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Climate change will have various effects on water resources and water management in Africa. The large variability in projected climate scenarios over Africa's most vulnerable river basin systems (such as the Nile) makes any policy reformulation in anticipation of climate change difficult. However, improved efficiency in irrigation systems and water use are strongly recommended modes of action because they will benefit the region regardless of the degree and direction of climate change. Detailed studies of the river basins are essential to provide adequate information for planning and negotiation purposes in this area that will continue to generate tension across many borders.
Sharma et al. (1996) have evaluated the sub-Saharan African countries with respect to their degree of national commitment and planning to address water problems in general and have developed a list of country performance indicators (Table 2-5). Columns 4-7 describe the enabling environment; columns 1 and 2 are poverty indicators; and columns 1, 2, and 3 are risk indicators, where problems will call for either more water or more efficient management of existing stocks. The following points are critical:
Knowledge also is needed about multiple cross-sectoral linkages relating to a nation's water development (competing demands from agriculture, industry, and municipalities; reliance upon international waters). Depending on how a country fares with regard to the three critical points above, the types of efforts and interventions required by funding agencies and nations will vary. Countries that fare poorly in this analysis will be most vulnerable to climate changes because they will have less capacity to adapt.
Many indicators of human development highlight Africa's relative poverty and
vulnerability (Table 2-6). With smaller holdings and
little investment in agriculture, household production faces difficulties in
meeting subsistence requirements or developing specialized export crops. Household
expenditures on food are high-more than half of the annual budget, on average.
Africa receives the largest amount of food aid of any continent. Low rates of
female literacy and high rates of infant mortality are indicative of populations
that have low status and inadequate infrastructure for education and health-two
essential requirements for vigorous rural development. The high numbers of refugees
highlight potential economic and political instability. Vulnerable populations
include smallholder agriculturists with inadequate resources, pastoralists,
rural landless laborers, and the urban poor. Rural populations are directly
affected by climatic variations. Reduced food supplies and high prices immediately
affect landless laborers who have little savings. The effect on agriculturists
and pastoralists depends on how much surplus they produce and the relative terms
of trade (e.g., between food and livestock). A dramatic increase in urban poverty
has been noted in the past decade-one consequence of stagnant rural development
and high population pressures. The urban poor are indirectly affected by climate
change through changes in prices and regional investment.
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Extensive droughts have afflicted Africa, with serious episodes since independence in 1965-1966, 1972-1974, 1981-1984, 1986-1987, 1991-1992, and 1994-1995 (WMO, 1995; Usher, 1997). The causes of African drought are numerous and vary among regions, seasons, and years. Local droughts occur every year; continental crises appear to occur once (or more recently twice) every decade. Major droughts tend to be connected to ENSO anomalies. It seems prudent to expect drought in Africa to continue to be a major climatic hazard. The potential effect of climate change on drought in Africa is uncertain. At a local level, increased temperatures are likely to lead to increased moisture demand. The balance between rainfall and higher evapotranspiration implies more frequent water scarcity. However, a great deal depends on vegetation response to higher CO2 concentrations and the timing of rainfall. The combination of higher evapotranspiration and even a small decrease in precipitation could lead to significantly greater drought risks. An increase in precipitation variability would compound temperature effects. For example, Hulme (1996b) reports that interannual variability increases on the order of 25% in much of southern Africa in the UKTR scenario for the 2050s. Within the region, however, some areas experience a similar decrease in variability. The temperature-precipitation-CO2 forcing of seasonal drought probably is less significant than the prospect of large-scale circulation changes that drive continental droughts that occur over several years. A change in the frequency and duration of atmosphere-ocean anomalies, such as the ENSO phenomenon, could force such large-scale changes in Africa's rainfall climatology. However, such scenarios of climate change are not well developed at the global level, much less for Africa. The effects of drought are cross-cutting, with severe direct impacts on agriculture, water resources, and natural vegetation and indirect effects on health, the economy, and institutions (see Benson and Clay, 1994, for an overview of drought impacts). The impacts of drought are confounded by environmental degradation, including soil erosion, water pollution, and deforestation. Intersectoral linkages, the diversity of the economy, the numbers of vulnerable people, the intensity of water use in the economy, the role of financial systems and public enterprises, and public revenue and expenditure affect the severity and distribution of drought impacts. Drought in the 1960s, 1970s, and 1980s triggered widespread starvation and loss of life, particularly in the Sahel and the Horn of Africa. Similar famine has been averted in the 1990s through more effective early warning systems and responses. The aggregate impact of drought on the economies of Africa can be large: 8-9% of GDP in Zimbabwe and Zambia in 1992, 4-6% of GDP in Nigeria and Niger in 1984 (Benson and Clay, 1994). The 1991-1992 episode in southern Africa amply illustrates the impact of drought. In that episode, the SADC countries experienced the worst drought of the century: From central Zambia through central Malawi and Mozambique southward, there were seasonal deficits of as much as 80% of normal rainfall (Zinyowera and Unganai, 1993). Large sections of the SADC subregion received scanty rainfall-20-75% of normal-during the rainy season from October 1991 through April 1992. Abnormally high temperatures (47�C along the South Africa-Zimbabwe border) exacerbated the extreme dryness. Regional grain production fell 60% short of expected levels. Food stocks had been depleted, largely as a consequence of exports. Roughly five times more food had to be brought into southern Africa than had been delivered to the Horn of Africa during the famine of 1984-1985. Six different transport corridors were used to deliver food aid, and 11 countries assisted in trying to alleviate the crisis wrought by the drought. Even though 1992-1993 and 1993-1994 could be considered post-drought periods, recovery in the subregion was slow. Nutritional status was affected by crop failure, depending on alternative sources of income and drought responses. The number of food-insecure households among communal farmers in Zimbabwe more than doubled during the 1991-1992 drought, especially in semi-arid zones (Christensen and Stack, 1992). The level of the reservoir at Kariba Dam, which supplies power to Zambia and Zimbabwe, fell below the level required to generate hydroelectric power (see IUCN, 1994). Water shortages, electricity shortages and rationing, input supply difficulties, reduction in demand, and macroeconomic constraints led to a 9% reduction in manufacturing output in Zimbabwe, with a 6% loss in foreign currency receipts (Benson and Clay, 1994). |
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