Mark Lynas believes that urban areas are the key to environmentalism:
In many parts of the world, if you want to marry the person you choose, be gay, be female and economically successful, or avoid daily backbreaking labour carrying water or fetching firewood, then you probably need to move to the city. In 1975 there were just three megacities of over 10 million people. Today there are 21. It sounds scary, but this unstoppable shift towards urbanisation actually ranks as one of the most environmentally beneficial trends of the last few decades.
As the UN Population Fund wrote in a recent report: ‘Density is potentially useful. With world population at 6.7 billion people in 2007 and growing at over 75 million a year, demographic concentration gives sustainability a better chance. The protection of rural ecosystems ultimately requires that population be concentrated (pdf) in non-primary sector activities and densely populated areas. City living is seldom lauded by environmentalists, but it may be our most environmentally friendly trait as a species, because urban dwelling is vastly more efficient than living in the countryside.