American democracy is in grave danger from the changes in the environment in which ideas either live and spread or wither and die.

Local and state governments have outrun the federal government. The EPA has served notice that it will enact a rule requiring CO2 reductions by major emitters in the absence of major legislation. But it's a blunt instrument that is a little more difficult to use than a legislative remedy.

I have absolutely no plans and no expectations of ever being a candidate again.

Of all the works of civilization that interfere with the natural water distribution system, irrigation has been by far the most pervasive and powerful.

The global environment crisis is, as we say in Tennessee, real as rain, and I cannot stand the thought of leaving my children with a degraded earth and a diminished future.

The catastrophe now threatening us is unprecedented - and we often confuse the unprecedented with the improbable.

If the only tool we use to analyse what's valuable is a price tag, then those things that don't have price tags begin to look like they have no value.