One degree turns out to be enough to really unhinge all sorts of earth's ecosystems.

We don't know exactly where all the tipping points are in the physical world for inescapable damage, but we're clearly reaching close to some of them.

Global warming is no longer a philosophical threat, no longer a future threat, no longer a threat at all. It's our reality.

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

Probably nothing that we have ever managed to do quite equals the basic undermining of the physical stability of the planet on which most of the world's poor people depend.

Especially in recent years, the more and more we understand what we are doing, the more we have the science to tell us what we're doing, the fact that we continue to do it without taking steps to address it strikes me as, among many other things, irreverent in an extreme.

In the States we've had by far the largest demonstrations in the last few years. The largest civil disobedience actions about anything in US history in the last 30 years have all been centred around the climate.