Saturday, 12 November 2011

Melting Permafrost

Permafrost is ground which is frozen and remains below 0C for two years or more. It can be classified into three groups:
-          Continuous permafrost: underlying 90-100% of the landscape
-          Discontinuous permafrost: 50-90%
-          Sporadic permafrost: 0-50%

It underlies up to 25% of the Northern Hemisphere and the map below (taken from International Permafrost Association) shows where it can be found.




Recent changes in temperature due to global warming have meant that melting of permafrost has begun. In the Northern communities this has had a great impact, particularly on transport and infrastructure.

When permafrost begins to melt it does so from the top- down. The active layer (the layer which isn’t frozen at the top) becomes larger. This thickening of the active layer causes previously frozen plant material to decompose and release CO2 and methane into the atmosphere. Secondly, the ice in the upper part of the permafrost becomes water leading to the ground surface subsiding (US Arctic Research, 2003). When this happens in or next to a human settlement, structural integrity of buildings, roads and pipelines are threatened.


This is the problem currently being faced by many communities in the North of Canada. The Arctic town of Salluit is considering relocating to escape the melting permafrost. Their newly built fire-station has sunk into the ground only a year after its completion. The roads and foundations of buildings have begun crumbling (The Canadian Press, 2010

“Sara Brown, director of community operational support with the Northwest Territories Association of Communities, says the costs to upgrade and fix buildings in Canada's North could range from $250 million to $420 million.” (CBC News, 2011

In an attempt to combat the problem The Canadian Standards Association has published guidelines for infrastructure design in permafrost regions. 

Wednesday, 9 November 2011

Direct and Indirect Health Impacts

Whilst research conducted on the health impacts of climate change in Northern Canadian communities is very limited and often still in the early stages, the research that has been done suggests wide and varying negative impacts.
Much of the research that has been undertaken has been done by talking to the communities and they have highlighted a range of health issues that they believe have been caused or worsened by climate change.
In the table below I have listed some of the most significant impacts:

Climate Change
Health Impact
Reduction in ozone layer
Increased UV exposure leading to higher risk of cancers and burns
Changes in ice
More accidents whilst hunting
Increasing incidences of storms and extreme weather events
More accidents
Increased air pollution
More respiratory illnesses especially in older people
Melting of permafrost
Higher risks of accident from collapsing buildings
Increased temperature extremes
More deaths because of extreme temperatures

Again, the capacity for the communities to cope and adapt to the changes is extremely important. However, when it comes to health effects, the communities are less likely to be able to adapt without help and advice from outside their communities.