Delhi is locked in a complete choking smog at the moment - they've had to close schools in one of the world's biggest cities. They have their own reasons for needing to get off fossil fuels fast.

If you look at the polling data, long before anyone had thought about Iraq, it was the [George W.] Bush Administration's decision in the first few weeks in its tenure in office to abnegate the Kyoto treaties that set our international perception into a nose-dive. People around the world looked on in amazement as the biggest part of the problem decided it wasn't going to make any effort to help with the solution.

If Apple is enslaving Chinese to make its iPhones, you don't need to eat the i-Phone, you need to make sure that Apple is paying a living wage to someone, and then it adds a dollar to the cost of iphones, and everybody's cool.

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.

If one wanted to stigmaitise, that's how one would do it - lots and lots of people saying "we're severing our ties".

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.

The Arctic and the Antarctic are melting quickly. We may have waited too long to get started. But this is a day for optimism because the battle is fully joined, and the idea that big oil is unbeatable is no longer true.