Anyone who deals with the climate crisis has an internal dialogue between hope and despair, because the challenge is so huge and the danger is so great and the stakes are so high. But I have always resolved that in favour of hope, and actually I'm more hopeful now than I was a decade ago when the solutions were visible on the horizon, but you had to seek reassurance that the technology experts that they're coming, they'll be here.

Here`s my point. I don`t want you to be in a position years from now where you welcome Hillary Clinton and say actually you did win. It just wasn`t close enough to make sure that all the votes were counted or whatever. Elections have consequences. Your vote counts. Your vote has consequences.

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

I have felt for a long time that the pathway to solving the climate crisis is through the building of a massive grassroots army of men and women who will go out there and win the conversation on climate, and persuade businesses, and universities, and towns to switch to renewable energy and to reduce emissions. And the big change from ten years ago is that people are way more receptive, not only to the message that we have to act, not only to the message that now we can act, we have the solutions now - that's the biggest change - but also willing to make a commitment that we will act.

It's a blessing to have work that feels fulfilling.

The golden thread of reason that used to be stretched taut to mark the boundary between the known and the unknown is now routinely disrespected.

The task of saving the earth's environment must and will become the central organizing principle of the post-Cold War world.