Global Climate Impacts of Thawing Permafrost
National Snow and Ice Data Center, University of Colorado
Tingjun Zhang
Kevin Schaefer
Tim Schaefer
Lin LiuMe
Alessio Gusmereli
Permafrost Primer
Skiklomanov [2007]
Permafrost: Ground at or below 0°C for at least 2 consecutive years
Active Layer: A layer over permafrost that freezes and thaws annually
Permafrost Degradation: A decrease in permafrost extent; an increase in active layer thickness.
Permafrost ProfilePermafrost ProfileVegetation
Active Layer
Permafrost
Organic Layer
Silt
Permafrost DistributionPermafrost Distribution• ~24% of Northern Hemisphere land ~24% of Northern Hemisphere land
Permafrost Distribution by Country
Permafrost Profile: Mackenzie River Permafrost Profile: Mackenzie River
Arctic Ocean Alberta
Types of Permafrost ModelsTypes of Permafrost Models
Observations Empirical ComponentLand Surface
Parameterizations
Land Ocean Atmosphere
ALT Degree Day TemperatureTemperature,
Moisture, CarbonClimate
Feedbacks
Prognostic Models
Diagnostic Models
Remote Sensing
Simple Complicated
CryoturbationCryoturbation• Movement of soil or rock due to Movement of soil or rock due to
repeated freezing and thawingrepeated freezing and thawing
Vegetation
Active Layer
Permafrost
Pleistocene Cryoturbation, France
Frost HeaveFrost Heave
Frost Boils, Yamal Stone Circles, Svalbard
Stone Circles, NW Territories Stripes, Glacier NP
Ice Wedges and PolygonsIce Wedges and Polygons
Active Layer
Permafrost
Frozen
100th Winter
Frozen
1st Winter
Soil contracts & cracks
Thawed
1st Spring
Crack fills with water & freezes
Thawed
100th Spring
Ice Wedge
Polygons, Lena Polygons, Prudhoe Bay [Zhang, 2009]
Ice Lenses and LayersIce Lenses and Layers
Active Layer
Permafrost
Year 1
Capillary suction of water to permafrost
Water freezes & expands
Year 10,000
Ice LayerIce Lens
Active Layer
Permafrost
Ice Lenses
ThermokarstThermokarst
• Collapse of soil due to melting Collapse of soil due to melting of excess ground iceof excess ground ice
Projected Temperature IncreasesProjected Temperature IncreasesIPCC
Temperature Projections 4th Assessment
Report
• 2° to 3° C globally by 21002° to 3° C globally by 2100
• Arctic warming is double the global averageArctic warming is double the global average
Projected Permafrost DegradationA1B Scenario Medium SensitivityA1B Scenario Medium Sensitivity
Active Layer Thickness ALT (cm)Active Layer Thickness ALT (cm)
Global Terrestrial Global Terrestrial NetworkNetwork-Permafrost-Permafrost
Circumpolar Active Layer Monitoring (CALM) measures active layer depth (168 sites)
Thermal State of Permafrost (TSP) measures permafrost temperature (780 sites)
Permafrost is Like ConcretePermafrost is Like Concrete
Wickland Schaefer
Impacts of Climate Change on Impacts of Climate Change on PermafrostPermafrost
Ecosystems Infrastructure
Impacts of DegradationImpacts of Degradation
Coastal Erosion near Barrow, Alaska
Qinghai-Xizang Highway Bridge
Alaska Road Heaves
Thermokarst in Yakutsk [Skiklomanov, 2005]
Global Carbon CycleGlobal Carbon Cycle
1.71.9 90 88
Ocean38,000 Gt
6
Fossil Fuel4000 Gt
Permafrost 1466 Gt
Atmosphere750 Gt + 3 Gt yr-1
119120
Soils 1400 GtVegetation 600 Gt
Impact of Thawing Permafrost on Impact of Thawing Permafrost on Global ClimateGlobal Climate
• ~1700 Gt of carbon in permafrost as frozen organic matter
• Thawing permafrost will release CO2 and CH4
Methane Release from Thawing Permafrost
K. Walter [email protected]
Thaw bulb
Permafrost
Peat
Methane production
Methane emissionemission Thermokarst
Erosion
Dead plant & animal remains
Burning methane over a thermokarst lake in Siberia (K. Walter)
Permafrost Carbon Burial
Permafrost Horizon
Deposition (loess, peat, erosion, volcanic) Soil
Depth
Permafrost
Active Layer
Permafrost Carbon
30,000 year old roots, Siberia [Zimov et al., 2006]Mammoth, Siberia
32,000 year old grass, Alaska 15,000 year old moss, North Slope [Schaefer , 2012]
The Permafrost Carbon FeedbackThe Permafrost Carbon Feedback
• Amplifies surface warmingAmplifies surface warming
• IrreversibleIrreversible
• Emissions for centuriesEmissions for centuries
Projected annual permafrost emissions for
A1B scenario
Permafrost Carbon Tipping Point
PCF Tipping Point 2023±4
Date (year)
Cum
ulat
ive
NE
E (
Gt C
)
Arctic switches from a sink to a source
Cumulative Permafrost Carbon Flux
Date (year)
Per
maf
rost
Car
bon
Flu
x (G
t C)
190±64 Gt
104±37 Gt
65±23% of cumulative global land sink (~160 Gt C)15-39% of fossil fuel emissions
0 100 200 300 400 500 600
Raupach and Canadell (2008)
MacDougall et al. (2012)
Schuur et al. (2013)
Burke et al. (2012)
Schaefer et al. (2011)
Gruber et al. (2004)
Schuur et al. (2009)
Koven et al. (2011)
Dutta et al. (2006)
Zuang et at. (2006)
Schneider et al. (2012)
Cumulative Emissions (Gt C)
Estimates of Permafrost EmissionsEstimates of Permafrost Emissions
5% to 39% of anthropogenic emissions5% to 39% of anthropogenic emissions
210022002300
Impact on Climate Change TreatyImpact on Climate Change Treaty
• 2°C warming target2°C warming target
• Account for permafrost Account for permafrost emissionsemissions
• Available Projections don’t Available Projections don’t include permafrost emissionsinclude permafrost emissions
• Temperatures higher with Temperatures higher with feedbackfeedback
• Emissions targets may be too Emissions targets may be too highhigh
Temperature Projections 4th Assessment Report
UNEP RecommendationsUNEP Recommendations
1)1) Special IPCC assessment Special IPCC assessment on permafrost emissions on permafrost emissions
2)2) National permafrost National permafrost monitoring networksmonitoring networks
3)3) National Adaptation National Adaptation PlansPlans
The EndThe End
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