It's not quite true to say that other animals don't damage anything. Sometimes, insects called locusts grow in vast swarms, eating every green plant in their path. This spells disaster for other animals, humans and the plants themselves. But nature soon restores the balance. Some of the insects get eaten by predators of course, but the real crunch comes when the locusts have eaten all the plants. They simply die of hunger. Their numbers crash and they disappear for a few years. You might think that's cruel but that's how nature works to regulate life that gets out of hand. Humans, though, are so clever that they can stop nature working against them and do a great deal of damage as a result. At least, they've stopped nature so far, but what of the future? Will humans go the way of the greedy locusts? That's what this guide is all about!