This [climate change] is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one?

Climate change is a result of the greatest market failure the world has seen...We risk damages on a scale larger than the two world wars of the last century.

How is it that, in the face of overwhelming scientific evidence, there are still some who would deny the dangers of climate change? Not surprisingly, the loudest voices are not scientific, and it is remarkable how many economists, lawyers, journalists and politicians set themselves up as experts on the science.

There is still time to avoid the worst impacts of climate change, if we take strong action now.

A diet that relies heavily on meat production results in higher emissions than a typical vegetarian diet. Different individuals will make different choices. However, the debate about climate change should not be dumbed down to a single slogan, such as 'give up meat to save the planet.

My father's generation's crisis was fighting fascism. Ours is fighting climate change. It is much harder because you can't see it, it is not an obvious threat. But the solution is in our hands.

If you look at all the serious scientists in the world, there is no big disagreement on the basics of this...it would be absolute lunacy to act as if climate change is not occurring.