Delhi is locked in a complete choking smog at the moment - they've had to close schools in one of the world's biggest cities. They have their own reasons for needing to get off fossil fuels fast.

We've been given a warning by science, and a wake-up call by nature; it is up to us now to heed them.

In the United States, cheap fossil fuel has eroded communities. We're the first people with no real practical need for each other. Everything comes from a great distance through anonymous and invisible transactions. We've taken that to be a virtue, but it's as much a curse. Americans are not very satisfied with their lives, and the loss of community is part of that.

I've spent my life living in rural America, some of it in blue state Vermont, some of it in red state upstate New York. They're quite alike in many ways. And quite wonderful. It's important that even in an urbanized and suburbanized country, we continue to take rural America seriously. And the thing that makes Vermont in particular so special, and I hope this book captures some of it, is the basic underlying civility of its political life. That's rooted in the town meeting. Each of the towns in Vermont governs itself.

We've lost half the summer sea ice in the Arctic. We've wiped out an enormous percentage of the world's coral reefs. We see huge changes in the planet's hydrology already, the cycles of drought and flood both amped up because warm air holds more water vapor than cold. These things are happening with a one-degree increase and going to two degrees won't be twice as bad, the increase in damage won't be linear, it most certainly will be exponential. So it was precisely the wrong moment to elect Trump.

We're going to need that kind of movement, because the fossil fuel industry is a sprawling adversary - at work everywhere, its tentacles in everybody's politics, invulnerable, I think, to direct frontal assault, but probably more brittle than it guesses if we come at it from all sides.

Scientists are telling us that 350 parts per million [of carbon] in the atmosphere is the upper limit. We're at 387 parts per million now, and we're up in that zone where the risk of going past irrevocable tipping points is elevated. It's no different than going to a doctor and learning your cholesterol is too high, and you're at risk for a heart attack. You have to work to lower your cholesterol and hope to get there before the heart attack comes.