Potentially, that could threaten food and water supplies to millions of people living in some of the world’s poorest regions, the study warned. “In the subtropics this [decrease] is devastating,” said the research centre’s Kevin Trenberth, “but the continent affected most is Africa. The prospects generally are for rainfalls, when they do occur, to be heavier and with greater risk of flooding and with longer dry spells in between, so water management becomes much more difficult.”
The scientists examined recorded data and computer models of flow in 925 rivers, representing 73% of the world’s supply of running water, from 1948-2004. Climate change had made an impact on about a third of the major rivers, they found. More than twice as many rivers experienced diminished flow as saw a rise in water levels.
Other big rivers in Asia, such as China’s Yangtze and India’s Brahmaputra, remained stable or registered an increase in flow, the study showed. But the scientists said they too could begin shrinking because of the gradual disappearance of the Himalayan glaciers.
See full story