Fear over shrinking Himalayan glaciers allayed
Glacier systems that feed two key rivers in South Asia will badly retreat this century, but demands for water are still likely to be met, a study predicted.
The health of glaciers in the Himalayas is a closely-watched issue, as they supply vital meltwater to a region facing surging population growth and rising demands for food.
Scientists agree that the onward march of the greenhouse effect will shrink the glaciers, but there is little consensus on the volume and rate of ice loss and the impact on water availability.
Dutch scientists led by Walter Immerzeel at Utrecht University did a computer simulation of what could happen to two glacial watersheds - the Baltoro, which drains into the Indus, and the Langtang, which feeds the Ganges - in two scenarios for global warming, comprising a modest and a strong rise in temperatures.
The two glaciers will shrink badly - by 2100, they will lose roughly half their volume under the higher warming scenario. But, at least as far as this century is concerned, water users will not experience scarcity, in part because the extra meltwater will help meet rising needs.
"In both cases glaciers will retreat, but net glacier melt run-off is on a rising limb at least until 2050," said the study.
"In combination with a positive change in precipitation, water availability this century is not likely to decline. We conclude that river basins that depend on monsoon rains and glacier melt will continue to sustain the increasing water demands."