Federal bureaucrats are preparing a wide-ranging assessment of the impacts of climate change on the U.S. to be released in 2018, and political and scientific interests are concerned about how the Trump administration will react to that report.

A draft copy of a portion of the report was the center of a story published by The New York Times on Aug. 8, and its findings contradict statements made by Trump administration officials regarding the role human activity has played in contributing to global warming.

For instance, U.S. Environmental Protection Agency Administrator Scott Pruitt in March said he does not agree that carbon dioxide is a primary contributor to global climate change and insisted that the impact of human activity on climate is still in dispute. That opinion is at odds with scientific research conducted by government agencies, including his own, which has concluded that emissions from human influences, including heat-trapping gases such as carbon dioxide, are affecting the climate.

While The New York Times initially claimed it had obtained exclusive access to a December 2016 draft of the report, it later acknowledged that version of the report had been made public previously. However, the paper later updated the story with a newer, June 28 version of the report.

The nearly 700-page June 28 draft, which provides the scientific backing that will be used to build the fourth National Climate Assessment, explores changes in temperature, sea level rise, extreme weather and other phenomena that have been attributed to climate change and adds to the increasing weight of evidence that supports humankind's involvement.

"Many lines of evidence demonstrate that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century," the draft report reads. "We find no convincing evidence that natural variability can account for the amount of global warming observed over the industrial era."

Regardless of the Trump administration's assertions on the cause of climate change, work on the report has continued unabated since Inauguration Day in January. The New York Times reported that scientists involved in the report are worried that the Trump administration could suppress or modify it.

Kathy Jacobs was the assistant director of the White House Office of Science and Technology Policy, or OSTP, as the third National Climate Assessment was developed for release in 2014. She reported to then-President Barack Obama's chief science adviser and director of the OSTP, John Holdren, and supervised the actions of the 13 agencies involved in the assessment's development.

Jacobs, now director of the University of Arizona's Center for Climate Adaptation Science and Solutions, recalled 30 different teams of authors, each responsible for an individual chapter, producing dozens of drafts of each one, which all were reviewed through the OSTP.

"It was a very intensive process," Jacobs said. Each draft was filtered up through the OSTP and reached at least Holdren and National Oceanic and Atmospheric Administration Director Jane Lubchenco, the agency that was in charge of the federal advisory committee for the assessment. Each agency chief had to approve the report as well.

Jacobs does not remember specifically what changes the White House directed during the exhaustive process but said White House officials conducted a scientific review of the materials and identified inaccuracies that needed to be corrected. For the most part, those changes included improving accuracy and clarifying the government's role relative to the private sector.

According to Jacobs, Holdren was personally involved in the process because of his background as an environmental scientist. She asserted that the White House never asked for certain parts to be removed to reflect the Obama administration's policies. If it had, Jacobs suspects the changes would have been difficult to move past the hundreds of scientists and experts who listed their names on the report.

"If the authors did not agree, we had to work it out until they were happy with the language. We would never have put them in a position of publishing a document that they didn't agree with," Jacobs said.

Jacobs has seen no evidence to suggest that the Trump administration might attempt to make politically driven changes but acknowledged the concern held by other scientists. If the White House did want to make changes, "the right way to do it" would be to work with the scientists producing the report to ensure there is agreement, Jacobs said.

"When the names of these scientists are on the report, they need to have a say in what it says — and that's the way it should be," Jacobs said. "I don't know if that's how it will be."

Rather than changing the report itself, the Trump administration could attempt to prevent the release of the assessment, Jacobs said. But with a congressional mandate to release it every four years, any delay would run afoul of the law, she predicted.

'A train wreck coming'

Conversely, one former Trump transition team adviser worries that the report could be released absent a critical review from the new administration, which could undermine Trump's future environmental policy initiatives. Myron Ebell, director of the Competitive Enterprise Institute's Center for Energy and Environment, said in a recent interview that he has concerns about the report being completed "on automatic pilot."

"I think that there could be a train wreck coming there," Ebell said. He noted that the OSTP is being staffed by "a career civil servant," as the Trump administration has not replaced Holdren, who left at the end of the Obama administration.

Holdren told the journal Science on July 11 that the OSTP has dropped from a peak of 135 staff under the Obama administration to just 35 since Trump took office. The drop is not altogether unusual during a presidential transition, but Holdren said the fact that Trump has not restaffed the office is strange. The office has just one political appointee serving as the "de facto" head of the agency, former Trump aide Michael Kratsios.

"From my perspective, that's not a good sign," Ebell said. "It's not the Trump National Climate Assessment, it's the Obama National Climate Assessment that just didn't get out before Obama left office, unless the Trump people get ahold of it and say, 'Hey, wait a minute, you've got all this stuff here, what's the evidence for it?'"

Ebell worries that the Trump administration will not be able to defend its own policies if the "Obama view of climate" becomes the "Trump administration view of climate."

Jacobs, meanwhile, called the report an "exhaustive effort" and asserted that its findings are "completely credible."

Each of the 13 agencies involved in the assessment must sign off on the June science report by Aug. 18.