Climate science in the public interest Coming Attractions from the Washington State Climate Impacts Assessment Lara Whitely Binder Alan Hamlet Marketa McGuire Elsner Climate Impacts Group Center for Science in the Earth System University of Washington October 2, 2008 CIG Climate and Water Fall Forecast Meeting Intro: The Climate Impacts Group is an interdisciplinary group whose goal is to conduct research on the impacts of climate change on natural resources as well as human communities. An additional goal is to provide the latest scientific information for use by decision makers. This morning I will present a project that is currently underway to assess what the consequences of climate change are on Washington State. I will also be presenting a poster this afternoon. This talk focuses on project background and framework, while the poster will focus on preliminary findings that were presented in an interim project report. Climate science in the public interest

A comprehensive climate change impacts assessment for Washington State Human Health Infrastructure Agriculture/Economics Water Resources A comprehensive climate change impacts assessment for Washington State Coasts Energy In this impacts assessment, we are evaluating the impacts of climate change on essentially eight sectors, including hydrology and water resources, energy, salmon, forest resources, coasts, agriculture, and human health. The Climate Impacts Group has performed similar assessments in the past; however, this work includes new sectors in which there is little past research. These include coasts, agriculture, health, and infrastructure. We will also be assessing barriers, both legal and institutional, to climate change adaptation. Forest Resources Salmon Adaptation

Project Domain: WA and the PNW To assess impacts in water and other sectors, the analysis must include all of the PNW = wide range of data available for all the PNW! Detailed case studies for water supply are being done for the Puget Sound Region and Yakima Basin The project domain is Washington state. However, in order to assess impacts to hydrology and other sectors, we must include the entire Pacific Northwest region in our analyses. The Pacific Northwest consists of the Columbia River basin (spanning multiple states) and the coastal drainages. We are also performing more detail case studies on the Puget Sound region of Washington, in which there are a number of resources competing for water, as well as the Yakima River basin, which contains many of the state’s high value crops like hops, grapes, and tree fruits.

Hydrology and Water Resources Reduced snowpack and changes in soil moisture will occur. Declines in April 1 SWE vary between 35%-41% for the 2040s, depending on the emissions scenario. There are 40 total greenhouse gas emissions scenarios used to drive global climate models. The 40 scenarios are grouped into four families: A1, A2, B1, and B2. The CIG is using the B1 and A1B scenarios for the HB 1303 work. The B1 emissions scenario represents a slower increase in greenhouse gas emissions with stabilization of CO2 concentrations by 2100 (the concentration of carbon dioxide will be 550ppm in 2100). The A1B emissions scenario has higher greenhouse gas emissions than the B1 scenario: the concentration of carbon dioxide will be 720ppm in 2100. The A1B and B1 scenarios have the same population projections (population peaking mid-century then declining). The main difference in the scenarios is energy use. The A1B scenario story line has a balance between fossil fuels and other energy sources, while the B1 story line assumes the use of more clean and resource-efficient technologies. 5

** Preliminary results - subject to change** Average annual SWE in the Yakima watershed above Parker is projected to be 31-68% of historic levels by the 2040s for two “middle of the road” scenarios Winter streamflows increase as basin shifts to rain-dominant basin ** Preliminary results - subject to change** 6

Projected Maximum Weekly Average Water Temperatures – 2040s Salmon Projected Maximum Weekly Average Water Temperatures – 2040s Increasing thermal stress likely to become most problematic for salmon in the interior Columbia River Basin. In Western WA salmon, increases in the magnitude of extreme high/low flows likely to be most problematic From the interim report: In the 2001-2006 period, 15% of the stations included in our analysis had an observed maximum weekly average water temperature greater than the 21ºC (70°F) water quality criteria, and all of those stations are located in the interior Columbia Basin. Under the A1B emissions scenario, 2040s August average air temperatures are projected to rise by 2.8ºC (approximately 5.0°F). Using the delta method by assuming an equivalent rise in the annual maximum weekly water temperature results in 49% of these stations exceeding the 21ºC (70°F) criteria, with many recording stations in southwest Washington and the Puget Sound Lowlands and all the stations in the Columbia Basin exceeding the 21ºC (70°F) criteria. Although this approach ignores a range of factors that give rise to the observed heterogeneity in stream temperatures, this simple projection should give a useful preview of the projected stream temperatures we will develop in the next year using the 1/16 degree gridded air temperature fields and empirically-based stream temperature models. The period of maximum temperatures will vary from stream to stream, therefore this figure is generally for summer temperatures and is not tied to a specific month (although most occurred in September). How were these values calculated? We took the average weekly maximum water temperature at each station for 2001-2007 and averaged those max temps at each site. Changes are calculated from this base period. 49% of stations exceed the 21ºC (70°F) water quality criteria (changes relative to 2001-2007) 7

Agriculture Longer growing seasons is projected, especially for summer crops. Range for the 2040s: +10 days for Franklin/Walla Walla counties to + 27 days for Whatcom County Changes in spring and summer aridity projected in all agriculturally important counties Diseases will generally become more problematic over the next century, especially as a result of warmer temperatures. The potential for adaptation will vary strongly by crop type. These results are based on previous work to date and literature reviews. 8

Energy Heating degree days will continue to dominate in the 2020s and 2040s, but cooling degree days become a much more important factor in eastern WA as the region warms. In the Spokane metro area, heating degree days will decline by about 15% in the 2040s compared to the historic condition, but cooling degree days will increase by 88%. 9

Improved Access to Hydrologic Scenarios in the Columbia River Basin Goals: Create a comprehensive, up-to-date, self-consistent, publicly available hydrologic database to support long-range planning Construct end-to-end process to allow updates of the database when new climate change scenarios are available As the public and professionals in the water management and policy arenas have become increasing concerned about the impacts of climate change on PNW water resources, demand for hydrologic scenarios suitable for planning purposes at a range of spatial scales has increased dramatically. Currently there does not exist an up-to-date, comprehensive, and self-consistent data base of hydrologic scenarios for the Columbia River basin that is suitable for the range of planning activities the Climate Impacts Group is being asked to support. Answers to FAQ regarding WA 2860 from the Department of Ecology website: http://www.ecy.wa.gov/pubs/0611014.pdf

Regional Study Partners WA State Department of Ecology Bonneville Power Administration Northwest Power and Conservation Council State of Oregon Province of British Columbia (BC Hydro and The Ministry of Environment)

Survey Participant Agency/Organization Affiliation 178 participants State and Federal employees make up 60% of the participants

Survey Participant Management Areas Water supply, ISF management, & hydropower production dominant management areas In addition to entire PNW, Snake, Yakima, and Okanogan regions were identified as important

271 Sites Upper Columbia River Basin Yakima River Basin Kootenai River Basin Salmon River Basin Mainstem Columbia River Basin Willamette River Basin Snake River Basin

Survey Response – Data Needs Data Variable 271 Sites Naturalized streamflow Regulated streamflow Changes in flood frequency (100 yr flood) Changes in low flow (7Q10) Drought frequency, severity, duration analysis Analysis of streamflow timing shifts Gridded Data (16th degree) Min/Max temperature Precipitation Soil Moisture Potential evapotranspiration Snowpack (SWE, depth) Date of peak SWE Date of 90% SWE melt Fraction of precipitation as rain Fine resolution Daily time step Spatial maps of data anomalies/patterns of mean changes Excel or ASCII (text) data format Web or ftp data transfer Top list: streamflow-specific locations; bottom list is gridded data over the whole domain (PNW) Most streamflow site specific info is daily, some 3-hourly Gridded data: daily and hourly (DHSVM runs at 3 hour time steps)

Sample Preliminary Spatial Maps Based on Delta Method Experiments