Publication Abstracts

Vaux et al. 2012

Vaux, H.J., Jr., D. Balk, E.R. Cook, P. Gleick, W.K.-M. Lau, M. Levy, E.L. Malone, R. McDonald, D. Shindell, L.G. Thompson, J.L. Wescoat, Jr., and M.W. Williams, 2012: Himalayan Glaciers: Climate Change, Water Resources, and Water Security. National Academies Press.

The Hindu Kush-Himalayan (HKH) region extends over 2,000 km from east to west across the Asian continent spanning several countries: Afghanistan, Bangladesh, Bhutan, China, India, Nepal, and Pakistan. This region is the source of numerous large Asian river systems, including the Indus, Ganges, and Brahmaputra, which provide water for over a billion people. The surface water of these rivers and associated groundwater constitute a significant strategic resource for all of Asia. Many of the countries in this region are already experiencing physical water scarcity. Existing water stress and projections of population growth have led to concern over possibilities of negative impacts from changes in the availability of water supplies in the coming decades. Scientific evidence indicates that glaciers in the HKH region are retreating at rates comparable to those in other parts of the world, and confirms that the rate has accelerated in the past century. In this region, conventional wisdom is that glacial meltwater is an important supplement to naturally occurring runoff from precipitation and snowmelt. The watersheds of the area each exhibit complex hydrology and the magnitude of the contribution of glacial meltwater to the total water supply in these rivers is not clear and the implications of accelerated rates of glacial retreat and the resulting increase in glacial wastage for downstream populations have not been precisely characterized. Important questions about regional water security need to be addressed in the context of incomplete science and unresolved uncertainties.

The eastern and western areas of the HKH region differ in climate, especially in timing and type of precipitation, and in glacier behavior and dynamics as well. The Sutlej Valley serves as a rough dividing line, with precipitation in the eastern end of the region dominated by monsoonal activity in summer while precipitation in the western end is dominated by the mid-latitude westerlies in winter. There is evidence of glacial retreat in the eastern and central Himalayas while glaciers in the western Himalayas appear to be more stable, and may even be advancing. The HKH region is geographically vast and complex both climatologically and hydrologically, and this complexity is dynamic and possibly changing. This large spatial variability makes it very difficult to generalize observations and findings over the entire region.

The HKH region's climate is changing. Although generally temperatures are increasing and these increases are likely to accelerate in coming decades, spatial variability and gaps in observational data mean that it remains unclear what specific manifestations of climate change will be in specific places — including where and how quickly glaciers might retreat and what the cumulative impacts on the hydrological system of the region will be. Moreover, it is difficult to separate the effects of changes in glacial wastage from other factors. These factors include changes in the timing and amounts of monsoonal rain and seasonal snowmelt, snow and ice dynamics, the effects of aerosols and black carbon, and the role of tectonic activity in destabilizing glaciers. In addition, water-use changes resulting from changes in population numbers and densities, livelihoods and consumption patterns, water management decisions including groundwater pumping, agricultural water-use dynamics, and the extent of pollutants will affect water availability in the region.

Despite these important uncertainties, not everything is uncertain or unknown. The National Research Council Committee on Himalayan Glaciers, Hydrology, Climate Change, and Implications for Water Security was charged with addressing questions about four aspects of water security in the region.

How sensitive are the Himalayan glaciers to changes in temperature, precipitation, and the surface energy budget?

What does current glaciological and climatological knowledge imply about potential changes in climate on downstream flows? What are the likely major impacts on water supplies and flood regimes?

What management systems (including water supply, water demand, land use, and other institutions and infrastructure) are in place to manage climate-induced changes in regional hydrology, and how might they be strengthened?

What are some of the main vulnerabilities to adjusting to changes in water supply in these downstream areas? What are the prospects for increased competition, or improved cooperation, between different downstream water users? What are some of the implications for national security in the region?

The Committee's overarching conclusions are that while there remains substantial scientific uncertainty, snow and glacial melt will likely continue to be important sources of water in the region and there will be several climatological, glaciological, and hydrological factors that control the rate, volume, and timing of snowmelt and icemelt. The means of adapting to change will mostly be small in nature, and adaptive solutions will be essential. Effective management institutions will also be critical and will need to operate flexibly. Monitoring systems will be critical to implementing effective adaptation solutions and improving water management systems.

  • ISBN 9780309260985.

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BibTeX Citation

@misc{va07100z,
  author={Vaux, Jr., H. J. and Balk, D. and Cook, E. R. and Gleick, P. and Lau, W. K.-M. and Levy, M. and Malone, E. L. and McDonald, R. and Shindell, D. and Thompson, L. G. and Wescoat, Jr., J. L. and Williams, M. W.},
  title={Himalayan Glaciers: Climate Change, Water Resources, and Water Security},
  year={2012},
  publisher={National Academies Press},
  address={Washington, D.C.},
  isbn={9780309260985}
}

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RIS Citation

TY  - RPRT
ID  - va07100z
AU  - Vaux, H. J., Jr.
AU  - Balk, D.
AU  - Cook, E. R.
AU  - Gleick, P.
AU  - Lau, W. K.-M.
AU  - Levy, M.
AU  - Malone, E. L.
AU  - McDonald, R.
AU  - Shindell, D.
AU  - Thompson, L. G.
AU  - Wescoat, J. L., Jr.
AU  - Williams, M. W.
PY  - 2012
BT  - Himalayan Glaciers: Climate Change, Water Resources, and Water Security
SN  - 9780309260985
PB  - National Academies Press
CY  - Washington, D.C.
ER  -

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