Announcing the next installment of "Climate Conversations," USGCRP's monthly seminar/webinar series, presented by Dr. Jeffrey S. Deems, and Dr. Thomas H. Painter:

Dust Impacts on Snowmelt Timing & Water Yield in the Upper Colorado River Basin

The waters of the Colorado River serve 27 million people in seven statesand two countries but are overallocated by more than 10% of the river'shistorical mean. Climate models project runoff losses of 7-20% from thebasin in this century due to human-induced climate change. Recent workhas shown that by the late 1800s, decades prior to allocation of theriver's runoff in the 1920s, a fivefold increase in dust loading fromanthropogenically disturbed soils in the southwest United States wasalready decreasing snow albedo and shortening the duration of snow cover by several weeks. We present new results showing that peak runoff atLees Ferry, Arizona has occurred on average 3 weeks earlier underheavier dust loading and that increases in evapotranspiration fromearlier exposure of vegetation and soils decreases annual runoff by more than 1.0 billion cubic meters or ~5% of the annual average. Thepotential to reduce dust loading through surface stabilization in thedeserts and restore more persistent snow cover, slow runoff, andincrease water resources in the UCRB may represent an importantmitigation opportunity to reduce system management tensions and regional impacts of climate change.

Jeffrey S. Deems, PhD, is a Research Scientist at the National Snow and IceData Center and at the NOAA Western Water Assessment at the Universityof Colorado at Boulder. He conducts research in snow hydrology, lidarremote sensing of snow depth, mountain system hydrologic modeling, anddust and climate change impacts to snow and water resources at catchment to regional scales. At NSIDC he is the Science Liaison for the NASAOperation IceBridge Mission.

Thomas H. Painter, PhD, is a Scientist at the Jet PropulsionLaboratory/California Institute of Technology and a Research Professorat the University of California, Los Angeles. His areas of interest aresnow hydrology, radiative impacts of light-absorbing impurities on snowand glacier melt, water resources from mountain snow and ice,multispectral remote sensing and imaging spectroscopy, and solar systemastrobiology. Dr. Painter has pioneered our understanding of the impacts of dust emission from land use change on snow and ice cover in mountain systems and the hydrologic response. He is Chairman and organizer ofthe Working Group on Light-Absorbing Impurities in Snow and Ice. He isthe Vice-Chair of the Cryosphere Focus Group of the American Geophysical Union and member of the AGU Eos Editorial Advisory Board.