Ever heard of pollution? Ever heard of the greenhouse effect? Yeah well those are all man-made problems that are having some serious consequences to the health of the planet.
Human beings do all sorts of unnatural things to survive on this planet: We farm animals to eat them, we have big machines and industry pumping out fumes that damage the ozone layer, we destroy natural habitats to build homes and cities - are those enough examples?
Let me know if you need more, there are most probably plenty of others I can find...
