Economics in time, space, and footprints 65den Bergh and Verbruggen 1999 ,Lenzenand Murray2001). Inverting the usual
carrying-capacity question of how many people can live in a given area, ‘‘eco-
footprinting” estimates how much area is needed to support a given population,
irrespective of where it is.
What are the ecological footprints of people in urban regions? The average
citizen of Europe, North America, Australia, and Japan, the most intensely urban
regions worldwide, requires 5--10 ha (12.5--25 acres) of productive land and water
per capita to support his or her current lifestyle. Residents of the Canadian
cities, Toronto and Vancouver, have 7.7 ha footprints on average (Rees2003), and
residents of the megacity London about 11 ha (28 acres). In striking contrast
the residents of developing nations on average have a footprint of about 1.0 ha
(2.5 acres). The population of each of the Canadian cities has a footprint about
300 times greater than the area of the metropolitan area. The much-larger
London requires a total productive area, not only larger than its urban region,
but equal to the total productive land area in Britain.
These ecological footprints are based on the total equivalent productive area
to provide the resource inputs to the city or person. However, as evident in the
ecological economics discussion above, both incoming resources and outgoing
effects on the environment are important. Thus, in an extensive study of the
29 largest European cities around the Baltic, the city-population footprints were
565--1130 times larger than the city areas (Rees2003). That study added the area
required for waste assimilation to the resource-consumption area.
Urban sustainability, as outlined in the previous section, is not promising,
because the human imprint, inputs, and outputs have normally overwhelmed
natural systems in a city or metropolitan area. However, a different bigger per-
spective might provide a solution and also provide further insight into ecological
footprints. Think of the primary inputs and outputs for a city. What areas or
landscapes do they mainly come from and go to? If the group of landscapes,
along with the city, were considered as a whole system, it could be planned
and managed for a positive balance of both nature and people. That would be a
sustainable system with the city a key part.
As an example, suppose the bulk of a city’s food comes from a distant grain-
growing area, a livestock area, and close-by market-gardening area. Much of
theoutside-manufactured products originate in a distant forested area and a
mining--industrial area. Water supply mainly comes from a forested aquifer in
the urban region. Also, most water pollutants and air pollutants end up in a large
downwind lake, solid waste in a huge dumpsite, and recreation and its impacts
in a nearby forested area. The city itself also provides industrial, commercial, and
residential resources. So, to plan this city’s whole system for nature and people,
or urban sustainability, requires planning and managing the city with its ten