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This story was updated on March 7 to include a statement from Richard Lindzen.

Richard Lindzen, an outspoken climate contrarian and retired Massachusetts Institute of Technology professor, sent a letter last month to President Donald Trump urging him to pull the United States out of the United Nations' climate change regime because global climate action is "not scientifically justified."

After MIT's climate researchers and faculty found out, they wrote their own open letter to the president, setting the record straight.

"As [Lindzen's] colleagues at MIT in the Program in Atmospheres, Oceans and Climate, all of whom are actively involved in understanding climate, we write to make it clear that this is not a view shared by us, or by the overwhelming majority of other scientists who have devoted their professional lives to careful study of climate science," said the March 2 letter, signed by 22 current and retired MIT professors.

The MIT staff addressed specific inaccuracies in Lindzen's letter, including his assertion that "carbon dioxide is not a pollutant."

"The risks to the Earth system associated with increasing levels of carbon dioxide are almost universally agreed by climate scientists to be real ones," they wrote. "These include, but are not limited to, sea level rise, ocean acidification, and increases in extreme flooding and droughts, all with serious consequences for mankind."

Richard Lindzen testifies at a House Science Committee hearing on global climate change on Nov 17, 2010. Credit: CSPAN

Lindzen has spent years downplaying the significance of man-made climate change through his published research, testimony in lawsuits and appearances before Congress. He has compared "global warming believers" to a "cult," and called the most recent assessment by the Intergovernmental Panel on Climate Change, the world's leading climate science body, "a political document." He served as a meteorology professor from 1983 to 2013. He is now a distinguished senior fellow at the Cato Institute, a Washington, D.C.-based conservative think tank.

Lindzen responded to InsideClimate News with a one-page statement that echoed the contrarian points he made in his letter. He also criticized MIT's climate program.

"Since MIT's administration has made the climate issue a major focus for the Institute with the Program in Atmospheres, Oceans, and Climate (PAOC) playing a central role, it is not surprising that the department would object to any de-emphasis of this issue," Lindzen wrote. "For far too long, one body of men, establishment climate scientists, has been permitted to be judges and parties on what the 'risks to the Earth system associated with increasing levels of carbon dioxide' really are," he said, referencing something James Madison wrote in 1787.

A petition accompanying Lindzen's letter was signed by 300 other people. Lindzen described the signatories as "eminent scientists and other qualified individuals" in his letter. A review of the names by the Guardian, however, revealed few biology, chemistry, climate, earth and physics scientists. Many are well-known climate contrarians and deniers. They include Willie Soon, an aerospace engineer at the Harvard-Smithsonian Center for Astrophysics; Steve Goreham of the Heartland Institute, an industry backed organization that denies climate science; and William Briggs, a statistician at Cornell University who questions climate models.

"In stark contrast to Lindzen's letter, ours was signed only by those who know something about the climate system," said Kerry Emanuel, an MIT professor of atmospheric sciences who signed the letter opposing Lindzen.

The science advocacy group the Union of Concerned Scientist also annotated the letter to point out its errors.

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The MIT letter noted that professional societies including the American Meteorological Society and the American Geophysical Union have all released statements affirming the scientific consensus on man-made climate change and its grave risks. A recent analysis found that 140 of the world's national academies and top scientific geosciences, biological, chemical, physical, agricultural and other organizations have issued statements about human-caused warming.

"We owe it to future generations to remain engaged with the international community to seek the widest possible efforts to understand and mitigate [climate change] threats," the letter said.