Subject: U.S. Report Says Humans Cause Climate Change, Contradicting Top Trump Officials
U.S. Report Says Humans Cause Climate Change, Contradicting Top Trump Officials
6 mins read
Smoke rose from trees burned in a wildfire in Wrightwood, Calif., last year.. A report from 13
federal agencies says extreme weather events have cost the United States $1.1 trillion since 1980.
Credit Jonathan Alcorn/Agence France-Presse — Getty Images
WASHINGTON — Directly contradicting much of the Trump administration’s position on climate
change, 13 federal agencies unveiled an exhaustive scientific report on Friday that says humans are
the dominant cause of the global temperature rise that has created the warmest period in the history
Over the past 115 years global average temperatures have increased 1.8 degrees Fahrenheit, leading
to record-breaking weather events and temperature extremes, the report says. 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. The United Nations convenes its annual
climate change conference next week in Bonn, Germany, and the American 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
“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. “It begs the question, where are members of the administration getting
their information from? They’re obviously not getting it from their own scientists.”
While there were pockets of resistance to the report in the Trump administration, according to
climate scientists involved in drafting the report, there was little appetite for a knockdown fight
over climate change among Mr. Trump’s top advisers, who are intensely focused on passing a tax
reform bill — an effort they think could determine the fate of his presidency.
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 science.
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The White House put out a statement Friday that seemed to undercut the high level of confidence of
the report’s findings.
“The climate has changed and is always changing,” Raj Shah, a White House spokesman, said in the
statement. “As the Climate Science Special Report states, the magnitude of future climate change
depends significantly on ‘remaining uncertainty in the sensitivity of Earth’s climate’” to
greenhouse gas emissions, he added..
Despite the scientific consensus presented in the report, the Environmental Protection Agency has
scrubbed references to climate change from its website and barred its scientists from presenting
scientific reports on the subject.
The E.P.A. administrator, Scott Pruitt, has said carbon dioxide is not a primary contributor to
warming. Rick Perry, the energy secretary, asserted Wednesday that “the science is out” on
whether humans cause climate change.
Their agencies referred questions to the National Oceanic and Atmospheric Administration, which
oversaw the research.
The report has provoked consternation in scientific circles for months. Though the study has been in
the works since 2015, several scientists said the election of Mr. Trump, who has labeled climate
change a “canard” and appointed cabinet members who disputed the scientific consensus, caused
them to worry the report would be blocked or buried.
That did not happen. Scientists who worked on the report said none of the 13 agencies that reviewed
it tried to undermine its findings or change its wording.
“I’m quite confident to say there has been no political interference on the message,” said
David Fahey, a NOAA scientist and a lead author of the report. “Whatever fears we had weren’t
Responsibility for approving the report fell to Gary D. Cohn, director of the National Economic
Council, who generally believes in the validity of climate science and thought the issue would have
been a distraction from the tax push, according to an administration official with knowledge of the
Phoenix experienced record highs in June. The report says there are “no convincing alternative
explanations” other than human activity to account for rising global temperatures. Credit Ralph
One of Mr. Cohn’s top policy deputies, Michael Catanzaro, had the authority to block, delay or
change the report. But Mr. Catanzaro, a former energy adviser to President George W. Bush and former
Speaker John A. Boehner, chose instead to follow the lead of the Obama administration by referring
the report back to more than a dozen federal agencies for feedback.
That review, according to two people familiar with the process, went relatively smoothly, surprising
some scientists who worked on the report who had expected more resistance.
The only significant turbulence, according to one person familiar with the process, came from a
midlevel political appointee at the Department of Energy who grilled the report’s authors on
changes that had been made to temperature and other climate data over the years. The authors
responded by adding a more detailed explanation of their methodology and all of the agencies then
gave their approval, the person said.
Mr. Trump was barely aware of the report’s existence, several White House officials said.
Some critics of climate change science attacked the report as the product of holdovers from the
Obama administration and chastised the Trump administration for allowing it to be published.
“I’m saddened that they have decided they will let the permanent government, the civil servants,
continue down this road without supervision,” said Myron Ebell, director of global warming policy
at the Competitive Enterprise Institute, a libertarian advocacy group.
Scientists said the report’s findings were clear.
“This new report simply confirms what we already knew. Human-caused climate change isn’t just a
theory, it’s reality,” said Michael E. Mann, a professor of atmospheric science at Pennsylvania
State University. “Whether we’re talking about unprecedented heat waves, increasingly
destructive hurricanes, epic drought and inundation of our coastal cities, the impacts of climate
change are no longer subtle. They are upon us. That’s the consensus of our best scientists, as
laid bare by this latest report.”
The report says the Earth has set temperature highs for three years running, and six of the last 17
years are the warmest years on record for the globe. Weather catastrophes from floods to hurricanes
to heat waves have cost the United States $1.1 trillion since 1980, and the report warns that such
phenomena may become common.
“The frequency and intensity of extreme high temperature events are virtually certain to increase
in the future as global temperature increases,” the report notes. “Extreme precipitation events
will very likely continue to increase in frequency and intensity throughout most of the world.”
In the United States, the report finds that every part of the country has been touched by warming,
from droughts in the Southeast to flooding in the Midwest to a worrying rise in air and ground
temperatures in Alaska, and conditions will continue to worsen.
“This assessment concludes, based on extensive evidence, that it is extremely likely that human
activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming
since the mid-20th century,” the report states. “For the warming over the last century, there is
no convincing alternative explanation supported by the extent of the observational evidence.”
The findings, other researchers said, create an unusual situation in which the government’s
policies are in direct opposition to the science it is producing.
“This profoundly affects our ability to be leaders in developing new technologies and
understanding how to build successful communities and businesses in the 21st century,” said
Christopher Field, director of the Stanford Woods Institute for the Environment. “Choosing to be
dumb about our relationship with the natural world is choosing to be behind the eight ball.”
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A version of this article appears in print on November 4, 2017, on Page A1 of the New York edition
with the headline: Climate Report