Washington Climate Change Impacts Assessment JISAO CSES Climate Impacts Group Jeremy Littell, Marketa Elsner, Ed Miles, Dennis Lettenmaier, Eric Salathé, Phil Mote, Nate Mantua, Lara Whitely Binder, Alan Hamlet, Amy Snover, Ingrid Tohver and University of Washington Washington State University Pacific Northwest National Laboratory Climate science in the public interest

HB1303 Study Region Focus is climate change impacts on Washington, but this requires attention to regional climate, hydrology, ecosystems, and economies.

VIC Hydrologic Model Projections of future hydrological conditions: soil moisture, streamflow, snowpack, etc. Domain: PNW Scale: 6 mi Regional Climate Change Scenarios Precipitation, temperature: 2020s, 2040s, 2080s Statistically downscaled to 6 mi for 39 scenarios Global Climate Models Two different emissions scenarios: 20 models using A1B (more emissions) and 19 models using B1 (less emissions) Domain: global Scale: ~60mi – ~120mi Impacts and Adaptation Research: 9 Sectors Adaptation Agriculture Coasts Forests Human Health Hydrology and Water Mgmt. Hydropower Energy Salmon Urban Stormwater Infrastructure Best estimates of future regional climate given known climate drivers and behavior of atmosphere and ocean Best estimates of future sub-regional climate given relationship between global model and observed regional variation

Projected Increases in Annual Temperature 2020s 2040s 2080s °C°C * Compared with average Mote and Salathé, ºF ( ºF) +3.2ºF ( ºF) +5.3ºF ( ºF) °F Choice of emissions scenario matter more after 2040s

Projected Changes in Annual Precipitation * Compared with average Changes in annual precipitation averaged over all models are small but some models show large seasonal changes, especially toward wetter autumns and winters and drier summers. Mote and Salathé, 2009

Key Impact: Loss of April 1 Snow Cover Why? Spring snowpack is projected to decline as more winter precipitation falls as rain rather than snow, especially in warmer mid-elevation basins. Also, snowpack will melt earlier with warmer spring temperatures -44% Elsner et al., Map: Rob Norheim

Lower summer flows (energy, salmon); lower soil moisture and higher water demand (forests, agriculture) Seasonal Runoff: Winter Increase, Summer Decrease Elsner et al. 2009, Miles et al. in review. Map: Rob Norheim

Changes in Flood Risks Floods in western WA will likely increase in magnitude due to the combined effects of warming and increasingly intense winter storms. In other parts of the State, changes in flooding are mixed, and in eastern WA projected reductions in spring flood risk are common due to loss of spring snow cover. Mantua et al. 2009, Elsner et al Mixed Rain/SnowRain Dominant Yakima River (Eastern WA)Chehalis River (Western WA)

Salmon and Aquatic Ecosystems August Mean Surface Air Temperature and Maximum Stream Temperature Historical ( ) 2040s medium (A1B) * Projections are compared with average Mantua et al Map: Rob Norheim.

Forest Ecosystems The area burned by fire regionally (in the U.S. Columbia Basin) will likely increase by 100% to 200% (medium scenario, A1B). The average area burned in 2080 is equivalent to the highest one or two fire years in the observed record. Mountain pine beetle outbreaks are projected to increase in frequency and to cause increased tree mortality due to increasing climatic stress on host trees. Climatically suitable habitat for Douglas-fir declines by 2060, even in western Washington. Littell et al. 2009

Agriculture Given sufficient irrigation, the projected impact of climate change on eastern Washington agriculture is unlikely to be severe. Likely changes in yields from climate alone are increases in winter wheat (2-8% by the 2040s), decreases in irrigated potatoes (15% by the 2040s) and decreases in apples (3% by the 2040s). Stöckle et al Yakima Economics – Production Value of Apples and Cherries. Reservoir system will be less able to supply water to all users, especially those with junior water rights. Production value declines are buffered somewhat by price increases and largely unchanged production on senior water user lands. Vano et al. 2009b

Adaptation and Planning Role of the UW Climate Impacts Group: –To provide information about the current state of climate science and its implications for our region –To assist local, regional, and federal stakeholders in evaluating strategies for how to adapt in a changing climate Planning for and increasing our ability to adapt to observed (historical) climate variability is a first step in adaptation to climate change

Funding provided by the State of Washington under House Bill 1303 JISAO CSES Climate Impacts Group The Climate Impacts Group WACCIA: waccia.shtml Climate science in the public interest UW Climate Impacts Group

CO 2 Annual Emissions Raupach et al. 2007, PNAS CDIAC updated emissions CDIAC = Carbon Dioxide Information Analysis Center, Oak Ridge National Lab (DOE)

Solar Irradiance: Normal Data: World Radiation Center,

Is Climate Change Over?

Aw Global Top 10 Warm Years (Jan- Dec) since 1880 Anomaly °CAnomaly °F No. Globally, 2008 tied for 8 th with 2001 for the warmest year on record since 1880 *Anomalies relative to

Ten year trends? Data: ftp://ftp.ncdc.noaa.gov/pub/data/anomalies/annual.land_ocean.90S.90N.df_ mean.dat

It may be cool (relative to the last 10 years or so) here but it’s still warm in much of the world.

Numbers refer F temperature, “normal” refers to rank in full record (115 years)

A note on “tricks” in the blogosphere Tree ring width from 300 circum-boreal sites N. Hemisphere Summer Temperature Temperature: Jones,P.D.&Briffa,K.R.Global surface air temperature variations during the twentieth century:Part 1, spatial, temporal and seasonal details. Holocene2, 165– 179(1992). Divergence: temperature no longer limits trees Difference between T and growth series Briffa, K. R., F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov and E. A. Vaganov Reduced sensitivity of recent tree-growth to temperature at high northern latitudes. Nature 391:678 doi: /35596

“The cause of this increasing insensitivity [post-1960] of wood density to temperature changes is not known, but if it is not taken into account in dendroclimatic reconstructions, past temperatures could be overestimated. Moreover, the recent reduction in the response of trees to air-temperature changes would mean that estimates of future atmospheric CO2 concentrations, based on carbon cycle models that are uniformly sensitive to high-latitude warming, could be too low.” Briffa, K. R., F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov and E. A. Vaganov Reduced sensitivity of recent tree-growth to temperature at high northern latitudes. Nature 391:678 doi: /35596

A profound lack of scientific sharing of data? Raw climate data is available all over the place

Comparing climate model sensitivity to observations Not all future model scenarios are equally plausible – some models do better than others at reproducing what we observe. Trend is not the only metric – annual means, seasonal cycle as or more important Mote and Salathé, 2009

Quick Projection Primer © 2006 by the PRISM Group and Oregon Climate Service, Oregon State University.

How global models see the land surface

Seasonal differences in temperature changes Mean temperature increases taken across models are comparable for winter, spring, and fall, but higher for summer. * Compared with average Mote and Salathé, 2009

Seasonal differences in precipitation changes Mean precipitation increases taken across models are comparable in terms of percentage for winter, spring, and fall. Most models project summer precipitation decreases. PNW winter precipitation 65-85% of annual, so autumn and winter increases mean a substantial amount of water; summer declines are declines from an already low number * Compared with average Mote and Salathé, 2009

Low Medium -29% -44% -65% -27% -37% -53% Key Impact: Snowpack loss Why? Spring snowpack is projected to decline as more winter precipitation falls as rain rather than snow, especially in warmer mid-elevation basins. Also, snowpack will melt earlier with warmer spring temperatures Elsner et al, Maps: R. Norheim

Municipal and Industrial, reliability measures differ across systems With current demands, system reliability able to accommodate changes (A1B) With demand increases, system reliability reduced, conservation measures matter Notes: –simulations assume current demand –simulations do not include adaptation Municipal Water Supply in Key Puget Sound Basins -1% -7%0% Vano et al. 2009a * Projections compared to water year average Tacoma, water allocations closer to current system capacity Everett, largest system capacity

Elwah River Historical and Projected 21 st C. Flows (A1B)

Hydropower Energy: Columbia System Energy Production Annual hydropower production is projected to decline by a few percent due to small changes in annual flow Hamlet et al Energy Demand Changes in energy demand: Winter demand for heating energy increases slightly due to population Summer demand for cooling energy increases dramatically Increase of % by the 2040s Decrease of 15% by the 2040s Note: summer cooling demand << winter heading demand (by one order of magnitude) Heating demand (winter) Cooling demand (summer) Warming with pop. Growth increase of 35% by the 2040s Warming with pop. Growth increase of 550% by the 2040s

Hydropower Energy: Changes in Demand Hamlet et al Heating demand (winter)Cooling demand (summer) Changes in energy demand affect total consumption too Winter demand for heating energy increases slightly due to population Summer demand for cooling energy increases dramatically Note: summer cooling demand << winter heading demand +200% +550% +1875% +22% +35% +50%

Urban Stormwater Infrastructure Precipitation intensity and the magnitude of extreme precipitation events are projected to increase in western Washington, according to two regional climate model simulations. Drainage infrastructure designed using historical rainfall records may not meet future required capacity as precipitation intensity and extremes become more severe. Rosenberg et al. 2009

Changes in heat events and projected excess deaths* * Population held constant at 2025 projection so numbers reflect influence of climate alone Greater Seattle High Moderate Low Expected number of heat events (>99% obs.) Expected Increased deaths

Human Health In Washington, climate change will lead to larger numbers of heat-related deaths due mainly to hotter summers. For example in greater Seattle, a medium climate change scenario projects 101 additional deaths for people over 45 by 2025 and another 50% increase by 2045 Although better control of air pollution has led to improvements in air quality, warmer temperatures threaten some of the sizeable gains that have been made in recent years. Jackson et al. 2009

Coasts Global SLR: 7-23” by 2100 Medium estimates of SLR for 2100: +2” for the NW Olympic Peninsula +11” for the central/southern coast +13” for Puget Sound Higher estimates (up to 4 feet in Puget Sound) cannot be ruled out at this time. Rising sea levels will increase the risk of flooding, erosion, and habitat loss along much of Washington’s 2,500 miles of coastline. 3” 6” 30” 50” ” 40” 20” 10” 6” Projected sea level rise (SLR) in Washington’s waters relative to , in inches. Shading roughly indicates likelihood. The 6” and 13” marks are the SLR projections for the Puget Sound region and effectively also for the central and southern WA coast (2050: +5”, 2100: +11”).