Vancouver, Canada (GLOBE-Net) - Whether it’s freshwater flooding or rising sea levels, the biggest climate change threat facing Atlantic Canada comes from water, and although the threat has been identified, questions remain whether the region is truly prepared for the inevitable impacts that are coming? 

This final GLOBE-Net installment on the Natural Resources Canada report, From Impacts to Adaptation: Canada in a Changing Climate, examines the impacts of climate change on Atlantic Canada - New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island - which combined have a population of 2.3 million. Atlantic Canada’s heavy reliance on marine and coastal eco-systems makes the region highly vulnerable to climate change impacts.

Impacts

According to the Natural Resources Canada report, Atlantic Canada will experience more storms, increased storm intensity, rising sea levels, more devastating storm surges, greater coastal erosion and more instances of flooding. There is growing evidence of recent trends toward greater extremes and higher frequencies of such events. The extreme flooding conditions in New Brunswick that have taken place in the past two weeks could become much more commonplace.

Coastal communities and their infrastructure and industries, including fisheries and tourism, will be highly vulnerable to these impacts.  Arguably the largest threat will come from rising sea levels resulting in coastal area flooding and erosion.  This will impact on infrastructure, such as bridges, roads and energy facilities, and will upset trade and tourism in the region. Some coastal communities are already experiencing saltwater intrusion into their groundwater aquifers.

Over the past century, sea levels in the Atlantic region have risen approximately 30 cm.  Areas such as the coast of southeastern New Brunswick could experience sea-level rise on the order of 50 to 70 cm during the current century.

Continued sea level increases will also amplify storm surges and flooding, which not only are physically devastating but can be very costly.  Hurricane Juan in 2003 killed eight people and was responsible for at least $200 million in damage to Nova Scotia and Prince Edward Island.

A storm surge in excess of 3.6m above the mean sea level occurs approximately once every 40 years in the southern Gulf of St. Lawrence, but could be expected to occur annually by 2100 as a result of climate change.

The Atlantic Provinces also face a threat from in-land flooding.  Increased precipitation and changes in temperature will result in an increase in rain-on-snow events that result in high volume water run-off rather than infiltrating the ground.

Rain-on-snow flooding events can be particularly destructive.  In the 1980s such an event carved a 10m deep channel through Bishops Falls, NL destroying the Abitibi-Price powerhouse and dam, major roadways and numerous structures, and required evacuation of the community at a cost of more than $34 million.

Spring temperatures in Atlantic Canada typically fluctuate between cold and mild days.  Increased temperatures will cause an increase in the occurrence of such fluctuations.  The result is the regular thawing and refreezing of freshwater bodies, causing large amounts of ice to jam rivers and cause flooding.  Such conditions are responsible for the massive flooding now underway in New Brunswick.

With increased summer temperatures, the rate of evaporation is expected to exceed precipitation levels, causing further declines in water flows.  Declining flows have been noted over the period 1970 to 2000 in the Saint John and St. Croix Rivers of New Brunswick.

Lowered water levels or decreased river flows could also lead to poor drinking water quality in some areas. Many municipalities throughout Atlantic Canada depend on surface water supplies, leaving them exposed to declines in water levels in ponds and rivers, and contamination.

For areas dependent on groundwater such as southern Nova Scotia, eastern New Brunswick and Prince Edward Island reductions in the water tables will result from a combination of reduced summer rainfall and enhanced surface runoff of winter rain.

Increases in temperatures, prolonged summer dry seasons and heavier rainfall also increase the risk of contamination of drinking water by waterborne parasites.  In 2005, orders to boil water before human consumption were in place for more than 200 communities in Newfoundland and Labrador.

Adaptation

Authors of the report found the region has high adaptive potential which could be realized in most communities through careful planning.  Identifying vulnerable infrastructure, incorporating river and coastal flooding in land-use policies, revising emergency response measures, and accounting for sea-level rise when planning and building infrastructure would reduce damage to infrastructure and the environment, and lessen the risk to human health and well-being.

According to the report, there are three generic categories of adaptation that can be used in areas affected by coastal erosion, sea-level rise and/or storm surge activity:

Planned retreat - involves recognition of the inevitability of coastal erosion, and responds by abandoning the areas closest to the shoreline or locating only temporary or expendable structures in these areas.

In New Brunswick, some planned retreat activities are possible through a Coastal Areas Protection Policy that is being implemented. This policy also encourages protection of the coastal areas through the avoidance of construction within 30 m of the high-tide shore, with permanent structures only permitted outside the set-back limit.

However there are currently no coastal protection policies in Prince Edward Island, Newfoundland or Nova Scotia and few individuals have considered retreat as an option.

Accommodation - involves constructing structures in ways that minimize damage (e.g. by placing buildings on elevated pylons) or developing land-use and zoning plans that allow only those structures that must be built on the shoreline (e.g. port facilities or fish-processing plants) to be located there, while prohibiting others (such as private residences).

Accommodation can allow impacts on natural systems to occur while adverse impacts on people are minimized by adjusting the human use of the coastal zone. At present, accommodation is not commonly employed as an adaptive strategy in Atlantic Canada.

Protection - involves physical reinforcement of the shoreline, either by ‘hard’ measures (seawalls, rip-rap, etc) or by ‘soft’ measures (e.g. vegetating dunes with grass).

Protection is frequently used as an adaptive strategy. Seawalls, breakwaters and emplacement of rip-rap are the most common adaptive measures and those most favoured by the majority of coastal residents and property owners.

Unfortunately such hard engineering structures are expensive, require frequent maintenance and observation, and can fail if not adequately designed and constructed. Repetitive storm activity and rising sea level both pose problems for the design and maintenance of hard coastal protection.

Although most provincial legislation and municipal development plans have provisions to protect coastal zones, very few integrate climate change into their long-term planning. 

Adaptation to changes to freshwater resources and in-land flooding represents application of well-established ‘best practices’. For example, construction of retention ponds for storage of water and reduction of flooding, common in many areas of Ontario and western Canada has not been common practice in Atlantic Canada.

Overall, Atlantic Canada’s adaptive potential is high, and proven methods of adaptation do exist, but have been given very little consideration.  The problem has been recognized, but according to the report appropriate adaptive measures have not been fully established. 

The report’s authors agree that the knowledge available is sufficient to begin adaptation, but there are important research and assessment needs that, if addressed, would help support adaptation decisions.  The report identifies many studies that note a lack of awareness in Atlantic communities of the seriousness of climate change impacts and the necessity for proactive adaptation and further research, as well as awareness-building, is necessary.

The Full report From Impacts to Adaptation: Canada in a Changing Climate can be found here.

The Atlantic Canada chapter of the report can be found here.

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For More Information: Natural Resources Canada