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Climate Change Impacts on Polar Terrestrial
Ecosystems: Their Importance to the Future
State of the Earth System
Craig E. Tweedie PhD
Department of Biology and the
Environmental Science and
Engineering Program, UTEP
[email protected]
www.armap.org
www.ipyroam.org
www.baidims.org
www.ceoninfo.org
www.ceonims.org
Current Research Directions
1. Assessing the impact and feedback of climate
change on arctic terrestrial ecosystems and other
extreme environments.
2. Improving interdisciplinary environmental observing
networks at local to international scales.
3. Building innovative technologies and
cyberinfrastructure to improve capacities for
environmental observation and analysis.
4. Improving future research capacities by providing
life changing educational opportunities to students
and teachers.
Temperature Trends
Atmospheric Change
Observed Air temperature trend 1949-06.
Global Change Models
predict that differential
warming of the Arctic will
continue throughout the
next century.
CGCM2 Modeled Air temperature trend 1990- 2100.
Change in temperature
greatest at northern high
latitudes (IPCC).
Arctic is connected to the
global system & cannot be
studied in isolation.
http://www.acia.uaf.edu/
System Science Approach
• Hardest thing to teach, learn and understand ~
excellent approach for inquiry based learning
• Aims to understand how change in one part of
the system regulates and/or invokes change
in another component of the system
• Understanding connectivity is key to
understanding the complexity of the system
• Concept originated in electrical engineering ~
switches, voltage regulators, circuit boards etc
Discussion Topics for Today
1. Carbon balance and cycling in arctic
terrestrial ecosystems – why the big deal?
2. Feedbacks in polar terrestrial ecosystems
– Carbon cycling ~ warming, species shifts
– Albedo ~ ice retreat, species shifts
3. Impacts of change on polar biodiversity
….. Learning activity using a system science
approach to predict changes in arctic
terrestrial ecosystems
Carbon Balance is important in
the Arctic!!!
• Arctic terrestrial ecosystems are
important to global carbon balance.
– Why is this?
– What are the major pools of carbon in arctic
terrestrial ecosystems?
– Why is carbon arranged in these pools?
– How does this compare to human greenhouse
gas emissions?
www.baidims.org
Distribution of the major terrestrial biomes
Campbell Biology 4th Edition
Global relevance of tundra land area, plant
carbon, Net Primary Production, and soil carbon
% Area
Land Area
=9%
% Plant Carbon
Tundra
Plant Carbon
=1%
Deserts
Grasslands
Boreal Forest
Net Primary
Production
=2%
% Soil Carbon
% Net Primary Production
Soil Carbon
= 28 %
Temperate Forest
Tropical Forest
Lakes and Wetlands
Croplands
Ice
(Adapted from WB GU, 1998)
Global relevance of tundra land area, Plant
carbon, Net Primary Production, and soil carbon
Land Area
=9%
Plant Carbon
=1%
Net Primary
Production
=2%
Soil Carbon
= 28 %
Controls:
• Coastal erosion, river and stream
erosion, treeline, human development.
• Species composition, historical factors,
many other physical and non-biological
factors e.g. herbivores, climate etc.
• Plant carbon, Net Primary Production,
cold temperatures, water logged soils,
permafrost, soil acidity, microbial and
fungal activity.
Arctic Carbon Rich Soils
Seasonal Active Layer
Carbon Store
C.E. Tweedie
Arctic Carbon Rich Soils
Seasonal Active Layer
Carbon Store
•Current atmosphere:
750 GT C
•Vulnerable arctic soils:
350-900 GT C
•Human C emissions:
5.4 GT C per year
•1% loss arctic soil C =
annual human C
emissions.
•Could equate to a
global warming
C.E. Tweedie
capacity of 4-8°C.
Feedbacks in Arctic Terrestrial
Ecosystems
• Understanding positive and negative
feedbacks in the Arctic system is important for
developing models that could predict the future
state of the Arctic and global system
• Understanding connections and feedbacks
are key to pinpointing vulnerabilities, processes
driving non-liner change, and how adaptation
and mitigation can be most effective e.g….
– Carbon cycling ~ potential changes to Arctic Carbon
pools
– Albedo ~ longer snow free period, species change,
glacial retreat
Atmospheric GHGs
CO2
CO2 CH4 = 23 x CO2
Photosynthesis
Soil
Aerobic CO2
MicrobialPERMAFROST
C
CH4
Anerobic
Respiration
Albedo
Observed Snow Cover Change Barrow, Alaska
Observed Snow Cover Change Barrow, Alaska
Carbon
CO2 Carbon Dioxide
CH4 Methane
Albedo
Lake Disappearance in Russia
Smith et al. (2005) Science 308:1429
Lake Disappearance in Russia
Carbon
CO2 Carbon Dioxide
CH4 Methane
Albedo
Smith et al. (2005) Science 308:1429
Greening trend (NDVI) 1982-91
Spring temp. trend 1982-90
(Myneni et al. 1997)
Summary of Observed Tree and Shrub Expansion
Arctic Report Card 2007
Shrub expansion
Alaska 1949 – 2001
(Sturm et al. 2001)
Shrub expansion
Alaska 1949 – 2001
Carbon
CO2 Carbon Dioxide
CH4 Methane
Albedo
(Sturm et al. 2001)
It is estimated that shrub and tree
expansion may magnify regional warming
by a factor of 2-7
IPCC (Intergovernmental Panel on Climate Change) 2007.
Species are Important!
• Albedo ~ shrubs and trees absorb more energy
than tundra
• Differences in photosynthesis
• Different Net Primary Production that leads to
the deposition of carbon in the soil
• Differences in ability to transport methane from
the soil to the atmosphere
• Differences in the way they impact soil thermal
properties and permafrost
• …Affect other ecosystem variables as well
Biological Change
5 Key ways species respond to environmental change:
1. Acclimation – individual physiological response that
can be linked to genetics
2. Adaptation – species respond genetically through
natural selection
3. Reorganization – some species compete for
resources better than others
4. Migration – behavioral response of animals only
5. No change – species could become vulnerable to
extinction
•
All of these can co-occur… simple isn’t it!!!
Cool – mean annual air
Temp ~ 0.5°C
Warm – mean annual air
Temp ~ 4.5°C
Flowering delayed with low temperature ~ plants
at low altitude finish flowering before plants at
high altitude start and therefore do not share
genetic material… natural selection acting
differently at low altitudes compared to high
altitudes.
Plot Based Land Cover Change at Barrow:
1972
2000
Dry heath:
• Little change in species cover and abundance.
• Little change in species richness.
Plot Based Land Cover Change at Barrow:
1972
2000
Pond communities:
• Dramatic change in species cover and abundance.
• Increase in species richness.
• Evidence of pond ‘closure’.
Barrow IBP Topographic Grid:
110m
390m
•
Significant change in vegetation cover has occurred across
the IBP site suggesting overall drying trend.
•
Model suggests a decline of 208 g/ha/16th August in Carbon fixing
potential due to land cover change alone ~900 g for the entire grid
10% 1972 total.
New challenges
present themselves
when we scale
biological change
across ecosystem
types and across
trophic levels…..
Wait till you get to
your learning activity
and realize the
challenge first hand
Conclusion
• System science ~ understanding
connectivity in the system is important
• Carbon balance in the arctic is important
~ pools, cycling, balance
• Feedbacks both positive and negative
– Carbon ~
– Albedo ~ snow, vegetation change
• Species response to change is important
• There are many challenges that lay
ahead.
Lots of fun… till it catches fire and you have to jump out
going full speed across the tundra!!!!…
The telly-tubbies conquest of the Russian Far East!!!
The Hilton Hotel
Laboratory
Hungry?
Lavrentia in Eastern Russia…
Was that you?
….the water
got warm all
of a sudden….
Acknowledgements
National Science Foundation
Office of Polar Programs
UTEP
Systems Ecology Lab – Alaska
•
Santonu Goswami
•
Amit Raysoni
•
Karla Martinez
•
Adrian Aguirre
•
Yenlai Chee
•
Edith Juarrieta
•
Mark Lara
•
Sandra Villareal
•
Amorita Armendariz
•
Perry Houser
•
Alex Benhumea
Follow-up
•
www.ipyroam.org
•
Ecological Society of America
•
SACNAS 2008
•
www.ipy.org
•
www.armap.org
California State University, Los Angeles
•
Dr. John Gamon
Florida International University
•
Dr. Steve Oberbauer
•
Paulo Olivas
•
Andrea Kuchy
Lund University, Sweden
•
Dr. Torben Christensen
•
Dr. Lena Ström
•
Mikhail Mastepanov
San Diego State University
•
Walt Oechel
•
Steve Hastings
•
Rommel Zulueta
•
Cove Sturtevalent
UC Berkeley
•
Dr. Robert Rhew
•
Dr. Yit Arn Teh
GIS SupportNuna Technologies
•
Allison Gaylord
Logistics Support
•
Barrow Arctic Science Consotrium
•
Swedish Polar Research Secretariat