Environmental Effects of Urbanization
"While the world's population is doubling, the world's urban population is tripling. Within the next few years, more than half the world's population will be living in urban areas... Many of the effects of urban areas on the environment are not necessarily linear. Bigger urban areas do not always create more environmental problems. And small urban areas can cause large problems. Much of what determines the extent of the environmental impacts is how the urban populations behave their consumption and living patterns not just how large they are."
Thanks to Kevin Leeson