- Climate change is expected to shrink many African rivers dramatically, triggering massive refugee movements and even war, according to scientists at the Africa Earth Observatory Network.
Researchers calculate that a predicted drop in rainfall will significantly reduce water supplies across a quarter of Africa by the end of this century, in a study published in the journal Science.
"Future climate change poses one of the greatest threats to poverty eradication on this continent, and related changes in surface water supply will exacerbate this," they warn.
Some 300 million Africans have no access to safe drinking water, and 313 million lack basic sanitation. Africa has an estimated population of over 800 million. The United Nations said on Sunday that, with the exception of Uganda and South Africa, sub-Saharan Africa is failing to meet U.N. targets set at the start of the millennium to halve the number of people without access to clean water or sanitation by 2015.
The AEON study - the first to examine the impact of climate change on Africa&${esc.hash}39;s rivers in such detail - points out that 75 percent of African countries fall at least partly into a rainfall band where changes in precipitation have a surprisingly large impact on surface drainage.
The research found that, in regions receiving 500mm of rain per year, a 10 percent fall in precipitation would cut surface water by 50 percent.
WATER REFUGEES AND WARSMaarten de Wit, a University of Cape Town professor and co-author of the study, said: "For those who already walk to rivers to get water, the question will be: should I move to another village? This is going to cause mass migration - in some cases across national borders - and it is going to have huge political implications."
He added that the potential number of "water refugees" could not yet be estimated, but the problem would be serious enough to require a co-ordinated response by African governments.
De Wit also warned that, with all major African rivers crossing international boundaries, there is a potential for conflicts over water resources to erupt into wars.
To reduce that risk, the study recommends that African countries that share river basins must address the issue of future access to water. It also proposes that states should focus their responses on rural areas where the risk of water loss is high and more likely to create scarcity.
"Politicians really need to focus on these issues now. If you put the numbers on the table, as we have done, then there will have to be some serious thinking about measures such as water basin management. This has to happen on a regional basis," de Wit told AlertNet.
CAPE TOWN AT RISKThe study highlights two areas likely to suffer most from reduced access to water: southern Africa and the Sahel strip stretching from Senegal to Sudan.
In southern Africa, areas near Cape Town are predicted to be hit hardest by an expected 20 percent drop in rainfall by 2070, reducing perennial water supply by nearly 60 percent.
"This region is South Africa&${esc.hash}39;s bread basket. People in Cape Town have not seen figures like this before, and I think they are quite frightened," said de Wit.
The upper reaches of the Orange River in southeast Africa are also forecast to experience strong to moderate decreases in water supply.
This would have a knock-on effect in southwest Africa, because the river is one of the area&${esc.hash}39;s key sources of water. Today this region is experiencing its biggest drought in over 100 years.
According to de Wit, a reduction in water supplies in the Sahel area is likely to have a major impact on the rural population. "There are already women having to walk around 25km to fetch water - maybe they&${esc.hash}39;ll have to walk 50-60km in 50 years&${esc.hash}39; time. Are they going to decide to move elsewhere instead?"
In East Africa, however, climate change models suggest rainfall could actually increase, and water supplies may improve. Somalia, for example, is expected to see a 20 percent rise in precipitation, boosting the water it receives from rivers by ten times.
One negative impact of higher rainfall may be that it creates the conditions for mosquitoes to breed, exacerbating the incidence of malaria.
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