Dr. Kathleen Miller Climate Change and Water Research
Water and Climate Change Research
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Climate Change Impacts on Water
Climate Change Impacts on Water Freshwater resources are highly sensitive to variations in weather and climate. The changes in global climate that are occurring as a result of the accumulation of greenhouse gases in the atmosphere will affect patterns of freshwater availability and will alter the frequencies of floods and droughts. Climate Change Impacts on Water
Climate model simulations and other analyses suggest that total flows, probabilities of extreme high or low flow conditions, seasonal runoff regimes, groundwater-surface water interactions and water quality characteristics could all be significantly affected by climate change over the course of the coming decades.
This suggests it is prudent to begin planning for changes that can be foreseen and to build resilience to deal effectively with the increased uncertainty arising from the potential, but as yet unpredictable impacts of climate change.
While it is virtually certain that there will be changes in the global quantity and distribution of precipitation and runoff, there are significant uncertainties regarding the specific nature of the local and regional impacts of climate change on hydrologic regimes.
Nevertheless, some types of changes can be foreseen with relatively high confidence. For example, a large and growing body of research suggests a high likelihood of the following changes. First, in watersheds where stream-flow currently depends on snowmelt, warmer temperatures will increase the fraction of precipitation falling as rain rather than as snow, causing the annual spring peak in runoff to occur earlier.
Depending on changes in the amount and seasonal distribution of precipitation, these watersheds may experience an increased likelihood of winter flooding and reduced late summer flows. Second, saltwater intrusion into coastal aquifers is likely to become an increasing problem as a result of sea-level rise. And finally, for many watersheds, there will be an increased likelihood of warmer summer water temperatures with associated impacts on aquatic ecosystems and water quality.
Climate change should be considered in the context of all of the other stresses impinging on our water resources: it may not be the largest source of stress, but it can potentially make it more difficult to deal with other challenges like population growth, endangered species and water quality issues. Dr. Millerís research has focused on exploring options for building resilience to the possible impacts of climate change through enhanced institutional flexibility and consideration of climate-related risks in the planning process.
North American Water Impacts Map
Water Impacts Map How will climate change affect North American water resources? Use the interactive water impacts map to find out.
Climate Change and Water Resources Conference
In recent years there has been growing evidence that the earth's climate will become warmer in 21st century, which raises the essential question: What impacts will global warming have on the environment and human activities? Warming will cause hydrologic changes that will affect freshwater resources. These are among the most significant potential impacts of climate change. As the climate warms, there will be changes in the nature of global precipitation, evaporation, snowpack, streamflow and other factors that will affect freshwater supply and quality. Climate change will present challenges to water utilities, and planning now could prevent freshwater crises in upcoming years.
For water utilities to plan appropriately for the effect of global warming on water resources, they need information on the scientific basis for climate change and the implications for hydrology. To facilitate communication between specialists in climatic change and professionals in water utilities, the National Center for Atmospheric Research and the Awwa Research Foundation will be hosting a conference on the subject of climate change and the impact on water resources. The conference will be held on March 15th and 16th, 2004 at the National Center of Atmospheric Research in Boulder, Colorado.
For More Information
Water Cycle Study Group (K. Miller member), A Plan for a New Science Initiative on the Global Water Cycle, U.S. Global Change Research Program, Washington, D.C., 2001.
This report proposes a water cycle research agenda for the U.S. Global Change Research Program. The goal of the proposed Integrated Water Cycle Science Plan is to improve understanding of: 1) the causes of water cycle variation on global and regional scales including human influences; 2) the predictability of those variations; and 3) links between water, carbon nitrogen, and other nutrient cycles in terrestrial and freshwater ecosystems.
S.J. Cohen and K.A. Miller (Convening Lead Authors), "North America," Ch.15, pp.733-800 in Climate Change 2001: Impacts Adaptation and Vulnerability. Intergovernmental Panel on Climate Change (IPCC), Working Group II Third Assessment Report. Cambridge, UK: Cambridge University Press, 2001.
This is one of 19 chapters in the Third Assessment Report of Working Group II of the Intergovernmental Panel on Climate Change (IPCC). IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP): 1) to assess available scientific and socioeconomic information on climate change and its impacts and on the options for mitigating climate change and for adapting to it; and 2) to provide advice, on request, to the Conference of Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). Working Group II focuses on the environmental, social, and economic consequences of climate change and potential adaptation responses.
In addition to serving as a convening lead author, Kathleen Miller wrote much of the material for the water resources and fisheries sections of this chapter. Dr. Miller's interactive map on this website summarizes the report's findings on the potential impacts of climate change on water resources in North America
Dennis Ojima, Luis Garcia, E. Elgaali, Kathleen Miller, Timothy Kittel and Jill Lackett, "Potential Climate Change Impact on Water Resources in the Great Plains", Journal of the American Water Resources Association, 35(6): 1443-1454, 1999.
This paper provides an assessment of the impacts of climate and potential climate change on water resources, including aquatic ecosystems, agricultural demands and water management in the U.S. Great Plains. Results are based on the climate scenarios used for the U.S. National Assessment and stakeholder input gathered during the regional assessment process. The paper is available for purchase on the American Water Resources Association website.
Kathleen A. Miller, Climate Variability, Climate Change and Western Water, Report to the Western Water Policy Review Advisory Commission, NTIS, Springfield, VA, 1997.
This is a comprehensive report on the science and policy aspects of the impacts of climate on water resources in the western United States. The federal Western Water Policy Review Commission was created by Congress to review all aspects of federal involvement in the management of western water resources. The Commission ordered this study as an essential element in the fact-finding part of its mission. The report covers both the science and policy aspects of this issue. It provides an overview of the current climate of the west, potential climate changes and sources of uncertainty, placing the impacts of global climate change in the context of existing climatic variability. Policy implications are considered within the framework of the prior appropriation system and existing federal and state laws and agency mandates.
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National Center for Atmospheric Research This website is maintained by Dr. Kathleen Miller of the Environmental and Societal Impacts Group (ESIG) of the National Center for Atmospheric Research (NCAR).   National Center for Atmospheric Research
PO Box 3000   Boulder, Colorado 80307
Tel: 303-497-8115; Fax: 303-497-8125