"The worst thing that you or I can do for the planet is to have children."

"If they behave as the average person in the rich world does now, they will emit some 11 tonnes of CO² every year of their lives. In their turn, they are likely to have more carbon-emitting children who will make an even bigger mess."

Yeah: "tonnes." British. Does that make you just want to scoff and skip the whole article? Here. I'll give you the last paragraph:

Some scientists, the German chancellor's adviser, Hans Joachim Schellnhuber among them, say that if the cuts are not achieved, we will end up with a planet with a "carrying capacity" of just 1bn humans. If so, we need to start cutting back population now with methods that offer a humane choice – before it happens the hard way.

Oh, great. Thanks for the warning about cutting back "population" the hard way. Germany.