A blockbuster study revealed in high science journal Nature final yr warned that unchecked climate change may slash international GDP by a staggering 62 p.c by century’s finish, setting off alarm bells amongst monetary establishments worldwide.
But a re-analysis by Stanford University researchers in California, launched Wednesday (August 6, 2025), challenges that conclusion — discovering the projected hit to be about thrice smaller and broadly in keeping with earlier estimates, after excluding an anomalous end result tied to Uzbekistan.
The saga could culminate in a uncommon retraction, with Nature telling AFP it would have “further information to share soon” — a transfer that might nearly actually be seized upon by climate-change skeptics.
Both the unique authors — who’ve acknowledged errors — and the Stanford staff hoped the transparency of the review course of would bolster, moderately than undermine public confidence in science.
Climate scientist Maximilian Kotz and co-authors on the famend Potsdam Institute for Climate Impact Research (PIK), revealed the unique analysis in April 2024, utilizing datasets from 83 nations to evaluate how modifications in temperature and precipitation have an effect on financial progress.
Influential paper
It turned the second most cited climate paper of the yr, in keeping with the UK-based Carbon Brief outlet, and knowledgeable coverage on the World Bank, International Monetary Fund, U.S. federal authorities and others. AFP was amongst quite a few media shops to report on it.
Yet the eye-popping declare that international GDP can be lowered by 62 p.c by the yr 2100 under a excessive emissions situation quickly 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 many researchers behind the re-analysis, additionally revealed in Nature, informed AFP.
When they tried to duplicate the outcomes, Hsiang and his Stanford colleagues noticed critical anomalies within the knowledge surrounding Uzbekistan.
Specifically, there was a evident mismatch within the provincial progress figures cited within the Potsdam paper and the nationwide numbers reported for a similar intervals by the World Bank.
“When we dropped Uzbekistan, suddenly everything changed. And we were like, ‘whoa, that’s not supposed to happen,'” Hsiang stated. “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, together with forex change points, and on Wednesday uploaded a corrected model, which has not but been peer-reviewed.
“We’re waiting for Nature to announce their further decision on what will happen next,” Kotz informed AFP.
He burdened that whereas “there can be methodological issues and debate within the scientific community,” the larger image was unchanged: climate change may have substantial financial impacts within the many years forward.
Undeniable climate affect
Frances Moore, an affiliate professor in environmental economics on the University of California, Davis, who was not concerned in both the unique paper or the re-analysis, agreed. She informed AFP the correction didn’t alter general coverage implications.
Projections of an financial slowdown by the yr 2100 are “extremely bad” whatever the Kotz-led study, she stated, 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 additionally famous.
Asked whether or not Nature can be retracting the Potsdam paper, Karl Ziemelis, the journal’s bodily sciences editor, didn’t reply instantly however stated an editor’s word was added to the paper in November 2024 “as soon as we became aware of an issue” with the information and methodology.
“We are in the final stages of this process and will have further information to share soon,” he informed AFP.
The episode comes at a fragile time for climate science, under heavy fireplace from the U.S. authorities under President Donald Trump’s second time period, as misinformation in regards to the impacts of human-driven greenhouse gases abounds.
Yet even on this setting, Hsiang argued, the episode confirmed the sturdy nature of the scientific methodology.
“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.”
