The only way major change in environmental policy is going to happen, the only way, is if there is a very strong, very active popular movement that demands it and such a movement would be unparalleled because it would be a popular movement that says, "Raise our taxes so that we change our behavior."

The idea that we would raise billions of sentient animals, treat them horribly, pollute our waterways with their waste, compromise the effectiveness of our antibiotics so that they grow faster, and then slaughter them with little regard to their suffering so that we can feed off their corpses, will seem to most people unthinkably cruel and barbarous - sort of in the way that we think of medieval punishments, or Europeans today think of the death penalty.

Climate change involves fundamental choices about how we want to live and what kind of world we want.

Climate scientists think of nothing but climate and then express their concerns in terms of constructs such as global mean surface temperature. But we live in a world in which all sorts of change is happening all the time, and the only way to understand what climate change will bring is to tell stories about how it manifests in people's lives.

Moral revolutions are typically seen retrospectively. Prospectively, the revolutionaries tend to look like crazy people, and sometimes they are.

If you look globally you see a patchwork of jurisdictions (nations, states, provinces, cities) that have taken aggressive action on climate change, and a patchwork of jurisdictions that have not. These various policies reflect the politics of each jurisdiction and the values of its citizens.

People and countries have done an enormous amount of damage in their attempts to bring about the best possible world. Communism is an obvious example. But so is British imperialism, which was not grubby self-interest all the way down, but at least in part a sincere attempt on the part of people who felt they were superior to other people to magnanimously improve the lot of their inferiors.