This study will explore the potential impacts of climate change on glacier-fed streamflow and regional water supplies in one region, the Himalayas. The glaciers in this region are the headwaters of several of Asia's great river systems, including the Ganges-Brahmaputra, Indus, Mekong, Yangtze, and Yellow rivers. These rivers are the sources of drinking water and irrigation supplies for billions of people. These rivers also generate hydropower and support important ecological values, such as fisheries. The study will summarize the current state of scientific understanding on questions such as:

• 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 additional observational and modeling resources are needed to improve knowledge of hydro-climate trends and forecasts?
• 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? In addressing this question, the committee will analyze the advantages and disadvantages of various options for improving existing management systems, which could include consideration of new management systems, but will not recommend specific options.
• 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?

To inform its analysis, the study committee will be supported by information gathered at an interdisciplinary workshop, using both invited presentations and discussion to explore the issues that may affect regional streamflow and water supplies in the face of a changing climate. The study will examine a few selected examples of changes in glacial melt and resultant streamflow for a specified time horizon as a way of developing boundaries for the workshop discussion. The thinking might potentially take the form of linking potential changes in temperature and precipitation to a range of changes in glacial mass balance and regional hydrology, which in turn could lead to a range of outcomes for downstream streamflow and water security, including water supplies and flooding regimes.