The debate's over. The people who dispute the international consensus on global warming are in the same category now with the people who think the moon landing was staged on a movie lot in Arizona.

In the end, we must restore a balance within ourselves between who we are and what we are doing. Each of us must take a greater personal responsibility for this deteriorating global environment; each of us must take a hard look at the habits of mind and action that reflect - and have led to - this grave crisis.

...the emergent capabilities bursting forth from the revolutionary advances in the life sciences are about to make us the principal agent of evolution.

We've seen the bankruptcy of many newspapers. We've seen a further erosion of the line between news and entertainment. But I do believe that there is reason to hope that over time we will see the higher-quality journalism rise to the surface.

I think I may have a future as a disembodied head.

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.

Remember that the problem is bigger than the car you drive or the types of lightbulbs in city hall. We need a fundamental shift away from dirty fossil fuels that spew carbon pollution. To make that happen, we need to put pressure on our leaders to take the bold actions necessary to move us off dirty sources of energy.