The ecological footprint has several connotations. It is basically a measure of the demands we place on our planet. It compares human demands with the planet’s capacity to regenerate itself. Although ecological footprint is bandied about, the methods used to calculate the ecological footprint vary.
Ecological Footprint - The History
The first mention of ecological footprint occurred in 1992 by William Rees. Mathis Wackernagel developed both the concept and the calculation method. He was a graduate student under Dr. Rees’ supervision. They worked at the University of British Columbia in Vancouver, Canada. Originally, they called the concept “appropriated carrying capacity” but a computer technician, who spoke of his computer’s “small footprint” on his desk, inspired Rees. In 1996, Wackernagel and Rees published a book, Our Ecological Footprint: Reducing Human Impact on the Earth.
Mr. Mathis Wackernagel
According to one system of measurement, in 2006, the total ecological footprint from human endeavors was estimated at 1.4 planet Earths. That means humans were using ecological services 1.4 times as fast as the Earth can renew them. There is a three year time lag because it takes the UN three years to collect and publish all the underlying statistics.
The ecological footprint accounting is based on six assumptions.
1. The majority of resources consumed and waters generated can be quantified and tracked.
2. Some of these resources and waste flows can be measured in terms of the biologically productive area necessary to maintain the flows.
3. By weighing each area in proportion to its bioproductivity, different types of areas can be converted into the common unit of global hectares.
4. Global hectares can be added up to obtain an aggregate indicator of ecological footprint or biocapacity.
5. Human demand, expressed as the ecological footprint, can be directly compared to nature’s supply, biocapacity, when both are expressed in global hectares.
6. Area demanded can exceed area supplied if demand on an ecosystem exceeds that ecosystem’s regenerative capacity.
Ecological Footprint - How Does It Work
Ecological footprint is a comparison of human demand on the biosphere and the ability of the planet to regenerate resources and provide services. It is calculated by taking into account the biologically productive land and marine area needed to produce what a population consumes. It also takes into account neutralizing the corresponding waste.
In order to understand the measurement of “global hectares” (gha) and how it relates to ecological footprint, let’s look the measurement itself. A hectare (ha) is a unit of area that is equal to 10,000 square meters. That is equivalent to 2.371 acres or one square hectometer. (100 meters squared).
A global hectare is a measurement of biocapacity of the entire earth. By taking the sum of the earth’s biocapacity and dividing it by the number of hectares on the planet’s surface, you get the biocapacity of one average earth hectare. The term “global hectare per person” refers to the amount of biologically productive land and water available per person on the planet. In 2005, there were 13.4 billion hectares of biologically productive land and water available. There were 6.5 billion people living on the planet. That works out to be an average of 2.1 global hectares per person. This number decreaes as the population increases.
By 2006, the average biologically productive area per person decreased to 1.8 global hectares.
- The U.S. ecological footprint per person was 9.0 gha.
- The UK’s average ecological footprint per person was 5.45 gha
- In Switzerland the ecological footprint per person was 5.6 gha
- In China the ecological footprint per person was 1.8 gha
Who is using the most resources? The numbers tell the story. The 2010 Data Tables contain the ecological footprint and the biocapacity results for more than 100 nations. It is based on data from 2007. These data table are available at the Global Footprint Network web site.
The ecological footprint is an average of the following categories:
- Cropland footprint
- Grazing footprint
- Forest footprint
- Fishing ground footprint
- Carbon footprint
- Built-up land
All of these comprise the ecological footprint of consumption.
The biocapacity is a measure of:
- Grazing land
- Fishing grounds
- Carbon footprint
- Built land
The difference between these two values yields an ecological reserve or deficit. As the human demand on our biosphere increases, there are indications that this demand is outpacing the regenerative and absorptive capacity of the planet.
Ecological footprint analysis measures the human appropriation of ecosystem products and services in terms of the amount of bioproductive land and sea area needed to supply these things. According to the 2010 Edition of the National Footprint Accounts, we demanded the resources and services of 1.51 planets in 2007! That demand has increases 2.5 times since 1961
There are a total of fifteen mathematical equations used in calculating the ecological footprint. You can see those formulae on the “National Footprint Accounts Method Paper 2010.” The calculation of these footprints is based primarily on international data sets published by the Food and Agriculture Organization of the United Nations, plus the UN Statistics Division and the International Energy Agency.
In conclusion, the demand that humans and their activities place on the biosphere in a given year – with prevailing technology and resource management of that year – is the ecological footprint.