2.1. Introduction

This chapter focuses on the potential impacts of climate change on ecosystems, natural resources, and various socioeconomic sectors of mainland Africa. To the extent permitted by the literature, it describes the functions and current status of a number of key resource sectors and ecosystems; the ways in which these systems would respond to changes in climatic conditions; options for adaptation to projected changes in climate; and the vulnerability of each system or sector, taking into account adaptation options as well as impediments to their implementation. Downing (1992, 1996) suggests that vulnerability is an aggregate measure of human welfare that integrates environmental, social, economic, and political exposure to a range of potentially harmful perturbations or threats. Vulnerability varies spatially and temporally for different communities, although they may face the same risk (Eele, 1996). Feasible strategies for coping with future climate changes therefore must be rooted in a full understanding of the complex structure and causes of present-day social vulnerability, through an understanding of vulnerability to climatic variability on seasonal to interannual time scales.

Although Africa, of all the major world regions, has contributed the least to potential climate change because of its low per capita fossil energy use and hence low greenhouse gas emissions, it is the most vulnerable continent to climate change because widespread poverty limits capabilities to adapt. The ultimate socioeconomic impacts of climate change will depend on the relative resilience and adaptation abilities of different social groups. In general, the commercial sector and high-income households in communal areas are better equipped to adjust adequately and in a timely fashion. Much will depend on the coping abilities and mechanisms used by governments and households over the next 50 years or so. Such abilities are determined by political stewardships. If the region manages to achieve reasonable economic growth, the prospects for proper adjustments to climate change are much better than if economic stagnation prevails (Hulme, 1996b).

Figure 2-1: The Africa region [compiled by the World Bank Environment Department Geographic Information System (GIS)].

2.1.1. Physical Geography

Africa has a total land area of 30,244,000 km². Countries considered in this chapter are listed in Box 2-1, and socioeconomic data are provided in Annex D.

Africa's physical features include a series of plateaus, higher in the east and gradually declining toward the west. The general elevation is relieved by great shallow basins and their river systems; by the deep incision of the 6,400-km Great Rift Valley; and by often-magnificent volcanoes, fault blocks, and inselbergs. Figure 2-1 shows capitals, other major cities, and elevations. The highest point is Mount Kilimanjaro (5,894 m); the lowest point is in the Qattara Depression, at 132 m below sea level. Africa's vast plateaus are broken only by a few rather low mountain ranges-of which the outstanding ones are the Atlas, Ahaggar, Cameroons, Tibetsi, and Ethiopian and east African highlands, as well as the Drakensberg Mountains. In east Africa are (in addition to Kilimanjaro) Mount Kenya (5,199 m), the Ruwenzoris (5,120 m), and Mount Elgon (4,321 m) (Pritchard, 1985).

The African continent encompasses a rich mosaic of ecological settings. Together these ecosystems harbor a wealth of economically and biologically important resources, from individual species to productive habitats (Huq et al., 1996). One quarter of Africa is hyper-arid desert; one third is in the humid climate zone; and the remainder of the continent is dryland, consisting of arid, semi-arid, and dry subhumid areas (UNEP, 1992). These drylands are home to about 400 million people-two-thirds of the continent's total population. Recurrent droughts have long been a permanent feature of life throughout the drylands of Africa. Over the past 30 years or so, however, unusually severe and/or prolonged droughts in these drylands have seriously affected agriculture and wildlife and caused many deaths and severe malnutrition. In some areas, desertification has accompanied these droughts, although the processes leading to desertification are much more varied than climate alone. Currently, 36 countries in Africa are affected by recurrent drought and some degree of desertification (UNEP, 1992). The risk of drought is highest in the Sudano-Sahelian belt and in southern Africa (Nicholson et al., 1988).

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