U.S. report contradicts Trump team: Warming mostly man-made

WASHINGTON — A massive U.S. report concludes the evidence of global warming is stronger than ever, contradicting a favorite talking point of top Trump administration officials, who downplay human’s role in climate change.

The report released Friday is one of two scientific assessments required every four years. A draft showing how warming affects the U.S. was also published.

Despite fears by some scientists and environmental advocates, David Fahey of the National Oceanic and Atmospheric Administration and several authors said there was no political interference or censoring of the 477-page final report.

“A lot of what we’ve been learning over the last four years suggests the possibility that things may have been more serious than we think,” said Robert Kopp of Rutgers University, one of dozens of scientists inside and outside the government who wrote the reports.

Since 1900, Earth has warmed by 1.8 degrees and seas have risen by 8 inches. Heat waves, powerful tropical storms and wildfires have become frequent.

Energy Secretary Rick Perry and Environmental Protection Agency chief Scott Pruitt have repeatedly said carbon dioxide isn’t the primary contributor to global warming.

It’s “extremely likely” — meaning with 95 to 100 percent certainty — that global warming is manmade, mostly from the spewing of carbon dioxide into the atmosphere from the burning of fossil fuels, scientists concluded.

“Over the last century, there are no convincing alternative explanations,” the report said.

Scientists calculated that human contribution to warming since 1950 is between 92 percent and 123 percent. It’s more than 100 percent on one end, because some natural forces — such as volcanoes and orbital cycle — are working to cool Earth, but are being overwhelmed by the effects of greenhouse gases, said study co-author Katharine Hayhoe of Texas Tech.

“This period is now the warmest in the history of modern civilization,” she said.

For the first time, scientists highlighted a dozen “tipping points” of potential dangers that could happen from warming, things that Hayhoe said “keep me up at night.”

They include the slowing down of the giant Atlantic Ocean circulation system, which could dramatically warp weather worldwide, cause much stronger El Ninos, and cause major decreases in ice sheets in Greenland and Antarctica, which would spike sea levels. Thawing permafrost could cause a massive release of methane and carbon dioxide, which could turbo-charge warming.

Researchers did not provide an estimate of how likely tipping points would occur.