Sometimes, I, anyway, get tired of playing defence, and like to play offence.

In reality, climate change is actually the biggest thing thats going on every single day.

There's no happy ending where we prevent climate change any more. Now the question is, is it going to be a miserable century or an impossible one, and what comes after that.

It's off the charts - and if you don't believe the scientists, ask the insurance industry, the people we pay to analyze risk in our society.

The latest computer modeling I've seen indicates that at mid-century, there might be 150 million people classified as "environmental refugees."

I don't spend a huge amount of time fixated on climate denial because I don't think that their objections, though sometimes couched in science, are based in science. I think they're based in ideology. And I don't think there's anything you can do.

In the scientific community, the debate is over, for all intents and purposes, about whether or not the planet is heating and who is causing it. In fact, it's more or less been over since 1995.