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.

There's such a wide variation in tax systems around the world, it's difficult to imagine a harmonized CO2 tax that every country agrees to. That's not in the cards in the near term. But the countries that are doing the best job, like Sweden, are already doing both of these. I think that eventually we'll use both of them but we need to get started right away and the cap-and-trade is a proven and effective tool.

Earlier in this century, the Heisenberg Principle established that the very act of observing a natural phenomenon can change what is being observed. Although the initial theory was limited in practice to special cases in subatomic physics, the philosophical implications were and are staggering.

Our way of life is at stake, our grandchildren are at stake, the future of civilization is at stake.

The choice to 'do nothing' in response to the mounting evidence is actually a choice to continue and even accelerate the reckless environmental destruction that is creating the catastrophe at hand.

And just as the false assumption that we are not connected to the earth has led to the ecological crisis, so to the equally false assumption that we arenot connected to each other that has led to our social crisis.

There's no such thing as clean coal. It's non-existent. Theoretically, it might be possible, many years from now, to come up with a way to clean it as it's burnt. But there's not a single demonstration project in the United States. [...] Clean coal doesn't exist.