Transcript Impacts of Climate Change on the Northwest

Global Warming:
Climate Impacts on the
Coastal Environment
Eric Salathé
Climate Impacts Group (JISAO/SMA)
University of Washington
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
Natural Climate Variability
(ENSO)
(PDO)
1900
University of Washington, JISAO
2000
1900
2000
Two primary patterns of winter/spring climate
in the Pacific Northwest
Nature’s “Greenhouse Effect”
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
Global warming in the past century
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
Will Warming Continue?
Will Warming Continue?
Will Warming Continue?
Future Climate Change
Climate is changing, and humans are at least partly
responsible.
Earth’s average temperature will probably increase by
1.8-6.3°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.
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 ???
The Main Impact: Less Snow
April 1
Columbia
Basin
Snow
Extent
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.
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
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
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
centimeters
SeasonalInterannual sea
level variations:
+/- 1 foot at SF
due to persistent
winds and coastal
ocean temperature
changes
centimeters
Natural Sea Level Variability
NOAA/PMEL Sea Level Center
El Niño Sea Level Rise
Dec 1997-Jan 1998 Sea Level Height Anomalies
Vertical Land Movement
Tectonic forces move the land
Rising sea levels add to the
land movement
Current rise: 1.0-2.5 mm/yr
Projected rise: 2.0-8.6 mm/yr
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?
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
Are We Prepared for a Changing
Climate?
“Some people are weatherwise, some are
otherwise”
-- Ben Franklin
Are We Prepared for a Changing
Climate?
Natural resource management presently assumes
Climate does not change
But what if it does?
Becoming Climatewise
Use climate information
Requires on-going dialogue between decisionmakers, climate scientists, and the general
public
Create centralized & adaptable management
strategies
Learn from the past
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)
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