Tuesday's surprising ruling raises the stakes of this year's election.

Helped along by both President Obama and Bernie Sanders, Clinton has broken her silence on fossil fuel extraction from public lands.

His positions are different in kind, and more extreme, than those of recent Republican nominees, but have received no scrutiny. Maybe that will change in Saturday's debate.

It wasn't the Green Party.

Hillary Clinton keeps adopting his positions, but not this one.

In an interview with the New Republic, the former Maryland governor takes the Democratic frontrunner to task on climate change.

Where does the green energy from your panels really go?

How a prominent leak like Aliso Canyon could get the EPA to clean up bigger leaks all over the U.S.

Scott Slater wants to pump billions of gallons to LA and other drought-hit cities—and make $2.4 billion in the process.

A moratorium on coal leases is another notch in his legacy. But it will be up to Hillary Clinton or Bernie Sanders to navigate the fallout.

This video shows seven years of global warming proposals—and how he did on each one.