Trump creates uncertainty for world's most cited climate report

Eric Roston, Sheryl Tian Tong Lee, Bloomberg News on Feb 23, 2025

By clicking submit, I authorize Arcamax and its affiliates to: (1) use, sell, and share my information for marketing purposes, including cross-context behavioral advertising, as described in our Privacy Policy , (2) add to information that I provide with other information like interests inferred from web page views, or data lawfully obtained from data brokers, such as past purchase or location data, or publicly available data, (3) contact me or enable others to contact me by email or other means with offers for different types of goods and services, and (4) retain my information while I am engaging with marketing messages that I receive and for a reasonable amount of time thereafter. I understand I can opt out at any time through an email that I receive, or by clicking here

Climate diplomats beginning work on the next report from the Intergovernmental Panel on Climate Change — the crucial assessment on global warming that helps shape policy for governments to companies — will meet in China this week without US officials.

U.S. government scientists participating in the IPCC’s global assessments were issued a stop-work order from the Trump administration, according to media reports late last week, and NASA’s chief scientist Kate Calvin, who holds a leadership role in the new report cycle, is no longer attending as a result, CNN said, citing a spokesperson from the space agency.

NASA, Calvin, the IPCC did not immediately respond to requests for comment.

The U.S. absence comes amid broader cuts to research funding and a retreat from climate diplomacy under the Trump administration, raising new questions on what the IPCC’s future might look like without U.S. leadership. The group’s assessments are widely viewed as the world’s most trusted source of information on climate change.

“Without the U.S., the IPCC fails,” said Benjamin Horton, director of the Earth Observatory of Singapore, who has contributed to past assessment reports. “The U.S. puts more money, more personnel, collects more data and runs more models for climate science than the rest of the world combined.”

About 18% of IPCC authors have been from the U.S., more than twice the next biggest national contributor, the U.K., according to a 2023 analysis by Carbon Brief.

The Feb. 24-28 meeting in Hangzhou will revolve around outlines and budgets for components of the IPCC’s seventh assessment report, which is expected to be released in 2029, and carbon removal and capture technologies. The reports summarize scientific consensus on the state of climate change, guiding policy decisions and negotiations.

It would be difficult to overstate the confidence the IPCC has in the vast basics of climate science and the influence of its findings in shaping global policy, business and investment. The world began a global charge towards net zero in 2018 after the panel published a special report on global temperatures.

The authoritative climate science body has now produced six assessments since its founding in 1988, each thousands of pages long. Over time the IPCC’s reports have become more confident and detailed on humankind’s contribution to the warming planet. In 1995 the IPCC agreed there was evidence of “a discernible human influence on global climate,” while in 2007 it found “warming of the climate system is unequivocal.” In 2021 they wrote: “It is unequivocal that human influence has warmed the atmosphere, ocean and land.”

Not every scientist thinks the IPCC's existence depends on the U.S. Detlef van Vuuren, a Utrecht University professor, climate researcher at PBL Netherlands Environmental Assessment Agency and a past IPCC contributor, said the group would survive if the U.S. decides to leave the organization for good, despite the country’s monumental role over the decades.

“It’s obviously highly problematic that a country that has contributed so much to IPCC, but also to global emissions, would decide that facts are not a good basis to inform climate policy,” he said.