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Alarmed that a Smithsonian Museum exhibit funded by oil-rich billionaire David Koch severely downplays climate change, top scientists are demanding natural history museums cut all ties to the fossil fuel industry.

Dozens of the world's leading scientists released an open letter Tuesday asking museums to stop accepting donations from oil companies or climate change deniers, and to kick Koch off the Board of Directors at the Smithsonian's National Museum of Natural History and the American Museum of Natural History in New York City.

"We are concerned that the integrity of these institutions is compromised by association with special interests who obfuscate climate science, fight environmental regulation, oppose clean energy regulation, and seek to ease limits on industrial pollution," the letter reads.

The letter notes that Koch Industries is one of the "largest contributors to greenhouse gas emissions" and that Koch has spent more than $67 million funding groups denying climate change science.

The Smithsonian's Hall of Human Origins, with a $15 million grant from Koch, currently misrepresents climate change, and news of the exhibit's funding showed that the concerns are "not just hypothetical," former museum president James Powell told VICE News.

"Science museums shouldn't have on their boards people who are actively funding the denial of science," Powell, one of the letter's signatories who formerly ran the Franklin Museum of Science and the Los Angeles County Natural History Museum, told VICE News. "It's a contradiction."

Eric Chivian, a psychologist and Nobel Peace Prize-winner, signed the letter and says the Smithsonian exhibit is an example of the dangers of allowing the fossil fuel industry to contribute to natural history museums. The exhibit did not mention humans' greenhouse gas emissions or the fact that the Earth's temperature had remained relatively stable until recently, he noted in a press statement.

"It should not be acceptable for the National Museum of Natural History and the American Museum of Natural History, anymore than it would be if a major tobacco company offered to fund an exhibit for them devoted to lung diseases, to accept any funding from the Koch brothers," Chivian, Director of the Center for Health and the Global Environment at Harvard Medical School, said, "or for that matter, from any fossil fuel company for an exhibit that has any connection to climate change whatsoever."

He added: "This is especially the case with the Smithsonian, our national museum that belongs to all of us."

And Michael Mann, another signatory who serves as Director of the Earth System Science Center for Pennsylvania State University, told VICE News the museum support by climate change deniers was "villainous."

"In my view there is a difference between true philanthropy — the selfless support of the arts and education for it's own sake — and the efforts by modern-day robber barons to ingratiate themselves with opinion leaders and the public by throwing money at science-themed institutions," Mann told VICE News, "while secretly funding efforts to undermine the public's faith in science they find inconvenient."

'The Koch brothers have been known to be the enemy of science and the enemy of the environment — and those are the two things the American Museum of Natural History stands for.'

Museums are obliged to "in all their activities foster an informed appreciation of the rich and diverse world we have inherited," the Code of Ethics for Museums delineates — but the misleading information undermines that purpose, the letter claims.

The scientists also formed a petition to "Kick Koch off the Board." By Tuesday afternoon it had already nearly 16,000 signatures.

"The Koch brothers have been known to be the enemy of science and the enemy of the environment — and those are the two things the American Museum of Natural History stands for," Mark Dion, an artist and critic who has spoken at the museum, told VICE News.

Koch's public relations office at Koch Industries did not return requests for comment, nor did the public relations offices for the Smithsonian or the American Museum for Natural History.

In a statement, however, the museum said donors have "no influence" on Smithsonian exhibitions, adding "Smithsonian's official statement on climate change, based upon many decades of scientific research, points to human activities as a cause of global warming."

Raising enough funds for museums can be tricky, Dion and others conceded — but Mann predicted that science museums would actually see a flood of financial support from other benefactors, including "ordinary individuals," if the institutions were to "publicly distance themselves from the forces of anti science."

"We simply cannot allow folks like the Koch Brothers to undermine efforts to preserve the habitability of the planet while greenwashing their public image, facilitated by museums that take their money," Mann said. "The stakes — the planet we leave behind for our children and grandchildren — are simply too high."