An overview of major scientific findings and local observations about climate change in Nunavut.
Changes to the Arctic include: glacier retreat, sea-ice and lake-ice thinning, permafrost thawing, coastal erosion from wave action, changes in ocean currents, and shifting ranges of plant and animal species. The timing, nature and severity of impacts on Nunavut communities are difficult to predict and will be different from place to place.
Like many nations across the globe, Nunavut is trying to reduce GHG emissions in response to climate change. A main focus for Nunavut is promoting adaptation to the new conditions that have come with climate change. This means adjusting planning, decisions, and activities for the expected impacts of climate change.
In the short term, neither mitigation nor adaptation actions alone can stop negative climate change impacts. However, taking adaptive action will minimize harm to people and communities.
Changes in Temperature
Over the last 100 years, the Arctic has seen an average warming of 1.5˚C. However, there have also been regional increases of 1- 3˚C. Recent reports by scientists, hunters, and elders suggest significant local warming trends across Nunavut in the last half century. These changes in temperature influence the length and onset of different seasons, particularly traditional Inuit seasons, which are closely tied to traditional land use activities. Temperature changes may have also caused changes in Nunavut’s weather, such as an increased frequency of storms and more variable and unpredictable winds.
Current projections indicate that the warming trend is likely to continue into the next century even if efforts to mitigate and stabilize global greenhouse gas emissions are successful. Climate models suggest that future warming will not be uniform across Nunavut; some areas (for example, Western Nunavut and the High Arctic) could warm much faster than other areas (South Baffin/Davis Strait). However, as with any forecast, there is uncertainty in these predictions.
Changes in Weather and Precipitation
The amount, type, and patterns of rainfall, or precipitation, in Nunavut are expected to change and influence existing cultural, social, and environmental factors. Arctic precipitation has increased by approximately 8 per cent in the last 100 years, and more increases are predicted. Similarly, the number and frequency of extreme weather events such as ice storms, wind storms and storm surges in a single year are expected to rise. Precipitation varies from place to place, and it is more difficult than temperature to predict. Future precipitation conditions for Nunavut are uncertain.
Changes in Sea Level
The range of sea-level rise projections varies. The Intergovernmental Panel on Climate Change recently predicted global sea-level rises ranging from less than 20 cm to nearly 60 cm during the 21st century.
The land is rising across Nunavut because of the disappearance of large ice sheets that covered most of Canada during the last ice age, almost 11,500 years ago. This is called Isostatic Rebound. Sea levels may seem to still be dropping because some of Nunavut’s landmass is rising so quickly. At any one place, the amount of sea-level change that happens depends on how fast the land is rising or sinking. This means the effect on each Nunavut community will be different. Monitoring land motion is necessary to better understand the current and future implications of sea level rise in Nunavut.
During the last ice age, Nunavut was covered in glaciers that soared kilometers high. This enormous weight pushed the land down. With the retreat of the glaciers, the land is now “springing” (rebounding) back and rising to its former height. Think of what would happen if you were to place a heavy rock on a sheet of rubber. The rubber sheet deforms and depresses, but when you remove the rock, it springs back to its original shape. This process is called isostasy. This is happening in areas of Nunavut such as Arviat.
Changes in Permafrost
Both permafrost depth and coverage throughout Nunavut are expected to decrease as average Arctic temperatures continue to rise. Permafrost is the subsurface ground material that remains frozen for more than two years in a row. As permafrost thaws, it weakens the structure of the ground, which in turn speeds up erosion. Shorelines that have ice-rich permafrost are at risk of higher rates of erosion from wave action. Thawing permafrost also increases the depth of the active layer, which can lead to changes in the flow, retention and absorption of water in a given area.
The active layer is the top layer of the soil (or surface material) that thaws in the summer and freezes up again in the fall. The depth of the active layer varies across Nunavut, and even in communities, it depends on factors such as soil type and location (e.g. proximity to a river).Thawing permafrost will have lingering and continuous impacts on northern infrastructure such as buildings and roads.
Changes in Ice Conditions
One of the more striking changes in the Arctic has been the decrease in summer sea ice. Satellite data shows that the extent of Arctic sea ice has decreased each decade since 1978, the first year that satellite data was available. The lowest extent of summer sea ice was in September 2007.
Collecting Sea Ice Data
Historical sea ice data can be collected from unique sources. This includes Bowhead whale bones found in and around ancient sites used by Thule. The age and distribution of these bones potentially demonstrate changing sea ice and occupancy patterns in the Northwest Passage.
The primary cause of decreased ice thickness and late summer ice coverage is because of the loss of multi-year ice, which is being replaced by younger, less stable ice. Formerly inaccessible waters will also become navigable, which expands opportunities for shipping, resource exploration and development. More access and development may translate into higher risk of environmental incidents that may need response efforts.
Iceberg calving is the sudden release and breaking off of large chunks of ice from glaciers, ice shelves or icebergs themselves.
A number of other changes in ice conditions have been observed. For example, the number of ice-free days on lakes, rivers and the ocean is greater than ever throughout the Arctic, as ice cover is developing later and melting earlier. There is also growing evidence that Nunavut’s glaciers are retreating and shrinking, in part due to iceberg calving. This can result in changes in run-off, affecting areas that rely on glacier-fed rivers and streams. The impacts of increased glacial run-off may include fluctuations in water levels, changes in salinity in salt and fresh water, water quality changes, and availability and quality of drinking water.
Changes in Wildlife and Vegetation
Changes in range distribution, habitats, abundance, genetic diversity, and behavior of migratory and non-migratory species have already been noticed due to climate change.
Overall, the number of species in Nunavut is expected to rise as southern species move further north because of a changing climate. Current Arctic species will see changes in their habitat including new plants, reduced ice cover, changing snow patterns, changing ocean salinity and increased acidity. This can affect species numbers and distribution.
For example, polar bears are highly intelligent and adapt quickly to changing conditions. They have lived through many climate change cycles in the past, so they can likely manage changes that might happen. However, it is possible there will be changes in their range distribution and composition. Some areas may experience reduced polar bear numbers. In other areas, polar bears may cease to exist during the warmest period. Other regions may experience higher numbers of polar bears as a changing climate improves polar bear habitat by reducing multi-year ice. Elsewhere, polar bear numbers and polar bear productivity may remain steady.
Wildlife has and will continue to play a vital role in the traditions, culture, economy and diet of Nunavummiut. It will be critically important for Nunavut to continuously monitor wildlife populations and adjust wildlife management systems accordingly.