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UNIT 1: WHERE DO WE STAND? THE STATE OF THE GLOBAL ENVIRONMENT
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Some facts on biodiversity losses:
• AFRICA
Cultivation and slash-and-burn agriculture account for 70% of
deforestation in Africa.
• ASIA AND THE PACIFIC
India is expected to produce 75% of its rice from just 10 varieties in
2005, compared with the 30,000 varieties traditionally cultivated. In
Indonesia, 1,500 varieties of rice disappeared from 1975 to 1990.
• EUROPE
Species under threat include 42% of all mammals, 52% of all fish, 45%
of all reptiles, 30% of all amphibians, and 15% of all birds.
• LATIN AMERICA
The region includes five of the world’s mega-biodiversity countries –
Brazil, Colombia, Ecuador, Mexico and Peru. The region lost over 7% of
its tropical forests during the last decade.
• NORTH AMERICA
728 species are listed as endangered or threatened.
• CARIBBEAN
Coral reefs have declined by over 20% and species such as lobster, shrimp,
grouper, conch and game fish are over-fished across the entire area.
• WEST ASIA
11% of remaining natural forests was lost in the 1980s, and natural
forests now cover less than 1% of the land area. The depletion of
groundwater reserves in the western Gulf is leading to the loss of
valuable ecosystems and freshwater springs.
• THE POLES
These regions, with their fragile ecosystems and short food chains,
represent the world’s largest remaining pristine environments.
Fisheries, mining, and tourism development are bringing with them the
threat of pollution and ecosystem destruction.
India is expected
to produce 75%
of its rice from
just 10 varieties
in 2005,
compared with
the 30,000
varieties
traditionally
cultivated. In
Indonesia, 1,500
varieties of rice
disappeared
from 1975 to
1990.
1. 5 Land Degradation
Land degradation is affecting vast areas worldwide. This is especially distressing
as it means productivity is declining at a time when rapidly rising populations
are demanding vastly increased supplies of food, fibre and fuel. UNEP reports
that land degradation affects 1,900 million hectares, i.e. about 16% of the world’s
agricultural land, and that another 5 to 6 million are lost each year. This implies
that several million acres of ‘new’ land have to be used for agriculture to offset the
unusable degraded areas.
There are many ways in which land can be degraded. Soil erosion and salination
are the most widespread. Erosion is the deterioration of the soil by the physical
movement of soil particles from a given site. It is vegetation that keeps the soil
(in its natural state) from eroding. Undisturbed by man, soil is usually covered
by shrubs, trees, grass and dead or decaying leaves, all of which protect it from
rain and wind, and prevent moisture, nutrient loss and leakage. Root systems
also help to consolidate the soil. Even in drought the roots of native grasses,
which can extend several metres into the ground, help tie down the soil and
Land
degradation is
affecting vast
areas worldwide.
This is especially
distressing as
it means
productivity is
declining at a
time when
rapidly rising
populations are
demanding
vastly increased
supplies of food,
fibre and fuel.