Past and Future Climate of Puget Sound and Implications for Decision Making Nate Mantua and Lara Whitely Binder Climate Impacts Group University of Washington Climate Science in the Public Interest Puget Sound Partnership Puget Sound Partnership webinar webinar June 14, 2011 June 14, 2011
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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.
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Past and Future Climate of Puget Sound and Implications
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
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
Sea-Tac average air temperatures: June 2010-June 2011
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 longer-term warming trend
1941
1958
19831998
1928
2000
The South The South Cascade Cascade glacier glacier
retreated retreated dramatically in dramatically in
the 20th the 20th centurycentury
Courtesy of the USGS glacier
group
Length of the Blue GlacierLength of the Blue Glacier~ 800 meter recession ~ 800 meter recession
since the early 1900s, and since the early 1900s, and ~1500 meter recession ~1500 meter recession since the early 1800ssince the early 1800s
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
Source: Climate Impacts Group, University of Washington
PDO ENSO (El Niño)
Warm phases
Climate has varied over long time periods
Last glacialmaximum18,000 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 human-caused 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
Current concentrations are higher than any time in at least the past ~780,000 years
~70% of CO2 emissions come from fossil fuel burning
From a long term perspective, these changes are enormous
CO2 over the last 160,000 yr
2010
The planet has gotten warmer…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
Either specify atmospheric concentrations, or use a carbon cycle model to develop them
2. Choose a global climate model - 20 were used in the IPCC’s Fourth
Assessment
3. 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?
Estimates depend on population and economic projections, future choices for energy, governance/policy options in development (e.g., regional vs. global governance)
A1B
A2
B1
A1B
A2
B1
CO2 Emissions Scenarios CO2 Concentrations
A1FI
A1FI
Karl & Trenberth (2003) Science
21st Century PNW Temperature and Precipitation Change Scenarios
• 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
Mote and Salathé (2009): WACCIA
21st Century PNW Climate Scenarios Relative to Past Variability
A robust impact of climate warming: rising snowlines
Snoqualmie Pass 3022 ft
} for a } for a ~ 2 °C ~ 2 °C warmingwarming
Low
Med
ium
-29% -44% -65%
-27% -37% -53%
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
Elsner et al. 2009
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
Oct Feb Jun
Skagit
Puyallup
Skokomish
Oct Feb Jun
Oct Feb Jun
Puget Sound Precip
Oct Feb Jun
1900’s
a warmer climatea warmer climate
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
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.
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”
2050 2100
13”
40”
20”
10”
6”
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”).
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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
Overland and Wang Eos Transactions (2007)
Box1
oC
Deg
rees
C
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)
The 4-As of Adaptation Planning
1. Awareness 2. Analysis 3. Action
1. Awareness: Recognize that the past may no longer be a reliable guide to the futureWorkshops, briefings, reportsBarrier: Planning paradigms rooted in the past
2. Analysis: Determine likely consequences of climate change for the specific sector or resource of interestClimate change scenarios for planning purposesBarrier: Lack of information 3. Action: Integrate climate
change projections into planning processesCase studies in water resources, Adaptation guidebookBarrier: Lack of authority, guidance, and leadership
Clim
ate
resi
lienc
e
4. Assessment: Evaluate climate adaptation efforts in light of progress to date & emerging scienceAdapting monitoring programs, trainingBarrier: Costs, long time horizon of some impacts
4. Assessment
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 (3-5 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
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 state-owned aquatic lands
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
Washington DNR Aquatic Resources Program cont.
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.
from 1948-2000More intense, but fewer fall/winter mid-latitude storms
Wave heights Increased over the 1975-2005 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 ProjectedNutrients 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
Floods
Warm, lowstreamflow
Salmon Affected Across Their Life-Cycle
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
Harley Soltes/Seattle Times
Increased winter flooding in transient rain+snow watersheds
a limiting factor for egg-fry survival for fall spawners + yearling parr overwinter survival in high-gradient reaches
Increased winter flooding in transient rain+snow watersheds
a limiting factor for egg-fry survival for fall spawners + yearling parr overwinter survival in high-gradient reaches