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Glacier Responses to Climate Change are Complex, as are the Impacts

By Guest Writer

Feb 7, 2010

By Kenneth Hewitt, China Dialogue
Part I of a three-part series

Glaciers are quite sensitive to climate change and, recently, there have been many reports of major changes in the Himalaya and other parts of High Asia; mostly of glaciers retreating fast. Impacts of a range of glacier hazards, and on the reliability of water resources, are of concern at local, national and transnational scales.

However, there is also a growing recognition that glacial conditions in the region are very diverse, and so are their responses to climate change.

There are some very different implications in different societal contexts, not least in relation to rapid socio-economic changes, water resource projects and security crises. The latter are often more urgent or immediate problems that disrupt or undermine peoples’ capacities to adapt to environmental change. Such complexities are the focus of this article.

The reality of climate change is not questioned, but some recent oversimplifications are, and claims about a narrow range of glacier hazards. In particular, unresolved problems of understanding high altitude glaciers and climate are emphasized, and the inadequacies of available information and monitoring. Recent evidence of glacier advances in the Karakoram Himalaya, and the author’s work there, illustrate many of these complexities.

Globally, most glaciers are reported to be diminishing more or less rapidly. Reports of “disappearing glaciers” have come from many parts of High Asia.

However, this is not the case in the upper Indus and upper Yarkand River basins. Here, the glaciers have been holding their own for several decades and recently, in the , many have started thickening and advancing. Not only is this opposite to the broader picture for Eurasian glaciers, but also to what had been happening to Karakoram glaciers.

Through most of the 20th century they, too, diminished and retreated. There is no question that today’s behaviour is a regionally distinct response to climate change. It may sound like good news, given the dominant lament for the loss of glaciers, but that too would be misleading. Advancing glaciers bring dangers as well.

Of immediate concern are a number of glaciers on the Indus and Yarkand Rivers, whose past advances gave rise to large ice dams and catastrophic outburst floods. In the longer term, existing and planned water resource uses, dependent on glacier-fed streams or at risk from glacial floods and sedimentation, are of major concern.

However, the largest challenges stem from inadequate information and monitoring, and limited scientific understanding of these high elevation glaciers. Misleading or exaggerated reports based on assumption rather than evidence are also a problem. Some have suggested that the Indus basin is in imminent danger of losing its glaciers. Glacier hazards, notably “” associated with retreating ice in other regions, have been assumed to be equally present in the Karakoram. The reports are simply wrong in this case.

Meanwhile, if the main trend in most of High Asia does seem to be glacier retreat, various lines of evidence show that it is occurring at very different rates in different mountain ranges, even within the same mountains.

A 2006 survey of 5,020 glaciers in the mountains of western China and the Tibetan Plateau found widely differing rates of reduction. It also found 894 glaciers, about 18%, have advanced in recent decades. The jury is still out on a from India, which questions the scale and reality of the extreme rates of retreat formerly reported for the Himalayas, and projections based on them.

None of this is to suggest that climate change is not a serious issue in the Karakoram.

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