I'm guessing the most efficient way would be to transfer an awful lot of technology, but also direct aid to deal with climate emergencies already underway. Hillary [Clinton] has already said $100 billion a year would be appropriate.

All the things that we've done as a species have had a limited scope. We're talking about melting the ice caps, raising the level of the seas dramatically, changing the distribution of every other species on Earth, perhaps wiping out one-third or half of them. The changes at work are geologic in scale. The level of change required to deal with it is enormous, too. It will require change in every country. It will require a degree of global cooperation that we haven't seen before.

We've built a new Earth. It's not as nice as the old one; it's the greatest mistake humans have ever made, one that we will pay for literally forever.

[Political actions] has to happen on the local and state level; we have to convince our cities to join the growing number of more than 200 American cities who have signed on to the mayor's climate campaign.

We'd like to get the fossil fuel industry on the back foot for a while, having to deal with us.

There's no huge mystery. If you dig up huge amounts of carbon, huge amounts of ancient biology, hundreds of millions of year's worth of ancient biology, and flush it into the atmosphere in a matter of decades, then it stands to reason that we're going to have enormous effects, and now we can see those effects all around us.

The latest computer modeling I've seen indicates that at mid-century, there might be 150 million people classified as "environmental refugees."