The global hectare (gha) is a measurement unit for the ecological footprint of people or activities and the biocapacity of the Earth or its regions.
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.
The term "global hectare" was introduced in the early 2000s,[4] based on a similar concept from the 1970s named "ghost acreage".
[6] The global hectare is a useful measure of biocapacity as it can convert things like human dietary requirements into common units, which can show how many people a certain region on earth can sustain, assuming current technologies and agricultural methods.
It can also be used to show that consuming different foods may increase the earth's ability to support larger populations.