Climate Change in the
Western US:
Focus on the San Juans
Koren Nydick
12 June 2008
MTNCLIM Managers Workshop
GET to the PUNCHLINE FIRST:
Climate is warming in the West and is likely to
do so more in the future. We are already
seeing some effects.
We don’t have a lot of information YET on
IMPACTS of warming in the SAN JUANs but
historical data show a pronounced warming
trend since ~1990.
A Quick & Dirty Overview:
• Warming in the West & San Juan Region
• Precipitation & Moisture
• Effects on Natural Resources
• New Studies in the San Juans
• Planning for the Future Now – what do we
need to do?
Key observation:
The West is warming, dramatically
NOAA Earth System Research Laboratory
Climate Trends in the San Juans
Increase in mean
annual surface air
temperature.
Decrease in
annual snowfall
By Imtiaz Rangwala,
PhD student, Rutgers
University – funded
by MSI mini-grant.
1990-2005 showed consistent warming for
average, max, min, and seasonal
temperatures for San Juans
Snow depth and snowfall more
consistently below average in recent
decades in San Juans
Future Projections: 2045-2055 compared to 19712000 base period: AVERAGE ANNUAL TEMP
+4 to 5 ˚F
Future Projections: 2045-2055 compared to 19712000 base period: AVERAGE SPRING TEMP
+4 to 5 ˚F
Future Projections: 2045-2055 compared to 19712000 base period: AVERAGE SUMMER TEMP
5 to 6 ˚F
Future Projections: 2045-2055 compared to 19712000 base period: AVERAGE AUTUMN TEMP
+4 to 5 ˚F
Future Projections: 2045-2055 compared to 19712000 base period: AVERAGE WINTER TEMP
+3-4 ˚F
Expected changes in
FROZEN-SEASON LENGTH
30-60 days/year less in 2050 for Colorado
2025
Derived from monthly IPCC
GCM-grid pdfs, and UW’s VIC
model daily inputs, 1950-1999
2050
Water in the West? Best bet is that we’ll see
the following by the late 21st century:
Precipitation: flip a coin for changes in the mean,
(but, many models show decrease south,
and increase north) plus:
• snow melt runoff season will be significantly
The Consensus
earlier and shorter
• evaporation and evapotranspiration will be
likely significantly higher in all seasons
• streamflow will be significantly earlier and lower,
especially in late spring and summer
AVERAGE
moisture
conditions in the
future could be
similar to or
even worse than
historical
droughts
(even without much
change in
precipitation).
Hoerling & Eischeid, 2007.
Southwest Hydrology.
Earlier onset of spring snowmelt already
observed in West, but not yet in San Juans (?)
CT =
center of
stream
flow mass
Stewart et al. 2004. Climatic Change.
But a new analysis shows earlier streamflow in
Colorado with greatest changes in San Juans
David Clow, USGS, unpublished study
Earlier streamflow correlates with earlier snowmelt
David Clow, USGS, unpublished study
Large wildfires increased suddenly and
dramatically in mid-1980s in West
• More large wildfires
• Longer wildfire
durations
• Longer wildfire
seasons
• Strongly associated
with increased
spring and summer
temperatures and
earlier spring
snowmelt
Westerling et al. 2006
Regional vegetation die-off in response to global-change-type drought.
2005 -- Proceedings of National Academy of Sciences USA
David Breshears, Neil Cobb, Paul Rich, Kevin Price, Craig. Allen, Randy Balice, William Romme, Jude Kastens, M. Lisa Floyd, Jayne
Belnap, Jesse Anderson, Orrin Myers & Clifton Meyer
In summer 2002, pinyon began dying en masse from drought stress and an
associated bark beetle outbreak.
Jemez Mts. near Los Alamos,
October 2002
What happens when you couple chronic warming
with drought? (an eye-opener for the future)
Conversion from PJ to J woodlands…
Jemez Mts., May 2004
Sudden Aspen Decline in the San Juan
Mountains?
Turkey Knolls area on
Dolores RD – San Juan NF
Mortality 2002 = 9%
Mortality 2006 = 60%
¾ Roots dead in affected
areas
Possible Causes
Aspens stands reaching maturity with little
regeneration?
Photo from Cortez
Journal
Warming? Drought? Insects? Disease?
Interactions?
Some flowering plants strongly
linked to snowpack (Gothic, CO)
Dwarf Larkspur
Photo::Daniel Mosquin
Plants start growing sooner with earlier snowmelt
but then are more prone to freezing.
Saavedra et al. GCB, 2003
Grinnell Wildlife Resurvey
Yosemite NP
• Trapping 1914, 2002-2005
• Four new species moved into
Yosemite
• Four species have contracted
their ranges
• Several species have shifted
ranges up to 2000 m higher
• One species extirpated
Observed Changes in Wildlife at Gothic, CO
Inouye et al. PNAS 2000
Marmots
emerging 38
days earlier
than in 1977
Robins arriving 14 days earlier
Some Species Like it Warmer!
•
•
•
•
•
Elk (Wang et al. 2002)
Pine Bark Beetle (Hicke et al. 2006)
Cutthroat trout (Cooney 2003)
Whirling Disease (Covich and Cooney 2003)
West Nile Virus (CDC)
Additional changes that could occur:
• Increased insects and disease
• Narrowing of tundra regions, reduction of
obligate tundra species habitat
• Synergies with air pollution – ozone, fires, etc.
• More visitors
• More elk
• More cutthroat trout habitat, but also
• More potential for whirling disease
New Studies in the San Juans…an effort to
close the knowledge gap with science
• New Instrumentation: High-elevation
meteorological and energy budget monitoring on
Red Mountain Pass
(Center for Snow & Avalanche Studies)
• Historical Analysis: 100 Years of San Juan
Climate Data
(Imtiaz Rangwala, Rutgers University; partial funding by
MSI mini-grant)
A Monitoring Program to Determine Effect of Climate
Change on Alpine Plant Communities in the San Juans
A New Site in the Global Observation Research Initiative in Alpine
Environments (GLORIA) Program
FUNDERS:
American Alpine Club
Colorado Mountain Club
Colorado Native Plant Society
Small Mammal Studies…
• Small Mammal Elevational
Transect from Canyon of the
Ancients to Lizard Peak Wilderness
(Christy McCain, UC Boulder, partial funding from an MSI
mini-grant)
• The Pika Project: U.S. Rocky Mountains including
Several Sites in the San Juans
(UC Boulder, partial funding from an MSI mini-grant)
Forest Health Monitoring…
Tree mortality, insect outbreaks, regeneration after
wildfire (US Forest Service)
REASON for this WORKSHOP:
Two things we can do to proactively respond to
climate change:
1) Mitigate: reduce greenhouse gas emissions
(or at least slow the rate of increase) &
sequester CO2 out of the atmosphere.
2) Plan for change and adapt when possible.
#2 is our focus for this workshop, but if we can integrate adaptation with
mitigation, all the better…
Integrating climate change knowledge
(and uncertainties) into management:
• What are your concerns? Priorities?
• What do you need to know that you don’t?
• What kind of help do you need?
• What kind of programs do you want to see
happen?
Planning is best done before crisis hits!
Time to make
a plan