Transcript Philip Mote - Water Resources Department

Global climate change and
Oregon’s water resources
Philip Mote
Climate Impacts Group
University of Washington
Alan Hamlet (UW), Iris Stewart (UCSD)
With thanks to Dave Hart, Jon Lea, Greg Johnson, Randy Julander, Scott Pattee
ftp://ftp.atmos.washington.edu/philip/SNOWPAPER/
The Climate Impacts Group
http://cses.washington.edu/
Goal: help the region become
more resilient to climate
variations and climate
change
Supported by NOAA Office of
Global Programs
Main points
• Human influence on climate has already
emerged
• Hydrologic changes in Oregon have
been profound and will continue
Earth’s radiation budget
From Kiehl and Trenberth, 1996
Science of climate change
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Thousands of peer-reviewed scientific papers
Intergovernmental Panel on Climate Change (IPCC)
Major reports in 1990, 1996, 2001, 2007
Conclusions:
– “An increasing body of observations gives a collective picture of a
warming world and other changes in the climate system.”
– “There is new and stronger evidence that most of the warming
observed over the last 50 years is attributable to human activities.”
Carbon dioxide: up 32%
Global Surface Temperature Variations
HALOE H2O
Convection Frequency
Tropopause
Randel et al 2001, fig 6
(0.5, 1, 5, 10%)
Larsen B
Ice shelf
Antarctica
January 31, 2002
MODIS data
Courtesy NSIDC
February 17
February 23
March 5
The South Cascade
glacier retreated
dramatically in the
20th century
1928
Courtesy of the USGS
glacier group
2000
At almost every
USHCN station,
winters warmed
+ signs: warming
but not statistically
significant
Natural Climate Influence
Human Climate Influence
All Climate Influences
Main points
• Human influence on climate has already
emerged
• Hydrologic changes in Oregon have
been profound and will continue
Snake River at Ice Harbor
140000
120000
Flow (cfs)
100000
base
comp 2020
comp 2040
80000
60000
40000
20000
0
O
N
D
J
F
M
A
M
J
J
A
S
As the West warms,
winter flows rise
and summer flows
drop
Figure by Iris Stewart,
Scripps Inst. of Oceanog.
(UC San Diego)
Trends in fraction of annual runoff for cells with more than 50 mm of SWE on April 1
March
Relative Trend (% per year)
June
By several measures,
Western snowfed
streamflow has been
arriving earlier in the
year in recent
decades
Spring-pulse dates
Center
time
Spring
pulse
Centers of Mass
Stewart et al., 2004; Stewart et al., in press, J. Clim.
Relative trends 1950-1997 in April 1 SWE
Trends in Simulated Average APR 1 SWE for the Cascades in WA and OR (1950-1995)
600
Effects of TMP and PCP -54%
500
SWE (mm)
400
1-Apr
300
Linear (1-Apr)
200
100
y = -3.3822x + 365.25
450
1995
1992
1989
1986
1983
500
Effects of TMP -26%
400
Effects of PCP -28%
450
400
350
350
300
300
250
1-Apr
Linear (1-Apr)
200
1-Apr
250
Linear (1-Apr)
200
150
150
y = -1.6073x + 319.11
1995
1992
1989
1986
1983
1980
1977
1974
1971
1962
1959
1956
1953
1950
1995
1992
1989
1986
1983
1980
1977
1974
1971
1968
1965
1962
0
1959
0
1956
50
1953
50
1968
y = -1.7927x + 337.32
100
1965
100
1950
SWE (mm)
1980
1977
1974
1971
1968
1965
1962
1959
1956
1953
1950
0
Trends in timing of peak snowpack
Figure by Alan Hamlet, UW
Change in Date
Natural Climate Influence
Human Climate Influence
All Climate Influences
21st century temperature change
IPCC (www.ipcc.ch)
Planning for climate change: water
resources in the Columbia basin
Water policy workshops have highlighted the need to inject
climate change information into existing river basin planning
activities and to provide free access to streamflow scenarios.
Partners:
Northwest Power
Planning Council
Idaho Dept of
Water Resources
www.ce.washington.edu/~hamleaf/climate_change_streamflows/CR_cc.htm
Simulated Natural Flow in the Willamette River at the Confluence with the Columbia
Simulated Natural Flow at Pelton Dam on the Deschutes River
Main points
• Human influence on climate has already
emerged
• Hydrologic changes in Oregon have
been profound and will continue
• Planning is essential
Examples of climate-change planning
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Portland, Seattle *
NWPCC *
IDWR
CRITFC *
CalFed *
CEC *
ACoE
* Quantitative study