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Climate Change as a Variable to Natural Resource Management. Lake Roosevelt Forum November 19, 2013. Nancy Stephan Project Manager, Columbia River Treaty Review Bonneville Power Administration. Why do we need to model climate change?.
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Climate Change as a Variable to Natural Resource Management Lake Roosevelt Forum November 19, 2013 Nancy Stephan Project Manager, Columbia River Treaty Review Bonneville Power Administration
Why do we need to model climate change? • Possible avoidance of potentially costly and un-informed decisions due to the lack of accurate system modeling and conclusions as to the impacts of climate change on the FCRPS and the Basin ecosystem • Support regional efforts and commitments to consider climate change impacts (Fish Accords, Bi-op) • Possible avoidance of challenges to major policy decisions, strategic planning, and system operations based on the lack of consideration of climate change in planning and proposed actions
RMJOC-I Study Base Assumptions • Based on IPCC-4 GCM results • Subset of full set of available projections • 6 projections for 2020s, 6 for 2040s • Annual 2-6°F (1.5-4°C) warming by the 2040s • Annual precipitation ranged from 20% decrease to 15% increase by the 2040s
Application to Columbia River Treaty Review Two approaches: • Quantitative: • Climate change assessment will be for the purpose of comparative analyses of the alternatives, and provide sufficient information to inform the broader recommendation to Department of State in the Fall of 2013 • Qualitative assessment based around the 2040’s (2030-2059) • Based on subset of RMJOC-1 GCM projections • Attempting to captured a range of reasonable climate change outcomes (chose the warmest and wettest and the driest and not quite so warm projections) • Two alternative operations (2A-TC and 2B-TC) • Semi-qualitative • Comparison of temperature and precipitation range used in the Treaty Review and other regional studies and the newly emerging IPCC-5 data • Look at 2040’s vs 2080’s
Selection for Columbia River Treaty Review More warming/Wet (#17) Less warming/Dry (#5)
Grand Coulee Elevation Grand Coulee Outflow
Comparison of Qualitative Range vs IPCC-5 • Trending toward warmer for the 2040s • IPCC-4: +0.8 to 3.2°C • RMJOC-1: +1.3 to 2.8°C • IPCC-5: +1.2 to 3.8°C • Somewhat better agreement that summers are likely to warm more than other seasons • RMJOC-1 didn’t capture full range of possible temperatures (both on the warm AND cool side) • Still large range of possible precipitation outcomes • RMJOC-I (5: driest, 17: wettest) captured the new annual temp/precipitation ranges well • RMJOC-I did not fully capture higher end of winter-spring-summer precipitation potential Rupp, et al., 2013; Abatzoglou, 2012
Recommendation “The region anticipates impacts from climate change to all of the elements described in this document. The strategy for adapting the Treaty to future change in climate should be resilient, adaptable, flexible, and timely as conditions warrant.”
Considerations • Assess the continued validity and associated reliability of current seasonal volume forecasts • Evaluate current reservoir flood risk operation guidance to see if timeliness and rate of refill are still appropriate to maintain current levels of flood risk • How will climate change impact the strategy and implementation of called upon and effective use of U.S. reservoirs • What impact will climate change have on load growth and shape with respect to Treaty planning and Canadian Entitlement • Further evaluation of thresholds and sensitivities to climate change for ecosystem • Evaluate embedding threshold triggers to implement adaption as warranted • Consider duration of Treaty to allow for responses to new information and changing conditions
RMJOC-II Project Objectives • Better capture and possibly quantify the range of possible outcomes • Objective GCM selection • Better depict modeling uncertainties • More than one downscaling approach • More than one hydrologic model • More than one university approach • Take into account the slight upward shift in temperatures (on the warmer scenarios) • Model glaciers explicitly (versus a permanent snowpack) • Determine whether dynamical downscaling (which requires a lot of computing) is “better” than statistical • Determine whether we should model land surface changes (i.e. larger areas of dry soils in summer due to longer “dry season”)?