U.S. President Donald Trump points while leaving the stage after speaking during the Unleashing American Energy event at the Department of Energy in Washington, D.C. (Photographer: Kevin Dietsch/Pool via Bloomberg)

Scientists to Trump: ‘Zero Reason’ to Expect a Climate Reversal

(Bloomberg) -- Donald Trump may not think climate change is a “hoax” anymore, but the president made clear he still doubts whether humans are driving the phenomenon and thinks the whole thing could reverse itself.

Trump reiterated his doubts on climate change during an interview with “60 Minutes” on CBS, even as he distanced himself from a past tweet asserting that global warming is a “hoax” perpetrated by the Chinese. Trump also used the interview to suggest scientists with “a very big political agenda” have fanned concerns about the phenomenon.

“I don’t think it’s a hoax. I think there’s probably a difference, but I don’t know that it’s man-made,” Trump said. “I’m not denying climate change. But it could very well go back.”

The president’s remarks aired one week after the United Nations Intergovernmental Panel on Climate Change issued a dire report warning that countries must take “unprecedented” action over the next 12 years to keep global warming in check and prevent a cascade of catastrophic consequences, from devastating droughts and savage storms to rising seas.

Trump’s comments contradict research about the way carbon dioxide and other heat-trapping greenhouse gases behave in the atmosphere. Global temperatures have already risen 1 degree Celsius since the industrial revolution. And scientists broadly agree that greenhouse gas emissions, including those released when oil and coal are burned to generate electricity, are the primary cause of global warming.

“There really is no serious scientific disagreement that if you put massive amounts of greenhouse gas in the atmosphere and you increase concentration, that traps heat,” said Kate Marvel, an associate research scientist at the NASA Goddard Institute for Space Studies. “There really is no dispute on that.”

Trump’s suggestion that the climate will snap back marks an evolution of his views on the issue. He previously told the New York Times in January that “there is a cooling and there is a heating.”

Now, he appears to be confidently forecasting a reversal of climate change.

“I think something’s happening,” Trump told CBS journalist Lesley Stahl. “Something’s changing and it’ll change back again.”

Trump delivered his analysis without offering additional scientific support for his views. White House officials did not respond to emailed requests for comment Monday.

Scientists draw a distinction between big shifts in the world’s climate stretching over millennia and the recent rapid warming trend. According to U.S. National Oceanic and Atmospheric Administration data, there hasn’t been a cooler-than-average year since 1976. Instead, it’s been hotter than average every year -- all 41 of them -- since.

And the Earth keeps setting temperature records -- 2014 was the hottest year for surface temperature, according to NOAA, until 2015, which was even hotter. Then 2016 topped even that. (2017 was the third-hottest year, after 2016 and 2015, NOAA says).

“The odds of that happening by chance are just statistically infinitesimal,” said Noah Diffenbaugh, a professor and senior fellow at Stanford University. “We also know that warming is not consistent with volcanoes or solar cycles or these non-human sources.”

The existence of past cool periods -- including the Ice Age -- aren’t evidence the current warming trend is illusory, scientists say. They help support it. Some of the strongest evidence and understanding of what causes Earth’s climate to change come from studies documenting conditions before humans showed up, Diffenbaugh said.

Ice Age

Andrew Dessler, a climate scientist at Texas A&M University, said it’s unclear what Trump meant in asserting the climate can “go back.”

“Given the scientific community’s view that the warming is driven by greenhouse gases, there’s zero reason to think that climate change will reverse itself,” Dessler said.

In the CBS interview, the president reiterated his view that he’s not willing to risk American jobs or the U.S. economy to confront climate change -- even if “something’s happening.”

“I don’t want to give trillions and trillions of dollars,” Trump said. “I don’t want to lose millions and millions of jobs. I don’t want to be put at a disadvantage.”

That’s in keeping with Trump’s June 2017 decision to pull the U.S. out of the landmark Paris climate accord, based on an argument that living up to the pact’s carbon-cutting commitments would punish America and deal a devastating cost to the economy. Under Trump, federal agencies also are easing a slew of Obama-era regulations designed to cut greenhouse gas emissions from oil wells, automobiles and power plants.

Trump has long questioned climate change, declaring in one November 2012 tweet that the entire “concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive.”

Although Trump told “60 Minutes” that “something’s changing,” he later added: “You don’t know whether or not that would have happened with or without man. You don’t know.”

Michael E. Mann, a scientist at Pennsylvania State University, calls that “one of the standard ‘stages of denial”’ on climate.

“The first stage is ‘it’s not happening,’ The second stage of denial, where Trump is currently located, is ‘it’s not human-caused,”’ Mann said. “In reality, there is an overwhelming scientific consensus that the warming we have seen over the past century can only be explained by human-caused climate change and in particular the burning of fossil fuels, something that Trump’s key supporters and funders profit from directly.”

Trump’s latest assertions dovetail with the careful refrain many of his top officials have adopted on climate change: acknowledging the climate is or may be changing, but questioning how much of it is caused by humans.

The posture, adopted by former EPA Administrator Scott Pruitt, Interior Secretary Ryan Zinke and Energy Secretary Rick Perry, may undercut accusations from environmental groups that they are “climate deniers.” The careful rhetorical formulation also provides room for administration officials to acknowledge climate change without pursuing policies to curb the use of fossil fuels that is driving the phenomenon.

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