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AFP
2 days ago
- Business
- AFP
Major climate-GDP study under review after facing challenge
But a re-analysis by Stanford University researchers in California, released August 6, 2025, challenges the conclusion of the climate paper (archived here and here). It found the projected hit to be about three times smaller and broadly in line with earlier estimates, after excluding an anomalous result tied to Uzbekistan (archived here). The saga may culminate in a rare retraction, with Nature telling AFP August 6 it will have "further information to share soon" -- a move seized upon by climate-change skeptics following the publication of the re-analysis and pre-print correction of the paper. Both the original authors -- who have acknowledged errors in their methodology and data processing -- and the Stanford team hoped the transparency of the review process would bolster, rather than undermine public confidence in science. Climate scientist Maximilian Kotz and co-authors at the renowned Potsdam Institute for Climate Impact Research (PIK) published the original research in April 2024, using datasets from 83 countries to assess how changes in temperature and precipitation affect economic growth (archived here). Influential paper It became the second most cited climate paper of the year, according to the UK-based Carbon Brief outlet, and informed policy at the World Bank, International Monetary Fund, US federal government and others (archived here and here). AFP was among numerous media outlets to report on it. Yet the eye-popping claim that global GDP would be lowered by 62 percent by the year 2100 under a high emissions scenario soon drew scrutiny. "That's why our eyebrows went up because most people think that 20 percent is a very big number," scientist and economist Solomon Hsiang, one of the researchers behind the re-analysis, also published in Nature, told AFP August 5, 2025 (archived here). When they tried to replicate the results, Hsiang and his Stanford colleagues spotted serious anomalies in the data surrounding Uzbekistan. Specifically, there was a glaring mismatch in the provincial growth figures cited in the Potsdam paper and the national numbers reported for the same periods by the World Bank. "When we dropped Uzbekistan, suddenly everything changed. And we were like, 'whoa, that's not supposed to happen,'" Hsiang said. "We felt like we had to document it in this form because it's been used so widely in policy making." The authors of the 2024 paper acknowledged methodological flaws, including currency exchange issues, and on August 6 uploaded a corrected version, which has not yet been peer-reviewed. "We're waiting for Nature to announce their further decision on what will happen next," Kotz told AFP. He stressed that while "there can be methodological issues and debate within the scientific community," the bigger picture was unchanged: climate change will have substantial economic impacts in the decades ahead. Undeniable climate impact Frances Moore, an associate professor in environmental economics at the University of California, Davis, who was not involved in either the original paper or the re-analysis, agreed (archived here). She told AFP on August 5 that the paper's correction did not alter overall policy implications. Projections of an economic slowdown by the year 2100 are "extremely bad" regardless of the Kotz-led study, she explained, and "greatly exceed the costs of reducing greenhouse gas emissions to stabilize the climate, many times over." "Future work to identify specific mechanisms by which variation in climate affects economic output over the medium and long-term is critical to both better understand these findings and prepare society to respond to coming climate disruption," she also noted. Image Riverbank dwellers carry banana produce over the dry Solimoes riverbed in the Pesqueiro community in Manacapuru, Amazonas state, northern Brazil, on September 30, 2024 (AFP / MICHAEL DANTAS, MICHAEL DANTAS) Hsiang said even smaller impacts on GDP should be considered "enough that it makes a lot of sense to invest in reducing climate change." "It's very cost effective," he told AFP. Heat stress on the economy manifests through various mechanisms, he said. For example, workforce productivity dips at high temperatures, risks of potential health complications rise, while machinery also deteriorates (archived here, here and here). "The very hottest countries in the world, near the tropics, we see this effect even more magnified," Hsiang said. "Every one degree of warming for them is a much larger impact on their economy." 'Final stages' Asked whether Nature would be retracting the Potsdam paper, Karl Ziemelis, the journal's physical sciences editor, did not answer directly but said an editor's note was added to the paper in November 2024 "as soon as we became aware of an issue" with the data and methodology (archived here). "We are in the final stages of this process and will have further information to share soon," he told AFP August 6. The episode comes at a delicate time for climate science, under heavy fire from the US government under President Donald Trump's second term, as misinformation about the impacts of human-driven greenhouse gases abounds. Yet even in this environment, Hsiang argued, the episode showed the robust nature of the scientific method. "One team of scientists checking other scientists' work and finding mistakes, the other team acknowledging it, correcting the record, this is the best version of science," he said. AFP has previously reported on other flawed reports and predatory studies on climate change.
The Hindu
4 days ago
- Business
- The Hindu
Major climate change-GDP study under review after facing challenge
A blockbuster study published in top science journal Nature last year warned that unchecked climate change could slash global GDP by a staggering 62 percent by century's end, setting off alarm bells among financial institutions worldwide. But a re-analysis by Stanford University researchers in California, released Wednesday (August 6, 2025), challenges that conclusion — finding the projected hit to be about three times smaller and broadly in line with earlier estimates, after excluding an anomalous result tied to Uzbekistan. The saga may culminate in a rare retraction, with Nature telling AFP it will have "further information to share soon" — a move that would almost certainly be seized upon by climate-change skeptics. Both the original authors — who have acknowledged errors — and the Stanford team hoped the transparency of the review process would bolster, rather than undermine public confidence in science. Climate scientist Maximilian Kotz and co-authors at the renowned Potsdam Institute for Climate Impact Research (PIK), published the original research in April 2024, using datasets from 83 countries to assess how changes in temperature and precipitation affect economic growth. Influential paper It became the second most cited climate paper of the year, according to the UK-based Carbon Brief outlet, and informed policy at the World Bank, International Monetary Fund, U.S. federal government and others. AFP was among numerous media outlets to report on it. Yet the eye-popping claim that global GDP would be lowered by 62 percent by the year 2100 under a high emissions scenario soon drew scrutiny. "That's why our eyebrows went up because most people think that 20 percent is a very big number," scientist and economist Solomon Hsiang, one of the researchers behind the re-analysis, also published in Nature, told AFP. When they tried to replicate the results, Hsiang and his Stanford colleagues spotted serious anomalies in the data surrounding Uzbekistan. Specifically, there was a glaring mismatch in the provincial growth figures cited in the Potsdam paper and the national numbers reported for the same periods by the World Bank. "When we dropped Uzbekistan, suddenly everything changed. And we were like, 'whoa, that's not supposed to happen,'" Hsiang said. "We felt like we had to document it in this form because it's been used so widely in policy making." The authors of the 2024 paper acknowledged methodological flaws, including currency exchange issues, and on Wednesday uploaded a corrected version, which has not yet been peer-reviewed. "We're waiting for Nature to announce their further decision on what will happen next," Kotz told AFP. He stressed that while "there can be methodological issues and debate within the scientific community," the bigger picture was unchanged: climate change will have substantial economic impacts in the decades ahead. Undeniable climate impact Frances Moore, an associate professor in environmental economics at the University of California, Davis, who was not involved in either the original paper or the re-analysis, agreed. She told AFP the correction did not alter overall policy implications. Projections of an economic slowdown by the year 2100 are "extremely bad" regardless of the Kotz-led study, she said, and "greatly exceed the costs of reducing greenhouse gas emissions to stabilize the climate, many times over." "Future work to identify specific mechanisms by which variation in climate affects economic output over the medium and long-term is critical to both better understand these findings and prepare society to respond to coming climate disruption," she also noted. Asked whether Nature would be retracting the Potsdam paper, Karl Ziemelis, the journal's physical sciences editor, did not answer directly but said an editor's note was added to the paper in November 2024 "as soon as we became aware of an issue" with the data and methodology. "We are in the final stages of this process and will have further information to share soon," he told AFP. The episode comes at a delicate time for climate science, under heavy fire from the U.S. government under President Donald Trump's second term, as misinformation about the impacts of human-driven greenhouse gases abounds. Yet even in this environment, Hsiang argued, the episode showed the robust nature of the scientific method. "One team of scientists checking other scientists' work and finding mistakes, the other team acknowledging it, correcting the record, this is the best version of science."
Business Times
4 days ago
- Business
- Business Times
Major climate-GDP study under review after facing challenge
[WASHINGTON] A blockbuster study published in top science journal Nature last year warned that unchecked climate change could slash global GDP by a staggering 62 per cent by century's end, setting off alarm bells among financial institutions worldwide. But a re-analysis by Stanford University researchers in California, released on Wednesday, challenges that conclusion - finding the projected hit to be about three times smaller and broadly in line with earlier estimates, after excluding an anomalous result tied to Uzbekistan. The saga may culminate in a rare retraction, with Nature telling AFP it will have 'further information to share soon' - a move that would almost certainly be seized upon by climate-change skeptics. Both the original authors - who have acknowledged errors - and the Stanford team hoped the transparency of the review process would bolster, rather than undermine public confidence in science. Climate scientist Maximilian Kotz and co-authors at the renowned Potsdam Institute for Climate Impact Research (PIK), published the original research in April 2024, using datasets from 83 countries to assess how changes in temperature and precipitation affect economic growth. Influential paper A NEWSLETTER FOR YOU Friday, 12.30 pm ESG Insights An exclusive weekly report on the latest environmental, social and governance issues. Sign Up Sign Up It became the second most cited climate paper of the year, according to the UK-based Carbon Brief outlet, and informed policy at the World Bank, International Monetary Fund, US federal government and others. AFP was among numerous media outlets to report on it. Yet the eye-popping claim that global GDP would be lowered by 62 per cent by the year 2100 under a high emissions scenario soon drew scrutiny. 'That's why our eyebrows went up because most people think that 20 per cent is a very big number,' scientist and economist Solomon Hsiang, one of the researchers behind the re-analysis, also published in Nature, told AFP. When they tried to replicate the results, Hsiang and his Stanford colleagues spotted serious anomalies in the data surrounding Uzbekistan. Specifically, there was a glaring mismatch in the provincial growth figures cited in the Potsdam paper and the national numbers reported for the same periods by the World Bank. 'When we dropped Uzbekistan, suddenly everything changed. And we were like, 'whoa, that's not supposed to happen,'' Hsiang said. 'We felt like we had to document it in this form because it's been used so widely in policy making.' The authors of the 2024 paper acknowledged methodological flaws, including currency exchange issues, and on Wednesday uploaded a corrected version, which has not yet been peer-reviewed. 'We're waiting for Nature to announce their further decision on what will happen next,' Kotz told AFP. He stressed that while 'there can be methodological issues and debate within the scientific community,' the bigger picture was unchanged: climate change will have substantial economic impacts in the decades ahead. Undeniable climate impact Frances Moore, an associate professor in environmental economics at the University of California, Davis, who was not involved in either the original paper or the re-analysis, agreed. She told AFP the correction did not alter overall policy implications. Projections of an economic slowdown by the year 2100 are 'extremely bad' regardless of the Kotz-led study, she said, and 'greatly exceed the costs of reducing greenhouse gas emissions to stabilize the climate, many times over.' 'Future work to identify specific mechanisms by which variation in climate affects economic output over the medium and long-term is critical to both better understand these findings and prepare society to respond to coming climate disruption,' she also noted. Asked whether Nature would be retracting the Potsdam paper, Karl Ziemelis, the journal's physical sciences editor, did not answer directly but said an editor's note was added to the paper in November 2024 'as soon as we became aware of an issue' with the data and methodology. 'We are in the final stages of this process and will have further information to share soon,' he told AFP. The episode comes at a delicate time for climate science, under heavy fire from the US government under President Donald Trump's second term, as misinformation about the impacts of human-driven greenhouse gases abounds. Yet even in this environment, Hsiang argued, the episode showed the robust nature of the scientific method. 'One team of scientists checking other scientists' work and finding mistakes, the other team acknowledging it, correcting the record, this is the best version of science.' AFP
Int'l Business Times
4 days ago
- Business
- Int'l Business Times
Major Climate-GDP Study Under Review After Facing Challenge
A blockbuster study published in top science journal Nature last year warned that unchecked climate change could slash global GDP by a staggering 62 percent by century's end, setting off alarm bells among financial institutions worldwide. But a re-analysis by Stanford University researchers in California, released Wednesday, challenges that conclusion -- finding the projected hit to be about three times smaller and broadly in line with earlier estimates, after excluding an anomalous result tied to Uzbekistan. The saga may culminate in a rare retraction, with Nature telling AFP it will have "further information to share soon" -- a move that would almost certainly be seized upon by climate-change skeptics. Both the original authors -- who have acknowledged errors -- and the Stanford team hoped the transparency of the review process would bolster, rather than undermine public confidence in science. Climate scientist Maximilian Kotz and co-authors at the renowned Potsdam Institute for Climate Impact Research (PIK), published the original research in April 2024, using datasets from 83 countries to assess how changes in temperature and precipitation affect economic growth. It became the second most cited climate paper of the year, according to the UK-based Carbon Brief outlet, and informed policy at the World Bank, International Monetary Fund, US federal government and others. AFP was among numerous media outlets to report on it. Yet the eye-popping claim that global GDP would be lowered by 62 percent by the year 2100 under a high emissions scenario soon drew scrutiny. "That's why our eyebrows went up because most people think that 20 percent is a very big number," scientist and economist Solomon Hsiang, one of the researchers behind the re-analysis, also published in Nature, told AFP. When they tried to replicate the results, Hsiang and his Stanford colleagues spotted serious anomalies in the data surrounding Uzbekistan. Specifically, there was a glaring mismatch in the provincial growth figures cited in the Potsdam paper and the national numbers reported for the same periods by the World Bank. "When we dropped Uzbekistan, suddenly everything changed. And we were like, 'whoa, that's not supposed to happen,'" Hsiang said. "We felt like we had to document it in this form because it's been used so widely in policy making." The authors of the 2024 paper acknowledged methodological flaws, including currency exchange issues, and on Wednesday uploaded a corrected version, which has not yet been peer-reviewed. "We're waiting for Nature to announce their further decision on what will happen next," Kotz told AFP. He stressed that while "there can be methodological issues and debate within the scientific community," the bigger picture was unchanged: climate change will have substantial economic impacts in the decades ahead. Frances Moore, an associate professor in environmental economics at the University of California, Davis, who was not involved in either the original paper or the re-analysis, agreed. She told AFP the correction did not alter overall policy implications. Projections of an economic slowdown by the year 2100 are "extremely bad" regardless of the Kotz-led study, she said, and "greatly exceed the costs of reducing greenhouse gas emissions to stabilize the climate, many times over." "Future work to identify specific mechanisms by which variation in climate affects economic output over the medium and long-term is critical to both better understand these findings and prepare society to respond to coming climate disruption," she also noted. Asked whether Nature would be retracting the Potsdam paper, Karl Ziemelis, the journal's physical sciences editor, did not answer directly but said an editor's note was added to the paper in November 2024 "as soon as we became aware of an issue" with the data and methodology. "We are in the final stages of this process and will have further information to share soon," he told AFP. The episode comes at a delicate time for climate science, under heavy fire from the US government under President Donald Trump's second term, as misinformation about the impacts of human-driven greenhouse gases abounds. Yet even in this environment, Hsiang argued, the episode showed the robust nature of the scientific method. "One team of scientists checking other scientists' work and finding mistakes, the other team acknowledging it, correcting the record, this is the best version of science." Researchers AFP spoke to said the effects of heat on economies of countries near the tropics is magnified, like the riverbank dwellers carrying banana produce in northern Brazil AFP
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
