Since I started filming in the 1950s, on average, wild animal populations have more than halved. I look at these images now and I realize that, altho… - David Attenborough

Fifty years ago, when the WWF was founded there were about three billion people on earth. Now there are almost seven billion. Over twice as many - and every one of them needing space. Space for their homes, space to grow their food (or to get others to grow it for them), space to build schools and roads and airfields. A little of that space might be taken from land occupied by other people but most of it could only come from the land which, for millions of years, animals and plants have to themselves.

If you watch animals objectively for any length of time, you're driven to the conclusion that their main aim in life is to pass on their genes to the next generation. Most do so directly, by breeding. In the few examples that don't do so by design, they do it indirectly, by helping a relative with whom they share a great number of their genes. And in as much as the legacy that human beings pass on to the next generation is not only genetic but to a unique degree cultural, we do the same. So animals and ourselves, to continue the line, will endure all kinds of hardship, overcome all kinds of difficulties, and eventually the next generation appears. This albatross is over 30 years old, she's already a grandmother, and this year once again she has produced a chick. She will devote the next 10 months of her life looking after it. She has faced the trials of life and triumphed, for her little 2 day old chick the trials are just beginning.

We must change our diet. The planet can’t support billions of meat-eaters.