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.

‎Using his burgeoning intelligence, this most successful of all mammals has exploited the environment to produce food for an ever increasing population. Instead of controlling the environment for the benefit of the population, perhaps it's time we controlled the population to allow the survival of the environment.

What humans do over the next 50 years will determine the fate of all life on the planet.

You have to steer a course between not appalling people, but at the same time not misleading them.

You can cry about death and very properly so, your own as well as anybody else's. But it's inevitable, so you'd better grapple with it and cope and be aware that not only is it inevitable, but it has always been inevitable, if you see what I mean.

It never really occurred to me to believe in God.

People are not going to care about animal conservation unless they think that animals are worthwhile.