We all know the leopard can't change his stripes.

We need to put a price on carbon, and that's what cap-and-trade does and that's also what a CO2 tax does. As long as our current valuation in the marketplace tells us every minute of every day that it's perfectly all right to dump 90 million tons of global warming into the thin atmosphere surrounding the planet every 24 hours as if that atmosphere is an open sewer, then the individual actions are not going to solve the problem.

I want to extend condolences to the families of those who died in the service of the United Nations.

The task of saving the earth's environment must and will become the central organizing principle of the post-Cold War world.

What changed in the United States with Hurricane Katrina was a feeling that we have entered a period of consequences.

If we did not take action to solve this crisis, it could indeed threaten the future of human civilization. That sounds shrill. It sounds hard to accept. I believe it's deadly accurate. But again, we can solve it.

Our democracy, our constitutional framework is really a kind of software for harnessing the creativity and political imagination for all of our people. The American democratic system was an early political version of Napster.