Settling the science on Himalayan glaciers

[OKIsItJustMe]

http://www.nature.com/climate/2010/1003/full/climate.2010.19.html

Nature Reports Climate Change
Published online: 2 March 2010 | doi:10.1038/climate.2010.19

Settling the science on Himalayan glaciers

The remote glaciers of the Himalayan mountains have been the subject of much controversy, yet little research. Mason Inman looks at the clues scientists have garnered on the fate of these glaciers from ground- and space-based studies.

“Every morning you have to rise and decide that it might be a good day not to die,” says John Shroder of the University of Oklahoma at Omaha, who has spent decades studying the glaciers of the Karakoram and Himalayan mountains, stretching from Pakistan in the west across India and into Nepal in the east. “Just getting to base camp at K2”, in Pakistan, the world's second tallest peak, “is an arduous trek,” he says, listing the innumerable hazards en route: rock falls, heatstroke, dehydration, freezing and diarrhoea, among others.

But such dangers are the least of the difficulties facing researchers who study these mountain ranges. Often called the world's highest battleground, the Siachen glacier has been the site of a standoff between the Indian and Pakistani armies for decades. Pakistan's mountains provide a stronghold for Taliban insurgents, and in Nepal, Maoist rebels are holed up in the Himalayas. Several countries in the region limit access to maps and photography of their borderlands. Glaciologists who want to climb these peaks, measuring the terrain using high-tech equipment, aren't always welcome.

So it's no surprise that field studies have been scarce on glaciers in this part of the world and that scientists have yet to paint a clear picture of how the region is expected to change in the coming decades. This question is not only academic, as rivers that feed more than half a billion people in Pakistan, India and Bangladesh all have their origins in the snow-covered peaks of the Himalayas and Karakoram.

One thing is clear: the glaciers won't vanish by 2035, as the Intergovernmental Panel on Climate Change (IPCC) claimed in its 2007 assessment report^{http://www.nature.com/climate/2010/1003/full/climate.2010.19.html#B1">1}. This error and others in the IPCC report's section on Himalayan glaciers — widely reported elsewhere^{http://www.nature.com/climate/2010/1003/full/climate.2010.19.html#B2">2} — have now been corrected. But the ensuing furore has highlighted how little is actually known about the fate of glaciers in this region. The errors “were mainly based on the desire to say something”, says glaciologist Richard Armstrong of the National Snow and Ice Data Center in Boulder, Colorado. “But you need to know that if there's no data, you shouldn't say anything.”

As it stands, no one is even sure how many glaciers are in this part of the world. Current estimates suggest there are about 12,000 to 15,000 in the Himalayas and about 5,000 in the Karakoram. Of these thousands of glaciers, only 15 have been measured on the ground to see if they are gaining or losing ice overall. Despite the scarcity of data, trends are emerging. “It is pretty clear that the Himalayan glaciers have been losing mass, with markedly greater loss in the past decade than earlier,” says geographer Graham Cogley of Trent University in Peterborough, Ontario.

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