Bill Gates is a relative newcomer to the fight against global warming, but he's already shifting the debate over climate change.

So if you want to know how Exxon Mobil can make $10 billion profit in 90 days, just look around. The whole world was built for them.

Americans don't pay much attention to environmental issues, because they aren't sexy. I mean, cleaning up coal plants and reining in outlaw frackers is hugely important work, but it doesn't get anybody's pulse racing.

Extracting oil from the tar sands is a nasty, polluting, energy-intensive business.

When it comes to climate and energy, Gates is a radical consumerist. In his view, energy consumption is good - it just needs to be clean energy.

Mark Ruffalo, aka the Incredible Hulk, is the natural gas industry's worst nightmare: a serious, committed activist who is determined to use his star power as a superhero in the hottest movie of the moment to draw attention the environmental and public health risks of fracking.

Nowhere has the political power of coal been more obvious than in presidential campaigns.