The global, long-term warming trend is “unambiguous,” it says, and there is “no convincing alternative explanation” that anything other than humans — the cars we drive, the power plants we operate, the forests we destroy — are to blame.

The report was approved for release by the White House, but the findings come as the Trump administration is defending its climate change policies on several fronts. The United Nations convenes its annual climate change conference next week in Bonn, Germany, and the US delegation is expected to face harsh criticism over President Trump’s decision to walk away from the 195-nation Paris climate accord and top administration officials’ stated doubts about the causes and impacts of a warming planet.

“This report has some very powerful, hard-hitting statements that are totally at odds with senior administration folks and at odds with their policies,” said Philip B. Duffy, president of the Woods Hole Research Center.

“Where are members of the administration getting their information from? They’re obviously not getting it from their own scientists,” Duffy said.

The climate science report is part of a congressionally mandated review conducted every four years known as the National Climate Assessment. The product of hundreds of experts within the government and academia and peer-reviewed by the National Academy of Sciences, it is considered the United States’ most definitive statement on climate change.