Want To Save The Environemnt? Move to the City!!

I was glancing over www.margianlrevolution.com today and came across a post from Tyler Cowen that showed portions of an article that appeared in the Financial Times. It's a colum where readers can write to an economist named Tim Harford. The writer was from London and she was asking if moving to the country and living a more "rural" life style would be the best way she could do her part to help the environment. Tim than went on to blast her and say that moving to the country is the worst thing she could do. If all of London's inhabitants were to do that the entire countryside would be destroyed. He then goes on to say, " Tightly packed, rich cities such as London are easily the most environmentally friendly way to enjoy modern life. Wealthy people squeeze into cozy apartments...Denser cities mean more efficient transport. Only 10 percent of commutes into central London take place in cars."Manhattan, the densest and richest city of all, was recently described in The New Yorker magazine as "a utopian environmentalist community" and it is vastly more energy-efficient, per person, than any of the 50 American states.
My advice is to forget all this self-centred nonsense about moving to the country. Instead, you should put double-glazing in your flat, travel to work by bike and relax in the smug knowledge that you are living in one of the greenest cities on the planet.
I find this argument interesting. It tends to go against your first intentions that city life is the problem when really more people leaving the cities and inhabiting the countryside would only create a bigger problem.