Climate Change Impacts in the Pacific Northwest

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Climate Change Impacts in the Pacific Northwest
Paul Hezel Dept of Atmospheric Sciences UW
Program on Climate Change (PCC) Special thanks
to Lara Whitely Binder Climate Impacts
Group University of Washington
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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 theres a lot of work to do)

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Greenhouse gases (water vapor, CO2, CH4, N2O)
play a critical role in determining global
temperature
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Arctic Sea Ice Minimums
2007
2008
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How different were 2007/2008?
2007
2008
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How different were 2007/2008?
2007
2008
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Average global temperature increase
Warming since the 1950s very likely (gt90 chance)
due to human increases in GHG. (IPCC AR4)
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Temperature on longer time scales
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CDIAC, US Department of Energy
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Figure source IPCC 2007
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How do we know its greenhouse gases?Require
GHG forcing to explain observed temperature rise
(with GHG)(without GHG)IPCC 2007
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Growth Rates (per year)
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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)

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Global Climate Change

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

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Projected CO2 Concentrations
NOW
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Projected 21st century Global Warming
IPCC best estimate range of global-scale
warming by the 2090s 3.2F-7.2F Warming in
the next few decades largely driven by current
and near-term atmospheric GHG concentrations
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Risks of future climate change
Source IPCC 2001
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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

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What climate signals are observed in PNW?

• Temperatures
• Glaciers/Snowpack
• Streamflow
• Frost days
• Signal is complicated by natural climate
  oscillations. ENSO/PDO.

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Nearly every glacier in the Cascades and Olympics
has retreated during the past 50-150 years
South Cascade Glacier, 1928 (top) and 2000 (right)
Photos courtesy of Dr. Ed Josberger, USGS Glacier
Group, Tacoma, WA
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Key Trends in PNW Climate
Average annual temperature increased 1.5?F in
the PNW during the 20th century
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Trends in Spring Runoff
Peak of spring runoff is moving earlier into the
spring throughout western U.S. and Canada
Stewart et al. 2005 Stewart I.T., Cayan D.R.,
Dettinger M.D., 2005 Changes toward earlier
streamflow timing across western North America,
Journal of Climate, 18(8)1136-1155.
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Fewer Frost Days in the Late 20th 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. 495-511
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Attribution

• 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
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Changes to come
UW Climate Impacts Group
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Projected Increases in PNW Temp

• Rate of change expected to be 3x greater
• Warming expected in all seasons, greatest in
  summer

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Modest Changes in PNW Precipitation
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 20th century
variability
 
Note there is high confidence in projected temp
changes, less in precipitation changes
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Lower Spring Snowpack
Spring snowpack is projected to decline as more
winter precipitation falls as rain rather than
snow, especially in warmer mid-elevation
basinsSnowpack will melt earlier with warmer
spring temperatures
4F, 4.5 winter precip
April 1 Snowpack
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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
2050s to 2080s
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Cascading impacts
UW Climate Impacts Group
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Impacts to Many Local Concerns
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Changing Risk for Todays Problems
Risk of drought increases With 3.6F 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
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Salmon Impacted Across Full Life-Cycle
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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)

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Coasts
Rising sea levels will increase the risk of
flooding, erosion, and habitat loss along much of
Washingtons 2,500 miles of coastline.

• Medium estimates of SLR for 2100
• 2 for the NW Olympic Peninsula 11 for the
  central/southern coast13 for Puget Sound
• Higher estimates (up to 4 feet in Puget Sound)
  cannot be ruled out.

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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
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Other Projected Regional Impacts

• Human HealthIncreased thermal stress from
  extreme heat events, decreased air quality
  (ozone particulate matter), changes in range
  of/habitat for/exposure to disease vectors likely
  
• RecreationShortened winter ski season (but
  improved access?), impacts in summer from forest
  fires
• HydropowerIncreased winter streamflows benefit
  winter hydropower production greater tradeoffs
  between hydropower, instream flows, irrigation,
  and recreation

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Other Projected Regional Impacts

• ForestsIncreased risk of wildfire, vulnerability
  to insects, decreased growth regeneration
• Agriculture Decreased irrigation supply,
  increased heat stress/insects, increased growing
  season
• InfrastructureThe potential for more intense
  winter precipitation would increase the already
  high costs of stormwater management.

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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.
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Historical Emissions
Billions of Tons Carbon Emitted per Year
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Historical emissions
8
0
1950
2000
2050
2100
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The Stabilization Triangle
Billions of Tons Carbon Emitted per Year
Current path ramp
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Stabilization Triangle
Interim Goal
Historical emissions
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Flat path
1.6
0
1950
2000
2050
2100
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Stabilization Wedges
Billions of Tons Carbon Emitted per Year
16 GtC/y
Current path ramp
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Eight wedges
Goal In 50 years, same global emissions as today
Historical emissions
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Flat path
1.6
0
1950
2000
2050
2100
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What are the wedge strategies?
Energy Efficiency Conservation
16 GtC/y

Renewable Fuels Electricity
Fuel Switching
Stabilization
Stabilization
Triangle
Triangle
CO2 Capture Storage
8 GtC/y
Forest and Soil Storage
2007
2057

Carbon Mitigation Institute, Princeton University
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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,
www.pewclimate.org
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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

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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

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Renewable Portfolio Standards
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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 govt and agencies

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The wedge approach...
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Originally published October 24, 2008 at 1200 AM
Page modified October 24, 2008 at 1053
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 Roberts Special to The Times
Originally published October 20, 2008 at 1200 AM
Page modified October 20, 2008 at 1058 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 Peirce Syndicated Columnist
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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 theres a lot of work to do). Wedge
  approach is useful.

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UW Program on Climate Change www.uwpcc.washington
.edu Paul Hezel phezel_at_atmos.washington.edu Tha
nks to Lara Whitely Binder and for More Info on
Local and Regional Impacts of Climate Change The
Climate Impacts Group www.cses.washington.edu/cig