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Himalayan Glaciers Retreating at Accelerated Rate in Some Regions but Not Others

Posted on 17 September 2012 by John Hartz

This is a reprint of a news release posted by the US National Research Council on Sep 12, 2012.

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Consequences for Water Supply Remain Unclear, Says New Report

Photo of Mt. Taboche in the Khumbu Valley, Nepal

Mt. Taboche in the Khumbu Valley, Nepal. Image source: Alton Byers, Khumbu, Nepal, The Mountain Institute,

Glaciers in the eastern and central regions of the Himalayas appear to be retreating at accelerating rates, similar to those in other areas of the world, while glaciers in the western Himalayas are more stable and could be growing, says a new report from the National Research Council.

The report examines how changes to glaciers in the Hindu Kush-Himalayan region, which covers eight countries across Asia, could affect the area's river systems, water supplies, and the South Asian population. The mountains in the region form the headwaters of several major river systems -- including the Ganges, Mekong, Yangtze, and Yellow rivers -- which serve as sources of drinking water and irrigation supplies for roughly 1.5 billion people.

The entire Himalayan climate is changing, but how climate change will impact specific places remains unclear, said the committee that wrote the report. The eastern Himalayas and Tibetan Plateau are warming, and the trend is more pronounced at higher elevations. Models suggest that desert dust and black carbon, a component of soot, could contribute to the rapid atmospheric warming, accelerated snowpack melting, and glacier retreat.

Photo of Chhota Shigri Glacier in the Indian Himalaya

Researchers stand on the Chhota Shigri Glacier in the Indian Himalaya. Image source: Mark W. Williams, University of Colorado, Boulder.

While glacier melt contributes water to the region's rivers and streams, retreating glaciers over the next several decades are unlikely to cause significant change in water availability at lower elevations, which depend primarily on monsoon precipitation and snowmelt, the committee said. Variations in water supplies in those areas are more likely to come from extensive extraction of groundwater resources, population growth, and shifts in water-use patterns. However, if the current rate of retreat continues, high elevation areas could have altered seasonal and temporal water flow in some river basins. The effects of glacier retreat would become evident during the dry season, particularly in the west where glacial melt is more important to the river systems. Nevertheless, shifts in the location, intensity, and variability of both rain and snow will likely have a greater impact on regional water supplies than glacier retreat will.

Melting of glacial ice could play an important role in maintaining water security during times of drought or similar climate extremes, the committee noted. During the 2003 European drought, glacial melt contributions to the Danube River in August were about three times greater than the 100-year average. Water stored as glacial ice could serve as the Himalayan region's hydrologic "insurance," adding to streams and rivers when it is most needed. Although retreating glaciers would provide more meltwater in the short term, the loss of glacier "insurance" could become problematic over the long term.

Water resources management and provision of clean water and sanitation are already a challenge in the region, and the changes in climate and water availability warrant small-scale adaptations with effective, flexible management that can adjust to the conditions, the committee concluded. Current efforts that focus on natural hazard and disaster reduction in the region could offer useful lessons when considering and addressing the potential for impacts resulting from glacial retreat and changes in snowmelt processes in the region.

Many basins in the region are "water-stressed" due to both social changes and environmental factors, and this stress is projected to intensify with large forecasted population growth, the committee concluded. Climate change could exacerbate this stress in the future.

Although the history of international river disputes suggests that cooperation is a more likely outcome than violent conflict in this region, social conditions could change. Therefore, modifications in water supplies could play an increasing role in political tensions, especially if existing water management institutions do not evolve to take better account of the region's social, economic, and ecological complexities, the committee said.

The National Research Council, the operating arm of the National Academy of Sciences and National Academy of Engineering, is an independent, nonprofit institution that provides science and technology advice under a congressional charter granted to the NAS in 1863.

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Comments 1 to 9:

  1. India has had a sub-standard monsoon season this year. Pakistan last year and 2 years ago lost almost all of their agriculture to floods. I wonder if the ice in the Himalayas could act as a rudder/buffer to stabilize the local climates. The loss of ice and snow cover could effect more than simply river flow.
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  2. Previous mentions of these more stable glaciers usually place them, rather than in the "western Himalayas", more specifically in the "Karakoram Range". "...a part of the greater Himalaya while north of the actual Himalaya Range." "The Karakoram is home to the highest concentration of peaks over 8000m in height to be found anywhere on earth..." "A significant part, 28-50% of the Karakoram Range is glaciated, compared to the Himalaya (8-12%) and European Alps (2.2%)." Per a 2011 study, the glacier retreat is less than in the Himalayas because "many Karakoram glaciers are covered in a layer of rubble which has insulated the ice from the warmth of the sun. Where there is no such insulation the rate of retreat is high." (Wikipedia) However, climate is the more frequent explanation.
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  3. SOF is correct it is not correct to refer to the Karokoram as the western Himalaya. The headline also gives the idea that there is a balance between those retreating faster and not. This is also not true, note the quite detailed look at inventory data from across the region published in BAMS 2011 but at SkS too. The retreat is widespread and getting more rapid as far west as the Himachal Pradesh, 1000 km west of Mount Everest.
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  4. Isn't this just about what one would expect. If climate change is causing more precipitation, glaciers which are high enough and hence cold enough should grow while lower glaciers should retreat. As the temperature ramps up, higher and higher glaciers will be retreating. Here in New Zealand, two of our glaciers, Fox and Frans Yosef flow down into temperate zones. They can only manage this because of the stupendous amounts of precipitation as snow where they start. Over all they are retreating but a particularly high snow fall leads to advances a few years later.
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  5. William the mountains are high everywhere in these ranges. It is that the Karokoram is less affected by the summer monsoon and has a greater percentage of total snowfall occur during the summer that makes them different. The glaciers around the highest mountain in the world are all retreating, Imja Glacier, Ngozumpa Glacier, Khumbu Glacier etc
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  6. The abstract of "Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings", a letter that appeared in Nature in July 2012,said "The Tibetan Plateau and surroundings contain the largest number of glaciers outside the polar regions1. These glaciers are at the headwaters of many prominent Asian rivers and are largely experiencing shrinkage[2], which affects the water discharge of large rivers such as the Indus[3,4]. The resulting potential geohazards[5,6] merit a comprehensive study of glacier status in the Tibetan Plateau and surroundings. Here we report on the glacier status over the past 30 years by investigating the glacial retreat of 82 glaciers, area reduction of 7,090 glaciers and mass-balance change of 15 glaciers. Systematic differences in glacier status are apparent from region to region, with the most intensive shrinkage in the Himalayas (excluding the Karakorum) characterized by the greatest reduction in glacial length and area and the most negative mass balance. The shrinkage generally decreases from the Himalayas to the continental interior and is the least in the eastern Pamir, characterized by the least glacial retreat, area reduction and positive mass balance. In addition to rising temperature, decreased precipitation in the Himalayas and increasing precipitation in the eastern Pamir accompanied by different atmospheric circulation patterns is probably driving these systematic differences." the letter is worth a look
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  7. As the temperature ramps up, higher and higher glaciers will be retreating. Here in New Zealand, two of our glaciers, Fox and Frans Yosef flow down into temperate zones.

    <snip of advertising link>

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    Moderator Response:

    [PS] Perhaps you were making a subtle point, but the provided link looks like spam to me. Spamming on this site results in instant and permanent ban. I am giving you benefit of doubt this time but you are not spelling Franz Joseph the way a local would so count me highly suspicious.

  8. Hey! Have we got a JAFA for a moderator? 

    It's Franz Josef!

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    Moderator Response:

    [PS] Blush! (and I am a southerner not a JAFA).

  9. As a non-Kiwi, I was puzzled as to what a JAFA was.  It turns out it refers to residents of Auckland (New Zealand's major city).

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