Fundamentally not to waste energy. If we were all to reduce our demands for energy, it would make an enormous amount of difference.

What humans do over the next 50 years will determine the fate of all life on the planet.

We can now destroy or we can cherish-the choice is ours.

Cameramen are among the most extraordinarily able and competent people I know. They have to have an insight into natural history that gives them a sixth sense of what the creature is going to do, so they can be ready to follow.

We really need to kick the carbon habit and stop making our energy from burning things. Climate change is also really important. You can wreck one rainforest then move, drain one area of resources and move onto another, but climate change is global.

It's like saying that two and two equals four, but if you wish to believe it, it could also be five ... Evolution is not a theory; it is a fact, every bit as much as the historical fact that William the Conqueror landed in 1066.

The correct scientific response to something that is not understood must always be to look harder for the explanation, not give up and assume a supernatural cause.