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Parts of Canadian Arctic may be spared from rising sea levels

An interview with Thomas James, Research Scientist, Geological Survey of Canada - 1/16/13


This interview is part of our series on Sea Level Rise. To get an idea of the Canadian perspective on Sea Level Rise, we talked with geophysicist Thomas James on Thursday January 3.

Water Today

You are a geophysicist with the Geological Survey of Canada, what are your main areas of interest?

Thomas James
My main research focus is vertical land movements and their effect on sea level change. In Canada, a major cause of vertical land motion (uplift and subsidence) is postglacial rebound . Relative sea level has been falling in recent millennia in many areas of Canada because the land is rising in response to the unloading caused by the thinning and retreat of the large ice sheets at the end of the last Ice Age.

Water Today
A recent NASA/ESA report estimates that the Greenland ice sheet is melting at a faster and faster rate since 1992, how does this affect Canada's Arctic coast in close proximity to the Greenland sheet?

Thomas James
There is another important natural phenomenon that comes into play that reduces the amount of sea-level rise near a shrinking glacier or ice sheet. It is the uneven redistribution of meltwater from glaciers, ice caps, and ice sheets. Owing to the reduced gravitational attraction of a shrinking ice mass, sea level falls close to a body of ice that is shrinking and providing meltwater to the oceans. On the whole, because of the interplay of land uplift and melt water redistribution from the Greenland ice sheet, sea levels in Canada's Arctic will either fall or be lower than the global rate of sea-level rise.

Water Today
NOAA's Climate Program office published a report on Sea Level Rise in the United States in December 2012. This was essentially a US-driven interagency initiative, which included USGS, EPA and USACE. Is there a similar initiative in Canada?

Thomas James
Yes, a National Coastal Assessment is currently underway. It is being led by Natural Resources Canada.

Water Today

When is it expected to be completed?

Thomas James
A scoping workshop was held last spring and initial metrics were collected from scientists and advisors. The national coastal assessment should be out in the fall of 2014. As one of the contributing scientists I have already published sea level scenarios for coastal communities in the Northwest Territories and Nunavut.

Water Today

What were your projections and what was the process you used to determine them?

Thomas James
I looked at a large number of global sea-level rise scenarios, including the IPCC 4th Assessment and more recent semi-empirical projections. I based my projections on an assessment of the likely amount of global sea-level change, spanning from 28 cm to 115 cm of sea-level rise from the year 2010 to 2100. I then factored in vertical land uplift and melt-water redistribution. All these factors rolled together allowed me to project minimum and maximum sea level rise rates in each community. In some instances this leads to a fall of sea level rather than a rise. Sea levels could decrease along the western coast of Hudson Bay - by as much as 75 cm at Whale Cove in the next 90 years (from 2010 to 2100).

According to my assessments, Whale Cove sea-level change would range between a minimum of -75 cm to a maximum of +20 cm ; Iqaluit between a minimum of 0 cm to a maximum of 70 cm and Cambridge Bay between -35 cm to 50 cm. In the NWT, sea level in Ulukhaktok could fall by 10 cm or rise by 70 cm, whereas at Tuktoyaktuk, where there is vertical land subsidence, the range of sea level rise would be between 20 and 100 cm.

Water Today

One of the scenarios proposed by the NOAAA sea level rise report projects a maximum of 2 metres rise by 2100. Your estimate is 115 cm or 1.15 metre. Why the discrepancy?

Thomas James
You have to realize that the NOAA report had a different goal. The maximum of 2 metres is proposed in the context of planning. The highest scenario would apply in a development where there is a very low tolerance for risk.

Water Today

It is widely perceived that the current federal government does not see climate change as a priority. Are there national, regional and local task forces in Canada evaluating climate change and managing risk as there are in the US?

Thomas James
Yes, there are many initiatives in Canada to deal with climate risk. In addition to the national Coastal Assessment mentioned above, there is, amongst others, a project in BC to upgrade the guidelines for dykes along the coast in the context of sea level rise and storm surges.

NOTE: This interview was reviewed by Thomas James to ensure the accuracy of the scientific information.


Related Info
2011 Geological Survey of Canada
Greenland ice sheets losing mass faster and faster - NASA/ESA Study - Water Today
The IMBIE Assessment - ESA/NASA Report
Clearest evidence yet of polar ice losses - University if Leeds - Press Release
Global Sea Level Rise Scenarios for the United States National Climate Assessment - NOAA
Sea Level Rise & Crisis Management - Interview with USGS Chief Climate Scientist - Water Today










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