Climate Change Impacts in the Pacific Northwest Climate Science in the Public Interest Paul Hezel Dept of Atmospheric Sciences UW Program on Climate Change (PCC) Special thanks to: Lara Whitely Binder Climate Impacts Group University of Washington

Take Home Messages Global and regional climate is changing and the human influence has emerged from the “noise” These changes are expected to accelerate in the coming decades Changes in snowpack and streamflow caused by rising temperatures will have important consequences for resources across the PNW Local, State and Regional Initiatives are starting to address mitigation and adaptation (but there’s a lot of work to do…)

Greenhouse gases (water vapor, CO 2, CH 4, N 2 O) play a critical role in determining global temperature Rapid increases in greenhouse gases are changing this natural balance

Arctic Sea Ice Minimums

How different were 2007/2008?

How different were 2007/2008?

Average global temperature increase Warming since the 1950s very likely (>90% chance) due to human increases in GHG. (IPCC AR4)

Temperature on longer time scales

CDIAC, US Department of Energy

+35% Figure source: IPCC 2007

How do we know it’s greenhouse gases? Require GHG forcing to explain observed temperature rise (with GHG) (without GHG) IPCC 2007

Growth Rates (per year)

Global Climate Change… Climate is changing Human activity is responsible – Greenhouse gases warm the planet – We are increasing the greenhouse gas concentration Have these atmospheric concentrations been higher? Yes, but not in at least 640,000 years (and for CO2, likely not for ~4 million years)

Current social, economic, and cultural systems based on a steady climate with known variability … and therein lie the challenges So where are we heading? Global Climate Change…

NOW Projected CO2 Concentrations

Scenarios Projected warming IPCC “best estimate” range of global-scale warming by the 2090s: 3.2°F-7.2°F Warming in the next few decades largely driven by current and near-term atmospheric GHG concentrations Projected 21 st century Global Warming

Risks of future climate change Source: IPCC 2001

Possible Threats and Global impacts… Increase of extreme weather events Sea level rise / Flooding of coastal communities Ocean acidification ‘Wet gets wetter, dry gets drier’ Loss of polar ice caps (esp Arctic) Feedbacks within the climate system can amplify changes Ecosystem change Spread of diseases

What climate signals are observed in PNW? Temperatures Glaciers/Snowpack Streamflow Frost days Signal is complicated by natural climate oscillations. ENSO/PDO.

Nearly every glacier in the Cascades and Olympics has retreated during the past years Photos courtesy of Dr. Ed Josberger, USGS Glacier Group, Tacoma, WA South Cascade Glacier, 1928 (top) and 2000 (right)

Average annual temperature increased +1.5  F in the PNW during the 20th century 3.6 °F 2.7 °F 1.8 °F 0.9 °F Cooler Warmer Mote 2003(a), updated Temperature Trends (°F per century), since 1920 April 1 snowpack has decreased throughout the PNW with losses of 30-60% at many individual stations ( ) Decrease Increase Similar snowpack declines are seen throughout the western United States Decrease Increase Key Trends in PNW Climate

Trends in Spring Runoff Stewart et al Stewart I.T., Cayan D.R., Dettinger M.D., 2005: Changes toward earlier streamflow timing across western North America, Journal of Climate, 18(8): Peak of spring runoff is moving earlier into the spring throughout western U.S. and Canada

Fewer Frost Days in the Late 20 th Century Largest trends observed in the PNW; most of the trend driven by decline in spring frost days G. A. Meehl, C.Tebaldi and D. Nychka (2004) Changes in frost days in simulations of 21st century climate. Climate Dynamics, Vol. 23, No. 5, pp

Are these changes due entirely to climate change? NO, modes of natural variability have a role in these trends (e.g., El Niño, PDO) Are these changes due entirely to natural climate variability? NO, natural variability cannot explain all of the trends …a climate change signal appears to be emerging Attribution

Changes to come… UW Climate Impacts Group

Projected Increases in PNW Temp Changes relative to °F 3.6°F 0°F 10.8°F 14.4°F +2.2ºF ( ºF) +3.5ºF ( ºF) +5.9ºF ( ºF) °C Rate of change expected to be 3x greater Warming expected in all seasons, greatest in summer Rate of change expected to be 3x greater Warming expected in all seasons, greatest in summer

Modest Changes in PNW Precipitation Note: there is high confidence in projected temp changes, less in precipitation changes Modest increases (1-2%) in annual average precipitation Most of the increase comes in the winter months (but in what intensity?) Projected increase in average does not exceed 20 th century variability

Spring snowpack is projected to decline as more winter precipitation falls as rain rather than snow, especially in warmer mid-elevation basins Snowpack will melt earlier with warmer spring temperatures Lower Spring Snowpack +4°F, +4.5% winter precip April 1 Snowpack

~2050s to 2080s Streamflow Impacts Higher winter streamflows Earlier and lower peak runoff (mid/high basins) Lower late spring streamflow Lower, warmer summer streamflow Projected streamflow changes in the Quinalt and Yakima Rivers +3.6 (~2050s) to +5.4°F (~2080s) ~2050s to 2080s

Cascading impacts … UW Climate Impacts Group

Impacts to Many Local Concerns Snow-dependent Water Supply Sea Level Rise Food production/ Ag Economies Forests/Timber Economies Flood Risk Instream Flows Energy Supply Water Quality Public Health

Changing Risk for Today’s Problems Risk of drought increases… With 3.6°F warming, 50-year droughts become 10-year droughts and 10-year droughts become 2.2-year droughts (Scott et al. 2006) Risk of flooding changes…. General increase in risk of winter flooding and combined sewer overflows in low- and mid-elevation basins Lower risk of spring flooding in snowmelt basins due to lower spring snowpack

Early peak flows Floods ?? Warm, low streamflow Salmon Impacted Across Full Life-Cycle

Sea Level Rise (SLR) in the PNW Thermal expansion of the global ocean; Melting of land-based ice; Atmospheric dynamics, particularly changes in wind which push coastal waters toward or away from shore; Local tectonic processes (subsidence and uplift)

Coasts 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. 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”

Inundation Levels in Olympia from Current and Projected Changes in High Tides A. Tidal datum elevation 18 feet B. Tidal datum elevation 19 feet C. Tidal datum elevation 20 feet D. Tidal datum elevation 22 feet

Human Health Increased thermal stress from extreme heat events, decreased air quality (ozone; particulate matter), changes in range of/habitat for/exposure to disease vectors likely Recreation Shortened winter ski season (but improved access?), impacts in summer from forest fires Hydropower Increased winter streamflows benefit winter hydropower production; greater tradeoffs between hydropower, instream flows, irrigation, and recreation Other Projected Regional Impacts

Forests Increased risk of wildfire, vulnerability to insects, decreased growth & regeneration Agriculture Decreased irrigation supply, increased heat stress/insects, increased growing season Infrastructure The potential for more intense winter precipitation would increase the already high costs of stormwater management. Other Projected Regional Impacts

Responding to Climate Change: Mitigation and Adaptation Mitigation activities Reducing emissions of greenhouse gases Adaptation activities Reducing the impacts of climate change as mitigation strategies are debated and enacted.

Billions of Tons Carbon Emitted per Year Historical emissions Historical Emissions

1.6 Interim Goal Billions of Tons Carbon Emitted per Year Current path = “ramp ” Historical emissions Flat path Stabilization Triangle The Stabilization Triangle

1.6 Billions of Tons Carbon Emitted per Year Current path = “ramp ” Historical emissions Flat path Stabilization Wedges 16 GtC/y Eight “wedges” Goal: In 50 years, same global emissions as today

Energy Efficiency & Conservation CO 2 Capture & Storage Stabilization Triangle Renewable Fuels & Electricity Forest and Soil Storage Fuel Switching What are the wedge strategies? Nuclear Fission GtC/y 16 GtC/y Triangle Stabilization Carbon Mitigation Institute, Princeton University

Regional Climate Initiatives Over half of US may be covered by a regional GHG cap-and-trade system in 1-2 years Strong desire by stakeholders and policy makers to reflect regional concerns RGGI has already influenced draft national legislation, e.g. increasing inclination to auction permits Source: Pew Center for Climate Change,

Climate Action In Washington State Western Climate Initiative WGA Clean and Diversified Energy Initiative West Coast Governor's Global Warming Initiative Washington Climate Plan Washington Commissions and Advisory Groups Washington Emissions Target Washington Power Plant Cap or Offsets Washington RPS (Renewable Portfolio Standards) Washington to Adopt CA Vehicle Standards Washington Appliance Standards Washington Biofuel Standard Washington EERS

Western Climate Initiative Regional Goal set in August 2007 – 15% below 2005 levels by 2020 – “do their share” to reduce global – emissions between 50% and 85% by 2050 September, 2008, announced regional cap-and-trade plan recommendations – Phase 1 by 2012; Phase 2 by 2015 Currently includes 7 states, 4 provinces, with another 6 states, 1 province and 6 Mexican states observing New entrants must have: – an equally stringent economy-wide GHG reduction goal – a comprehensive multi-sector climate action plan to achieve the goal – committed to adopt GHG tailpipe standards for passenger vehicles

Renewable Portfolio Standards

Local Actions… Over 884 municipalities have signed US Mayors Climate Agreement (representing 81 million people) – GHG emissions 7% below 1990 by 2012 Like states, cities/mayors – are adopting detailed action plans focus on green buildings, low- carbon electricity supply, transportation alternatives, building energy efficiency – testifying in Congress – influencing regional policy (e.g. Texas coal plants) – are, like governors, in a race to the top King County - Ron Sims' Global Warming Initiative Concrete action in county gov’t and agencies

The wedge approach...

Originally published October 24, 2008 at 12:00 AM | Page modified October 24, 2008 at 10:53 AM Guest columnist Solving the financial crisis by averting the climate crisis Despite the Wall Street meltdown and ongoing financial crisis, the next U.S. president must address the challenges of climate change and energy security. Investment in energy alternatives will help draw the nation out of financial doldrums. By Chip Giller and David RobertsChip GillerDavid Roberts Special to The Times Originally published October 20, 2008 at 12:00 AM | Page modified October 20, 2008 at 10:58 AM Neal Peirce / Syndicated columnist States, cities step up climate-change responses To meet the climate-change challenge, thousands of low-carbon strategies need to be fashioned from America's grass roots. Seattle and King County get it. By Neal PeirceNeal Peirce Syndicated Columnist

Summary Global and regional climate is changing and the human influence has emerged from the “noise” These changes are expected to accelerate in the coming decades. (Increasing rates of change) Regional signals are clearer in Pacific Northwest. Significant regional impacts are expected. Local, State and Regional Initiatives are starting to address mitigation and adaptation (but there’s a lot of work to do…). Wedge approach is useful.

UW Program on Climate Change Paul Hezel Thanks to Lara Whitely Binder and for More Info on Local and Regional Impacts of Climate Change The Climate Impacts Group

Blue line is 10-year running mean; Green bar is 2006 (provisional value)