Unsustainably high human population growth rate and
natural resource consumption
Lack of knowledge and understanding in the
management and conservation of biodiversity
The concentration of agriculture, forestry and fishing
on a narrowing spectrum of products
Global factors
Climate Change
1 degree temperature rise: 10% of land species face
extinction. Coral-reef bleaching more frequent.
Species-rich tropical mountains likely to lose many
species
2 degree temperature rise: Between 15% and 40% of land
species face extinction, including 25-60% South African
mammals and 15-25% Australian butterflies. Coral reefs
bleached annually in many areas. Almosy 5% of the low
tundra and 25% of coniferous forest could be lost.
3 degree temperature rise: Anything
between 20% and 50% of land
species could face extinction.
Massive losses in biodiversity
expected in hotspots. Large areas of
coastal wetlands will be lost as a
result of rising sea levels. Mangroves
will be flooded, removing a natural
coastal defence. Coral reefs will die.
Strong drying in the tropics could
lead to destruction of rainforests.
Deforestation: clearance of forest cover
results in loss of biodiversity and
resources, with knock on effects on the
food web and nutrient cycling. Removal of
forest cover leads to increased soil
erosion and flooding.
Pollution
Nitrate and phosphate pollution in lakes and
coastal waters
Airborne pollution e.g. DDT
Ozone depletion by CFCs
Acidification of oceans
Local factors
Fire
Habitat Change
Recreational use
Large-scale agriculture
Overexploitation
Mineral exploitation
Alien or exotic species
Eutrophication: the pollution of ecosystems with excessive nitrate and phosphate