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Dynamics of Permafrost in a Changing Climate
Steve Kokelj, NWT Geological Survey
Permafrost and the environment
People and Wildlife
Dynamics of Permafrost in a Changing Climate Steve Kokelj, NWT - - PowerPoint PPT Presentation
Dynamics of Permafrost in a Changing Climate Steve Kokelj, NWT - - PowerPoint PPT Presentation
Dynamics of Permafrost in a Changing Climate Steve Kokelj, NWT Geological Survey Permafrost and the environment People and Wildlife Permafrost Canada is a permafrost country Heginbottom, 1995 Permafrost thickness 0 100 200 300 400 from S
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Canada is a permafrost country
Heginbottom, 1995
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400 200 300 100
from S Wolfe, NRCan
Permafrost thickness
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Active layer
Active layer Post-disturbance active layer Ice-rich permafrost Surface subsidence
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Active layer and permafrost
Active layer Near-surface permafrost Ice-rich zone
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Ground temperatures in permafrost
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Relations between air and ground temperatures
- S. Smith, NRCan
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The influence of water bodies
Lake 3oC Talik (unfrozen) MAGT
- 7 oC
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Lake 5oC Talik (unfrozen) MAGT
- 3oC
Lake 3oC Talik (unfrozen) MAGT
- 7 oC
Talik adjustment due to warming and shoreline instability
Cold permafrost Warm permafrost
Massive ice
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Warming permafrost, talik adjustment and lake bottom subsidence
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Shoreline stability
INF
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The world of underground ice
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Near-surface ice lenses
Surface disturbance – increased thaw depth = Surface subsidence
Ice-rich permafrost Active layer Active layer
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Drunken forest = ice-rich terrain
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Tundra polygons
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Ice-wedge ice
Thermal- contraction crack
Photo from CR Burn French, 1996
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Polygonal terrain
Polygon Trough
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Polygonal terrain
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Massive ground ice
Massive tabular ice
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Massive ice and retreat of Laurentide ice sheet
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Climate warming and permafrost
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Warming air temperatures
- ver the past 50 years
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Hay River & Inuvik Mean Annual Temperatures
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Hay River = 3oC per 100 years Inuvik = 7oC per 100 years
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Future Climate Projections
Potential increase in winter temperatures 11.6 °C from -28.6 to -16.3 http://tinyurl.com/snap-nwt
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Projections of mean annual temperature made in 2003
Climate interval
- 10
- 8
- 6
- 4
- 2
Mean annual temperature (C)
- 10
- 8
- 6
- 4
- 2
51-80 61-90 71-00 81-10 10-39 40-69 Dawson Inuvik
1987-2016 1987-2016 Upper forecast Lower forecast
From CR Burn; Camsell Lecture, 2017
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Projections of summer rainfall made in 2003
From CR Burn; Camsell Lecture, 2017
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Permafrost is warming
1970 2005
Mackay, 1974; GSC Burn and Kokelj, 2009; PPP
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Chadburn et al., 2017; Nature Climate Change
Permafrost change under future scenarios
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Mean annual ground temperature profiles
Wolfe et al. 2015 GeoQuebec
Yellowknife region Inuvik Quarry – Navy Road
Burn et al., 2009, PPP
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Landscapes are responding to warmer and wetter conditions
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Eastern Banks Island
1960s
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2005
Eastern Banks Island
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2016
Rudy et al., 2017 GRL
Eastern Banks Island
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Increasing late season precipitation and landsliding
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Increasing fall precipitation (9 years since 2002 in top 16)
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Reindeer Station landslides occur after heavy rains, September 2017
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Reindeer Station landslides occur after heavy rains, September 2017
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Capacity to develop geohazard risk maps are increasingly important for safety of residents and for planning infrastructure
Rudy et al., NWT Geoscience Forum, 2017
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How will the landscape respond?
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Impacts to northern infrastructure
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2015
Fill Tongue Slumps Failure precursor
2016
Embankment Failure
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Embankment fill
2015
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Displacement vectors 1 Year movement
- R. Fraser, CCRS
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Monitoring, analysis, informed decisions and adaptation
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Inuvik to Tuktoyaktuk Highway Geotechnical legacy and informed decisions
Thermal monitoring Several hundred geotechnical boreholes Remote sensing and terrain data Stream water quality
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Management of permafrost geotechnical, ground temperature and geohazard data
Available ground temperature monitoring data Potential ground temperature monitoring data
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Summary
- Permafrost is the geological manifestation of climate and provides
foundation for billions of dollars of northern infrastructure and ecosystems
- The state of permafrost is being altered by climate warming
- Some permafrost landscapes are inherently susceptible to change
- Consider uncertainty and anticipate encountering conditions without
precedent
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Summary
- Information on permafrost temperature and geotechnical properties is
critical for design and mitigation
- Assessing geohazards and risk related to permafrost thaw is critical for
public safety and for informed design
- Monitoring can inform mitigation and future design
- Managing this information is a foundational activity
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Summary
- Expect surprises, consequence of a poor knowledge base will be bigger
and more costly surprises
- Interaction between Engineers and Geoscientists will lead to advances in
knowledge, design and adaptation
- Resilience – build in flexibility and develop multiple options to deal with
change and uncertainty
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Summary
Training and capacity is required
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