Here’s a brilliant fact of the day:

“Since the beginning of civilization to 2011, the human race has created goods containing about 43 billion tonnes of iron. Of this huge amount of metal…. almost half has been made since 1990.”

But even at 2011 rates of use, there’s a billion years’ worth of iron left on earth, before we have to start on the asteroids. I’m a chapter in to Peter Marsh’s The New Industrial Revolution and already thoroughly enjoying it.