But tolerance by itself can be a cover for moral laziness.

There's no happy ending where we prevent climate change any more. Now the question is, is it going to be a miserable century or an impossible one, and what comes after that.

Absent the net, we certainly couldn't have organized in 190 countries around the world. It's no substitution for face to face interaction - that's why we have "days of action" where people are in real contact with each other - but it's the cheap (and low-carbon) way to do an awful lot of the planning and organizing. And we can build, for $20k, a website as good as one Exxon can build for $20 million.

The polling data shows not an unbelievable level of concern [on climate issue] but a general awareness of this problem. And now I think it's up to all sorts of people who really care about these things to continue on this new ground to try and make this the central political issue it needs to be.

The fight around climate change, which I've spent my life on, is somewhat more difficult than gay marriages because no one makes trillions of dollars a year being a bigot, and that's how much the fossil-fuel industry pulls in pumping carbon into the air. But the principle is the same, I think.

I'm probably the wrong person to ask. My partner in much of this work [climate movement], who really came up with the divestment campaign with me, Naomi Klein, I think has written powerfully about this.

But the truth is that we could win every other fight that we face and if we lose the climate fight, the other victories will be pyrrhic. I don't think even people who are worried about climate change quite understand the scale and speed with which we're now shifting the planet.