Transcript Evaluation of Climate Change

Planning for Climate Change
in the
Pacific Northwest
Amy Snover, PhD
Climate Impacts Group
Center for Science in the Earth System
University of Washington
[email protected]
The Climate Impacts Group
Columbia
River Basin
Goal: to increase the region’s
resilience to climate variations
and climate change
Areas of study:
Water resources
Forests
- The past is the key to the future -
Salmon
Coasts
Considerations for management
Responsible management looks forward...
• Needs of a growing population
• Environmental stewardship
• Climate change
Outline of Talk:
• Brief review of climate change
• Implications for Pacific Northwest climate
• Consequences for PNW natural resources
• Application to regional policy & planning
Brief Review of Climate Change
• Carbon dioxide and other greenhouse gases
warm the planet
• Greenhouse gases have been increasing (CO2
up 30%) and will increase for a long time as a
result of human activities
• The planet has warmed ~1°F since 1900, in
part due to human activities
• Further warming of 2.5-10.4°F by 2100
Earth’s Surface Temperature Past and Future
From 1900 to
2000 the planet
warmed ~1°F.
+ 10° F
Global average
temperature
projected to
increase 2.510.4°F by 2100.
+ 5° F
Very significant
change from
historical
perspective.
1000
Source: IPCC TAR 2001
1900 2000 2100
Future Climate Change
• Earth’s average temperature projected to
increase during the 21st century at a rate
2-10 times that observed in the 20th
century (+2.5-10.4°F by 2100)
• Expect additional changes in climate
(precipitation, storm tracks)
• Global average sea level projected to rise
4-35 inches by 2100
• These changes will have far-reaching
consequences
Climate change in the PNW
Temperature
Precipitation
summer winter summer winter
low
mean
high
+3.1F
+3.2F
-7%
-2%
+4.7F
+5.2F
+2%
+9%
+6.7F
+6.7F
+9%
+22%
Warmer, wetter winters.
Warmer summers.
Estimated climate change from 20th century to the 2040s using 8 climate
model scenarios (“summer”=April-September, “winter” = October-March).
PNW Temperature: Past and future
The Main
Impact:
Less Snow
April 1 Columbia Basin Snow Extent
Historical Average
~ 2025
~ 2045
Changes in the Water Cycle
Less snow, earlier melt:
 More water in winter
 Less water in summer
 winter flooding
• Changes in amount &
timing of peak flows
•  spring/summer water
temperature
•  spring/summer flows
•
Naturalized Columbia River flow - the Dalles, OR.
Columbia Basin:
• Decreased spring/summer flows -salmon & irrigation
• Increased competition & conflict
among uses
• More $$ summer drought
• Increased vulnerability
Planning for Climate Change:
Municipal water supply
• More winter streamflow
• Less spring/summer streamflow
Cedar Current Climate
Cedar pcm3dec4
Cedar echam4dec4
Cedar had2dec4
Cedar had3dec4
600
500
For western Washington
rivers (Sultan, Tolt, Cedar,
Green) in the 2040s:
400
300
Winter: +30 to 40%
200
Summer: -20 to –30%
100
0
Oct
Nov Dec Jan
Feb Mar
Apr May Jun
Jul
Aug Sep
Planning for Climate Change:
Municipal water supply
• More winter streamflow
• Less spring/summer streamflow
• Increased demands
Puget Sound demand
changes from population
projections
Total
Demand increases with:
• population growth
King
• warmer temperatures
Snohomish
Pierce
Planning for Climate Change:
Municipal water supply
• More winter streamflow
• Less spring/summer streamflow
• Increased demands
2040s WATER NEEDS IN
PORTLAND (OR):
Regional growth: +40 mgd
Climate change: +20 mgd
Climate change impacts =
50% of growth impacts
Average Monthly Bull Run Inflows
1950-1999
2200
2000
1800
14,000
12,000
10,000
Million Galllons
1600
Inflows, cfs
ECHAM4 Decade 2040 Climate Change Impacts
Measured as Difference in Annual Minimum Storage less Shortfalls
from Current Climate/Current Demands (2000 Demands)
Current Climate
PCM3 2040
ECHAM4 2040
HadCM2 2040
HadCM3 2040
1400
1200
1000
1952
1966
1968
1982
1987
1992
1994
8,000
6,000
4,000
800
600
2,000
400
0
200
Climate impact on
hydrology
0
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Climate impact on
demand
Impact of growth on
demand 2040
Impact of climate
change on 2040
demand and
hydrology
Changes in the Water Cycle
Landslides
 Increased frequency /
magnitude
 Exacerbated by sea
level rise around Puget
Sound
Skiing
 Later season opening
 Shorter season
 More rainy days
Stevens
(4000’)
4
1
2 3
Snoqualmie
(3000’)
Mission Ridge
(4500’)
Schweitzer
(4000’)
Current Conditions
Salmon
• Climate influences habitat quality
(stream, estuarine, and ocean habitat)
• Future scenarios indicate increased climate
stress in the freshwater environment
– Winter: floods
– Summer/Fall: low flows & high temperatures
• Future changes in crucial coastal and ocean
habitat are uncertain
Forests
Future vegetation
changes unclear
• Continued forest
encroachment into
alpine meadows
• Overall forest dieback or expansion??
Vegetation Carbon Change by 2070-2100
Big Questions:
• Seasonality of
precipitation change
• CO2 fertilization
effect
Preparing for a changing
climate ...
Becoming climate-wise:
water, salmon, forests
• Consider climate a component of any
long-term plan
• Water: increase supply, decrease
demand, increase management flexibility
• Salmon: promote biodiversity by
increasing healthy and connected habitat
• Forests: maintain a full range of
biodiversity
Tools for Planning
Bringing a global
issue to the local
level

Working with the cities of Portland & Seattle and watershed planning leads
under the 1988 Washington State Watershed Planning Program

Developing new tools for planning:


Detailed projections of potential scenarios
low tech/low cost vulnerability assessments
Planning for climate change:
Scenarios of future streamflow
Web based streamflow scenario tool provides climate change
information, including free access to streamflow scenarios and data.
Partners:
Northwest Power
Planning Council
Idaho Dept of
Water Resources
Summary
• Some global warming is very likely (1-4°F by 2040s)
• Regional warming likely to be faster than global
warming (3-6°F by 2040s)
• In the PNW, climate change will:
– Reduce winter snowpack & summer streamflow
– Increase winter flooding, alter the amount and timing of
streamflows with consequences for urban and irrigation
water supplies, hydropower production
– Negatively affect salmon habitat, alter forest & coastal
ecosystems and exacerbate some coastal hazards
• Knowledge & tools exist to support planning now.
Resources
Global and National Assessments
(based on thousands of peer-reviewed papers):
•
•
•
•
IPCC reports in 2001, 1996, 1990
National Academy of Sciences 2001
National Resource Council 2000
U.S. National Assessment 2001
Regional Assessments:
• The Climate Impacts Group, UW
http://www.jisao.washington.edu/PNWimpacts
[email protected]
Questions?