Africa is facing a dramatic increase in air and water pollution, drought and wildlife extinction unless immediate action is taken to clean up the continent's environment, says the United Nations.

A report from the United Nations Environment Programme (UNEP) calls on African leaders to pursue environmentally-friendly development as well as to reduce greenhouse gas emissions to avoid irreparable damage to Africa's environment.

Among the report's findings:

• Over the next 30 years, growing populations, wars, climate change and the introduction of alien plants and animal species will increase poverty, destroy the environment and spread disease.

• Uncontrolled expansion of cities and pollution from cars and industry - which will all increase as the population grows - will need to be carefully managed otherwise pollution will get worse.

• Diseases like malaria are likely to spread into new areas as the climate changes.

• A loss of wildlife would not only be devastating for the environment but would also seriously dent the tourism industry, affecting local economies.

The UNEP, based in Nairobi, says Africa's annual rainfall has been decreasing since 1968 because of global warming.

Its report warns that the continent's emission of carbon dioxide - the main global warming gas - has risen eight-fold since 1950, to 223 million metric tonnes of carbon.

Africa's rate of urbanisation is the highest in the world

South Africa accounts for 42% of these emissions. Egypt, Nigeria and Algeria combined account for another 35.5%.

As a result of the ensuing climate change, natural disasters like drought have become more common in countries such as Botswana, Burkina Faso, Chad, Ethiopia, Kenya, Mauritania and Mozambique.

The study says Africa's high rate of urbanisation is also encouraging use of dirty fuel and older cars that emit 20 times more pollution than newer ones.

More sea, less rain

Refineries and coal power stations - especially in northern Africa - are doubling the levels of the continent's sulphur dioxide, while use of wood as fuel is posing a health risk to women and children in African homes.

At the same time rising sea levels are threatening the Gulf of Guinea, Senegal, Egypt, The Gambia, the eastern African coast as well as the western Indian Ocean islands.

A significant drop in rainfall could also lead to the extinction of plants and wildlife such as hartebeest, wildebeest and zebra in southern Africa, the report says.

It warns that invasive alien species, poaching, poor conservation laws are also putting increasing pressure on the continent�s wildlife.

The study says 126 animal species have become extinct, while about 2,000 are now threatened.

Air and water pollution could lead to the extinction of wildlife

It warns that malaria-carrying mosquitoes could spread to Namibia and South Africa which have so far been malaria-free as temperatures climb, allowing them to breed.

However, the report notes that many African countries have already begun to address these issues through an Africa-wide development scheme.

But UNEP insists more drastic changes are needed.

These include cutting Africa's debt burden, boosting overseas aid, introducing green technologies and allowing African countries fair access to international markets for their goods and services.