Think on a 50-year scale, which is a much more natural time-scale for global warming. The US is right now spending about 200 million dollars annually on research into renewable energy.

Surely the biggest problem we have in the world is that we all die. But we don't have a technology to solve that, right? So the point is not to prioritize problems; the point is to prioritize solutions to problems.

I tentatively believe in a god. I was brought up in a fairly religious home. I think the world is compatible with reincarnation, karma, all that stuff.

Listen, global warming is a real problem, but it's not the end of the world. A 30-centimetre sea level rise is just not going to bring the world to a standstill, just like it didn't over the last 150 years.

When thinking about the future, it is fashionable to be pessimistic. Yet the evidence unequivocally belies such pessimism. Over the past centuries, humanity's lot has improved dramatically - in the developed world, where it is rather obvious, but also in the developing world, where life expectancy has more than doubled in the past 100 years.

Wishful thinking is not sound public policy.

The fact that we're catching more fish per person than we've ever done before doesn't mean that there are not particular places where we've managed fisheries badly.