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ENVIRONMENTAL COSTS OF
CONVENTIONAL INTENSIFICATION AND
EXPANSION OF FOOD PRODUCTION
Modern agricultural methods and technologies brought spec-
tacular increases in food production (Tilman
et al
., 2002), but
not without high environmental costs. Efforts to boost food
production, for example, through direct expansion of cropland
and pastures, will negatively affect the capacity of ecosystems to
support food production and to provide other essential services.
Food production will undoubtedly be affected by external fac-
tors such as climate change, but the production and distribu-
tion of food is itself is also a major cause of climate change.
Despite its crucial role in feeding the world population, ag-
riculture remains the largest driver of genetic erosion, spe-
cies loss and conversion of natural habitats (MA, 2005). The
conversion of natural habitats to cropland and other uses
typically entails the replacement of systems rich in biodiver-
sity with monocultures or systems poor in biodiversity. Large-
scale agriculture brings ecosystem simplification and loss of
(bio)diversity, thus reducing the potential to provide ecosys-
tem services other than food production. Of some 270,000
known species of higher plants, about 10,000 –15,000 are ed-
EXPANSION OF CROP- AND RANGELANDS
ible and only about 7,000 are used in agriculture. However,
globalization and agricultural intensification have diminished
the varieties traditionally used, with only 30% of the available
crop varieties dominating global agriculture. These, together
with only 14 animals species, provide an estimated 90% of the
world’s consumed calories (FAO,1998).
Habitat modification through agriculture and a variety of other
causes is, in general, the most important factor in increasing
species’ risk of extinction. Most of this habitat loss arises from
encroaching farmland and habitat conversion for food and bio-
fuel production (Figures 25, 26 and 27). Clearance for cropland
or permanent pasture has reduced the extent of natural habi-
tats on arable land by more than 50% (Green
et al
., 2005), with
much of the rest altered by temporary grazing (Groombridge
and Jenkins, 2002). Habitat modification already affects more
than 80% of the globally threatened mammals, birds and plants
(Groombridge and Jenkins, 2002), with serious implications
for ecosystem services and human wellbeing. Indeed, the most
significant threat by far to the world’s 5,500 mammal species