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.

California's biggest contributor to climate change is a rupture at an Aliso Canyon well.

After the Cold War, Cuba faced many of the agricultural challenges that the rest of the world is now anticipating.

So think twice before chucking them in the blue bin.

Tough policies are the ones that would truly change commuter habits, but we're barely seeing them.