Global Climate Impacts of Thawing Permafrost National Snow and Ice Data Center, University of Colorado Tingjun Zhang Kevin Schaefer Tim Schaefer Lin Liu Me 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 Profile Vegetation Active Layer Permafrost Organic Layer Silt

Permafrost Distribution ~24% of Northern Hemisphere land~24% of Northern Hemisphere land

Permafrost Distribution by Country

Permafrost Profile: Mackenzie River Arctic OceanAlberta

Types of Permafrost Models Observations EmpiricalComponent Land Surface Parameterizations Land Ocean Atmosphere ALTDegree DayTemperature Temperature, Moisture, Carbon Climate Feedbacks Prognostic Models Diagnostic Models Remote Sensing Simple Complicated

Cryoturbation Movement of soil or rock due to repeated freezing and thawingMovement of soil or rock due to repeated freezing and thawing Vegetation Active Layer Permafrost Pleistocene Cryoturbation, France

Frost Heave Frost Boils, YamalStone Circles, Svalbard Stone Circles, NW TerritoriesStripes, Glacier NP

Ice Wedges and Polygons Active Layer Permafrost Frozen 100 th Winter Frozen 1 st Winter Soil contracts & cracks Thawed 1 st Spring Crack fills with water & freezes Thawed 100th Spring Ice Wedge Polygons, LenaPolygons, Prudhoe Bay [Zhang, 2009]

Ice Lenses and Layers Active Layer Permafrost Year 1 Capillary suction of water to permafrost Water freezes & expands Year 10,000 Ice Layer Ice Lens Active Layer Permafrost Ice Lenses

Thermokarst Collapse of soil due to melting of excess ground iceCollapse of soil due to melting of excess ground ice

Projected Temperature Increases IPCC Temperature Projections 4 th 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 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 WicklandSchaefer

Impacts of Climate Change on Permafrost EcosystemsInfrastructure

Impacts of Degradation Coastal Erosion near Barrow, Alaska Qinghai-Xizang Highway Bridge Alaska Road Heaves Thermokarst in Yakutsk [Skiklomanov, 2005]

Global Carbon Cycle Ocean 38,000 Gt 6 Fossil Fuel 4000 Gt Permafrost 1466 Gt Atmosphere 750 Gt + 3 Gt yr Soils 1400 Gt Vegetation 600 Gt

Impact of Thawing Permafrost on Global Climate ~1700 Gt of carbon in permafrost as frozen organic matter Thawing permafrost will release CO 2 and CH 4

Methane Release from Thawing Permafrost K. Walter Thaw bulb Permafrost Peat Methane production Methane emission 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 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) Cumulative NEE (Gt C) Arctic switches from a sink to a source

Cumulative Permafrost Carbon Flux Date (year) Permafrost Carbon Flux (Gt C) 190±64 Gt 104±37 Gt 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

Impact on Climate Change Treaty 2°C warming target2°C warming target Account for permafrost emissionsAccount for permafrost emissions Available Projections don’t include permafrost emissionsAvailable Projections don’t include permafrost emissions Temperatures higher with feedbackTemperatures higher with feedback Emissions targets may be too highEmissions targets may be too high Temperature Projections 4 th Assessment Report

UNEP Recommendations 1)Special IPCC assessment on permafrost emissions 2)National permafrost monitoring networks 3)National Adaptation Plans

The End