The final draft of the U.S. Global Change Research Program's Climate Science Special Report, prepared and meticulously peer reviewed by dozens of federal climate scientists and academic consultants, is as weighty as it is stark. And after an eleventh-hour leak to The New York Times, it may become as definitive as the thoroughly footnoted body of science it encompasses.
Overwhelming evidence, the report says, shows that manmade climate change is being felt every day, and is worsening fast.
The U.S. Global Change Research Program, an interagency umbrella group that the Trump administration has moved to deprive of significant financing, made no bones on crucial elements of the modern scientific consensus on climate change:
- "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century," the report said. "There is no convincing alternative explanation."
- With significant reductions in emissions of greenhouse gases, it is possible to keep warming within the Paris treaty's target of below 2 degrees Celsius; without them, expected warming could reach 5 degrees or more by the end of the century.
- "To stabilize climate, however, it is not enough to halt the growth in annual carbon emissions. It is projected that global net carbon emissions will eventually need to reach zero."
None of this should come as any surprise—the report is basically a synthesis of the current climate science consensus.
Indeed, its gist had been known for months. An early draft was released for public comment a month before President Obama left office. It was reviewed in detail by an expert panel at the National Academy of Sciences, the gold standard for peer review, which gave its imprimatur in April.
But now, the final draft—the fifth revision, approaching 700 pages—is ready for final approval by the Trump Administration, which includes environmental, energy and other regulatory agencies run by people deeply opposed to the mainstream scientific views that run through this report, chapter and verse.
Would the Trump Administration deep-six the report? Some scientists involved in the process reportedly were worried about that.
So someone arranged to get it published on the website of The New York Times—a leak that broke protocol but ensured that no last-minute blue pencils could be surreptitiously applied by anyone politically inspired to meddle with the opus, a part of a long formal process that by law produces a National Climate Assessment every four years.
There have, after all, been cases where that happened in past Republican administrations—and the one in power now is so outright opposed to much of the science presented here that the watchdogs were wide awake.
Peter Frumhoff, director of science and policy at the Union of Concerned Scientists, said that "federal scientists' concerns that the administration will try to change or suppress this report are well-founded. The Trump administration has consistently demonstrated its lack of regard for science and evidence, including on climate change."
The White House said it would not comment on the draft until it was approved for release, and it criticized how the Times had put it out.
Starting on Monday night, the newspaper published a story apparently based at first on an earlier, third draft that had been released last year for public comment and expert review; then, on Tuesday, it published the full text of the fifth and final draft, which was just completed in late June. The two differed in the wording of significant sections, but not in their overall thrust.
Publication of the third draft, since it had long been available, didn't constitute a leak. But publication of the fifth and final draft did, and effectively foreclosed any unnoticed, last-minute changes by political appointees who the Times reported were supposed to complete their review by August 18.
Any editing that has occurred so far is of the kind that is normal for peer-reviewed science. That it occurred transparently—partly by design, partly by the artifice of a leak—only serves to underscore the insistence by established climate scientists that understanding of the causes of climate change and the urgent need for action to address it are well founded.
That's why most scientists dismiss suggestions by some in the administration, such as Environmental Protection Agency Administrator Scott Pruitt, that some kind of "red team" exercise to challenge the existing consensus would be useful.
Some may consider the Times-published version to be definitive, although depending on what happens next, others may dispute its authority. Those who oppose strong action on climate, for example, might seek to underscore that this report carries no direct regulatory authority.
Even so, the publication of this fifth edition lays down a marker. It would be hard, for example, for any revisionist to try to undo the EPA's landmark "endangerment finding" that underpins regulations of carbon dioxide under the Clean Air Act without taking into account the findings that are so completely laid out here.