DANGEROUS ANTHROPOGENIC
INTERFERENCE OF MOUNTAIN CLIMATES
Steven W. Running
University of Montana
MTNCLIM 2005, Chico Hot Springs
March 2005
PROGRESSION OF U.S. CLIMATE CHANGE POLICY
QUESTIONS
First, is the Earth warming?
YES
Second, is human activity causing warming YES
Third, is the warming “dangerous”
???
1992 Framework Convention on Climate Change,
key language:
DANGEROUS ANTHROPOGENIC INTERFERENCE IN
THE GLOBAL CLIMATE SYSTEM
Jim Hansen at GISS has chosen
SEA LEVEL RISE
as the most clearly illustratable “dangerous impact”
of climate change to build public awareness.
WHAT ABOUT THE MOUNTAINS??
Temperature Trends: 1901 to 1998
Red circles reflect warming; Blue circles reflect cooling
All Stations/Trends displayed regardless of statistical significance.
Source: National Climatic Data Center/NESDIS/NOAA
Precipitation Trends: 1901 to 1998
Blue circles reflect increasing precipitation; Red circles reflect decreasing
precipitation
All Stations/Trends displayed regardless of statistical significance.
Source: National Climatic Data Center/NESDIS/NOAA
Dai et al. J. Hydromet (2004)
Potential climate limits to plant growth derived from long-term
monthly statistics of minimum temperature, cloud cover and rainfall.
Nemani et al., Science June 6th 2003
Earlier
Growing
Season
>
Net Primary
Production
Invasive
Species?
Human
Health &
Comfort?
Water Balance
Increasing
> Spring
Temps
Early
Snowmelt
Longer
Growing
Seasons
Water Balance
Decreasing
Earlier
Growing
Season
>
Vegetation
Stress
Insect/
Disease
Mortality
Wildfires/
Low
Streamflows
ECOLOGY
2-3 week
Earlier Spring
phenology
Longer
Growing
season
>
Aquatic
Health
>
NPP
Insect/
disease?
METEOROLOGY
2-3 week Longer
Freeze - free
season
Summer
Water Balance
POSITIVE
HYDROLOGY
Snowmelt
2-3 weeks
early
Adequate
streamflow
>
Thunderstorm
Intensity
>
Flood
Potential
ECOLOGY
2-3 week
Earlier Spring
phenology
Earlier
Growing
Season
Summer
Vegetation
Stress
Forest
Mortality
Wildfire
METEOROLOGY
2-3 week Longer
Freeze - free
season
Summer
Water Balance
NEGATIVE
HYDROLOGY
Snowmelt
2-3 weeks
early
Stream
Runoff peak
2-3 wks early
Low summer
Stream flow
Restricted
Irrigation
Recreation
Elec. Power
Aquatic health
Decrease Increase
Mote 2003(b)
Trends in timing of spring snowmelt (1948-2000)
+20d later
–20d earlier
Courtesy of Mike Dettinger, Iris Stewart, Dan Cayan
CHANGING SEASONAL WATER BALANCE
6
DAILY AVE ET (MM)
4
2
Summer Water Deficit +50%
0
1
6
11
16
21
26
-2
-4
-6
WEEK
31
36
41
46
51
Spring bud-burst dates for Aspen in
Edmonton, Beaubien and Freeland I.J.Biomet 44:53-59, 2000
NDVI DEFINED
GROWING SEASON
1982 - 1999
From Myneni et
al 2001 JGR
Change in Terrestrial NPP from 1982 to 1999.
Nemani et al., Science June 6th 2003
CANADIAN FOREST FIRE TREND
Gillett et al GRL 2004
NEEDED TIME-SERIES 1950s-2000 DATASETS
• INSECT/DISEASE AREA IMPACT TRENDS
• US ANNUAL WILDFIRE AREA TRENDS
• SUMMER STREAM BASEFLOW/AQUATIC
HEALTH
• HUMAN HEALTH??
• Other impacts??????
Contact me at swr@ntsg.umt.edu