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 ftkmw1@uaf.edu

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