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Earth’s land surface and about 20% of its net primary productivity. Added to
this are the resource-hungry activities of industrial agribusiness – everything
from the crop need for irrigation water, synthetic fertilizers and pesticides to
the resource costs of food packaging, transport (now a major part of global
trade) and retail. Food is essential to life. But the list of environmental costs
of food production is a long one: topsoil depletion, erosion and conversion to
desert from constant tillage of annual crops; overgrazing; salinization;
sodification; waterlogging; high levels of fossil fuel use; reliance on
inorganic fertilizers and synthetic organic pesticides; reductions in genetic
diversity by the mass use of monocultures; water resource depletion;
pollution of waterbodies by run-off and groundwater contamination; social
problems including the decline of family farms and weakening of rural
communities.
All of these environmental problems associated with industrial
agriculture and agribusiness are now being addressed through such
movements as sustainable agriculture, organic farming and more sustainable
business practices.
Extinctions
Although biodiversity loss can be monitored simply as loss of species,
effective conservation demands the protection of species within their natural
habitats and ecosystems. Following human migration and population growth,
species extinctions have progressively increased to a rate unprecedented
since the Cretaceous–Tertiary extinction event. Known as the Holocene
extinction event this current human-induced extinction of species ranks as
one of the worlds six mass extinction events. Some scientific estimates
indicate that up to half of presently existing species may become extinct by
2100. Current extinction rates are 100 to 1000 times their prehuman levels
with more than 10% birds and mammals threatened, about 8% of plants, 5%
of fish and more than 20% of freshwater species.
The 2008 IUCN Red List warns that long-term droughts and extreme
weather put additional stress on key habitats and, for example, lists 1,226
bird species as threatened with extinction, which is one-in-eight of all bird
species. The Red List Index also identifies 44 tree species in Central Asia as
under threat of extinction due to over-exploitation and human development
and threatening the region's forests which are home to more than 300 wild
ancestors of modern domesticated fruit and nut cultivars.
Biological invasions
In many parts of the industrial world land clearing for agriculture has
diminished and here the greatest threat to biodiversity, after climate change,
has become the destructive effect of invasive species. Increasingly efficient
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