There's such a wide variation in tax systems around the world, it's difficult to imagine a harmonized CO2 tax that every country agrees to. That's not in the cards in the near term. But the countries that are doing the best job, like Sweden, are already doing both of these. I think that eventually we'll use both of them but we need to get started right away and the cap-and-trade is a proven and effective tool.

Today we're dumping 70 million tons of global-warming pollution into the environment, and tomorrow we will dump more, and there is no effective worldwide response. Until we start sharply reducing global-warming pollution, I will feel that I have failed.

If the people that believed the moon landing was staged on a movie lot had access to unlimited money from large carbon polluters or some other special interest who wanted to confuse people into thinking that the moon landing didn't take place, I'm sure we'd have a robust debate about it right now.

What's at risk [in 100 years] if we do not take action, truly is the survival of civilization as we know it... Literally that is the case. We have seen global warming so far of just a little bit less than one degree Celsius and look at what's happened. Superstorm Sandy. Boulder Colorado. All these fires. Hurricane Irene one year before.

Having cameras follow you is something that requires a little personal adjustment, but you actually do begin to forget they're there. It's impossible to maintain that awareness all the time, and when you're going through an emotional or absorbing experience, you really don't have any spare attention to think, "Got to remember that the camera is rolling."

The survival of the United States of America as we know it is at risk. And even more — if more should be required — the future of human civilization is at stake.

Consider what kind of car you get. Buy cars and other products that have the least impact environmentally.