Conservative billionaire, philanthropist and oil mogul David H. Koch stepped down from the board of New York's American Natural History Museum in December. He has given millions of dollars to the museum, and the famed dinosaur wing was named after him. His position on the board has also drummed up controversy, drawing the ire of climate scientists and activists who cite the conflict of Koch's oil interests and the representation of climate science at the museum.

Koch gave about $23 million to the museum over many years. He served on the board for 23 years.

A museum spokesperson said Koch simply did not renew his seat on the board. The New York Times reported that Koch's spokeswoman cited a lack of time as a factor since Koch serves on about 20 boards and was not able to attend all meetings. Koch, 75, will devote more time to cancer research, she said.

Koch's departure is seen as "a victory for the scientists, climate activists, and museum professionals who have been calling for museums to break ties with Koch and other fossil fuel interests," said Beka Economopoulos, Director, The Natural History Museum, which describes itself as a "new, mobile and pop-up museum that highlights the socio-political forces that shape nature, yet are excluded from traditional natural history museums."

Economopoulos says a letter initiated by her group last spring, and signed by dozens of the world’s top scientists, urged science and natural history museums to cut all ties to fossil fuels. It picked up momentum and she says the result was "more than 550,000 people signed a petition urging the American Museum of Natural History to kick David Koch off its board."

Koch serves as Advisory Board member of the Smithsonian National Museum of Natural History.