Devastation could arise insidiously, rather than suddenly, through unsustainable pressure on energy supplies, food, water and other natural resources. Indeed, these pressures are the prime 'threats without enemies' that confront us.

The important point there is that when people talk about a mean temperature rise of say two, three or four degrees that's a sort of global average which really is a signature of large scale change in climatic patterns.

I hope that by 2050 the entire solar system will have been explored and mapped by flotillas of tiny robotic craft.

I suspect there could be life and intelligence out there in forms that we can't conceive. And there could, of course, be forms of intelligence beyond human capacity-beyond as much as we are beyond a chimpanzee.

We need to broaden our sympathies both in space and time - and perceive ourselves as part of a long heritage, and stewards for an immense future.

Most educated people are aware that we are the outcome of nearly 4 billion years of Darwinian selection, but many tend to think that humans are somehow the culmination. Our sun, however, is less than halfway through its lifespan. It will not be humans who watch the sun’s demise, 6 billion years from now. Any creatures that then exist will be as different from us as we are from bacteria or amoebae.

We should all oppose - as Darwin did - views manifestly in conflict with the evidence, such as creationism... But we shouldn't set up this debate as 'religion v science'; instead we should strive for peaceful coexistence with at least the less dogmatic strands of mainstream religions, which number many excellent scientists among their adherents.