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.

The presidency is more than a popularity contest.

Airplane travel is nature's way of making you look like your passport photo.

The will to act is a renewable resource.

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.

America's political system has evolved over the last 50 years in ways that have enhanced the power of business lobbies.

The wind and the sun are free.