I'm a vegetarian, but I don't expect other people not to eat meat.

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.

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'm an old member of Greenpeace. I worried intensely, as I think most of my friends did, that the world was coming apart.

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.

For the longest time in Denmark I didn't want to say what I was politically. I thought it was irrelevant.

Of course, the world is full of problems. But on the other hand it's important to get the sense... are we generally moving in the right direction or the wrong direction?