The impending release of a key government report on climate change will force President Trump to choose between accepting the conclusions of his administration’s scientists and the demands of his conservative supporters, who remain deeply unconvinced that humans are the cause of the planet’s warming.
A White House official said on Tuesday that it was still reviewing the draft document that was written by scientists, some of whom have said they fear Mr. Trump will seek to bury it or alter its contents before it is formally released. Sarah Huckabee Sanders, the White House press secretary, said the administration would not comment on the report before its scheduled release this fall.
But the looming publication of the climate report — which concludes that “evidence for a changing climate abounds, from the top of the atmosphere to the depths of the oceans” — once again raises a contentious policy issue that has deeply divided Mr. Trump’s closest advisers since he arrived in the Oval Office.
Like his June decision to withdraw from the Paris climate accord, Mr. Trump’s response to the scientific conclusions in the forthcoming Climate Science Special Report will have broad implications for the American scientific community; local and state governments; and the global effort to combat the effects of rising temperatures that are already unfolding.
“We’ll be watching the administration very carefully on this,” said Kassie Siegel of the Center for Biological Diversity, which sued President George W. Bush after his administration repeatedly stalled the release of a previous climate change assessment. Ms. Siegel said her group would be “assessing all legal options, and returning to court at the earliest possible time to ensure that this essential report is released as required.”
The special report is part of the National Climate Assessment, which presidents are required by law to conduct every four years. The assessment details the risks that climate change poses to the United States, so as to inform federal agencies and local policy makers as they prepare for droughts, rising sea levels and other effects. But presidents have historically had wide latitude in how to play the findings.
For Mr. Trump, that means deciding whether his message on the campaign trail will guide his actions as president. In a speech in South Carolina in December 2015, Mr. Trump criticized President Barack Obama for talking about climate change, suggesting strongly that he would take a different approach if elected.
“A lot of it’s a hoax, it’s a hoax,” said Mr. Trump, then a Republican primary candidate. “I mean, it’s a moneymaking industry, O.K.? It’s a hoax, a lot of it.”
Since taking office, Mr. Trump and his advisers have argued that the global fight against climate change is a threat to the American economy. In his speech withdrawing from the Paris accord, the president said the agreement imposes “draconian financial and economic burdens” that are “unfair, at the highest level, to the United States.”
Mr. Trump could quietly publish the special report this year and the broader assessment when the final version is due in 2018. He could also make the case that the findings should be tempered by the economic effects that fighting climate change could have on American workers and businesses.
Or, as some scientists fear, he could try to alter or suppress the special report before it is actually released.
President Bill Clinton’s administration released the first National Climate Assessment in 2000 to little fanfare, wary of injecting the scientific report into a presidential campaign in progress. Mr. Bush’s administration delayed for years on releasing an updated version until the environmental groups successfully sued it. A final version was quietly released beginning in May 2008.
The Obama administration, by contrast, trumpeted the third version of the assessment in 2014, with the government building a graphics-heavy website to tout the findings and Mr. Obama conducting TV interviews on weather networks about the effects of global warming.
The draft special report on climate change now under review by the White House focuses primarily on the physical science of global warming, and will feed into a much broader evaluation of the potential social and economic consequences of climate change.
The current draft of the climate science report was written by scientists inside and outside government, with input from the public and the National Academy of Sciences, whichpraised an earlier draft and recommended relatively minor changes.
The report will now go before a White House committee staffed by political appointees from 13 agencies who are expected to complete their review by Aug. 18.
Ms. Sanders said the issue was still under consideration inside the administration, and she criticized The New York Times for writing about a draft that was not yet complete.
Scientists who fear that the White House could tamper with the report have focused on this review, noting that political appointees could demand major changes or deletions, or simply refuse to approve the report at all.
So far, there are no signs of such tampering, said Robert E. Kopp of Rutgers University, one of the contributing authors of the draft. “I would be surprised if they chose to make major changes, given that the report is already public,” he said. “I suspect we will know more later this month.”
A bigger question is whether Mr. Trump will choose to discuss the climate science report and the broader National Climate Assessment when they are finally released — or if he will play them down.
“At some point, the political and communications staff gets involved and decides how they want to handle the report,” said Paul Bledsoe, who coordinated communications strategy in the Clinton White House for the first assessment report in 2000.
In past administrations, the White House science adviser has been closely involved in these discussions, working with both the president and political operatives to map out a strategy for talking about the report. But Mr. Trump has not yet selected a science adviser, and his Office of Science and Technology Policy, which typically oversees the release of these reports, remains mostly empty.