Michael Bloomberg tackles climate change instead of 2020 presidency

What's next: Bloomberg didn't offer details beyond calling it a "grassroots effort to begin moving America as quickly as possible away from oil and gas and toward a 100 percent clean energy economy."

• His aides declined to provide more, though a spokesperson told Axios that the Sierra Club will "remain an important partner along with others."

Quick take: On its face, this is a more complicated undertaking. While "Beyond Coal" has helped to retire coal plants, that advocacy effort basically swims with the current.

• That's because cheap natural gas, the rise of renewables, regulations and other forces have all been shoving coal aside in power markets.

But, but, but: The oil-and-gas industry is bigger than coal and has deeper pockets. And trying to get "beyond" those fuels is trickier.

• Take oil in transportation, for example. Electric vehicles are a tiny (though fast-growing) fraction of the car market, and it's even harder to wring oil from other forms of transportation, like heavy trucking, shipping, planes.

I'll be curious to see this campaign unfold.