Thirty prominent climate scientists sent a letter to Environmental Protection Agency Administrator Scott Pruitt on Monday, refuting his recent false statement that carbon dioxide is not a primary driver of climate change.
"Just as there is no escaping gravity when one steps off a cliff, there is no escaping the warming that follows when we add extra carbon dioxide and other greenhouse gases to the atmosphere," the scientists wrote. The group included Nobel laureate chemist Mario Molina of the University of California, San Diego, and eight members of the National Academies of Science.
The EPA did not immediately respond to a request for comment on the letter.
It joined the avalanche of response to Pruitt's statement last week in an interview on CNBC that he did not agree carbon dioxide was the primary contributor to global warming, a statement contrary to the overwhelming scientific consensus.
Phone calls to Pruitt's main line reached such a high volume the following day that officials created an impromptu call center, the Washington Post reported. By Saturday morning, calls were going straight to voice mail, which said it was full and would not accept messages.
In addition to the letter by the climate scientists, the American Meteorological Society (AMS) forwarded a letter to Pruitt that contained its official statement on climate change and carbon dioxide's role in the rapid change of the past half-century. That conclusion is "based on multiple independent lines of evidence that have been affirmed by thousands of independent scientists and numerous scientific institutions around the world," wrote AMS executive director Keith Seitter. "We are not familiar with any scientific institution with relevant subject matter expertise that has reached a different conclusion."
The American Geophysical Society last week posted on its website a response to Pruitt's statement, noting that its own statement on global warming "leaves no doubt that increasing atmospheric concentrations of carbon dioxide resulting from human activity is the dominant source of climate change during the last several decades."
Michael Oppenheimer, an atmospheric scientist at Princeton University who was one of the signers of the scientists' letter, said that he and his colleagues began contemplating an official response to Pruitt soon after his statement.
"I have no idea how he made this error, whether it's intentional spinning of the facts, or, as I prefer to think, he really doesn't know," Oppenheimer said. " We and any number of climate scientists would be perfectly happy to brief him about what's known and what isn't known and what the uncertainties really are."
Pruitt made clear in his CNBC interview, as he did in his confirmation hearing, that he thought the uncertainties were great enough to forestall policy.
"I think that measuring with precision human activity on the climate is something very challenging to do and there's tremendous disagreement about the degree of impact," Pruitt said. The doubts he expressed went further than in his testimony before Congress, however, as he said of carbon dioxide, "No, I would not agree that it's a primary contributor to the global warming that we see."
The scientists said Pruitt was misrepresenting how much scientists do know. "Focusing on disagreements over details, or among a few individuals on the margins of consensus, or on the uncertainties that are part of any accurate statement of scientific knowledge, misses the big picture: Human beings are changing the Earth's climate," they wrote.