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 webinarPuget Sound Partnership webinar

June 14, 2011June 14, 2011

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

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)

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

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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

Source: CAKE adaptation database; photo source: CIG

Washington DNR Aquatic Resources Program

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.

The Clearest Trends

Observed ProjectedOcean 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 ProjectedStorminess Increasing storminess

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