The insistence on complete certainty about the full details of global warming-the most serious threat we have ever faced-is actually an effort to avoid facing the awful, uncomfortable truth: that we must act boldly, decisively, comprehensively, and quickly, even before we know every last detail about the crisis. Those who continue to argue that the appropriate response is merely additional research are simply seeking to camouflage timidity or protect their vested interest in the status quo.

Fake news has been around as long as news has been around.

George Orwell once wrote that a false belief sooner or later collides with physical reality, usually on a battlefield.

The physical relationship between CO2 molecules and the atmosphere and the trapping of heat is as well-established as gravity, for God's sakes. It's not some mystery.

You can push your local communities to adopt more sustainable sources of energy and environmentally-friendly practices.

A lot of people go straight from denial to despair without pausing in the middle and doing something about it.

I flew on Air Force Two for eight years, and now I have to take off my shoes to get on an aeroplane.