I suppose happiness is something one enjoys, but I suspect that happiness is not a state but rather a transition.

I have no doubt that the fundamental problem the planet faces is the enormous increase in the human population

I had a huge advantage when I started 50 years ago - my job was secure. I didn't have to promote myself. These days there's far more pressure to make a mark, so the temptation is to make adventure television or personality shows. I hope the more didactic approach won't be lost.

[W]hen we look at the graphs of rising ocean temperatures, rising carbon dioxide in the atmosphere and so on, we know that they are climbing far more steeply than can be accounted for by the natural oscillation of the weather ... What people (must) do is to change their behavior and their attitudes ... If we do care about our grandchildren then we have to do something, and we have to demand that our governments do something.

Dealing with global warming doesn't mean we have all got to suddenly stop breathing. Dealing with global warming means that we have to stop waste, and if you travel for no reason whatsoever, that is a waste.

I've never actually met one in the wild, but I have seen a king cobra. They go towards people, they rear up six feet tall and they're very aggressive and they are very fast. And one bite means certain death. So if I encountered a king cobra in the wild I would be very alarmed.

I mean, it is an extraordinary thing that a large proportion of your country and my country, of the citizens, never see a wild creature from dawn 'til dusk, unless it's a pigeon, which isn't really wild, which might come and settle near them.