Climate Change Impacts on Polar Terrestrial Ecosystems: Their Importance

to the Future State of the Earth System

Craig E. Tweedie PhDDepartment of Biology and the Environmental Science andEngineering Program, UTEP

ctweedie@utep.edu

www.armap.orgwww.ipyroam.orgwww.baidims.orgwww.ceoninfo.orgwww.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 TrendsTemperature Trends

Atmospheric Change

Global Change Models predict that differential warming of the Arctic will continue throughout the next century.

Change in temperature greatest at northern high latitudes (IPCC).Arctic is connected to the global system & cannot be studied in isolation.

Observed Air temperature trend 1949-06.

CGCM2 Modeled Air temperature trend 1990- 2100.

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

(Adapted from WB GU, 1998)

Land Area

= 9 %

Soil Carbon

= 28 %

Plant Carbon

= 1 %

Net Primary

Production

= 2 %

Tundra

Deserts

Grasslands

Tropical Forest

Temperate Forest

Boreal Forest

Lakes and Wetlands

Croplands

Ice

Global relevance of tundra land area, Plant carbon, Net Primary Production, and soil carbon

Land Area

= 9 %

Soil Carbon

= 28 %

Plant Carbon

= 1 %

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.

Net Primary

Production

= 2 %

Seasonal Active Layer

Carbon Store

Arctic Carbon Rich Soils

C.E. Tweedie

Seasonal Active Layer

Carbon Store

Arctic Carbon Rich Soils

C.E. Tweedie

•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 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

C

CO2

Photosynthesis

CO2Soil Microbial Respirati

on

Aerobic

AnerobicCH4

CH4 = 23 x CO2 CO2

PERMAFROSTPERMAFROST

Albedo

Observed Snow Cover Change Barrow, Alaska

Observed Snow Cover Change Barrow, Alaska

CarbonCO2 Carbon DioxideCH4 Methane

Albedo

Smith et al. (2005) Science 308:1429

Lake Disappearance in Russia

Smith et al. (2005) Science 308:1429

Lake Disappearance in Russia

CarbonCO2 Carbon DioxideCH4 Methane

Albedo

Greening trend (NDVI) 1982-91 Spring temp. trend 1982-90

(Myneni et al. 1997)

Arctic Report Card 2007

Summary of Observed Tree and Shrub Expansion

Shrub expansion Alaska 1949 – 2001

(Sturm et al. 2001)

Shrub expansion Alaska 1949 – 2001

(Sturm et al. 2001)

CarbonCO2 Carbon DioxideCH4 Methane

Albedo

IPCC (Intergovernmental Panel on Climate Change) 2007.

It is estimated that shrub and tree expansion may magnify regional warming by a factor of 2-7

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 genetics2. Adaptation – species respond genetically through

natural selection3. Reorganization – some species compete for

resources better than others4. Migration – behavioral response of animals only5. 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.

Dry heath:• Little change in species cover and abundance.• Little change in species richness.

Plot Based Land Cover Change at Barrow:

1972 2000

1972 2000

Pond communities:• Dramatic change in species cover and abundance.• Increase in species richness.• Evidence of pond ‘closure’.

Plot Based Land Cover Change at Barrow:

• 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.

110m

390m

Barrow IBP Topographic Grid:

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 HotelLaboratory

Hungry?

Lavrentia in Eastern Russia…

Was that you? ….the water got warm all

of a sudden….

AcknowledgementsNational Science FoundationNational Science FoundationOffice of Polar ProgramsOffice of Polar Programs

UTEPUTEPSystems Ecology Lab – AlaskaSystems Ecology Lab – Alaska• Santonu GoswamiSantonu Goswami• Amit RaysoniAmit Raysoni• Karla MartinezKarla Martinez• Adrian AguirreAdrian Aguirre• Yenlai CheeYenlai Chee• Edith JuarrietaEdith Juarrieta• Mark LaraMark Lara• Sandra VillarealSandra Villareal• Amorita ArmendarizAmorita Armendariz• Perry HouserPerry Houser• Alex BenhumeaAlex Benhumea

Follow-upFollow-up• www.ipyroam.org• Ecological Society of AmericaEcological Society of America• SACNAS 2008SACNAS 2008• www.ipy.org• www.armap.org

California State University, Los AngelesCalifornia State University, Los Angeles• Dr. John GamonDr. John Gamon

Florida International UniversityFlorida International University• Dr. Steve OberbauerDr. Steve Oberbauer• Paulo OlivasPaulo Olivas• Andrea KuchyAndrea Kuchy

Lund University, SwedenLund University, Sweden• Dr. Torben ChristensenDr. Torben Christensen• Dr. Lena StrömDr. Lena Ström• Mikhail MastepanovMikhail Mastepanov San Diego State UniversitySan Diego State University• Walt Oechel Walt Oechel • Steve HastingsSteve Hastings• Rommel ZuluetaRommel Zulueta• Cove SturtevalentCove Sturtevalent

UC BerkeleyUC Berkeley• Dr. Robert RhewDr. Robert Rhew• Dr. Yit Arn TehDr. Yit Arn Teh

GIS SupportNuna TechnologiesGIS SupportNuna Technologies• Allison GaylordAllison Gaylord

Logistics SupportLogistics Support• Barrow Arctic Science ConsotriumBarrow Arctic Science Consotrium• Swedish Polar Research SecretariatSwedish Polar Research Secretariat