The drought, famine and spreading deserts that have plagued Africa for the past 30 years look set to get worse as the global climate changes.
Most Africans live between the parched deserts and dripping rainforests in regions of variable rainfall where small changes have big impacts on water and food supplies. To assess future vulnerability, Maarten de Wit of the University of Cape Town in South Africa used existing hydrological data to calculate the likely effects of expected climate change on 2 million kilometres of the continent鈥檚 rivers (Science, DOI: 10.1126/science.1119929).
The 100 million or so people living in southern Africa face 鈥渁 very disturbing situation鈥�, he concludes. With several studies predicting a 10 per cent cut in rainfall across the region by 2050, de Wit calculates that the flow in the region鈥檚 rivers will fall by as much as half.
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The Orange river is the continent鈥檚 fifth largest, and one of the few perennial sources of water supply in south-western Africa, yet it will be among the worst hit. The severest drought in 100 years in the region has already led to little water being discharged from the river鈥檚 dams.
Other unstable areas include east Africa, parts of which may become wetter, although only by a relatively small amount, the headwaters of the Nile and much of the Sahel region on the southern fringes of the Sahara desert. Trends in rainfall in these areas are less clear than for southern Africa, which faces rampant desertification.
