The wind and the sun are free.

I am a passionate advocate of getting special interest money out of politics.

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.

I think the cost of energy will come down when we make this transition to renewable energy.

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.

The moral imperative to make big changes is inescapable...that what we take for granted may not be here for our children

The answer is to end our reliance on carbon-based fuels... If we succeed, we create booming new industries, wealth, clean secure energy and maybe we prevent the greatest disaster so far in human history, saving millions of lives while improving billions more. If we fail, basically it's business as usual while things slowly get worse all around us.