“When some of the biggest contributors to climate change and funders of misinformation on climate science sponsor exhibitions in museums of science and natural history, they undermine public confidence in the validity of the institutions responsible for transmitting scientific knowledge,” the letter states. “This corporate philanthropy comes at too high a cost.”

The letter does not mention specific companies, but it does name David H. Koch, who sits on the boards of the American Museum of Natural History in New York and the Smithsonian National Museum of Natural History and has given tens of millions of dollars to those institutions.

Koch Industries is a privately held corporation with subsidiaries in energy and other industries. Mr. Koch and his family have funded conservative causes, including scientists and organizations that contest the role of humans in climate change.