The Hot Zone

In Himalayas rocks buffer retreat of glaciers

Posted by Alison Hawkes on January 24, 2011
Category : Climate Science and Scientists

Ever since the Intergovernmental Panel on Climate Change erroneously reported that the Himalaya mountains would be glacier-free by 2035, the actual fate of the world’s highest range has been questioned.

An accurate picture has been hard to develop because of differences in retreat rates and a lack of basic data on the glaciers. One study published this week in the journal Nature Geoscience sheds some new light on mountaintop glacial dynamics in the Himalayas. Lead author Dirk Scherler from the Institute of Geoscience at the University of Potsdam, Germany, found that some of the glaciers in the Himalayas are relatively stable because of the prevalence of rocks underneath.

In the Himalayas, glacial melt is happening unevenly as rock cover emerges as stabilizing force. Photo: Reurinkjan on Flickr

It appears that having a rocky base to a glacier helps insulate the cold, even as atmospheric temperatures rise. They call them “debris-covered glaciers,” and they’re present in rugged central part of the Himalayas, although not the Tibetan plateau where retreat rates are higher.

The good news, the researchers report, is that more than 50 percent of the glaciers in the Karakoram region in the northwestern Himalaya are advancing or stable, buffering them a bit from the effects of climate change.

The researchers used satellite data to estimate ice changes in 255 of the Himalaya’s 286 glaciers between 2000 and 2008. The highest concentration of retreating glaciers, and those at the highest rates, also had low amounts of debris, the researchers reported.

All this has important implications on future water resources for the region. The researchers say that rocky glaciers should factor into the equations of climate change impacts, and not just those glaciers that are melting fastest. They write:

For realistic predictions of future water availability, and global sea-level change, debris cover and its influence on glacial-melt rates should be added to analyses that have determined glacier mass balances using data from mostly debris-free glaciers

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