Date: Sept. 12, 2012

FOR IMMEDIATE RELEASE

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

Consequences for Water Supply Remain Unclear, Says New Report

WASHINGTON -- 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.

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. A committee roster follows.





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Luwam Yeibio, Media Relations Assistant

Office of News and Public Information

202-334-2138; e-mail news@nas.edu

Pre-publication copies of Himalayan Glaciers: Climate Change, Water Resources, and Water Security are available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).

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NATIONAL RESEARCH COUNCIL

Division on Earth and Life Studies

Board on Atmospheric Sciences and Climate

and

Water Science and Technology Board

Division of Behavioral and Social Sciences and Education

Committee on Population

Committee on Himalayan Glaciers, Climate Change, and Implications for Downstream Populations

Henry J. Vaux Jr. (chair)

Professor Emeritus of Resource Economics

University of California at Berkeley and Riverside

El Cerrito, Calif.

Deborah Balk

Acting Associate Director

Institute for Demographic Research, and

Associate Professor

Baruch School of Public Affairs

Baruch College

City University of New York

New York City

Edward R. Cook

Associate Research Scientist

Tree Ring Research Laboratory

Lamont-Doherty Geological Observatory

Palisades, N.Y.

William K. Lau

Chief

Laboratory for Atmospheres

NASA Goddard Space Flight Center

Greenbelt, Md.

Marc Levy

Deputy Director

Center for International Earth Sciences Information Network

Columbia University

Palisades, N.Y.

Elizabeth L. Malone

Staff Scientist IV

Joint Global Change Research Institute

College Park, Md.

Robert McDonald

Vanguard Scientist

The Nature Conservancy

Arlington, Va.

Drew Shindell

Senior Scientist

NASA Goddard Institute for Space Studies

New York City

Lonnie G. Thompson*

Distinguished University Professor

Byrd Polar Research Center

Ohio State University

Columbus

James L. Wescoat Jr.

Professor

Aga Khan Program for Islamic Architecture

School of Architecture and Planning

Massachusetts Institute of Technology

Cambridge

Mark W. Williams

Professor

University of Colorado

Boulder

RESEARCH COUNCIL STAFF

Maggie Walser

Study Director

____________________________________

* Member, National Academy of Sciences