Most people in politics draw energy from backslapping and shaking hands and all that. I draw energy from discussing ideas.

One tragic example of the loss of forests and then water is found in Ethiopia. The amount of its forested land has decreased from 40 to 1 percent in the last four decades. Concurrently, the amount of rainfall has declined to the point where the country is rapidly becoming a wasteland.

The Founders of the U.S. gave the senators a term of office three times longer than that of a representative precisely to encourage a reflective frame of mind, a distance from the passions of the voters, and a capacity for deliberative consideration.

The cumulative amount of man-made global pollution that's in the atmosphere now traps as much extra heat energy every day as would be released by 400,000 Hiroshima-class atomic bombs exploding every day. It's a big planet, but that's an awful lot of energy.

As important as it is to change the light bulbs, its more important to change the laws

Humanity is sitting on a time bomb. If the vast majority of the world's scientists are right, we have just ten years to avert a major catastrophe that could send our entire planet's climate system into a tail-spin of epic destruction involving extreme weather, floods, droughts, epidemics and killer heat waves beyond anything we have ever experienced - a catastrophe of our own making.

I don't have the illusion that there's any position or role in the world with as much potential for bringing about change as that of president of the United States.