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Past and Future Climate of
Puget Sound and Implications
for Decision Making
Nate Mantua and Lara Whitely Binder
Climate Impacts Group
University of Washington
Puget Sound Partnership webinar
June 14, 2011
Climate Science in the
Public Interest
CLIMATE is what you expect
WEATHER is what you get
weather is the exact state of the
atmosphere at a specific time and place
weather elements: air temperature, air
pressure, humidity, clouds, precipitation,
visibility, wind
Sea-Tac average air temperatures:
June 2010-June 2011
Climate is simply the
statistics of weather:
at right are 3 ways to
view Sea-Tac’s
observed daily
temperatures from the
past year
Slide 2
Race Rocks sea surface temperature:
1921-2009
 Surface
temperature
variations for
Puget Sound as a
whole closely
track those at
Race Rocks
 Note the large
year-to-year
changes, decadal
cycles, and longerterm warming
trend
1998
1941
1983
1958
The South
Length of the Blue Glacier
Cascade glacier
~ 800 meter recession
since the early 1900s, andretreated
~1500 meter recession
dramatically in
since the early 1800s
the 20th century
1928
Courtesy of the
USGS glacier
group
2000
El Niño and La
Niña play a
prominent role in
causing year to
year variations in
Northwest
Climate
(especially our
winter climate)
Pacific Decadal Oscillation
El Niño/Southern
Oscillation
20-30 year periods
6-18 month events
North Pacific
Equatorial Pacific
Warm phases
PDO
ENSO (El Niño)
Source: Climate Impacts Group, University of Washington
Climate has varied over long time periods
Last glacial
maximum
18,000
years ago
Observed Impacts of 20th Century Climate Changes in
the PNW Region

Warming trends over land and in the coastal ocean
(~ 1.5 F/century), small trends in precipitation

Retreating glaciers

Declines in low elevation and Olympic Peninsula
snowpack (at least from 1930s to 2007)

Timing shifts in snowmelt runoff (from 1948-2000)

Recent modeling studies suggest that ~35-60% of the
observed hydrologic trends from 1950-99 across the
western US are a consequence of human-caused
global warming (Barnett et al. 2008: Science)
David Horsey, Seattle Post-Intelligencer
Four key points about the greenhouse
effect and climate change
1. There is a natural Greenhouse Effect
2. Humans are strengthening the natural
Greenhouse Effect by adding Greenhouse
Gases to the atmosphere
3. Effects of a changing climate are already
apparent
4. There is very likely much more humancaused global warming to come
Some Facts
 Earth’s natural greenhouse effect warms
surface temperatures by ~33°C (60°F)
 H2O vapor the most powerful greenhouse gas
(GG)
 Other important GG’s are CO2, CH4, N2O,
HFCs, PFCs, and SF6 …


Human caused emissions of these GG’s are
increasing the natural greenhouse effect
Without drastic changes in current emissions
trends, GG concentrations will increase
dramatically in the next few centuries
Carbon-dioxide Concentrations
 Seasonal
changes
driven by the
“breathing” of
the biosphere
have been
riding on top of
a rising trend
source - http://www.esrl.noaa.gov/gmd/ccgg/trends/
The Industrial Revolution and the Atmosphere
The current concentrations of key greenhouse gases,
and their rates of change, are unprecedented in the last
10,000 years.
Carbon dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N2O)
CO2 over the last 160,000 yr
 Current concentrations
are higher than any
time in at least the past
~780,000 years
2010
 ~70% of CO2 emissions
come from fossil fuel
burning
From a long term perspective, these changes are enormous
The planet has gotten warmer…
The ten warmest years on record are since 1998; 2010 tied 2005 as the
warmest year on record. 2001-2010 is the warmest decade on record.
A chain of assumptions and models are needed
for developing future climate change scenarios
1.
Start with a greenhouse gas emissions scenario

2.
Choose a global climate model 
3.
Either specify atmospheric concentrations, or use
a carbon cycle model to develop them
20 were used in the IPCC’s Fourth Assessment
Downscale the coarse resolution climate model
output

To develop more realistic regional temperature
and precipitation fields required for impacts (e.g.
hydrologic, stream temperature) model inputs
How much CO2 will be released into the
atmosphere?
CO2 Emissions Scenarios
CO2 Concentrations
A1FI
A2
A1FI
A1B
A2
A1B
B1
B1
Estimates depend on population and economic projections, future choices
for energy, governance/policy options in development (e.g., regional vs.
global governance)
Karl & Trenberth (2003) Science
21st Century PNW Temperature and
Precipitation Change Scenarios
Mote and Salathé (2009): WACCIA
•
Projected changes in
temperature are large
compared to historic
variability
•
Changes in annual
precipitation are
generally small
compared to past
variations, but some
models show large
seasonal changes
21st Century PNW Climate Scenarios
Relative to Past Variability
A robust impact of climate warming:
rising snowlines
Snoqualmie Pass 3022 ft
} for a
~ 2 °C
warming
Low
-29%
-44%
-65%
-27%
-37%
-53%
Elsner et al. 2009
Medium
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
Runoff patterns are temperature dependent, but the basic
response is more runoff and streamflow in winter and
early spring, with less in late spring and early summer
a warmer climate Skagit
Puget Sound Precip
1900’s
Oct
Feb
Jun
Oct
Feb
Jun
Puyallup
Oct
Feb
Jun
Skokomish
Oct
Feb
Jun
Sea Level Rise (SLR) in the PNW
Major determinants:
 Global SLR driven by the thermal expansion of the
ocean;
 Global SLR driven by the melting of land-based
ice;
 Atmospheric dynamics, i.e., wind-driven “pile-up”
of water along the coast; and
 Local tectonic processes (subsidence and uplift)
Washington’s
Coasts
?
50”
40”
Rising sea levels will increase the risk of
flooding, erosion, and habitat loss along
much of Washington’s 2,500 miles of
coastline.
 Global SLR: 7-23” by 2100
 Medium estimates of SLR for 2100:
+2” for the Olympic Peninsula
+11” for the central coast
+13” for Puget Sound
 Higher estimates (up to 4 feet by
2100) cannot be ruled out at this
time.
30”
?
20”
13”
10”
6”
6”
3”
2050
2100
Projected sea level rise (SLR) in Washington’s waters
relative to 1980-1999, 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”).
Climate change and Natural Variations
 Climate change may be manifest partly as a
change in the relative frequency of natural
variations (e.g., El Niños vs. La Niñas)
 Likely changes with ENSO are very uncertain

It currently isn’t clear if ENSO will be
stronger, weaker, or unchanged in a
warmer future! (see Collins et al 2010,
Nature Geosciences)
The future will not present itself in a simple,
predictable way, as natural variations will still be
important for climate change in any location
Degrees C
Box1
oC
Overland and Wang Eos Transactions (2007)
Modeled trends and variations in
pH/Aragonite saturation states
 Model scenario has
aragonite saturation
state at OS PAPA
leaving historical range
of variability in 2031
Cooley et al. (in press):
Fish and Fisheries
Summary for Puget Sound
Climate Change Scenarios
 All climate model projections will be wrong

Emissions scenarios are stories about what might
happen; informing climate system models with
these stories yields “scenarios”, not predictions
 Confidence in some aspects of climate and
environmental change is higher than in others


Highest confidence is in rising air and water
temperatures, increased ocean acidification, and
rising sea levels
Lowest confidence in future precipitation, future
wind patterns important for coastal upwelling,
storminess and wave heights
Integrating Adaptation Into Planning
Goal: Developing more “climate resilient” organizations,
communities, economies, and ecosystems
What does this mean?
Taking steps to avoid or minimize those climate change
impacts that can be anticipated while increasing the ability
of human and natural systems to “bounce back” from the
impacts that cannot be avoided (or anticipated)
1. Awareness
2. Analysis
3. Action
4. Assessment
1. Awareness: Recognize that the past
may no longer be a reliable guide to
the future
Workshops, briefings, reports
Barrier: Planning paradigms rooted in
the past
3. Action: Integrate climate change
projections into planning processes
Case studies in water resources,
Adaptation guidebook
Barrier: Lack of authority, guidance,
and leadership
Climate resilience
The 4-As of Adaptation Planning
2. Analysis: Determine likely consequences of
climate change for the specific sector or resource
of interest
Climate change scenarios for planning purposes
Barrier: Lack of information
4. Assessment: Evaluate climate adaptation
efforts in light of progress to date & emerging
science
Adapting monitoring programs, training
Barrier: Costs, long time horizon of some impacts
Mainstreaming Planning
 Watershed Planning Program (EHSB 2514)
 Salmon recovery (ESHB 2496)
 Habitat conservation planning process
 Water supply planning
 Local land use planning
 Flood control planning
 Forest management plans
 Nearshore and coastal planning
 Water quality management (state, federal reqs)
 Others….
At its core, planning for climate change is about
risk management
How might (INSERT YOUR CONCERN HERE) affect my
program’s goals and objectives?
What are the consequences of those impacts?
What steps can be taken to reduce the consequences?
Swinomish Indian Tribal Community:
Climate Change Initiative
 Vulnerability assessment (2009) and adaptation plan
(2010)
 Focused on impacts related to: sea level rise, storm
surge, wildfire risk, extreme heat, changes in habitat,
changing hydrology
Shelter Bay, source: http://www.goskagit.com/home/article/shelter_bay_residents_bracing_for_increase/
Swinomish Indian Tribal Community: Climate
Change Initiative (cont.)
 Priority actions include (time frame if funded):





Delineating coastal protection zones (1-3 yrs)
Evaluate/study alternatives & solutions for impacts to
sensitive coastal resources (shellfish, etc.) (3-5 yrs)
Establish dike maintenance authority and program for
short-term support shoreline diking, where appropriate (35 yrs)
Establish/promote new reservation-wide program for
wildfire risk mitigation (1-3 yrs)
Coordinator with local jurisdictions on regional
access/mobility preservation (1-3 yrs)
City of Olympia:
Planning for Sea Level Rise
 Used LIDAR elevation
data to refine land
surface elevation
measurements in the
downtown area
 Mapped areas
impacted by varying
levels of sea level rise
(represented by
mapping of higher high
tide levels)
Future 20 Foot Tide…22” Increase
City of Olympia:
Planning for Sea Level Rise (contd.)
 Looking at implications for the storm sewer & combined
storm/sanitary sewer system
 Invested in geological monitoring equipment to monitor
land subsidence or uplifting
 Consolidating # of stormwater outfalls (from 14 to 8) to
reduce the number of possible entry points for marine
water to flow into downtown
 Analyzing potential shoreline sea walls/barriers
 Incorporating sea rise issues in Comprehensive Plan and
Shoreline Master Plan revisions
Washington DNR Aquatic
Resources Program
 Staff surveys identified impacts on:
aquaculture, overwater structures, log
booming and storage, dredged
materials, invasive species, derelict
vessel removal
 Priority planning areas: sea level rise,
providing public benefits
 Challenge: no authority over uplands
that may ultimately becomes stateowned aquatic lands
Source: CAKE adaptation database; photo source: CIG
Washington DNR Aquatic
Resources Program cont.
Recommended actions include:
 Incorporating climate change into internal/external
activities,
 Encouraging climate-centric research and tools
decision-support development,
 Education and outreach to aquatic lands lesees,
 Increased monitoring,
 Reducing non-climate stressors,
 Encouraging new uses of state-owned aquatic lands
(e.g., wind and tidal energy),
 Facilitating managed retreat
Source: CAKE adaptation database
Vulnerability of Wastewater Facilities
to Flooding from Sea-Level Rise
 Developed and conducted GIS based
methodology combining sea level rise
projections + storm surge, compared to
facility elevations
Recommendations include:
 Raise elevation of Brightwater sampling
facility and flow monitor vault sites.
 Raise weir height and install outfall flap
gate for Barton Pump Station
improvements.
 Conduct terrain analysis of five lowest
sites and West Point Treatment Plant.
Slide source: Matt Kuharic, King County
CIG’s Work with the 2011 Action Agenda
 Developing written guidelines to help integrate climate
change into strategies and near-term actions selection &
prioritization.
 Consulting and reviewing PSP work products related to
target setting and strategy updates, including:



Working with PSP staff, technical experts, and
consulting staff
Identification of key climate change-related scientific
uncertainties about adaptation strategies that need to
be reduced to make more informed policy choices
Analysis of draft Action Agenda and Biennial Science
Work Plan for overall treatment of climate.
Closing Thoughts on Climate Impacts and
Adapting to Climate Change

Human activities are altering and will continue to alter 21st
century climate. How we experience climate change is a
function of natural variability and climate change.

Projected “high confidence” impacts include increasing
temperatures, sea level rise, ocean acidification, declining
snowpack, and shifts in streamflow patterns and timing.

Climate change is the new “norm”. Planning for climate
change is a risk management activity, not being “green”.

Adapting to climate change is not a one-time activity.
Integrate climate change planning into existing decision
making processes.
The Clearest Trends
Observed
Projected
Ocean acidity
Increasing extremely rapidly
Increasing extremely rapidly; incr.
frequency of extreme corrosive water
events along the coast
SST
~ 1 deg C/century warming
~ 2 to 3 deg/century warming; added
to natural variability, expect
increased frequency of extremely
warm SSTs
Coastal sea level
+ 8”/century
+13” (range: +6 to +50”) by 2100 for
Puget Sound; incr freq of extreme
high water events (flooding and
inundation)
Poleward shifting
wind systems
Subtle but clear trends
A few degrees latitude by 2100
Earlier streamflow
timing
A few days to a few weeks over
the 1948-2000 period (due in
part to natural variability)
Comparable trends over the next 50
years
Trends that are less certain
Observed
Projected
Storminess
Increasing storminess
from 1948-2000
More intense, but fewer
fall/winter mid-latitude
storms
Wave heights
Increased over the 19752005 period from buoys
off WA/OR
Continued increases on
west coast of N. America
(different models have
different trend patterns)
Factors with the greatest uncertainty
Observed
Projected
Nutrients
Highly variable, related to local and remote
winds, currents, and upper ocean
stratification. In past century, increased
stratification correlated with reduced nutrient
supply to euphotic zone
One recent model scenario has increases
due to changes in offshore wind and
circulation patterns, even in the presence of
increased stratification.
ENSO
variability
Interdecadal variations
No consensus on variability
ENSO pattern
Trends for increased frequency of “central
Pacific warm” (CPW) events
Most scenarios show continued trend for
increased frequency CPW events, but
climate models challenged to reproduce
observed ENSO characteristics
NPGO
variability
Near decadal variations
Increased amplitude /increase in CPW
PDO
Interannual to interdecadal variations. No
significant trends
Continued interannual to interdecadal
variations, no clear trends
Local upwelling
winds
Interdecadal variations in spring upwelling
off OR/WA; 1950-2005 trends to increased
curl-driven upwelling off S.Cal; upwelling
source waters influenced by PDO and
NPGO variations
One regional model shows delayed onset of
curl-driven upwelling and increased intensity
in summer; global models tend to show
stronger summertime coastal upwelling off
OR/WA
Ocean currents
and circulation
Related to local and remote winds, strongly
influenced by ENSO, NPGO, and PDO
Weaker wind systems yield weaker ocean
circulation patterns
Salmon Affected Across Their Life-Cycle
Floods
Warm, low
streamflow
warming, winds
Earlier
freshet &
warmer,
lower
flows in
summer
Modified from Wilderness Society (1993)
Impacts will vary depending on life history and
watershed types
 Low flows+warmer water = increased
pre-spawn mortality for summer run
and stream-type salmon and steelhead

Clear indications for increased
stress on sockeye, summer
steelhead, summer Chinook, and
coho more generally
 Increased winter flooding in transient
rain+snow watersheds

Harley Soltes/Seattle Times
a limiting factor for egg-fry survival for
fall spawners + yearling parr
overwinter survival in high-gradient
reaches