Steyer is an obvious pick for this list, as a retired California hedge fund billionaire focused full time on philanthropic and political giving aimed at moving the needle on climate change. He’s pout up big money for this fight, including some major gifts for the energy research and other grands run through the foundation he started with his wife Kathryn Taylor — the TomKat Charitable Trust.

That said, Steyer isn’t yet in the game of large scale professionalized grant making, and the TomKat is a lean operation. This is a funder who’s been ore focused on big bets .