We rich nations, for that is what we are, have an obligation not only to the poor nations, but to all the grandchildren of the world, rich and poor. We have not inherited this earth from our parents to do with it what we will. We have borrowed it from our children and we must be careful to use it in their interests as well as our own. Anyone who fails to recognise the basic validity of the proposition put in different ways by increasing numbers of writers, from Malthus to The Club of Rome, is either ignorant, a fool, or evil.