1. Climate Impacts on the Coastal Environment
Global Warming:
Climate Impacts on the Coastal Environment
Eric Salathé
Climate Impacts Group (JISAO/SMA) University of Washington

2. The Climate Impacts Group
Elements of the PNW we study:
Water resources
Salmon
Forests
Coasts
Goal: make the region more resilient to climate variations and climate change
Interdisciplinary research team at UW

3. Natural Climate Variability
(PDO)
(ENSO)
1900
2000
1900
2000
University of Washington, JISAO

4. Two primary patterns of winter/spring climate in the Pacific Northwest

5. Nature’s “Greenhouse Effect”

6. Humans are altering the atmosphere
carbon dioxide concentration has increased by ~30% since 1750’s
from a very long term perspective, these changes are enormous

7. Global warming in the past century

8. Is Our Climate Changing? Temperature
113 stations with long records
Almost every station shows warming
Urbanization not a major source of warming
100-year Temperature Trends
warming cooling

9. Will Warming Continue?

10. Will Warming Continue?

11. Will Warming Continue?

12. Future Climate Change
Climate is changing, and humans are at least partly responsible.
Earth’s average temperature will probably increase by °F (1-3.5°C) in the next 100 years.
Other climate changes are likely to accompany this warming (precipitation, storm tracks).
These changes will have both positive and negative consequences.

13. What Might Climate Change Look Like in the Northwest?
We looked at 7 scenarios of future climate from climate models
Averages of 7 scenarios, compared to 20th century:
2F warmer by 2020s
4F warmer by 2050s
Slightly wetter
Winters wetter
Summers ???

14. The Main Impact: Less Snow
April 1
Columbia
Basin
Snow
Extent

15. Impacts of Hydrologic Changes
Less snow, earlier melt means
More water in winter
Less water in summer
Flooding
Irrigation
Salmon
Hydropower
Municipal water
Natural Columbia River flow at the Dalles, OR.

16. Coastal Issues: Current
Coastal erosion
Ocean shores: development on a shifty beach
El Niño year storm damage and armoring
Landslides
Bluff failures from heavy rainfall
Flooding and inundation
The southwest coast of Washington now faces a net loss of coastal lands, reversing a long term trend of sediment buildup. Beachfront erosion now threatens an area that represents more than 10% of Ocean Shores’ tax base. Ocean Shores also has a wastewater treatment plant that’s currently threatened by erosion and flooding.
A study of the Oregon Coast found that the amount of armored shoreline increased in dramatic pulses following El Nino winters in the past few decades. El Nino’s tend to alter Pacific winds in ways that raise sea levels coast-wide, and also produce large waves from a more southerly than usual direction, a combination that is especially good at eroding beaches.
Wet winters and heavy rainfall events frequently cause coastal flooding, especially when high flows coincide with high tides.
Because the land mass of South Puget Sound is subsiding, the risk of inundation is especially large in low-lying parts of Olympia.

17. Coastal Issues: Climate Change
Coastal erosion
 Rising sea levels
/ Changing wave climate
Landslides
 With increased winter rainfall
Flooding and inundation
 Due to sea level rise and increased winter stream flows; Olympia perhaps most vulnerable
The southwest coast of Washington now faces a net loss of coastal lands, reversing a long term trend of sediment buildup. Beachfront erosion now threatens an area that represents more than 10% of Ocean Shores’ tax base. Ocean Shores also has a wastewater treatment plant that’s currently threatened by erosion and flooding.
A study of the Oregon Coast found that the amount of armored shoreline increased in dramatic pulses following El Nino winters in the past few decades. El Nino’s tend to alter Pacific winds in ways that raise sea levels coast-wide, and also produce large waves from a more southerly than usual direction, a combination that is especially good at eroding beaches.
Wet winters and heavy rainfall events frequently cause coastal flooding, especially when high flows coincide with high tides.
Because the land mass of South Puget Sound is subsiding, the risk of inundation is especially large in low-lying parts of Olympia.

18. Climate Impacts on Sea Levels
Several key mechanisms:
seasonal-interannual sea level rise natural annual and decadal variability
land movement tectonic motions
sea level rise thermal expansion and melting icecaps

19. Natural Sea Level Variability
Seasonal-Interannual sea level variations:
+/- 1 foot at SF
due to persistent winds and coastal ocean temperature changes
centimeters
centimeters
NOAA/PMEL Sea Level Center

20. El Niño Sea Level Rise
Dec 1997-Jan 1998 Sea Level Height Anomalies

21. Vertical Land Movement
Tectonic forces move the land
Rising sea levels add to the land movement
Current rise: mm/yr
Projected rise: mm/yr

22. Climate Impacts on Biology
Impacts are speculative -- Natural variability
(ENSO, PDO) mixed with Global Warming
Likely sensitivities:
Changes in streamflow
alters nutrient supply and mixing in estuaries
impacts production and algal blooms (HABs)
Ecosystem changes
invasive species (e.g. cordgrass)
Climate link to Oyster Condition Index?

23. Upwelling Food Webs in our Coastal Ocean
Cool water, weak stratification
abundant nutrients, and a
productive “subarctic”
food-chain
Warm stratified ocean, few
nutrients, low productivity “subtropical”
food web

24. Are We Prepared for a Changing Climate?
“Some people are weatherwise, some are otherwise” Ben Franklin
As Ben Franklin put it…
The question is, are we...

25. Are We Prepared for a Changing Climate?
Natural resource management presently assumes
Climate does not change
As Ben Franklin put it…
The question is, are we...
But what if it does?

26. Becoming Climatewise Use climate information
Requires on-going dialogue between decision-makers, climate scientists, and the general public
Create centralized & adaptable management strategies
Learn from the past
1. The single most important thing that the region can do to prepare for climate change is to use climate information in our planning and decision-making processes.
-- increased awareness of how climate affects the region will enable decision makers to better manage the region’s natural resources as the climate changes
-- as scientists learn how climate forecasts are used, they can make more useful forecasts and provide more useful information on climate change
2. Management needs to be flexible/agile enough to operate differently under different climate conditions. Much water res mgt based on strict rule curves that define how managers must operate and don’t allow them to adapt to conditions that may vary from year-to-year. Following flood prevention rule curves was one of the reasons SPU experienced water shortages in 1992.
3. Climate variations such as El Nino/La Nina and the PDO have been with us throughout this century. By examining how well we dealt with these climate variations in the past, we can prepare for the future. When the SPU learned how EN had impacted them in the past, they used that knowledge and forecasts of EN to help them better prepare for the future.
*Applies to management of nat resources in general as the climate changes
* Now address specific ways to adapt to projected impacts of climate change on water, salmon...

27. Becoming Climatewise: Water, Salmon, Forests and Coasts
Water: increase supply, decrease demand, increase management flexibility
Salmon: promote biodiversity by increasing healthy and connected habitat
Forests: maintain a full range of biodiversity
Coasts: recognize role of climate variability and change in coastal issues (erosion & flooding)
WATER -- As Alan the major impact of cc on water resources is a decrease in summer sf. To cope with these decreases, and the increased conflicts over water that are likely to go along with them, we should examine ways to:...
SALMON -- resilience to environmental variations depends on the diversity of their population as a whole, which in turn depends on the availability of healthy and complex habitat in streams, estuaries, and the open ocean. THE MOST EFFECTIVE CLIMATE INSURANCE WE CAN PURCHASE FOR PACIFIC SALMON MAY BE TO …
FORESTS -- Managed forests tend to be monocultures. Its important to ….. in order to maintain flexibility under climate change and to decrease vulnerability to pest outbreaks
COASTS -- few coastal communities have considered the potential threat posed by climate change. However, long-term economic impacts may be dictated by planning decisions that are made now. Coastal planner must …… for example, coastal erosion and flooding all have a climate component. Policies on flood plain and coastal development need to recognize this.

28. Conclusions
Climate change likely to significantly affect the pacific northwest
Main impact: reduction in snowcap, summer streamflow
Will exacerbate existing stresses in many cases
Need to retool institutions and government agencies to respond to climate information and to plan for a changed climate
Consider climate a component of any long-term plan
CC: As Phil described, we know from the past that subtle variations in climate can have profound impacts on the region, and the changes projected by the climate models are anything but subtle.
IMPACTS: are likely to be felt among the natural resources of the region -- the water res….
RETOOL: At present, the region is ill-prepared to tackle a changing climate, but some improvements are being made. …… climate change will also bring some benefits, but we will be most likely to reap those benefits if we are prepared for them.
LONG-TERM: Think about some long-range plans and decisions that are currently being made: habitat conservation plans, salmon recovery plans, plans to ensure future water supply for cities and towns, dam relicensing, land use planning near shore and bluffs and in potential flood areas, and planting of trees for commercial timber. CV’s and CC have an important bearing on each of these decisions. We know enough already to begin the process of changing how we think about climate in the context of natural resources decisions.
It’s time to start.

30. Is Our Climate Changing? Rain
76 stations with long records
Most stations becoming wetter
Average: +2.9 inches (14%)
Opposite trends next to each other shows how uncertain this kind of calculation can be
100-year Precipitation Trends
wetter drier

31. Another stress on the Pacific Northwest
NW Population
Land Use
Water Demand
Energy Demand
Ecosystems

32. Impacts of Natural Climate Variability on the Pacific Northwest
El niño
The pacific decadal oscillation (PDO)
Warm phase:
Less snow, summer water
Lower salmon returns
Bigger forest fires
But small temperature, precipitation anomalies!

33. Salmon Northwest salmon crisis is already with us
Causes are many: harvest, hydropower (dams), hatcheries and habitat
Climate influences the quality of stream, estuarine, and ocean habitat
Future scenarios point to increased climate stress
Increased flood frequencies, low flows and high temperatures in summer and fall
In March of stocks of NW salmon were listed as threatened under the Federal Endangered Species Act, one was listed as endangered.
Causes for the NW salmon crisis have been boiled down to the 4 H’s: harvest, hydropower dams, hatcheries and habitat.
Climate variations influence salmon habitat at every stage of their unusual life-cycle:
for example: incubating eggs can be damaged by nest scouring floods;
fry and parr are sensitive to in stream temperatures, flows, and water quality;
smolts appear to be especially vulnerable to changes in the coastal ocean environment, and how those changes alter their food supply and their exposure to predators.
Finally, adult salmon returning to their natal rivers to spawn sometimes face thermal barriers: in the summer and fall of 1997, estuary temperatures were so high that many salmon died at river mouths, or burned up their stored energy while waiting for rivers and estuaries to cool down.

34. Forests Important factors to consider in future climate:
Temperature
Precipitation
Carbon
Vegetation models account for all those, use input from climate models
Greatest uncertainty: physiological effects of CO2
Dry summers limit where trees now grow and determine types of trees
Direct effect: good conditions --i.e., moist soil in the summer (from deeper snowpack) lead to better growth (bigger trees)
Northwest conifers long-lived and have lived through climate variations in the past; trees are generally most vulnerable at the establishment phase, and when growing in an existing forest, they have an easier time than when starting over on bare ground
Disturbances -- fires, pest outbreaks, logging -- reset the forest. Sensitive time in a forest’s history. Climate affects fires -- huge fires in PDO warm phase, before fire suppression --

35. Potential change in vegetation cover
Best case scenario:
higher CO2 allows plants
to deal better with higher
temperatures
More likely scenario for
NW conifer forests:
higher CO2 can’t offset problems caused by hotter, longer summers and increase in forest fires
Figure courtesy of Ray Drapek,
Oregon State University

36. Are We Climatewise? A success story: Seattle public utility
Droughts & water shortages: 1987 and 1992
Drought but no shortage: 1998
To be climate-wise means to base decisions on the best available information about climate.
Let me give you an example of the benefits of being climate-wise.
SPU - which manages Seattle’s water supply was challenged by significant droughts in 1987 and Combo of precip patterns, lower sf and operating decisions resulted in water shortages and other impacts to Seattle water supply (lawn-watering restrictions).
When the utility looked at what went wrong, they learned both years = EN. learned that EN makes low summer sf, and warmer drier summers that increase water demand more likely.
When a strong EN event was predicted for 1998, the utility responded quickly -- augmented supply, reduced demand. These actions were successful -- despite low sfs in 1998, seattle avoided water shortages.
This skill at incorporating climate info into decision-making turns out to be quite unusual in the PNW.
-- 3 years ago, we interviewed 30 public agencies in the nw who were likely to use climate info in their decision-making. Turns out only 2 of them did. (some improvements since)
-- also, managers constrained. Even if they get forecasts, many feel discouraged from using them.