Why are we counting in square measures and what the global hectare means?
The use of area, as unit of natural capital is based on the fact that that part of the planet on which the photosynthesis takes place is the base for the services provided by the ecosystem.
If the different areas are weighted with their "biomass productivity", the areas can be expressed as standard, average productivity areas. This standard value is called global hectare; indicated as [gha]. The productivity of a global hectare equals to the average expected value of a hectare in the world for the given year. This standard calculation is valid both for the ecological footprint and for the available bio capacity.
The aggregated human needs (the ecological footprint) and the services provided by the nature (biocapacity) can be directly compared, as both of them can be measured in hectares.
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