The global hectare (gha) is a measurement unit for quantifying both the ecological footprint of people or activities as well as the biocapacity of the earth or its regions. One global hectare represents the average productivity of all biologically productive areas (measured in hectares) on earth in a given year. Examples of biologically productive areas include cropland, forests, and fishing grounds; they do not include deserts, glaciers, and the open ocean. "Global hectare per person" refers to the amount of biologically productive land and water available per person on the planet. The total number of global hectares is approximately 11.3 billion, averaging about 1.8 global hectares per person (2004). A total of 13.4 billion hectares were used, or 2.2 global hectares per person, meaning about 20% more was consumed than produced. This is possible because there are natural reserves all around the globe that function as backup food, material and energy supplies, although only for a relatively short period of time. Due to rapid population growth, these reserves are being depleted at an ever increasing tempo. See Earth Overshoot Day.
The global hectare is a useful measure of biocapacity as it can convert things like human dietary requirements into a physical area, which can show how many people a certain region on earth can sustain, assuming current technologies and agricultural methods. It can be used as a way of determining the relative carrying capacity of the earth.
A given hectare of land may be measured in equivalent global hectares. For example, a hectare of lush area with high rainfall would be scale higher in global hectares than would a hectare of desert.
It can also be used to show that consuming different foods may increase the earth's ability to support larger populations. To illustrate, producing meat generally requires more land and energy than what producing vegetables requires; sustaining a meat-based diet would require a less populated planet.
The average global hectare would occupy the area of a standard hectare. A hectare (//; symbol ha) is a unit of area equal to 10,000 square metres (107,639 sq ft) (a square 100 metres on each side, or, a square 328.08 feet on each side), 2.471 acre, 0.00386102 square miles, or one square hectometre (100 metres squared).
- "Frequently Asked Questions". Footprint Basics. Global Footprint Network. Retrieved 8 May 2012.
- "Living Planet Report 2004". http://wwf.panda.org/about_our_earth/all_publications/living_planet_report/living_planet_report_timeline/lpr04/. WWF. Retrieved 2 June 2014. External link in
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