MAAT, Permafrost Characterization and Climate Warming Jim Cassie, P.Eng. BGC Engineering Inc.

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming model estimates 6.Conclusions

1. MAAT VALUE FOR SITE Few definitions to review Nearby long term climate stations Review MAAT values from those stations Add mine site weather stations (slightly shorter term) Rationalize MAAT versus latitude

CLIMATE - DEFINITION Climate, in a narrow sense, is usually defined as the “average weather”. “Climate is what you expect, weather is what you get.” More rigorously, as the statistical description in terms of the mean and variability of relevant quantities, over an appropriate period of time. The classical time period is 30 years, as defined by the World Meteorological Organization (WMO). Long period to account for climate cycles.

MAAT - DEFINITION Mean annual air temperature value is for either one specific year (e.g. 2007) or for period of record (e.g to 2000). One single temperature parameter used to define the climate of an area. Used to define the mean and the ranges of the expected temperature. Used in climate, geography and permafrost work as opposed to annual ground temperatures.

REASONABLE - DEFINITION 1. Capable of reasoning; rational: a reasonable person. 2. Governed by or being in accordance with reason or sound thinking: a reasonable solution to the problem. 3. Being within the bounds of common sense: arrive home at a reasonable hour. 4. Not excessive or extreme; fair: reasonable prices.

CLIMATE STATIONS

PROXIMAL MAAT VALUES Station NameDistance and Direction from High Lake Period of Record MAAT Cambridge Bay300 km NE1929-recent-14.7 o C Coppermine200 km WNW o C Kugluktuk200 km WNW1978-recent (29 years) o C Contwoyto Lake (65.48 o N) 280 km S o C Lupin (65.76 o N)200 km S1982-recent (25 years) o C

PLUS 3 MINES

MAAT vs. LATITUDE RWDI o C

MAAT CONCLUSION Based on interpolation/extrapolation of nearby long-term climate station, a MAAT value of o C for the High Lake site appears reasonable. Any warmer value is not scientifically defensible and does not appear reasonable from data trends.

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming estimates 6.Conclusions

2. PERMAFROST WORK Two definitions to start Thermistor locations Results – both deep and shallow

DEFINITIONS Permafrost is ground that remains below 0 o C for at least two years. Definition is purely thermal – no commentary on “frozen” nature or on ground ice content. Permafrost types – sporadic, discontinuous and continuous.

DEFINITIONS Talik – unfrozen zone within continuous permafrost. Usually caused by water bodies (heat source). Closed, open and through types.

THERMISTORS AT SITE 2 DEEP CABLES 16 SHALLOW CABLES

THERMAL REGIME Permafrost zone defined by its thermal regime – trumpet curve

RESULTS Permafrost is 440 m deep (measured at the West Zone). In the associated talik modeling, mean annual ground temperature of -7 o C matched permafrost depth and measured geothermal gradient at depth. Estimated mean annual ground temperatures of -6 o C found for the site. Ground temperatures (10 to 25 m depth) of -4 o to -5 o C under three dams. Also found -3.5 o to -4 o C under two dams directly beside water.

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming estimates 6.Conclusions

3. GROUND TO AIR TEMPS Offset from air to ground temperatures Impact of nearby water bodies Validation of site ground temperatures

AIR TO GROUND GROUND IS 3 o TO 6 o C WARMER THAN THE AIR (AVERAGE +/- 4.5 o C )

IMPACT OF WATER BODIES LARGE LAKE HAS PROFOUND THERMAL IMPACT ON NEARBY TEMPERATURES

RESULTS MAAT of o C. Warming in the ground (3 o to 6 o C with 4.5 o C average) = -8.8 o to -5.8 o C (-7.3 o C) which correlates to -6 o C found in the area Within 20 to 30 m of major water body, 2 o to 3 o C warming can be felt Ground temperatures of -4 o to -5 o C under three dams. Also found -3.5 o to -4 o C under two dams directly beside water. Measured ground temperatures are reasonable with MAAT of o C.

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming estimates 6.Conclusions

4. CLIMATE CHANGE Few definitions Observations Causes

CLIMATE CHANGE - DEFINITION Changes in the variability or average state of the atmosphere over appropriate time scales relative to a given reference period. These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) and, more recently, human activities.

CLIMATE CHANGE - OBSERVATIONS Early decline of the spring snow cover Arctic melt seasons are longer Rivers and lakes are melting earlier Permafrost is warming or disappearing Arctic lakes are disappearing Shorter winter road seasons Less sea ice Thunder and lightning in the north

CLIMATE CHANGE - CAUSES These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) and, more recently, human activities. 1.Natural Solar variability, volcanic dust levels, ocean variability, geological change 2.Human related (anthropogenic) Greenhouse gases, aerosols, ozone depletion

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming model estimates 6.Conclusions

5. GLOBAL WARMING MODELS To simulate the effects of human warming, scientists formulate very large and very complex mathematical models in computers. General Circulation Models (GCMs) are a class of computer-driven models for understanding climate and projecting climate change. Models require input assumptions regarding greenhouse gases (scenarios) in terms on amount and trend.

MODEL LIMITATIONS Mathematical model simulating the interaction of the earth, atmosphere, oceans and ice cover (WOW!). Models have numerous noted errors. Generally, the mean of the results has relatively good agreement for temperature but not so good agreement for precipitation. Models also have large nodes and hence are NOT site specific. RGM’s

GOVERNMENT / RESEARCHERS GCM’s extracted from the Canadian Institute for Climate Studies (CICS) at U of Vic (average of 4 different scenarios and 7 different models) = 7.6 o C/100 years Canadian RCM for eastern Arctic = 5.1 o to 6.1 o C/100 years Environment Canada (2007) = 3.8 o and 6.8°C of warming until the period 2070 to 2099.

COPPERMINE / KUGLUKTUK 63 YEARS 2.5 o C/ 100 YEARS

CONTWOYTO / LUPIN 48 YEARS 5.6 o C/ 100 YEARS

ALL DATA POST YEARS ~6 o C/ 100 YEARS

INAC REVIEWER’S APPROACH WHY?

SUMMARY OF ESTIMATES Government / Researcher GCM Estimates Factual Warming Trends BGC Proposed Allowances INAC Proposal

WARMING ALLOWANCES ON OTHER PROJECTS

PRESENTATION OUTLINE 1.Validation of proposed mean annual air temperature (MAAT) value for the site 2.Overview of permafrost assessment work 3.Relationship of ground temperatures to air temperatures 4.Introduction to climate change and global warming 5.Global warming estimates 6.Conclusions

6. CONCLUSIONS High Lake MAAT Value = o C is reasonable. Air temperatures correlate with deep permafrost and shallow ground temperatures, allowing for heating due to large water bodies. Warming estimates of 5 o to 6.5 o C / 100 years are reasonable in light of government/researcher estimates and actual warming over climate period in the north. These estimates still have an additional Factor of Safety when applied to dam design.