Whichever way you look at it, all our wealth comes from the Earth. Very slowly we are beginning to recognise an uncomfortable but increasingly important truth. We cannot allow the many economic activities in which we all engage to exceed the carrying capacity of our planet. The awareness that the planet we live on is very much like a fragile spaceship only came in the second half of the 20th century. We need to keep it in good shape because we cannot live without it.
