Nearly three hundred scientists have endorsed a letter pressuring the American Museum of Natural History in New York to sever ties with board member Rebekah Mercer, a billionaire who has helped fund climate-change denial organizations. Mercer, a benefactor of Breitbart and a significant patron of Donald Trump’s presidential campaign, has been one of the board’s forty-one members since 2013.

Between 2008 and 2016, the Mercer Family Foundation gave $5.9 million to the Heartland Institute, a conservative think tank that has continually promoted forums for climate-change skeptics. This amount is nearly two million dollars more than the Mercers’ total donations to the American Museum of Natural History in the same time frame. The foundation also gave sizable grants to the CO2 Coalition and the Center for the Study of Carbon Dioxide, organizations that uphold the belief that increased carbon dioxide is beneficial to the environment, a stance contradicted by an international scientific consensus.

“The most important asset any museum has is its credibility. This can be damaged by ties to donors and board members who are publicly known for investing in climate science obfuscation and opposing environmental solutions,” said the letter. In addition to the two hundred scientists and academics who released the letter last night, twenty-eight tenured curators within the American Museum of Natural History have also protested Mercer’s connection to the museum, reports the New York Times.