U.S. report cites climate change threats
White House didn’t attempt to prevent assessment release.
WASHINGTON — The Trump administration released a dire scientific report Friday detailing the growing threats of climate change. The report stands in stark contrast to the administration’s efforts to downplay humans’ role in global warming, withdraw from an international climate accord and reverse Obama-era policies aimed at curbing America’s greenhouse-gas output.
The White House did not seek to prevent the release of the government’s National Climate Assessment, which is mandated by law, despite the fact that its findings sharply contradict the administration’s policies. The report affirms that climate change is driven almost entirely by human action, warns of potential sea level rise as high as 8 feet by the year 2100, and enumerates myriad climate-related damages across the United States that are already occurring due to 1.8 degrees Fahrenheit of global warming since 1900.
“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” the document reports. “For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”
The report’s release underscores the extent to which the machinery of the federal scientific establishment, operating in multiple agencies across the government, continues to grind on even as top administration officials have minimized or disparaged its findings. Federal scientists have continued to author papers and issue reports on climate change, for example, even as political appointees have altered the wording of news releases or blocked civil servants from speaking about their conclusions in public forums. The climate assessment process is dictated by a 1990 law that Democratic and Republican administrations have followed.
Environmental Protection Agency Administrator Scott Pruitt, Energy Secretary Rick Perry and President Donald Trump have all questioned the extent of humans’ contribution to climate change. One of EPA’s web pages posted scientific conclusions similar to those in the new report until earlier this year, when Pruitt’s deputies ordered it removed.
The report comes as Trump and members of his Cabinet are working to promote U.S. fossil fuel production and repeal several federal rules aimed at curbing the nation’s carbon output, including ones limiting greenhouse-gas emissions from existing power plants, oil and gas operations on federal land and carbon emissions from cars and trucks. Trump has also announced he will exit the Paris climate agreement, under which the U.S. has pledged to cut its overall greenhouse-gas emissions between 26 and 28 percent compared to 2005 levels by 2025.
The report could have considerable legal and policy significance, as the scientific matter provides new and stronger support for EPA’s greenhouse gas “endangerment finding” under the Clean Air Act, which lays the foundation for regulations on emissions.
“This is a federal government report whose contents completely undercut their policies, completely undercut the statements made by senior members of the administration,” said Phil Duffy, the director of the Woods Hole Research Center.
The government is required to produce the National Assessment every four years. This time, the report is split into two documents, one that lays out the fundamental science of climate change and the other that shows how the United States is being impacted on a regional basis. Combined, the two documents total over 2,000 pages.
The first document, called the Climate Science Special Report, is now a finalized report, having been peer reviewed by the National Academy of Sciences and vetted by experts across government agencies. It was formally unveiled Friday.
“I think this report is basically the most comprehensive climate science report in the world right now,” said Robert Kopp, a climate scientist at Rutgers who is an expert on sea-level rise and served as one of the report’s lead authors.
It affirms that the U.S. is already experiencing more extreme heat and rainfall events and more large wildfires in the West, that more than 25 U.S. coastal cities are already experiencing more flooding, and that seas could rise by between 1 and 4 feet by the year 2100, and perhaps even more than that if Antarctica proves to be unstable, as is currently feared. The report says that a rise of over 8 feet is “physically possible” with high levels of greenhouse-gas emissions, but there’s no way right now to predict how likely it is to happen.
Most striking, perhaps, the report warns of the unpredictable — changes that scientists cannot foresee that could involve tipping points or fast changes in the climate system. These could switch the climate into “new states that are very different from those experienced in the recent past.”
Given these strong statements — and how they contradict Trump administration statements and policies — some members of the scientific community had speculated that the administration might refuse to publish the report or alter its conclusions. During the last Republican presidential administration, that of George W. Bush, the national assessment process was highly controversial, and a senior official at the White House Council on Environmental Quality edited aspects of some government science reports.
Yet multiple experts, as well as some administration officials and federal scientists, said that Trump political appointees did not change the special report’s scientific conclusions. While some edits have been made to its final version — for instance, omitting or softening some references to the Paris climate agreement — those are focused on policy.
A senior administration official, who asked for anonymity because the process is still underway, said in an interview that top Trump officials decided to put out the assessment without changing the findings of its contributors even if some appointees may have different views.
A federal scientist involved in writing the report, who asked not to be identified because he was not authorized to speak to the press, said that political appointees made no effort to change the scientific findings after being briefed on them.