Satellite Atlas Reveals a Changing Africa

The glaciers in the Rwenzori mountains straddling Tanzania and Uganda are fiercely disputed as the source of the river Nile, but a new series of satellite images show how they have shrunk nearly 50% since 1993 as a direct result of climate change.

Their rapid retreat, echoed on Mount Kilimanjaro, threatens not just the livelihoods of the 2 million people who depend on the melt water, but increases pressure on the gorillas who live in the nearby Virunga park, according to a new UN atlas of the changing African environment.

The atlas, launched today by President Thabo Mbeki of South Africa, charts the march of cities over the countryside, protected areas shrinking as farms encroach on city boundaries and the driving of roads through forests.

Before and after satellite images, sometimes spread over decades, show Dakar, the capital of Senegal, expanding from a small urban center to a great metropolitan area of 2.5 million people spread over a wide area. They show falling water levels in Lake Victoria, the loss of forests in Congo DRC, and the decline of plant varieties in South Africa.

But other pairs of images in the atlas suggest that good management is having a positive effect on many environments. Wetlands in Mauritania have been restored, tree planting in Niger has transformed once deforested areas, and action on overgrazing in Tunisia has revitalized pastures.

"There are many places across Africa where people have taken action. These are beacons we need to follow to ensure the survival of Africa's peoples and their economically important nature-based assets", said Achim Steiner, the UN environment program's executive director.

He added that the atlas, "shows the vulnerability of people in the region to forces often outside their control, including the shrinking of glaciers and impacts on water supplies linked with climate change."

According to the atlas authors, refugee migrations caused by conflicts are now causing significant pressure on the environment. But the greatest environmental threats, they say, come from land degradation, which is now affecting 32 African countries; forest loss, which is a concern in 35 countries; and biodiveresity loss which is taking place in 34 countries.

According to the atlas, Africa is losing more than 4m hectares of forest a year ? twice the world's average deforestation rate, with some areas consequently losing over 50 tonnes of soil per hectare a year due to the erosion of exposed areas.

"Climate change is emerging as a driving force behind many of the problems and is likely to intensify the already dramatic transformations taking place across the continent", the atlas states.