According to Allison, I must be "psychopathological": I find overcrowded streets and transport systems unpleasant and even threatening. There is for me something threatening about huge crowds. To put it in perspective, I don't begrudge Allison his/her adorable granddaughters, and I find China's sadistically enforced one-child policy utterly repugnant. BUT, as "Anonymous", above, points out, we have made inroads into our planet's resources. Even damp South-East England has annual water shortages, and we are never more than a few days away from food shortages. Appealing to people to use less water/eat less meat isn't going to work. There is a global problem of youth unemployment, which isn't I believe, cyclical. Rather, it's the shape of things to come. Some countries' leaders (Iran, Russia,Chile) are anxious about decreasing fertility. The Chilean president is offering cash incentives to families to encourage them to have larger families. Meanwhile, in Spain, youth unemployment is above 50%. So, instead of putting yet more people on our planet, why don't the Chileans welcome their fellow Spanish-speakers to come over and work? Movement of labour is the answer to shortages of workers.

It is certainly true that human population cannot grow indefinitely century after century, until there is standing room only. There will be scientific advances and technical innovations. But does anyone want the whole globe covered in adjoining cities? Long before that we will have run out of food and fresh water. We do not know when overpopulation will become a significant global problem (as it already is in some countries), but the idea, propagated by some, that it could never be a problem is ridiculous. We live on a finite planet with finite resources, and we are already destroying the natural environment upon which all life, including human life, depends. Urban based politicians and business leaders seem incapable of understanding this basic fact about human existence on Earth.