Right now we are facing a man-made disaster of global scale, our greatest threat in thousands of years: climate change. If we don’t take action, the … - David Attenborough

I'm very aware that this programme may be regarded as bleak or depressing - an increasing population with an ever decreasing supply of resources – but humans have capabilities that animals don't: to think rationally; to study; to plan ahead. The number of people on the planet depends on the personal decisions we each make regarding the number of children we have even setting aside the moral responsibility we have to protect other species, if we continue to damage our ecosystem, we damage ourselves. Its clear that we'll have to change the way that we live and use our resources. We're at a crossroads where we can chose to cooperate or carry on regardless. Can our intelligence save us? I hope so. m46s24-m47s15

How is it that [birds] can withstand the pull of gravity that keeps the rest of us tied so firmly to the ground? The secret is a wing with a thick, rounded front edge that curves gently downwards toward the back edge which is very thin. As thin, in fact, as a feather. As the bird glides forward, the air flowing under the wing is impeded by the wing's downward curve so it becomes slightly compressed, and that pushes the wing up. At the same time, the air flowing across the top of the wing is deflected upwards by the wing's front edge, so reducing its pressure. If the air is moving fast enough, then the slight suction from above, combined with the push from beneath will be enough to lift the bird into the air [...] and ample to keep it aloft.

Human beings are good at many things, but thinking about our species as a whole is not one of our strong points. m4s45-m4s53