Setting the Scene: The Sub-Saharan Africa Context | 5

in Africa including several species of millet and sorghum, the oil palm and coffee (UNEP, 2006a). The Afrotropic terrestrial realm is among the most productive in terms of net primary productivity and biomass values (MA, 2005b), suggesting that agricultural output in this region could also be highly productive under suitable conditions.

Principal threats to biodiversity in Africa include land use and land cover change, mainly through conversion of natural ecosystems, particularly forests and grasslands, to agricultural land and urban areas. It is likely that land clearing and deforestation will continue and hence threaten genetic diversity as species loss occurs.

Only about 6% of sub-Saharan Africa, or 142 million ha, falls under protected areas (WRI, 2005), with the best protected being the savannah habitats of eastern and southern Africa, while the least protected are found in Madagascar, the drier parts of South Africa, and the most heavily deforested parts of West and East Africa (Figure 1-3). Plants are also less well covered by the network of protected areas than charismatic animals, such as large mammals (UNEP, 2006a). Forests
About 19% of the land area of SSA is classified as forest (defined as more than 10% tree cover) although estimates range between 18-52% depending on the percentage tree covers (WRI, 2005). The percentage of an individual country covered by forests ranges from a high of 85% in Gabon to a low of 0.5% in Lesotho (FAO, 2007a). The greatest extent of forest cover is found in Central Africa—the Congo basin covers 200 million ha and is the world’s second largest continuous tropical rain forest after the Amazon (Bruinsma, 2003). Other significant areas include the Guinea Forest of West Africa, the Eastern Arc Mountain Forests of East Africa, the Mopane and Miombo woodlands of southern Africa and in eastern Madagascar.

Forests and woodlands are facing increasing pressures from a growing human population including encroachment and conversion for agricultural expansion, illegal logging and poaching of wild animals, overgrazing leading to loss of woody vegetation, and the impacts of conflicts. One of the prominent forest cover changes in sub-Saharan Africa has been in the sub-tropical dry Miombo forests in southern Africa (Lepers et al., 2005).

Forests provide a number of important ecosystem services: provisioning services such as supplying timber and non-timber forest products including wild foods, medicines, pharmaceuticals and genetic resources; regulating services such as flood and climate regulation; cultural services including spiritual, aesthetic, as well as recreational values; and supporting services including primary production, nutrient cycling and soil formation. The large majority of households in sub-Saharan Africa, rural and urban, still depend on biomass in the form of wood or charcoal for their energy needs and many also depend on wood and fiber for their shelter and household items, and for income generation (see SSA Chapter 2). Climate
Climate variability is the single most important atmospheric phenomena in sub-Saharan Africa. The region experiences a


high degree of variability and uncertainty in climatic conditions, with associated droughts and floods, which occur regularly (UNEP, 2002a). A recent analysis of long-term trends (1900 to 2005) indicates rising temperatures in Africa as a whole, as well as drying, or decreased precipitation, in the Sahel and southern Africa (IPCC, 2007a). In addition, the El Nino Southern Oscillation (ENSO) causes significant climatic disturbances in many parts of the continent, either inducing drought or flooding, or increasing sea temperatures, which lead to cyclones, particularly over the Indian Ocean. Overall, longer and more intense droughts have been observed since the 1970s, particularly in the tropics and sub-tropics (IPCC, 2007a).

Generally the continent suffers from relatively little atmospheric pollution, except in major cities where emissions from industry, motor vehicles and household use of biomass for energy are rising (UNEP, 2006a). Nevertheless, sub- Saharan Africa is the most vulnerable region to the impacts of climate change (IPCC, 2007b) and yet it contributes the least in terms of greenhouse gas (GHG) emissions such as carbon dioxide, the principal GHG responsible for global warming. The region only contributes about 2-3% of global CO2 emissions from energy and industrial sources. On average 0.8 tonnes per capita were released in 2000 compared with a global per capita average of 3.9 tonnes (12.4 tonnes per capita in high income countries and 19.8 tonnes per capita in the United States, the world’s highest emitter) (UN, 2006; World Bank, 2006). In other words, an inhabitant of the USA emits about 24 times as much CO2 as an inhabitant of sub-Saharan Africa.

There is now unequivocal evidence that the climate system is warming, and that this is very likely a result of observed increases in anthropogenic GHG levels. These increases result primarily from agriculture—both from inputs such as fossil fuels, and land-use changes associated with agricultural practices (IPCC, 2007a). Climate data for Africa for the last 30 to 40 years shows that if the current trends continue, by 2050, SSA will be warmer by 0.5 to 2 C°, and drier, with 10% less rainfall and water loss exacerbated by higher evaporation (Nyong, 2005). Sub-Saharan Africa is vulnerable to climate change and global warming because of widespread poverty and limited adaptive capacity (IPCC, 2007b). The impact of these climatic changes are already manifesting in SSA as evidenced by the loss of 82% of ice mass on Kilimanjaro mountain, 40-60% decrease in available water in Niger, Senegal, and Lake Chad during the last two centuries (CBD, 2007). The impacts of climate change are likely to be manifest at various spatial and temporal scales. These include sea level rise and flooding of low-lying coastal and estuarine areas (among the most densely populated). Climate change will particularly affect small islands such as those of the western Indian Ocean (e.g., Seychelles, Comoros and Mauritius) as well as mangrove forests, with consequences for coastal fisheries.

Changes in rainfall and temperature patterns are likely to negatively affect water availability and growing conditions, reducing food production and security, as well as hydroelectricity production. Biodiversity and ecosystems, including agroecosystems, are likely to be severely affected as many species may not be able to adapt or migrate to more suitable areas. The intensity of tropical cyclones is also