Satellite images show scale of environmental change in Africa

Posted: 12 June 2008

New satellite imagery shows that Africa is losing more than four million hectares of forest every year, that some areas are losing over 50 metric tonnes of soil per hectare per year, and that erosion and chemical and physical damage have degraded about 65 per cent of the continent's farmlands.

Africa's rapidly changing environmental landscape, from the disappearance of glaciers in Uganda's Rwenzori Mountains to the loss of Cape Town's unique 'fynbos' vegetation, is revealed in a new UN report, Africa: Atlas of Our Changing Environment.

Lake Victoria, population density 1960-2006
Lake Victoria, population density 1960-2006
The area around Lake Victoria has seen the highest population growth rates in Africa. Graphic shows population density in 1960 and 2005.
The Atlas, compiled by the UN Environment Programme (UNEP), underlines how development choices, population growth, climate change and, in some cases, conflicts are shaping and impacting the natural and nature-based assets of the region.It features over 300 satellite images taken in every country in Africa in over 100 locations. The 'before' and 'after' photographs, some of which span a 35-year period, offer striking snapshots of local environmental transformation across the continent.

In addition to well-publicized changes, such as Mount Kilimanjaro's shrinking glaciers, the drying up of Lake Chad and falling water levels in Lake Victoria, the Atlas presents, for the first time, satellite images of new or lesser known environmental changes and challenges including:

  • Disappearing glaciers in Uganda's Rwenzori Mountains, which decreased by 50 per cent between 1987 and 2003.
  • The widening corridors of deforestation that have accompanied expanding roads in the northern Democratic Republic of the Congo since 1975. New roads threaten to bring even greater traffic to this biologically rich rainforest and further fuel the bushmeat trade.
  • The disappearance of a large portion of Madagascar's South Malagasy spiny forest between 1973 and 2003 as a result of farming and fuelwood gathering.
  • The northern edge of Cape Town, which has seen much of its native 'fynbos' vegetation replaced with farms and suburban development since 1978. 'Fynbos' make up 80 per cent of the plant varieties in the Cape Floristic Region, an area with over 6,000 plant species which are found nowhere else in the world and are an economic asset for tourism.
  • The loss of trees and shrubs in the fragile environment of the Jebel Marra foothills in western Sudan as a result of population growth due in part to an influx of refugees fleeing drought and conflict in neighbouring Northern Darfur.
  • The dramatic expansion of Senegalese capital Dakar over the past half century from a small urban centre at the tip of the Cap Vert Peninsula to a metropolitan area with 2.5 million people spread over the entire peninsula.
Dramatic deforestation: Gishwati Forest, Rwanda
Dramatic deforestation: Gishwati Forest, Rwanda
Dramatic deforestation: Gishwati Forest, Rwanda. Satellite image 1978. Click to enlarge
Dramatic deforestation: Gishwati Forest, Rwanda
Dramatic deforestation: Gishwati Forest, Rwanda
Dramatic deforestation: Gishwati Forest, Rwanda. Satellite image 2006. Click to enlarge

UNEP Executive Director Achim Steiner said: "The Atlas clearly demonstrates the vulnerability of people in the region to forces often outside their control, including the shrinking of glaciers in Uganda and Tanzania and impacts on water supplies linked with climate change."

The Atlas shows that loss of forest is a major concern in 35 countries, including the Democratic Republic of the Congo, Malawi, Nigeria and Rwanda, among others. This is closely followed by biodiversity loss - which is occurring in 34 countries such as Angola, Ethiopia, Gabon and Mali.

Land degradation, similarly, is a major worry for 32 countries in Africa including Cameroon, Eritrea and Ghana. Other problems include desertification - in Burkina Faso, Chad, Kenya and Niger among others - as well as water stress, rising pollution and coping with rapid urbanization.

Shantytown growth, Ouagadougou 1986
Shantytown growth, Ouagadougou 1986
Growth of unplanned settlements: Ouagadougou, Burkina Faso. Satellite image 1986. Click to enlarge
Shantytown growth, Ouagadougou 2004
Shantytown growth, Ouagadougou 2004
Growth of unplanned settlements: Ouagadougou, Burkina Faso. Satellite image 2004. Click to enlarge

Africa is losing more than four million hectares of forest every year - twice the world's average deforestation rate, says the Atlas. Meanwhile, some areas across the continent are said to be losing over 50 metric tonnes of soil per hectare per year.

The Atlas also shows that erosion and chemical and physical damage have degraded about 65 per cent of the continent's farmlands. In addition, slash and burn agriculture, coupled with the high occurrence of lightning across Africa, is thought to be responsible for wild fires.

Water stress, Africa
Water stress, Africa
An increase in the need for fresh water by growing populations, coupled with a history of periodic drought and evidence of recent increased rainfall variability due to climate change, has created conditions of water scarcity and water stress in many regions throughout Africa. Over 300 million people in Africa currently face water scarcity conditions. By 2025, 18 African countries are expected to experience water stress.
Over 300 million people on the continent already face water scarcity, and areas experiencing water shortages in Sub-Saharan Africa are expected to increase by almost a third by 2050.

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

Gas flaring, Niger Delta, 1992-2006
Gas flaring, Niger Delta, 1992-2006
There is good news too. Nigeria has been gradually reducing the amount of gas flared in the Niger Delta.This composite satellite image shows a reduction in gas flaring in the Niger Delta over 14 years. The year 2006 is in red, 2000 is in green and 1992 is in blue.
Although Africa produces only 4 per cent of the world's total carbon dioxide emissions, its inhabitants are poised to suffer disproportionately from the consequences of global climate change. The continent's capacity to adapt to climate change is relatively low, with projected costs estimated to reach at least 5-10 per cent of GDP.

Refugee migrations are also causing further pressure on the environment, with major population movements due to conflict but also increasingly as a result of food and water shortages. Cooperative approaches involving several bordering countries are becoming essential for the conserving and enhancing of shared ecosystems if they are to remain productive into the 21st century.