CLIMATEWIRE | The Trump administration’s abrupt retreat from global climate action is threatening to delay a pivotal scientific report that can be used by countries to shape their responses to rising temperatures.
Delegates from more than 190 countries are meeting in Hangzhou, China, this week to make decisions related to the content and timing of the seventh assessment report by the Intergovernmental Panel on Climate Change, a U.N. body that evaluates the science behind climate change.
The conclusions of the assessments — which are released every five to seven years — help inform governments about the sources of greenhouse gas emissions, the pollution’s effects on the planet and the risks of not acting to curb it. The comprehensive reports are also integral to ascertaining whether countries are doing enough to reduce emissions — a process under the Paris climate agreement known as a stocktake.
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The U.S. delegation was prevented from attending the IPCC meeting by the Trump administration, said a government official who was granted anonymity because they were not authorized to discuss the situation. The move follows President Donald Trump’s announcement last month that he would immediately withdraw from the Paris deal.
Among the delegates who were blocked from attending the meeting is a federal scientist, Katherine Calvin, who was co-chairing one of three working groups that help assemble the next assessment. The Trump administration also halted a technical support unit that was backing that working group, according to two other government officials.
Losing that unit would ensure delays at the working group level of the assessment’s preparation, said one of those officials.
The State Department declined to comment.
Flouting the IPCC meeting is another signal that the Trump administration is pulling back from global climate engagement. U.S. officials did not attend a board meeting last week of the Green Climate Fund, the primary vehicle for helping poorer countries fund climate efforts. That’s been coupled with a complete assault on climate science at home, the shuttering of climate programs administered by the U.S. Agency for International Development and a broad freeze on foreign assistance.
There were already concerns among delegates and advocates about delays related to the IPCC’s seventh assessment following disagreements last year over some key elements of the report’s timeline. The main synthesis report is due in late 2029, but only after reports from the three working groups are completed. The idea is some of those would be published before the next stocktake in 2028.
“The Paris Agreement process must be informed by the best and latest available science,” a group of countries known as the High-Ambition Coalition urged in a statement Friday. Signatories include the United Kingdom, Germany, the European Union’s climate commissioner and several small island nations.
Katherine Calvin, NASA chief scientist and senior climate advisor, answers a question during a news conference to discuss the latest global temperature data at NASA headquarters in Washington, D.C., on Aug. 14, 2023. A NASA spokesperson confirmed that Calvin will not attend the IPCC meeting.
Joel Kowsky/NASA/Handout via Xinhua/Alamy Stock Photo
A European official said the statement was in response to growing concerns that the IPCC will delay its seventh assessment cycle as a result of U.S. funding cuts to climate research, as well as pushback from petrostates like Saudi Arabia.
“Please, as policymakers, we cannot afford to keep ignoring science,” Spain’s ecological transition minister, Sara Aagesen, said in a statement.
The U.S. contributes money and expertise to the IPCC process. Calvin, NASA’s chief scientist and senior climate adviser, is currently co-chair of Working Group III, which focuses on methods for reducing greenhouse gas emissions and removing them from the atmosphere.
A NASA spokesperson confirmed that Calvin will not attend the IPCC meeting.
Technical support units are the “core machinery” of the working group, said a longtime IPCC contributor who spoke on condition of anonymity to avoid retribution. They often do the administrative, technical and editorial work needed to deliver reports.
“If U.S. support disappears — and not just the co-chair is not showing up but equally the technical support disappears — that is a hole that needs to be filled,” the person said.
Despite the importance of those technical units, the current disruption doesn’t necessarily mean the assessment will be delayed, said Jesse Keenan, an author of the IPCC’s sixth assessment report, segments of which were released over several years, with the final synthesis report being published in 2023. The consulting firm ICF International is on the technical support contract for the seventh assessment, and another country could pay the firm to continue its work, he noted.
Yet Keenan said the Trump administration could throw up obstacles for U.S. scientists who are participating in the IPCC process. He said it’s unclear whether the State Department will withdraw nominations to the IPCC. The administration could also break with tradition by refusing to cover travel expenses for nongovernmental scientists to attend IPCC meetings.
During Trump’s first term, the U.S. participated in international climate meetings but with a lower profile. That suited some experts.
“They didn’t have strong positions. They are really good diplomats. They were helpful and constructive,” said the IPCC contributor.
Some advocates said it might be beneficial if U.S. delegates skip this week’s IPCC meeting, especially if the U.S. takes a hard line against synchronizing the assessment’s timing with the global stocktake, which is essentially a report card on countries’ progress to slow climate change.
The meeting could also offer an indication of how other countries might try and fill the void created by America’s departure.
This “is the first opportunity to see how China may react to the absence of the U.S. in international climate processes,” said Li Shuo, director of the China Climate Hub at the Asia Society Policy Institute.
Some scientists said the long-term implications are more troubling. Keenan said Trump’s effort to downsize the federal government — which has led to the culling of staffers who work on climate and energy programs — is being sold as a transformation in favor of fiscal stewardship.
“But really, it’s a nihilist fantasy to abolish government,” he said.
Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2025. E&E News provides essential news for energy and environment professionals.