Permafrost, climate change and northern communities Steve Kokelj and Steve Wolfe INAC & NRCan
Outline What is permafrost? Climate change and permafrost Landscape change Permafrost and communities
What is permafrost? Active Layer (freezes and thaws annually) Permafrost (below 0 C all year) Unfrozen
Permafrost distribution * Heginbottom, 1995
Permafrost thickness 0 100 200 300 400 S. Wolfe, NRCan
Depth (m) Ground temperatures in permafrost Temperature ( o C) -12-8 -4 0 4 0 5 Minimum Maximum 10 15 20 25
Buffer layer The atmosphere Buffer Layer Vegetation canopy Snow cover Organic layer Mineral soil Ground thermal regime
Temperature differences Snow Burn and Kokelj, 2009
Temperature differences Water Uplands Delta Burn and Kokelj, 2009
The influence of water bodies Lake Permafrost Talik (unfrozen)
Differences in ground temperatures Climate Vegetation Snow Soils Water and lakes DISTURBANCE
Ground ice
Active-layer deepening and surface subsidence Active layer Surface subsidence Post-disturbance active layer Ice-rich permafrost
Recognizing thaw sensitive terrain
Recognizing thaw sensitive terrain
Climate warming and permafrost
Climate warming and permafrost 1970 2005 Mackay, 1974; GSC Burn and Kokelj, 2009; PPP
Active-layer deepening Active layer Thawing Active layer Ice-rich permafrost Ice-rich permafrost
Active-layer freezeback Freezing Water movement Ice-rich permafrost
Shoreline instability due to warming Lake 3 o C Lake 5 o C Massive ice Permafrost -7 o C Talik (unfrozen) Permafrost -4 o C Talik (unfrozen) Cold permafrost Warm permafrost
Retrogressive thaw slumps Mackenzie Delta Inuvik Lantz and Kokelj, 2008, GRL
Thermal influence of water bodies DOT
Expect the unexpected - Mega slumps
18/06/2010 19/06/2010 20/06/2010 21/06/2010 22/06/2010 23/06/2010 Sediment transport index (rate x width x surface lowering) Net radiation (Wm2) Daily debris flow pulses - hot dry weather 2.5 2 1.5 1 0.5 0 900 800 700 600 500 400 300 200 100 0
6/20/2010 6/30/2010 7/10/2010 7/20/2010 7/30/2010 8/9/2010 Precipitation (mm) 20/06/2010 30/06/2010 10/07/2010 20/07/2010 30/07/2010 09/08/2010 Sediment transport index (rate x width x surface lowering) Debris flow activity and rain 60 50 40 30 20 10 0 30 25 20 15 10 5 0
Infrastructure concerns
Permafrost and Environment Integral part of the north Impacted by: Environmental change Disturbance Development Climate change Anticipate the unanticipated Track change, develop the right knowledge Need informed decisions
Permafrost and communities Permafrost is: a temperature condition of the ground Active Layer (freezes and thaws annually) Permafrost (below 0 C all year) Unfrozen - defined by temperature - soil or rock that remains below 0 C throughout the year - potentially unstable material containing ice, that is sensitive to impacts caused by: - natural processes - human impacts - climate change
Permafrost is affected by: Climate and Vegetation 140 120 100 Treeline Taiga Cordillera Boreal Cordillera Northern Arctic Southern Arctic 70 Taiga Plain Yellowknife Taiga Shield 60 Montaine Cordillera Boreal Plain 0 km 500 Boreal Shield
Geology and Surface Sediments 140 120 100 Arctic Continental Shelf Arctic Platform 70 Frame Lake Niven Lake Cordilleran Mountain System Canadian Shield Yellowknife Interior Platform 0 km 500 Hudson Platform 60 Yellowknife Bay Bedrock 0 m 100 Sandy plain Clay/Silt
Thaw-Stable Ground New Town August, 1949
and Unstable Ground Yellowknife Bay Bedrock 0 m 100 Sandy plain Clay/Silt YELLOWKNIFE S SCHOOL DRAW SUBDIVISION FOUNDATIONS AND SOIL CONDITIONS Soil conditions throughout the subdivision are not, in all cases, suitable to the use of conventional foundation systems. The purchaser should bear this in mind when investigating and selecting his lot.
and thaw Sedge peat Pond Peat Mineral soil Spruce peat SLANT 6 Permafrost Bedrock Thaw settlement Thaw settlement BOWLING GREEN
Northern buildings SUMMER WINTER SPRING Frozen soil Frost jacking Ice lens Displacement Unfrozen soil Unfrozen soil Void Unfrozen soil
Northern utilities
Northern roa
43 STREET 42 STREET Borehole location S a n d a n d g r a v e l Silt and clay Ice-rich clay ICE-RICH CLAY ICE-RICH
Permafrost and communities