventing the collapse … is to physically stabilize the ice sheets,” he says.
That will require what is variously described as active conservation, radical adaptation, or glacier geoengineering.
Moore and others have laid out several ways that people could intervene to preserve key glaciers. Some of the schemes involve building artificial braces through polar megaprojects, or installing other structures that would nudge nature to restore existing ones. The basic idea is that a handful of engineering efforts at the source of the problem could significantly reduce the property damage and flooding dangers that basically every coastal city and low-lying island nation will face, as well as the costs of the adaptation projects required to minimize them.
If it works, it could potentially preserve crucial ice sheets for a few more centuries, buying time to cut emissions and stabilize the climate, the researchers say.
But there would be massive logistical, engineering, legal, and financial challenges. And it’s not yet clear how effective the interventions would be, or whether they could be done before some of the largest glaciers are lost.
Redirecting warming waters
In articles and papers published in 2018, Moore, Michael Wolovick of Princeton, and others laid out the possibility of preserving critical glaciers, including the Thwaites, through massive earth-moving projects. These would involve shipping in or dredging up large amounts of material to build up berms or artificial islands around or beneath key glaciers. The structures would support glaciers and ice shelves, block the warm, dense water layers at the bottom of the ocean that are melting them from below, or both.
More recently, they and researchers affiliated with the University of British Columbia have explored a more technical concept: constructing what they’ve dubbed “seabed anchored curtains.” These would be buoyant flexible sheets, made from geotextile material, that could hold back and redirect warm water.
The hope is that this proposal would be cheaper than the earlier ones, and that these curtains would stand up to iceberg collisions and could be removed if there were negative side effects. The researchers have modeled the use of these structures around three glaciers in Greenland, as well as the Thwaites and nearby Pine Island glaciers.
If the curtains redirected enough warm water, the eastern ice shelf of the Thwaites could begin to thicken again and firmly reattach itself to the underwater formations that have supported it for millennia, Moore says.
“The idea is to return the system to its state around the early 20th century, when we know that warm water could not access the ice shelf as much as today,” he wrote in an email.
They’ve explored the costs and effects of strategically placing these structures in key channels where most of the warm water flows in, and of establishing a wider curtain farther out in the bay. The latter approach would cost on the order of $50 billion. That’s a big number, but it’s not even half what one proposed seawall around New York City would cost.
Researchers have floated other potential approaches as well, including placing reflective or insulating material over portions of glaciers; building fencing to retain snow that would otherwise blow into the ocean; and applying various techniques to dry up the bed beneath glaciers, eliminating water that acts as lubricant and thus slowing the glaciers’ movement.
Will it work?
Some scientists have criticized these ideas. Seven researchers submitted a response in Nature to Moore’s 2018 proposals, arguing that the concepts would be partial solutions at best, could in some cases inadvertently accelerate ice loss, and could pull attention and resources from efforts to eliminate the root of the problem: greenhouse-gas emissions.
The lead author, Twila Moon, a scientist at the National Snow and Ice Data Center at the University of Colorado, Boulder, says the efforts would be akin to plugging a couple of holes in a garden hose riddled with them.
And that’s if they worked at all. She argues that the field doesn’t understand ice dynamics and other relevant factors well enough to be confident that these things will work, and the logistical challenges strike her as extreme given the difficulty of getting a single research vessel to Antarctica.
“Addressing the source of the problem means turning off that hose, and that is something that we understand,” she says. “We understand climate change; we understand the sources, and we understand how to reduce emissions.”
There would also be significant governance and legal obstacles, as Charles Corbett and Edward Parson, legal scholars at University of California, Los Angeles, School of Law, noted in a forthcoming essay in Ecology Law Quarterly.
Notably, Antarctica is governed by a consortium of nations under the Antarctic Treaty System, and any one of the 29 voting members could veto such proposals. In addition, the Madrid Protocol strictly limits certain activities on and around Antarctica, including projects that would have major physical or environmental impacts.
Corbett and Parson stress that the obstacles aren’t insurmountable and that the issue could inspire needed updates to how these regions are governed amid the rising threat of climate change. But they also note: “It all raises the question of whether a country or coalition could drive the project forward with sufficient determination.”
Moore and others have noted in earlier work that a “handful of ice streams and large glaciers” are expected to produce nearly all the sea-level rise over the next few centuries, so a few successful interventions could have a significant impact.
But Moore readily acknowledges that such efforts will face vast challenges. Much more work needs to be done to closely evaluate how the flow of warm water will be affected, how well the curtains will hold up over time, what sorts of environmental side effects could occur, and how the public will respond. And installing the curtains under the frigid, turbulent conditions near Antarctica would likely require high-powered icebreakers and the sorts of submersible equipment used for deep-sea oil and gas platforms.
As a next step, Moore hopes to begin conversations with communities in Greenland to seek their input on such ideas well ahead of any field research proposals. But the basic idea would be to start with small-scale tests in regions where it will be relatively easy to work, like Greenland or Alaska. The hope is the lessons and experience gained there would make it possible to move on to harder projects in harsher areas.
The Thwaites would be at the top rung of this “ladder of difficulty.” And the researchers have been operating on the assumption that it could take three decades to build the public support, raise the needed financing, sort out the governance challenges, and build up the skills necessary to undertake such a project there.
There’s a clear problem with that timeline, however: the latest research suggests that the critical eastern buttress may not even be there by the end of this decade.
Source: Potsdam Institute for Climate Impact Research (PIK)
Summary: Economic growth goes down when the number of wet days and days with extreme rainfall go up, a team of scientists finds. The data analysis of more than 1,500 regions over the past 40 years shows a clear connection and suggests that intensified daily rainfall driven by climate-change from burning oil and coal will harm the global economy.
Economic growth goes down when the number of wet days and days with extreme rainfall go up, a team of Potsdam scientists finds. Rich countries are most severely affected and herein the manufacturing and service sectors, according to their study now published as cover story in the journal Nature. The data analysis of more than 1,500 regions over the past 40 years shows a clear connection and suggests that intensified daily rainfall driven by climate-change from burning oil and coal will harm the global economy.
“This is about prosperity, and ultimately about people’s jobs. Economies across the world are slowed down by more wet days and extreme daily rainfall — an important insight that adds to our growing understanding of the true costs of climate change,” says Leonie Wenz from the Potsdam Institute for Climate Impact Research (PIK) and the Mercator Research Institute on Global Commons and Climate Change (MCC) who led the study.
“Macro-economic assessments of climate impacts have so far focused mostly on temperature and considered — if at all — changes in rainfall only across longer time scales such as years or months, thus missing the complete picture,” explains Wenz. “While more annual rainfall is generally good for economies, especially agriculturally dependent ones, the question is also how the rain is distributed across the days of the year. Intensified daily rainfall turns out to be bad, especially for wealthy, industrialized countries like the US, Japan, or Germany.”
A first-of-its-kind global analysis of subnational rainfall effects
“We identify a number of distinct effects on economic production, yet the most important one really is from extreme daily rainfall,” says Maximilian Kotz, first author of the study and also at the Potsdam Institute. “This is because rainfall extremes are where we can already see the influence of climate change most clearly, and because they are intensifying almost everywhere across the world.”
The analysis statistically evaluates data of sub-national economic output for 1554 regions worldwide in the period 1979-2019, collected and made publicly available by MCC and PIK. The scientists combine these with high resolution rainfall data. The combination of ever increasing detail in climatic and economic data is of particular importance in the context of rain, a highly local phenomenon, and revealed the new insights.
“It’s the daily rainfall that poses the threat“
By loading the Earth’s atmosphere with greenhouse gases from fossil power plants and cars, humanity is heating the planet. Warming air can hold more water vapour that eventually becomes rain. Although atmospheric dynamics make regional changes in annual averages more complicated, daily rainfall extremes are increasing globally due to this water vapour effect.
“Our study reveals that it’s precisely the fingerprint of global warming in daily rainfall which have hefty economic effects that have not yet been accounted for but are highly relevant,” says co-author Anders Levermann, Head of the Potsdam Institute’s Complexity Science domain, professor at Potsdam University and researcher at Columbia University’s Lamont Doherty Earth Observatory, New York. “Taking a closer look at short time scales instead of annual averages helps to understand what is going on: it’s the daily rainfall which poses the threat. It’s rather the climate shocks from weather extremes that threaten our way of life than the gradual changes. By destabilizing our climate we harm our economies. We have to make sure that our burning of fossil fuels does not destabilize our societies, too.”
Maximilian Kotz, Anders Levermann, Leonie Wenz. The effect of rainfall changes on economic production. Nature, 2022; 601 (7892): 223 DOI: 10.1038/s41586-021-04283-8
Cold era, lasting from early 15th to mid-19th centuries, triggered by unusually warm conditions
Date: December 15, 2021
Source: University of Massachusetts Amherst
Summary: New research provides a novel answer to one of the persistent questions in historical climatology, environmental history and the earth sciences: what caused the Little Ice Age? The answer, we now know, is a paradox: warming.
New research from the University of Massachusetts Amherst provides a novel answer to one of the persistent questions in historical climatology, environmental history and the earth sciences: what caused the Little Ice Age? The answer, we now know, is a paradox: warming.
The Little Ice Age was one of the coldest periods of the past 10,000 years, a period of cooling that was particularly pronounced in the North Atlantic region. This cold spell, whose precise timeline scholars debate, but which seems to have set in around 600 years ago, was responsible for crop failures, famines and pandemics throughout Europe, resulting in misery and death for millions. To date, the mechanisms that led to this harsh climate state have remained inconclusive. However, a new paper published recently in Science Advances gives an up-to-date picture of the events that brought about the Little Ice Age. Surprisingly, the cooling appears to have been triggered by an unusually warm episode.
When lead author Francois Lapointe, postdoctoral researcher and lecturer in geosciences at UMass Amherst and Raymond Bradley, distinguished professor in geosciences at UMass Amherst began carefully examining their 3,000-year reconstruction of North Atlantic sea surface temperatures, results of which were published in the Proceedings of the National Academy of Sciences in 2020, they noticed something surprising: a sudden change from very warm conditions in the late 1300s to unprecedented cold conditions in the early 1400s, only 20 years later.
Using many detailed marine records, Lapointe and Bradley discovered that there was an abnormally strong northward transfer of warm water in the late 1300s which peaked around 1380. As a result, the waters south of Greenland and the Nordic Seas became much warmer than usual. “No one has recognized this before,” notes Lapointe.
Normally, there is always a transfer of warm water from the tropics to the Arctic. It’s a well-known process called the Atlantic Meridional Overturning Circulation (AMOC), which is like a planetary conveyor belt. Typically, warm water from the tropics flows north along the coast of Northern Europe, and when it reaches higher latitudes and meets colder Arctic waters, it loses heat and becomes denser, causing the water to sink at the bottom of the ocean. This deep-water formation then flows south along the coast of North America and continues on to circulate around the world.
But in the late 1300s, AMOC strengthened significantly, which meant that far more warm water than usual was moving north, which in turn cause rapid Arctic ice loss. Over the course of a few decades in the late 1300s and 1400s, vast amounts of ice were flushed out into the North Atlantic, which not only cooled the North Atlantic waters, but also diluted their saltiness, ultimately causing AMOC to collapse. It is this collapse that then triggered a substantial cooling.
Fast-forward to our own time: between the 1960s and 1980s, we have also seen a rapid strengthening of AMOC, which has been linked with persistently high pressure in the atmosphere over Greenland. Lapointe and Bradley think the same atmospheric situation occurred just prior to the Little Ice Age — but what could have set off that persistent high-pressure event in the 1380s?
The answer, Lapointe discovered, is to be found in trees. Once the researchers compared their findings to a new record of solar activity revealed by radiocarbon isotopes preserved in tree rings, they discovered that unusually high solar activity was recorded in the late 1300s. Such solar activity tends to lead to high atmospheric pressure over Greenland.
At the same time, fewer volcanic eruptions were happening on earth, which means that there was less ash in the air. A “cleaner” atmosphere meant that the planet was more responsive to changes in solar output. “Hence the effect of high solar activity on the atmospheric circulation in the North-Atlantic was particularly strong,” said Lapointe.
Lapointe and Bradley have been wondering whether such an abrupt cooling event could happen again in our age of global climate change. They note that there is now much less Arctic sea ice due to global warming, so an event like that in the early 1400s, involving sea ice transport, is unlikely. “However, we do have to keep an eye on the build-up of freshwater in the Beaufort Sea (north of Alaska) which has increased by 40% in the past two decades. Its export to the subpolar North Atlantic could have a strong impact on oceanic circulation,” said Lapointe. “Also, persistent periods of high pressure over Greenland in summer have been much more frequent over the past decade and are linked with record-breaking ice melt. Climate models do not capture these events reliably and so we may be underestimating future ice loss from the ice sheet, with more freshwater entering the North Atlantic, potentially leading to a weakening or collapse of the AMOC.” The authors conclude that there is an urgent need to address these uncertainties.
This research was supported by funding from the National Science Foundation.
Francois Lapointe, Raymond S. Bradley. Little Ice Age abruptly triggered by intrusion of Atlantic waters into the Nordic Seas. Science Advances, 2021; 7 (51) DOI: 10.1126/sciadv.abi8230
IS IT NEARLY over? In 2021 people have been yearning for something like stability. Even those who accepted that they would never get their old lives back hoped for a new normal. Yet as 2022 draws near, it is time to face the world’s predictable unpredictability. The pattern for the rest of the 2020s is not the familiar routine of the pre-covid years, but the turmoil and bewilderment of the pandemic era. The new normal is already here.
Remember how the terrorist attacks of September 11th 2001 began to transform air travel in waves. In the years that followed each fresh plot exposed an unforeseen weakness that required a new rule. First came locked cockpit doors, more armed air marshals and bans on sharp objects. Later, suspicion fell on bottles of liquid, shoes and laptops. Flying did not return to normal, nor did it establish a new routine. Instead, everything was permanently up for revision.
The world is similarly unpredictable today and the pandemic is part of the reason. For almost two years people have lived with shifting regimes of mask-wearing, tests, lockdowns, travel bans, vaccination certificates and other paperwork. As outbreaks of new cases and variants ebb and flow, so these regimes can also be expected to come and go. That is the price of living with a disease that has not yet settled into its endemic state.
And covid-19 may not be the only such infection. Although a century elapsed between the ravages of Spanish flu and the coronavirus, the next planet-conquering pathogen could strike much sooner. Germs thrive in an age of global travel and crowded cities. The proximity of people and animals will lead to the incubation of new human diseases. Such zoonoses, which tend to emerge every few years, used to be a minority interest. For the next decade, at least, you can expect each new outbreak to trigger paroxysms of precaution.
Covid has also helped bring about today’s unpredictable world indirectly, by accelerating change that was incipient. The pandemic has shown how industries can be suddenly upended by technological shifts. Remote shopping, working from home and the Zoom boom were once the future. In the time of covid they rapidly became as much of a chore as picking up the groceries or the daily commute.
Big technological shifts are nothing new. But instead of taking centuries or decades to spread around the world, as did the printing press and telegraph, new technologies become routine in a matter of years. Just 15 years ago, modern smartphones did not exist. Today more than half of the people on the planet carry one. Any boss who thinks their industry is immune to such wild dynamism is unlikely to last long.
The pandemic may also have ended the era of low global inflation that began in the 1990s and was ingrained by economic weakness after the financial crisis of 2007-09. Having failed to achieve a quick recovery then, governments spent nearly $11trn trying to ensure that the harm caused by the virus was transient.
They broadly succeeded, but fiscal stimulus and bunged-up supply chains have raised global inflation above 5%. The apparent potency of deficit spending will change how recessions are fought. As they raise interest rates to deal with inflation, central banks may find themselves in conflict with indebted governments. Amid a burst of innovation around cryptocoins, central-bank digital currencies and fintech, many outcomes are possible. A return to the comfortable macroeconomic orthodoxies of the 1990s is one of the least likely.
The pandemic has also soured relations between the world’s two great powers. America blames China’s secretive Communist Party for failing to contain the virus that emerged from Wuhan at the end of 2019. Some claim that it came from a Chinese laboratory there—an idea China has allowed to fester through its self-defeating resistance to open investigations. For its part, China, which has recorded fewer than 6,000 deaths, no longer bothers to hide its disdain for America, with its huge death toll. In mid-December this officially passed 800,000 (The Economist estimates the full total to be almost 1m). The contempt China and America feel for each other will heighten tensions over Taiwan, the South China Sea, human rights in Xinjiang and the control of strategic technologies.
In the case of climate change, the pandemic has served as an emblem of interdependence. Despite the best efforts to contain them, virus particles cross frontiers almost as easily as molecules of methane and carbon dioxide. Scientists from around the world showed how vaccines and medicines can save hundreds of millions of lives. However, hesitancy and the failure to share doses frustrated their plans. Likewise, in a world that is grappling with global warming, countries that have everything to gain from working together continually fall short. Even under the most optimistic scenarios, the accumulation of long-lasting greenhouse gases in the atmosphere means that extreme and unprecedented weather of the kind seen during 2021 is here to stay.
The desire to return to a more stable, predictable world may help explain a 1990s revival. You can understand the appeal of going back to a decade in which superpower competition had abruptly ended, liberal democracy was triumphant, suits were oversized, work ended when people left the office, and the internet was not yet disrupting cosy, established industries or stoking the outrage machine that has supplanted public discourse.
Events, dear boy, events
That desire is too nostalgic. It is worth notching up some of the benefits that come with today’s predictable unpredictability. Many people like to work from home. Remote services can be cheaper and more accessible. The rapid dissemination of technology could bring unimagined advances in medicine and the mitigation of global warming.
Even so, beneath it lies the unsettling idea that once a system has crossed some threshold, every nudge tends to shift it further from the old equilibrium. Many of the institutions and attitudes that brought stability in the old world look ill-suited to the new. The pandemic is like a doorway. Once you pass through, there is no going back. ■
This article appeared in the Leaders section of the print edition under the headline “The new normal”
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