Urban Ecological Footprint
Along with the rapid growth of the human population in the twentieth century has come extensive migration into large cities. The resultant reductions of biodiversity and alterations of ecosystems rival any of the mass extinctions Earth has experienced in the past. Most changes in the ecosystem are a result of human land-use practices, including agricultural and industrial utilization. Urbanization is unique in this land-use practice, in both the intensity and the extent of its impact on natural ecosystems.
The concept of an “ecological footprint,” the amount of land required to produce the resources needed by one person, attempts to quantify humanity’s impact on nature. A personal ecological footprint is comprised of resources used to meet a person’s food, water (and implicitly air), transportation, and housing demands. The per capita ecological footprint of an average American is ~11 hectares – almost ten times the global average. However, the footprint of an American urbanite is rather less, perhaps some 5 hectares, an area equivalent to about three city blocks, suggesting an urban lifestyle may be less damaging to the ecosystem.