“Even those who are not ideological believers are taking the cues from the financial markets, which have no interest in oil production growth anymore,” Arnold said. The former trader also said capital available to oil and gas has dried up while “every” private equity firm in Houston is raising money for clean energy. “The markets are rewarding those in a growth industry (zero carbon energy) vs one in secular decline.”

Arnold, who closed his hedge fund in 2012 at age 38 to pursue philanthropy, said the shift has made him more optimistic about the speed of decarbonization, which requires the scale and financial resources that large companies possess. “The fossil fuel industry has that expertise and is now focusing on a low carbon future.”