When you have solar panels, your electricity gets there for free, no one's figured out how to meter the sun yet. And that's good.

I think that some of it is electoral - helping candidates that are willing to take dramatic actions, not just to say a few words about how climate change might be a problem.

We believe that we live in the 'age of information,' that there has been an information 'explosion,' an information 'revolution.' While in a certain narrow sense this is the case, in many important ways just the opposite is true. We also live at a moment of deep ignorance, when vital knowledge that humans have always possessed about who we are and where we live seems beyond our reach. An Unenlightenment. An age of missing information.

We'd won the argument 15 years before, we were just losing the fight. And so it became clear to some of us that we would need to organise to fight, that we weren't going to win.

A spiritual voice is urgently needed to underline the fact that global warming is already causing human anguish and mortality in our nation and abroad, and much more will occur in the future without rapid action.

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.

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.