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Global Climate Impacts of Thawing Permafrost. Alessio Gusmereli. Tim Schaefer. Tingjun Zhang. Me. Lin Liu. Kevin Schaefer. National Snow and Ice Data Center, University of Colorado. Permafrost Primer. Permafrost: G round at or below 0°C for at least 2 consecutive years
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Global Climate Impacts of Thawing Permafrost AlessioGusmereli Tim Schaefer Tingjun Zhang Me Lin Liu Kevin Schaefer National Snow and Ice Data Center, University of Colorado
Permafrost Primer 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. Skiklomanov [2007]
Permafrost Profile Vegetation Active Layer Organic Layer Silt Permafrost
Permafrost Distribution • ~24% of Northern Hemisphere land
Permafrost Profile: Mackenzie River Arctic Ocean Alberta
Types of Permafrost Models Land Ocean Atmosphere Land Surface Parameterizations Empirical Component Observations Complicated Simple Temperature, Moisture, Carbon Climate Feedbacks ALT Degree Day Temperature Remote Sensing Diagnostic Models Prognostic Models
Cryoturbation • Movement of soil or rock due to repeated freezing and thawing Vegetation Active Layer Permafrost PleistoceneCryoturbation, France
Frost Heave Frost Boils, Yamal Stone Circles, Svalbard Stone Circles, NW Territories Stripes, Glacier NP
Ice Wedges and Polygons 1stWinter 1st Spring 100th Winter 100th Spring Frozen Thawed Frozen Thawed Ice Wedge Crack fills with water & freezes Soil contracts & cracks Polygons, Lena Polygons, Prudhoe Bay [Zhang, 2009] Active Layer Permafrost
Ice Lenses and Layers Year 10,000 Year 1 Active Layer Capillary suction of water to permafrost Active Layer Ice Layer Permafrost Ice Lens Water freezes & expands Permafrost Ice Lenses
Thermokarst • Collapse of soil due to melting of excess ground ice
Projected Temperature Increases IPCC Temperature Projections 4th Assessment Report • 2° to 3° C globally by 2100 • Arctic warming is double the global average
Projected Permafrost Degradation A1B Scenario Medium Sensitivity Active Layer Thickness ALT (cm)
Global Terrestrial Network-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 Concrete Wickland Schaefer
Impacts of Climate Change on Permafrost Ecosystems Infrastructure
Impacts of Degradation Alaska Road Heaves Coastal Erosion near Barrow, Alaska Qinghai-Xizang Highway Bridge Thermokarst in Yakutsk [Skiklomanov, 2005]
Global Carbon Cycle Atmosphere 750 Gt + 3 Gt yr-1 120 119 1.9 1.7 90 88 6 Vegetation 600 Gt Soils 1400 Gt Ocean 38,000 Gt Permafrost 1466 Gt Fossil Fuel 4000 Gt
Impact of Thawing Permafrost on Global Climate • ~1700 Gt of carbon in permafrost as frozen organic matter • Thawing permafrost will release CO2 and CH4
Methane Release from Thawing Permafrost Methane emission emission Methane production Dead plant & animal Thermokarst Erosion remains Peat Thaw bulb Permafrost Burning methane over a thermokarst lake in Siberia (K. Walter) K. Walter ftkmw1@uaf.edu
Permafrost Carbon Burial Deposition (loess, peat, erosion, volcanic) Soil Depth Active Layer Permafrost Horizon Permafrost
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 Feedback • Amplifies surface warming • Irreversible • Emissions for centuries Projected annual permafrost emissions for A1B scenario
Permafrost Carbon Tipping Point Cumulative NEE (Gt C) PCF Tipping Point 2023±4 Date (year) Arctic switches from a sink to a source
Cumulative Permafrost Carbon Flux Permafrost Carbon Flux (Gt C) 190±64 Gt 104±37 Gt Date (year) 65±23% of cumulative global land sink (~160 Gt C) 15-39% of fossil fuel emissions
Estimates of Permafrost Emissions 5% to 39% of anthropogenic emissions 2100 2200 2300
Impact on Climate Change Treaty • 2°C warming target • Account for permafrost emissions • Available Projections don’t include permafrost emissions • Temperatures higher with feedback • Emissions targets may be too high Temperature Projections 4th Assessment Report
UNEP Recommendations • Special IPCC assessment on permafrost emissions • National permafrost monitoring networks • National Adaptation Plans