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19
Ecological Footprints tell the extent towhichpeople usewhat the
biosphere provides. The Footprint methodology can therefore
also measure the environmental demands of food production
and show to what extent food production contributes to the
overall demand of people on the biosphere.
Ecological Footprint accounting quantifies both the annual
availability of biocapacity and human demand on that capacity
(Wackernagel
et al.
2002; Borucke
et al.
2013). Demand on
ecosystems is mapped onto land uses, which are divided into six
Footprint components, or area types: cropland for food and fiber
production, including feed for animals; grazing land for livestock
production; forest land for both timber and other forest products;
forest land for the carbon Footprint to sequester the carbon
dioxide from fossil fuel burning; built-up land for housing and
infrastructure; and fishing grounds for fish products (marine and
inland).Twodemandcategoriesareprovided for byonebiocapacity
category: forest products and the carbon Footprint both compete
for forestland. Hence only five categories make up biocapacity.
Results are expressed in a globally comparable, standardized
unit called the global hectare (gha). A global hectare is a
biologically productive hectare with world average productivity
in a given year (Galli
et al.
2007; Monfreda
et al.
2004). Average
bio-productivity differs between land use types, as well as
between countries. For any given land use, the global hectare
is normalized to take this into account. For example, a global
hectare of high-yielding cropland would occupy a smaller
physical area than an area of pastureland with less biologically
productivity, as more pasture area is needed to provide the
same productivity as one hectare of cropland.
With this metric, one can assess human demand on nature,
and guide personal and collective action in support of a world
where humanity lives within the Earth’s bounds. According
to Global Footprint Network estimates, humanity demanded
resources and services equivalent to the capacity of 1.5 Earths
in 2008. Since 1961, the total Footprint has increased by 150
per cent (being now 2.5 times larger). In the meantime, with
changing management practice and increased agricultural
inputs, biocapacity expanded globally by 20 per cent (Global
Footprint Network 2013, Borucke
et al.
2013).
When total demand for ecological goods and services exceeds
the available capacity of a given location to meet this demand,
the situation is referred to as overshoot. Global overshoot is
Ecological Footprint accounting for food production
Global hectares per capita
Planets needed to sustain footprint
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0.5
1.0
1.5
2.0
2.5
3.0
Source:TheGlobal Footprint Network, 2013
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Stretching the ecosystems beyond their limits
Biocapacity
de cit
Footprint
Footprint
Business as
usual
Rapid
reduction
Biocapacity