It's much to the credit of the rest of the world that they have gone ahead and tried to do the Kyoto accords on their own. It makes it unbelievably difficult to do that, for a variety of economic and regulatory reasons, without the participation of the biggest energy user in the world.

There's always the danger that people will simply sign online petitions, the way they used to just mail in checks, and there's the greater possibility we'll just spend our whole lives staring at screens and never get anything done.

Without a movement pressing for change, there's little hope. We've got to work the political system to make this happen fast. The physics and chemistry are daunting. The resources on the other side are very large.

At the moment, the 4 percent of us in this country produce a quarter of the world's carbon dioxide - once you look at maps of rising sea levels and spreading mosquitoes, you realize that we've probably never figured out a way to hate our neighbors around the world much more effectively.

When we think about global warming at all, the arguments tend to be ideological, theological and economic.

[Political actions] has to happen on the local and state level; we have to convince our cities to join the growing number of more than 200 American cities who have signed on to the mayor's climate campaign.

If you look at the polling data, long before anyone had thought about Iraq, it was the [George W.] Bush Administration's decision in the first few weeks in its tenure in office to abnegate the Kyoto treaties that set our international perception into a nose-dive. People around the world looked on in amazement as the biggest part of the problem decided it wasn't going to make any effort to help with the solution.