What is happening in some parts of world, particularly Africa, is pointing to what professor Maarten and Jacek Stankiewicz had predicted.
According to Professor Maarten de Wit and Jacek Stankiewicz supplies of water could be significantly be depleted by climatic change by the 21st century.
They say small reductions in rain would affect the rivers saying most of the rivers would dry up.
In the Sahel in Kenya , there has been on average a 25 per cent decrease in annual rainfall over the past 30 years . This is nowhere more apparent than in the Turkana region of Northwest Kenya. According to Intergovernmental Panel on Climate Change (IPCC), Agriculture in Sub-Saharan Africa – of which up to 90 per cent is rain fed – accounts for 70 per cent of the region’s employment and 35 per cent of its gross national product (GNP).
While many farmers have successfully adapted to slow changes in the region’s climate, the level of unpredictability which global warming introduces may overwhelm their capacities to cope. Crop yields in Sub-Saharan Africa are projected to fall by 20 per cent under global warming. Tropical and subtropical areas will be hardest hit.
For 40 years there have been five major droughts in Turkana. Rains were sporadic and inconsistent in 1960, 1970 as well as 1979-1980.
There was then a gap of 12 years before the prolonged four-year drought of 1992-95.
During this time some livestock died and non governmental organizations came into the area to give people food before they could starve to death, according to Intergovernmental Panel on Climate Change (IPPC), a grouping of many non governmental organizations involved in global climatic change.
The non governmental organization , under the chairmanship of Dr R K Pachauri, say The nomads of Turkana are paying with their lives and their way of life for the profligate consumption of fossil fuels by others .
The report concurs with Southern Africa Development Community(SADC) Report edited by Mike Hulme from Climatic Research Unit, School of Environmental Sciences at the University of East Anglia . According to the report, Rainfall in the region is variable from year-to-year and droughts have always occurred from time-to-time. Hulme says the last twenty years have seen a trend towards reduced rainfall and, during the early 1990s, two or three serious droughts occurred.
He said the decade 1986-95, as well as being the warmest this century, Have also been the driest.