In 1994 William E. Rees and Mathis Wackernagel created a measurement of the “ecological footprint”.
An ecological footprint is a measure of human impact on Earth’s ecosystems. It’s typically measured in area of wilderness or amount of natural capital consumed each year. A common way of estimating footprint is, the area of wilderness of both land and sea needed to supply resources to a human population; This includes the area of wilderness needed to assimilate human waste.
Test Ecological Footprint: www.footprintcalculator.org
Source: Wackernagel, Mathis & Beyers, Bert (2010). Der Egological Footprint. Die Welt neu vermessen. Leipzig: Europäische Verlagsanstalt GmbH. and Wikipedia