a multiyear drought in western Pakistan to relatively unusual tropical depressions and cyclones hitting southern Pakistan. Floods in the main-stem Indus River in northwestern Pakistan are extremely rare; the historic 2010 floods were one such occurrence. Pakistan has the largest contiguous surface irrigation system in the world. Much of the water entering the system is withdrawn for irrigation purposes, reducing the amount of water available to flush the system. This leads to a reduction of channel capacity, which was one of the factors in the floods of 2010. Incorporation of concerns about differential vulnerability, environmental quality, and social equity will be critical to building a climate-resilient future for Pakistan. Pakistani water managers will have to incorporate local people’s multiple values for water within their management paradigms and seek to realize multiple social objectives from Pakistan’s water systems beyond just economic growth.

The Glaciers of the Hindu Kush-Himalayan
Region: A Summary of the Science Regarding
Glacial Melt and Retreat in the Himalayan,
Hindu Kush, Karakoram, Pamir, and Tien
Shan Mountain Ranges

Richard L. Armstrong, University of Colorado, Boulder

Many of the glaciers in the Himalayas are retreating, especially at the lower elevations in the eastern Himalayas. However, there is no spatially comprehensive or regionwide evidence to support the claim that the glaciers of the Himalayas are retreating faster than any other location in the world. Data are sparse in the region, but the most common is terminus location. The terminus is a point measurement intended to describe the glacier but it does not do an adequate job of describing the entire system. Conditions in the region contrast between the east and the west; data in the region should be compiled. In the east, the river runoff system is dominated by the monsoon. As you move to the west, glacial ice and seasonal snow play a much bigger role. In the west, both the seasonal snow cover and glacier volumes are much more stable that they are in the east. The fact that glaciers across the Himalayas may not be disappearing at as rapid a rate as had been previously thought does not in any way reduce the need for mitigation and adaptation to the response of these glacier systems to climate change in the region. In the short term, well-planned management, conservation, and efficient use of water currently available are certainly as important as any changes that may take place in the regional climate in the near future.

Glacial Lakes and Glacial Lake Outburst Floods
(GLOFs) in the Hindu-Kush Himalayas

Alton C. Byers, The Mountain Institute

As glaciers have melted in the Hindu Kush-Himalayas (HKH) and Andes, hundreds of new glacial lakes have formed behind dams usually consisting of soil and loose boulders. These lakes present a risk of glacial lake outburst floods (GLOFs). GLOFs often cause large loss of life and property downstream. Glacial lakes can become dangerous because they are held at bay by fragile terminal moraines that are susceptible to collapse (earthquakes, slides, etc.). When this breaks, the result is a GLOF. When overhanging ice is present, it can fall, and water can go over the wall. In terms of mitigation possibilities for this type of event, the Andes provide a good example. Between 1940 and 1950, they had several of these sorts of floods killing 10,000 people. In response, the government started working on how to control these floods through the fortification of the terminal moraine with a drainpipe or drilling through bedrock to create a canal to lower the lake level and use the water. A workshop and field expedition were held to discuss whether these technologies might be applicable in Nepal, and researchers discovered the value of local knowledge. The team formed a Global Glacial Lake Partnership to promote and enhance collaboration and communication between scientists.

Himalayas, the Water Towers of Asia:
Can We Reconcile Water Demands
for Livelihood in a Changing Climate?

Shama Perveen, Columbia University

The Himalayan region contains the largest area of glaciers, permafrost, and the largest freshwater resources outside the poles. It is the source of 10 of Asia’s largest rivers and more than a billion people



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement