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Washington Post
7 days ago
- Business
- Washington Post
A study predicted huge climate damages. But it had a fatal flaw: Uzbekistan.
A year ago, a paper published in the journal Nature made a sweeping claim: The world economy was already on track to lose 19 percent of global gross domestic product by 2050, compared with what it would have been without climate change. By 2100, under a high emissions scenario, it predicted that global GDP would be roughly 62 percent lower than without climate change. Those numbers were a whopping three times higher than previous estimates — sparking concern that climate change would hinder the global economy much more than expected. The paper made waves across social media; according to one analysis by the U.K.-based outlet CarbonBrief, it was the second-most cited paper in the media in 2024. The paper's analysis and dataset, meanwhile, have been used for financial planning by the U.S. government, World Bank and other institutions. There was just one problem, according to a new analysis: The paper's findings were flawed. A new commentary published Wednesday in Nature found that the massive damages predicted by the paper were predicated on data errors stemming from one country — Uzbekistan. With Uzbekistan removed from the dataset, the predictions dropped substantially — from 62 percent GDP loss in 2100 to 23 percent and from 19 percent by 2050 to 6 percent, said Solomon Hsiang, director of the global policy laboratory at Stanford University and one of the authors of the new commentary. 'Everybody who works with data has some responsibility to look at the data and make sure it's fit for purpose,' Hsiang said. The authors of the original paper, however, argue that their analysis still holds. Karl Ziemelis, chief applied and physical sciences editor at Nature, wrote in an email that the journal was reviewing the study, and 'appropriate editorial action would be taken once the matter was resolved.' 'Science has worked, and always will work, through a process of constant interrogation and review, whether that be during the course of research, in peer review or in post publication assessment,' Ziemelis added. Hsiang and his co-authors, graduate students Tom Bearpark and Dylan Hogan, , discovered the error by removing one country at a time from the dataset. Every other country they removed only slightly changed the GDP predictions. But when Uzbekistan was taken out, the results changed dramatically. They then looked closer at the Uzbekistan data. The paper's dataset showed the country's GDP plummeting dramatically in the year 2000, losing almost 90 percent. Then in 2010, it showed the GDP climbing in some regions by over 90 percent. Other years also showed wild oscillations. According to the World Bank, the country's growth over the past 40 years has actually been quite modest — ranging from a 0.2 percent loss to a 7.7 percent growth. Those swings were so dramatic in the initial paper's data that they dominated the underlying model, which connected temperature and precipitation changes with economic growth. That resulted in a model that showed GDP would take sharp hits from climate change. Hsiang found the results surprising. 'When you have a lot of data points, the idea that a small country could be so influential is not intuitive,' Hsiang said. That's why, he said, it's essential to rigorously test the results and the data. The authors of the original paper, scientists at the Potsdam Institute for Climate Impact Research in Germany, have a different take. The error in the Uzbekistan data, they said, was due to problems with how the original data was processed. In an additional analysis, they corrected the Uzbekistan data, and also changed how their model controlled for underlying economic trends. 'We find actually that by doing that, our estimates in general get more robust,' said Maximilian Kotz, a postdoctoral researcher at the Potsdam Institute. Using this altered method, they found results that agreed closely with their original findings. Instead of 19 percent damages by 2050, for example, the new analysis shows 17 percent. 'We are grateful, and I think it's a good part of the scientific process that they've pointed out these issues,' said Leonie Wenz, professor of environmental economics at the Technical University of Berlin and another author of the initial study. 'But importantly, the main conclusions of the paper hold, and there are only slight changes to the estimates.' That change, however, required modifying the methodology of the paper, and critics are still skeptical. 'Science doesn't work by changing the setup of an experiment to get the answer you want,' Hsiang said. 'This approach is antithetical to the scientific method.' Concerns about the large magnitude of the GDP changes were already clear in the peer review process. In a peer review document, posted publicly by Nature, one anonymous reviewer wrote, 'I find all of this well explained and fairly convincing, yet, purely subjectively, I have a hard time in believing the results, which seem unintuitively large given damages aren't perfectly persistent.' After some back-and-forth with the authors, the reviewer later approved of the paper going to publication. Hsiang says the study is an important example of how science corrects itself, and that 'The fact that there's one car accident due to driver error doesn't mean that we think cars are fundamentally dysfunctional.' 'If people are at all skeptical about how science functions — the answer is well, our team discovered this issue, and we believe transparency is super important,' he said. 'That's the ethos of science.'
Yahoo
29-06-2025
- Science
- Yahoo
Researchers warn of catastrophic consequences from rapidly intensifying threat: 'As a species, we have never confronted anything like this'
Sustained higher-than-average temperatures and warming seas are projected to severely disrupt agriculture, CNN reports, and scientists are concerned about how to "ensure future food security" in a changing climate. Americans born today could "live in a world where the U.S. can only produce half as much of its key food crops," CNN's recent headline read. The ensuing reporting focused on a groundbreaking study recently published in Nature — one of the most widely cited scientific journals globally — and the outlet described its findings as "stark." Study authors examined the impacts of rising temperatures through a universally understood and relevant lens: the global food supply. Put plainly, the researchers' calculations were grim: Every 1°C (1.8°F) increase in average global temperatures will result in a worldwide reduction in food production equivalent to 120 fewer calories per person, per day. Study author Solomon Hsiang of the Stanford Doerr School of Sustainability broke it down further when discussing their findings. "If the climate warms by 3 degrees, that's basically like everyone on the planet giving up breakfast," Hsiang warned. It's well-documented that climate-related matters are routinely and misleadingly cast in doubt, framed as a matter of belief rather than settled science. Not everybody lives in a region routinely walloped by extreme weather — such as wildfires or increased coastal flooding — and the issue can seem abstract, localized elsewhere, or more of a problem for the distant future. However, food is a great equalizer, something all humans require to survive — farmers have long been ringing the alarm about the impacts of unpredictable weather and temperatures on crop yields. Professor and food policy expert Tim Lang told CNN that adaptations to fortify the global food supply are halting and insufficient. "The data pile up. The politicians turn a blind eye … Land use is not altering fast or radically enough," he lamented, addressing the speed at which agriculture is adapting to changes in the climate. Do you worry about how much food you throw away? Definitely Sometimes Not really Never Click your choice to see results and speak your mind. "This is a major problem. It's incredibly expensive. As a species, we have never confronted anything like this." Experts reiterated that "adaptation" and "mitigation" were critical steps to safeguard crops in an increasingly unpredictable climate, one in which the United States could lose half its crop yields. Growing your own food is one approach to guard against food supply instability at a personal level, whereas donating to climate-related causes is a good way to make a broader impact. Join our free newsletter for good news and useful tips, and don't miss this cool list of easy ways to help yourself while helping the planet.
Kuwait Times
21-06-2025
- Science
- Kuwait Times
Climate change could cut crop yields up to a quarter
PARIS: Climate change is on track to reduce by 11 percent in 2100 the yields that today provide two-thirds of humanity's calories from crops, even taking into account adaptation to a warming world, scientists said Wednesday. As soon as 2050, this 'moderate' scenario in which greenhouse gas emissions peak around 2040 and slowly taper off - a trajectory aligned with current trends - would see global losses of nearly eight percent. And if carbon pollution worsens, the loss of calories across the same six staples - corn, wheat, rice, soybeans, sorghum and cassava - rises to nearly a quarter by century's end, the researchers reported in Nature. More generally, every additional degree Celsius of warming reduces the world's ability to produce food from these crops by 120 calories per person per day, or nearly five percent of current daily consumption, they calculated. 'If the climate warms by three degrees, that's basically like everyone on the planet giving up breakfast,' said co-author Solomon Hsiang, a professor at the Stanford Doerr School of Sustainability in California. The steepest losses will occur at the extremes of the agricultural economy: in modern, Big Ag breadbaskets that currently enjoy some of the world's best growing conditions, and in subsistence farming communities that typically rely of small cassava harvests. North America would be hit hardest, losing a fifth of yields by 2100 in the moderate carbon pollution scenario, and two-fifths if emissions from burning fossil fuels continue apace. Working with more than a dozen scientists, Hsiang and co-leader Andrew Hultgren, an assistant professor at the University of Urbana-Champaign, sifted through data from more than 12,000 regions in 55 countries. Previous calculations of how a warming world will impact crop yields generally failed to consider the ways in which farmers would adapt, such as switching crop varieties, shifting planting and harvesting dates, and altering fertilizer use. The scientists estimated such adjustments would offset about a third of climate related losses over the next 75 years in the scenario of rising emissions, but that residual impacts would still be devastating. 'Any level of warming, even when accounting for adaptation, results in global output losses for agriculture,' said Hultgren. With the planet about 1.5C hotter than preindustrial levels in the late 1900s, farmers in many regions are already experiencing longer dry spells, unseasonable heatwaves and erratic weather that undermines yields. The nutritional value of most crops also declines with hotter temperatures, earlier research has shown. The study revealed sharp variations in the impact of global warming on different crops and regions. In the 'worst-case' scenario of rising carbon emissions, corn yields would plummet 40 percent by 2100 across the grain belt of the United States, eastern China, central Asia, and the Middle East. For soybeans, yields in the US would decline by half, and increase by a fifth in Brazil. Wheat losses would drop by a fifth in eastern and western Europe, and by 30 to 40 percent in other wheat-growing regions: China, Russia and North America. Cassava would be hit hard everywhere it's grown. 'Although cassava does not make up a large portion of global agricultural revenues, it is an important subsistence crop in low- and middle-income countries,' the researchers pointed out. Among the six crops examined, rice is the only one that stands to benefit in a warmer climate, mainly due to warmer nights. — AFP
USA Today
20-06-2025
- Science
- USA Today
Climate change threatens world food supply. How bad could it be in the U.S.?
It's especially worrisome in the United States, where top crop production could drop by as much as 50% by 2100. The planet's food system faces growing risks from climate change, a new study says. It's especially worrisome in the United States, where top crop production could drop by as much as 50% by 2100. The study, published June 18, assessed six staple crops – maize (corn), soybeans, rice, wheat, cassava and sorghum – and found that only rice might avoid substantial losses from rising temperatures. 'If the climate warms by 3 degrees, that's basically like everyone on the planet giving up breakfast," study co-author Solomon Hsiang of Stanford University said in a statement. Will there still be a Corn Belt? The projected losses for U.S. agriculture are especially steep, according to the study. 'Places in the Midwest that are really well suited for present-day corn and soybean production just get hammered under a high warming future,' said lead study author Andrew Hultgren of the University of Illinois Urbana-Champaign. 'You do start to wonder if the Corn Belt is going to be the Corn Belt in the future.' Scientists estimated that for every 1.8-degree Fahrenheit increase in temperature above pre-industrial levels, production will decline by 120 calories per person per day, the equivalent of 4.4% of today's daily consumption. That will push up prices and make it harder for people to access food, Hsiang told CNN. Wheat, soy and corn most affected Wheat and corn will be among the crops most at risk, the study found. The study suggested that under a high-emissions scenario, by the end of the century, maize production could decline by up to 40% in the United States, Eastern China, Central Asia, Southern Africa and the Middle East. Wheat loses could range from 15% to 25% in Europe, Africa and South America and 30% to 40% in China, Russia, the United States and Canada. 'This is basically like sending our agricultural profits overseas," Hsiang said in a statement from Stanford. "We will be sending benefits to producers in Canada, Russia, China. Those are the winners, and we in the U.S. are the losers. The longer we wait to reduce emissions, the more money we lose.' Data center: Hot, hotter, hottest: How much will climate change warm your county? Steepest losses at the extremes The steepest losses occur at the extremes of the agricultural economy, according to a statement from Stanford University. That includes modern breadbaskets that now enjoy some of the world's best growing conditions, such as the United States, and subsistence farming communities that rely on small harvests of cassava. In terms of food production capacity from staple crops, the analysis found yield losses may average 41% in the wealthiest regions and 28% in the lowest-income regions by 2100. In the study, scientists concluded further adaptation and the expansion of cropland may be needed to ensure food security and limit the effects of climate change. A favorable climate, Hsiang said, is a big part of what keeps farmland productive across generations. 'Farmers know how to maintain the soil, invest in infrastructure, repair the barn,' Hsiang said. 'But if you're letting the climate depreciate, the rest of it is a waste. The land you leave to your kids will be good for something, but not for farming.' The study was published in the peer-reviewed British journal Nature.
Axios
20-06-2025
- Business
- Axios
Climate poses big threat to crop production, new study says
Adaptation can't outrun climate change, and rich farming nations — including the U.S. — face jeopardy despite their resources, according to a major new paper on global warming and crop production. Why it matters: It's the first look at climate effects on staple crops to weigh farmers' "real-world adaptation measures" and fold them into projections of future damage, a summary states. The Nature paper projects losses for all staples analyzed except rice, though there's lots of regional variation. The big picture: The paper estimates that for every 1°C of temperature rise, global food production capacity falls by 120 calories per day per person. "If the climate warms by 3 degrees, that's basically like everyone on the planet giving up breakfast," said co-author Solomon Hsiang, a Stanford environmental policy professor, in a statement. Hot and relatively low-income regions are showing more adaptation to date than wealthier breadbaskets in more moderate climates. That's one reason future risks are so high. State of play: The authors analyze over 12,600 regions in 54 countries, looking at six staple crops — corn, soybeans, rice, wheat, cassava and sorghum. It's "one of the most comprehensive samples of subnational crop yields ever assembled," the study states. It sees future gains in some areas, but declines on a global basis for most crops. Threat level: One reason for the conclusions? Realism. A clear-eyed look at how farming evolves is needed, the paper states, comparing its work to prior models that assume optimal responses. In reality, financial constraints, market failures, human error and more influence farming. What they found: Under a moderate emissions growth case, central estimates in 2100 — with adaptation and income growth — are -12% for corn, -13.5% for wheat, and -22.4% for soybeans, to name three. But the uncertainty bands are quite big because they're looking well into the future. What's next: Adaptation and higher wealth alleviate 6% of global losses in 2050 and 12% in 2100 in that moderate emissions scenario. That's RCP 4.5 for you wonks out there, which still sees enough emissions to warm the world beyond Paris Agreement targets. The paper also explores a runaway emissions case (RCP 8.5), though many scientists no longer consider this CO2 growth likely. Zoom in: Check out the country-level projections for various crops. The paper estimates that even with adaptation, parts of the U.S. could see corn and wheat declines in the 25% range in the moderate emissions case. Here's the same map under runaway emissions. summary notes.
