Ecological footprint

An ecological footprint (also called city footprint in connection to cities) is the measure of the amount of imagined arable and agricultrually or ecologically productive land area it takes to sustain one human or group of humans, say in a family or city, based on their use of energy, food, water, building material and other consumables. It is a way of determining relative consumption.

It can be combined with overpopulation concerns and stated as "the number of Earths it would take to support every human living exactly the way you do." Ecological footprints have been used to argue that current lifestyles are not sustainable. The concept of ecological footpriniting has been challenged on several grounds. Firstly, many factors of the calculations are besed on crude estimates and it is questioned whether the numbers are applicable on other places. Secondly, the model does generally not count multiple uses of a land: a forest is there as a carbon sink and the same area is not counted for food production. Finally, some of the processes involved are currently poorly understood.

To counter these uncertainties, the models of ecological footprinting are constantly refined.

Ethically, the number of Earths "consumed" alludes to the categorical imperative, which requires everyone to behave in such a way that they can consistently advise all others to behave.