I discovered science, and in the process I hope I became a better environmentalist.

Once the 'portals of the future close - in Amazonia, Siberia or the Arctic - we will find ourselves powerless to affect the outcome of this dreadful tale.

Conventional economic theory... counts the depletion of resources as the accumulation of wealth.

We no longer need to discuss whether or not it is safe – over a decade and a half with three trillion GM meals eaten there has never been a single substantiated case of harm. You are more likely to get hit by an asteroid than to get hurt by GM food.

If we are to save humanity and the planet from the worst mass extinction of all time, worse even than that at the end of the Permian, we must stop at two degrees.

You'd be forgiven for thinking that climate change means we'll have to sacrifice our creature comforts. But it doesn't have to be that way.

The worst case scenario sees the Amazon rainforest burning, huge amounts of methane being released by Siberian peat bogs and so on - by the time today's six year olds are 60, such a scenario would see global warming already out of control.