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 had a detailed plan for my life, but it turned out life had a completely different plan for me. And I feel joy that I have work that feels like it justifies pouring everything I have into it. I never have fallen prey to the illusion that there's any job with as much ability to influence the future as that of President of the United States, but I do feel grateful that I found other ways to do work that serves the public interest.

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

Many of the green places and open spaces that need protecting most today are in our own neighborhoods. In too many places, the beauty of local vistas has been degraded by decades of ill-planned and ill-coordinated development.

For me, the most serious problem is how America became so vulnerable to the assertion of blatant falsehoods that drive policy and are not corrected by the so-called immune system of democracy, a free press and a free democratic discourse.

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.

While President Bush likes to project an image of strength and courage, the real truth is that in the presence of his large financial contributors, he is a moral coward.