Monday, May 11, 2009

The melting ice sheets of the world: What will it mean in Central Asia?

Joseph Romm tells us that Bolivia’s 18,000 year-old Chacaltaya glacier is gone. Chacaltaya glacier was famous because it has been studied for many years. One reason for the scholarly interest in Chacaltaya has been its location on the equator where the shifts in the axes of the earth have had a different effect from the ice sheets at the poles. It provided information on the history of the earth that some other glaciers did not. Now it's gone. [Click on the title for a link to his article.]

This is not to lament the loss of a famous glacier so much as to use the occasion to reflect on what it could mean if the glaciers of the Himalayas would similarly disappear. Joseph Romm reminds us that the waters that run off in spring provide the surface flows that enable the irrigation of crops; millions of people live on water that originates as glacial runoff. The runoff of the winter snows on the mountains, which replenish the glacial ice, also supply the aquifers that supply wells and sometimes rise to the surface further downstream.

So when he tells us that there is already massive loss of glacier ice in the Himalayas comparable to the loss of glaciation in South America Romm is sounding a warning about the eventual risks for populations who depend on the water flows from the great ice-covered mountains of Inner Asia -- altogether a substantial portion of the world's populations. Romm quotes a report by Swiss geologists who say that as many as half a billion people are at risk.

An eventual problem that could further complicate affairs in an already complicated social world.

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