The obvious issue is providing clean drinking water and sanitation to every single human being on earth at the cost of little more than one year of the Kyoto treaty.

Im no expert on American politics.

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.

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.

I think it's great that we have organisations like Greenpeace. In a pluralistic society, we want to have people who point out all the problems that the Earth could encounter. But we need to understand that they are not presenting a full and rounded view.

Obviously any group that has to have funding also needs to get attention to their issues.

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.