An Integrated Assessment of the Impacts of Climate Change on Washington State

Elsner will outline the Washington State Climate Impacts Assessment program. This is a comprehensive state climate change assessment that includes the impacts of global warming. She will detail the goals, challanges, and data needs of the program. She will also describe the projections of the assessment in the areas of temperature increases, changes in hydrology and water resources, and the projected impacts on coasts, agriculture, salmon, forests, infrastructure, energy, and human health. The work of the Climate Impacts Group can be reviewed at: http://cses.washington.edu/cig

Regional Climate and Hydrologic Change in the Northern US Rockies and Pacific Northwest: Internally Consistent Projections of Future Climate for Resource Management

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Increased drought severity tracks warming in the United States’ largest river basin

Across the Upper Missouri River Basin, the recent drought of 2000 to 2010, known as the “turn-of-the-century drought,” was likely more severe than any in the instrumental record including the Dust Bowl drought. However, until now, adequate proxy records needed to better understand this event with regard to long-term variability have been lacking. Here we examine 1,200 y of streamflow from a network of 17 new tree-ring–based reconstructions for gages across the upper Missouri basin and an independent reconstruction of warm-season regional temperature in order to place the recent drought in a long-term climate context. We find that temperature has increasingly influenced the severity of drought events by decreasing runoff efficiency in the basin since the late 20th century (1980s) onward. The occurrence of extreme heat, higher evapotranspiration, and associated low-flow conditions across the basin has increased substantially over the 20th and 21st centuries, and recent warming aligns with increasing drought severities that rival or exceed any estimated over the last 12 centuries. Future warming is anticipated to cause increasingly severe droughts by enhancing water deficits that could prove challenging for water management. Includes supplemental fil

1200 years of Upper Missouri River streamflow reconstructed from tree rings

Paleohydrologic records can provide unique, long-term perspectives on streamflow variability and hydroclimate for use in water resource planning. Such long-term records can also play a key role in placing both present day events and projected future conditions into a broader context than that offered by instrumental observations. However, relative to other major river basins across the western United States, a paucity of streamflow reconstructions has to date prevented the full application of such paleohydrologic information in the Upper Missouri River Basin. Here we utilize a set of naturalized streamflow records for the Upper Missouri and an expanded network of tree-ring records to reconstruct streamflow at thirty-one gaging locations across the major headwaters of the basin. The reconstructions explain an average of 68% of the variability in the observed streamflow records and extend available records of streamflow back to 886 CE on average. Basin-wide analyses suggest unprecedented hydroclimatic variability over the region during the Medieval period, similar to that observed in the Upper Colorado River Basin, and show considerable synchrony of persistent wet-dry phasing with the Colorado River over the last 1200 years. Streamflow estimates in individual sub-basins of the Upper Missouri demonstrate increased spatial variability in discharge during the Little Ice Age (similar to 1400-1850 CE) compared with the Medieval Climate Anomaly (similar to 800-1400 CE). The network of streamflow reconstructions presented here fills a major geographical void in paleohydrologic understanding and now allows for a long-term assessment of hydrological variability over the majority of the western U.S. Published by Elsevier Ltd.National Science Foundation (NSF) Paleo Perspectives on Climate Change (P2C2) Program [1404188, 1403957, 1401549]; NSF Graduate Research Fellowship Program (GRFP)National Science Foundation (NSF)NSF - Office of the Director (OD) [1049562]; Graduate Research Internship Program (GRIP); U.S. Bureau of Reclamation WaterSMART Program (Sustain and Manage America's Resources for Tomorrow); state of Montana Department of Natural Resources and Conservation; U.S. Geological Survey Land Resources Mission Area; North Central Climate Adaptation Science Center24 month embargo; published online: 15 October 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]