All our environmental problems become easier to solve with fewer people and harder - and ultimately impossible to solve - with ever more people.

All our environmental problems become easier to solve with fewer people and harder - and ultimately impossible to solve - with ever more people.

Can a growing human population still leave space for wildlife?

Climate change will affect the whole of humanity, while terrorist attacks will only affect a small section of humanity. Of course, you wouldn't say that if you were related to someone who had been beheaded or blown up or murdered. But humanity is facing a very big, slow, long, drawn-out threat, and that is to do with the way the weather is changing and the size of the population.

If we were all to reduce our demands for energy, it would make an enormous amount of difference.

The reverse side of the coin in having this extraordinary ability to go anywhere, is that no one anywhere is remote any more.

I'm luckier than my grandfather, who didn't move more than five miles from the village in which he was born.