Permafrost, climate change and northern communities. Steve Kokelj and Steve Wolfe INAC & NRCan

Transcription

1 Permafrost, climate change and northern communities Steve Kokelj and Steve Wolfe INAC & NRCan

2 Outline What is permafrost? Climate change and permafrost Landscape change Permafrost and communities

3 What is permafrost? Active Layer (freezes and thaws annually) Permafrost (below 0 C all year) Unfrozen

4 Permafrost distribution * Heginbottom, 1995

5 Permafrost thickness S. Wolfe, NRCan

6 Depth (m) Ground temperatures in permafrost Temperature ( o C) Minimum Maximum

7 Buffer layer The atmosphere Buffer Layer Vegetation canopy Snow cover Organic layer Mineral soil Ground thermal regime

8 Temperature differences Snow Burn and Kokelj, 2009

9 Temperature differences Water Uplands Delta Burn and Kokelj, 2009

10 The influence of water bodies Lake Permafrost Talik (unfrozen)

11 Differences in ground temperatures Climate Vegetation Snow Soils Water and lakes DISTURBANCE

12 Ground ice

13 Active-layer deepening and surface subsidence Active layer Surface subsidence Post-disturbance active layer Ice-rich permafrost

14 Recognizing thaw sensitive terrain

15 Recognizing thaw sensitive terrain

16 Climate warming and permafrost

17 Climate warming and permafrost Mackay, 1974; GSC Burn and Kokelj, 2009; PPP

18 Active-layer deepening Active layer Thawing Active layer Ice-rich permafrost Ice-rich permafrost

19 Active-layer freezeback Freezing Water movement Ice-rich permafrost

20 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

21 Retrogressive thaw slumps Mackenzie Delta Inuvik Lantz and Kokelj, 2008, GRL

22 Thermal influence of water bodies DOT

23 Expect the unexpected - Mega slumps

24

25 18/06/ /06/ /06/ /06/ /06/ /06/2010 Sediment transport index (rate x width x surface lowering) Net radiation (Wm2) Daily debris flow pulses - hot dry weather

26 6/20/2010 6/30/2010 7/10/2010 7/20/2010 7/30/2010 8/9/2010 Precipitation (mm) 20/06/ /06/ /07/ /07/ /07/ /08/2010 Sediment transport index (rate x width x surface lowering) Debris flow activity and rain

27 Infrastructure concerns

28 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

29 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

30 Permafrost is affected by: Climate and Vegetation 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

31 Geology and Surface Sediments 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

32 Thaw-Stable Ground New Town August, 1949

33 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.

34 and thaw Sedge peat Pond Peat Mineral soil Spruce peat SLANT 6 Permafrost Bedrock Thaw settlement Thaw settlement BOWLING GREEN

35 Northern buildings SUMMER WINTER SPRING Frozen soil Frost jacking Ice lens Displacement Unfrozen soil Unfrozen soil Void Unfrozen soil

36 Northern utilities

37 Northern roa

38 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

39 Permafrost and communities