Section 7.1: The ecological footprint

The Ecological Footprint (EF) was developed by William Rees and Mathis Wackernagel initially to think about the concept of the Earth’s carrying capacity, in terms of the demands humans place on nature to support our lives and the economy.

The EF tracks the biologically productive area that is needed to provide us with everything from food, to space for our housing, buildings, roads, as well as wood and the absorption of carbon dioxide for fossil fuel use. The underlying concept of the EF is biocapacity, or the area of productive land, and sea, that can be regenerated in order to meet human needs.

The EF is a very flexible framework and can be applied at the individual level (we can calculate our own footprints and will be doing so in class), as well as at organizational, regional, national and global levels.

Calculating the EF is somewhat similar to Life Cycle Analysis (This will be covered in Week 8).

This short video summarizes what the EF is, and elaborates on the value it brings towards helping us understand our impacts on the natural world: “The Ecological Footprint Explained” – Moovly

Demand and Supply

On the demand side, the EF measures ecological assets that a given population requires to produce the resources it consumes, and absorb the waste by-products of its activities. This includes the production of plant and animal based products, timber and forestry products, the production of renewable resources, accommodation of urban development infrastructure, and the assimilation of waste products – particularly carbon dioxide from fossil fuel combustion.

On the supply side, a city, state, or nation’s biocapacity represents the productivity of it available ecological assets, including cropland, grazing land, fishing grounds, forested areas and built-up land. These areas, if left unharvested, can absorbed much of the waste generated, especially our carbon emissions.

Source: Global Footprint Network 2017

Human Demand on Nature

The EF determines human demand on nature through the comparison of that demand to the supply available on Earth. The calculated “footprint” of human activities is tallied against how much productive land and sea available, in order to measure their impacts.

If a population’s EF exceeds its geographical region’s biocapacity, the population and its region runs an ecological deficit. This means that its demand for the goods and services that its land and seas can provide, exceeds the region’s ecosystems’ replenishment and renewal rate.

The world’s ecological deficit is referred to as global ecological overshoot. Global ecological footprints have indicated that since the 1970s, humanity has been in ecological overshoot. This means that humanity’s annual demand on resources well exceeds what the Earth can regenerate in a year. In 2017, we reached this overshoot day on August 2nd (which happens to be my birthday and it is not exactly the gift I would have wished for).

Source: National Footprint Accounts 2016 (
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