Forests are the world's air-conditioning system-the lungs of the planet-and we are on the verge of switching it off.

I think it's something that dawns on you with the most ghastly, inexorable sense. I didn't suddenly wake up in my pram one day and say 'Yippee, I - ', you know. But I think it just dawns on you, you know, slowly, that people are interested in one, and slowly you get the idea that you have a certain duty and responsibility.

Your greatest achievement is to love me.

We don't, in a sensible world, want to hand on an increasingly dysfunctional world to our grandchildren.

Humility is to make a right estimate of one's self. It is no humility for a man to think less of himself than he ought, though it might rather puzzle him to do that.

The sustainability revolution will, hopefully, be the third major social and economic turning point in human history, following the Neolithic Revolution - moving from hunter-gathering to farming - and the Industrial Revolution

One of the main reasons for the conflict in Syria, and the terrorism that it's spawned, is climate change and drought.