The National Climate Assessment, America’s premier contribution to climate knowledge, stands out for many reasons. Hundreds of scientists across the federal government and academia join forces to compile the best insights available on climate change. The results, released just twice a decade or so, shape years of government decisions.

Now, as the clock runs down on President Donald Trump’s time in office, the climate assessment has gained a new distinction: It is one of the few major U.S. climate initiatives that his administration tried, yet largely failed, to undermine.

How the Trump White House attempted to put its mark on the report, and why those efforts stumbled, demonstrates the resilience of federal climate science despite the administration’s haphazard efforts to impede it. This article is based on interviews with nearly a dozen current and former government officials and others familiar with the process.

In November, the administration removed the person responsible for the next edition of the report and replaced him with someone who has downplayed climate science, though at this point it seems to be too little, too late.

But the efforts started back in 2018, when officials pushed out a top official and leaned on scientists to soften their conclusions — the scientists refused — and then later tried to bury the report, which did not work either.

“Thank God they didn’t know how to run a government,” said Thomas Armstrong, who during the Obama administration led the U.S. Global Change Research Program, which produces the assessment. “It could have been a lot worse.”

What makes the failure to impede the climate assessment remarkable is that Trump has made it a top priority to undercut efforts to address climate change.

And on most fronts, he succeeded, reversing scores of environmental rules, relaxing restrictions on air pollution, and opening new land to oil and gas drilling.

The national assessment enjoys unique prominence, pulling together the work of scientists across the federal government. The law requires a new one every four years.

For Trump, who has called climate change a hoax, the assessment posed a particular challenge.

Trying to politicize or dismiss climate science is one thing when the warnings come from Democrats or academics. But this report comes from his administration’s own agencies.

The first evidence of this tension came in the summer of 2018 as federal scientists were finishing the fourth National Climate Assessment.

The report warned that climate change would endanger public safety and economic growth. And it said that cutting emissions “can substantially reduce climate-related risks,” in contradiction of the Trump administration’s efforts to reverse such cuts.

Stuart Levenbach, a political appointee who was then chief of staff at the National Oceanic and Atmospheric Administration, which oversees the assessment, pushed the scientists preparing the document to tone down the findings in their report summary, according to people involved in the discussions.

Levenbach, who is now a senior adviser at the White House National Economic Council, said in a statement that he simply wanted the summary to be more clear about the assumptions it relied upon about future emissions.

The career staff refused to make those changes.

That refusal came at a cost: Virginia Burkett, a climate scientist at the U.S. Geological Survey who was chairwoman of the Global Change Research Program, was forced out of her role. Still, the language in the report remained untouched.

The White House referred questions about Burkett to the Geological Survey. A spokesperson there did not respond to a request for comment.

The administration then released the document on the day after Thanksgiving, in an apparent attempt to minimize attention.

(A White House spokesperson, who declined to be identified by name, said by email, “The day after Thanksgiving is a Federal work day, and it is not unusual for Federal business to be conducted on days surrounding Federal holidays.”)

That approach backfired: Many news organizations interpreted the timing as evidence of the report’s importance, giving it prominent coverage.

Having failed to either change or bury the report, Trump and his senior officials then tried dismissing it.

Trump, asked about the assessment’s findings that global warming could devastate the economy, responded, “I don’t believe it.”

His press secretary at the time, Sarah Huckabee Sanders, said the assessment was “not based on facts.” Ryan Zinke, who was secretary of the interior at the time, said that its findings emphasized “the worst scenarios.”

Once the climate assessment had been issued, the White House Office of Science and Technology Policy, which oversees the Global Change Research Program, decided it was best to stop talking about it at all, according to people involved.

The office put a halt to any activities that might draw attention to the assessment. Additional reports, meant as periodic updates, stopped getting released.

Plans for the authors to meet with local officials in places threatened by climate change and talk about their findings were shelved.

The White House spokesperson called the descriptions of the White House actions “false.” She declined a request to make senior officials involved with the assessment available for an interview.

Urging staff not to talk about their work succeeded in keeping it off the radar of Trump and his senior officials, at least for a time. It helped that energy lobbyists were focused on the actions of other parts of government, whose regulations directly affected their businesses.

But the decision to avoid attention came at a cost, officials say, reducing the public’s awareness of the report’s findings and slowing the work on the next one.

Another White House decision would also help keep the climate assessment out of the news: The head of the science office, Kelvin Droegemeier, delayed the release of the next installment to 2023 from 2022, according to people familiar with his decision.

The Global Change Research Program’s website now says the “anticipated delivery” for the next report is 2023. The White House spokesperson said the final timeline has not been set.

But that delay had a silver lining, said Jesse Keenan, a professor at Tulane University who edited two chapters for the previous assessment. Each report relies on the scientific research it draws on — and under the Trump administration, new climate research has slowed, Keenan said.

Delaying the release of the next assessment “is going to give us an opportunity to catch our breath and get some output in the next year” from federal scientists, he said.

This year, the White House turned its attention to the climate assessment again.

An important step in creating each new version is the call for authors, who shape the tone of the report. That notice, which typically also provides an outline of what topics will be covered, was delayed for months by the Trump administration, according to several people familiar with the decision. And when it was finally released in October, the language had been changed: Political appointees had removed information about the specific topics to be addressed.

Federal scientists worried the change signaled a plan to truncate the scope of the assessment — allowing the administration to meet the letter of the law while avoiding topics that might run counter to what the White House wanted to hear.

The White House spokesperson said “the organization of information into specific chapters remains a work in progress.”

Those worries increased in November, when the White House removed the head of the Global Change Research Program, Michael Kuperberg, a climate scientist from the Department of Energy. Kuperberg was replaced by David Legates, a Trump appointee at NOAA who previously worked closely with groups that deny climate change.

The Department of Energy did not respond to a request for comment.

A second NOAA political official, Ryan Maue, who has criticized climate scientists for what he has called unnecessarily dire predictions, was moved to a role in the White House that gave him authority over the climate program.

The appointments produced anxiety among scientists, who worried it represented an effort by the administration to learn from its failure to change the previous assessment — by installing loyalists who could shape the next edition.

The White House declined to make Legates or Maue available for an interview.

But several people familiar with the process say it may not be too late for some sort of Hail Mary pass by the Trump administration — for example, rushing to select authors who might downplay the science of climate change or try to present that science as uncertain. That would force the Biden administration to work around those authors or remove them, potentially stirring up a political fight.

But the more likely outcome, current and former officials say, is that the recent hires are another example of how the Trump administration’s agenda was hindered by its own shortcomings: the failure to understand how the programs it wanted to undercut actually work, or moving too late to make a difference.

The administration should have moved sooner to put its stamp on the climate assessment, said Judith Curry, a former chairwoman of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology who said she has been in contact with Maue and other officials.

“It just didn’t bubble up on the priority list,” Curry said. “Why they started doing this at the eleventh hour, I honestly don’t know.”

John Holdren, who as science adviser to President Barack Obama helped oversee the climate assessment process, said he believed the Biden administration would be able to get it back on track and push aside anyone trying to undermine it.

“Holdover climate wafflers from the Trump period, in any of the relevant agencies, will be removed,” Holdren said, “or, if that’s not possible, told to butt out.”

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