“He deployed his stupendous fortune funding climate denial in the years when the science was clear and there was still time to avert catastrophic warming. He died as fires raged from the Amazon to the Arctic.”

David Koch, billionaire industrialist and powerful right-wing political activist, died early on Friday. David and his brother Charles are most famous for sponsoring climate change denialism, having funded a vast political network to spread doubt about climate science.

The brothers transformed the oil business they inherited from their father into an industrial empire. Each of the Kochs is estimated to be worth over $50 billion dollars.

David was the more social of the two brothers and was a generous donor to the arts and medical causes.

The Kochs have been fighting climate change legislation since at least 1991, when President George H.W. Bush announced his support for a treaty limiting carbon emissions. As the New Yorker’s Jane Mayer wrote, Republicans at the time largely accepted the scientific consensus from expert groups such as the Intergovernmental Panel on Climate Change.

As Mayer writes, the Koch’s multi-billion dollar lobbying machine “worked to hijack the Tea Party movement and, eventually, the Republican Party itself.”

The Kochs’ political activism has been influenced both by their hardline, anti-government ideology, as well as self-interest in enriching their fossil fuel-based profits.

“You’d have a carbon tax, or something better, today, if not for the Kochs,” Kert Davies, director of the Climate Investigation Center, told Mayer. “They stopped anything from happening back when there was still time.”

Mayer, the investigative journalist who wrote Dark Money, an account of the Koch brothers’ wide-ranging efforts to transform the American political system, described how David’s departure from the family industry last year would have minimal effect on Charles’ influence:

“Charles and David Koch, who came to be known as ‘the Koch brothers,’ were equals in bloodlines and in wealth, but Charles has always been the brains behind the brothers’ vast corporate and political operations,” wrote Mayer last year. “Those who know the brothers predict that David’s retirement will have scant impact, particularly in the political realm, where the Kochs exert enormous influence.”

Although David’s health had been deteriorating, Mayer wrote that Charles forced his brother out of the business despite David’s protests. “Only when Charles goes will everything change,” a Koch business associate told Mayer.

David and Charles’ two other brothers, Frederick and Bill, were involved with Koch Industries until suing the two more well-known brothers for allegedly cheating them out of $1 billion dollars in 1998.

As the Associated Press reported, the Koch’s father foresaw the potential of his family’s vast fortune to tear it apart.

“It will be yours to do with what you will,” Fred Koch wrote in a 1936 letter to his two oldest sons. “It may be either a blessing or a curse.”

While some have used David’s passing to focus on his donations to cancer research and art, critics believe his role as one of the primary sponsors of climate denialism will define his legacy.

Alexander Kaufman, an environmental writer at HuffPost, tweeted: “He deployed his stupendous fortune funding climate denial in the years when the science was clear and there was still time to avert catastrophic warming. He died as fires raged from the Amazon to the Arctic.”

“Today, many are talking about David Koch’s legacy,” tweeted The Sunrise Movement. “The #KochBrothers spent billions blocking congressional action on climate change & spreading false science. @KochIndustries continues to dump carcinogenic pollution into our air & water. His legacy is actively harming the living.”