In the end, climate change is a math problem.

I try not to be either optimistic or pessimistic. I try not to think about outcomes on that scale. My job, it seems to me, is to wake up every morning and figure out how to cause as much trouble for the fossil fuel industry as I can.

There is a tendency at every important but difficult crossroad to pretend that it's not really there.

We're mathematically past the point where the accumulation of individual actions can add up quickly enough to make a difference. The individual action that actually matters is not being an individual. It's joining together with other people in groups large enough to change the political dynamic around climate change.

In the scientific community, the debate is over, for all intents and purposes, about whether or not the planet is heating and who is causing it. In fact, it's more or less been over since 1995.

Certainly, packets of sea ice, in say the Arctic, which have failed to fully reform in the last couple of years.

If you consider that there are a million people forced out of their homes by Katrina, multiply that by 150, and then stick those people in countries who, as inconceivable as it seems, are less prepared than we were to deal with the whole thing.