The oil billionaire David Koch has stepped down from the board at the American Museum of Natural History, after 23 years and more than $20m in donations to the New York museum.
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The conservative magnate’s departure from one of the US’s preeminent science museums was cheered by climate scientists and activists who have campaigned for the museum to cut ties with fossil fuel companies and those who head them.
A spokesperson for the museum, Roberto Lebron, told the Guardian that Koch’s term on the board ended on 9 December, at the trustees’ annual meeting.
“This change was one of several that took effect at the meeting as part of the normal course of business,” Lebron said.
Cristyne Nicholas, a spokeswoman for Koch, said the billionaire was “honored to have served on the board” and to have helped make possible the museum’s dinosaur halls, which bear his name . She added that Koch plans to prioritize contributions to cancer research, and noted some $250m in donations to New York hospitals.
Elsewhere, Nicholas denied that Koch was at all moved by calls for his resignation.
Activists and some scientists nonetheless hailed a victory for their cause, which won national attention last year when dozens of scientists signed an open letter that singled out Koch. The scientists – including climatologist James Hansen , ecologist George Woodwell, and three Nobel laureates – called for science institutions to sever relations with fossil-fuel interests.
“I think his name is still associated with the dinosaur hall, which with his political opinions is in some ways appropriate,” said Judith Weis, a signatory and marine biologist at Rutgers University.
“This is one little chink out” of the divestment campaign, Weis said. “There’s a lot more still going on, a lot more museums.”
Beka Economopoulos, a campaign organizer and director of the mobile and politically minded Natural History Museum , said: “Regardless of the reason for his decision, it’s a step in the right direction.”
“We think the letter provoked some sector-wide soul searching, so we’re kind of happy that the American Museum of Natural History no longer has this figure there.”
Citing a petition that has received more than 200,000 signatures, Economopoulos added: “I’m not attributing the decision to [activists], but I think it’s safe to say he stepped down in the context of a lot of public pressure.”
A 2013 Drexel University study found that Charles and David Koch, along with ExxonMobil and a network of donor foundations, poured hundreds of millions into efforts to deny the reality of climate change, which the overwhelming majority of American and international scientists agreethreatens life around the planet .
The brothers also back a conservative group that recently declared its only climate change “ hero ” to be senator Ted Cruz of Texas, an opponent of environmental regulation who recently asked whether climate science was based on “ data or dogma ”.
Related: US museums asked to sever ties with fossil fuel industry
The Kochs’ conservative contributions, including $122m for Republican campaigns in the 2012 election and an $889m budget for 2016, have largely overshadowed their support for reforming immigration and the criminal justice system .
David Koch remains on the advisory board of the Smithsonian National Museum of Natural History, where his name adorns the Hall of Human Origins .
In response to scientists’ calls to cut ties with its rightwing donor last year, the Smithsonian released a statement that said: “Donors and supporters have no influence on the content or presentation of Smithsonian exhibitions, regardless of their private interests.”
The institution also repeated its official statement on climate change, that says “many decades of scientific research [point] to human activities as a cause of global warming”.
Koch is also a major funder for the Metropolitan Museum of Art, where his donations have occasionally provoked protests .