This indicator is an estimate of the amount of space on the earth that an individual uses in order to survive using existing technology. This space includes the biologically productive land and water area that produces the resources consumed by that individual such as food, water, energy, clothing, and building materials. It also includes the amount of land and water required to assimilate the wastes generated by that person. In other words, the ecological footprint measures a person's demand on the bio-capacity of the Earth.