Canadian Communities at High Risk of Coastal Floods

Rising Sea Levels Threaten to Displace 3.9 Million Canadians by 2100

Coastal flooding has become an increasingly pressing issue in Canada, with rising sea levels posing significant risks to communities along the coastline. According to the World Meteorological Organization (WMO), sea levels are rising at a rate that has more than doubled in the past 30 years – from an average of 2.13 millimetres per year between 1993 and 2002 to around 4.77 millimetres between 2014 and 2023. This acceleration is attributed to climate change-induced thermal expansion of oceans and the melting of glaciers and ice sheets.

To shed light on the potential impact of rising sea levels, our team at MyChoice conducted a comprehensive study estimating the number of dwellings and population situated in areas that are most vulnerable to coastal flooding. Using the sea level rise and population data from the National Collaborating Centre for Environmental Health and Statistics Canada’s data on coastal dwellings below the one-meter elevation level, we determined which provinces/communities will be most vulnerable to the rising sea levels.

The key findings of the study are summarized below.

• An estimated 3.9 million Canadians live in areas that will be at risk of coastal flooding over the next century as a result of rising sea levels.
• At least 11,814 dwellings across the country located at an elevation of 1 metre above sea level are expected to be flooded by 2100. This number could be significantly higher, as some provinces are anticipated to experience sea-level rises well beyond 1 metre, potentially impacting more dwellings and communities.
• British Columbia is projected to be the most affected province, with an average sea-level rise (SLR) of 127.4 cm by 2100. Approximately 3.18 million people reside in communities vulnerable to coastal flooding, and at least 3,190 dwellings situated at 1 metre elevation within 10 km of the coastline are at risk.
• Nova Scotia faces an even higher average SLR of 159.3 cm, with around 508,114 residents living in at-risk areas. The province has 2,231 dwellings at 1 metre elevation within 10 km of the coastline that are susceptible to flooding.
• Newfoundland and New Brunswick face an average SLR of 149 cm and 145.2 cm, respectively.
• Although the population of the coastal communities at risk in Quebec is relatively small (12,190), a rise of 156 cm in mean sea level puts at least 1,968 dwellings at risk.

Below is an infographic that shows the areas of Canada that have the highest coastal flood risk.

“The findings of the study highlight the importance for all Canadians, particularly those who live in coastal areas, to be aware of the risks associated with rising sea levels,” says Matt Roberts, COO of MyChoice. Beyond the environmental and safety concerns, there are significant financial implications. Homeowners need to understand their insurance coverage and take proactive steps to protect their properties from potential water damage. We advise homeowners to review their insurance policies to ensure adequate flood coverage and to implement preventative measures like installing sump pumps and backwater valves to protect their properties.”

In response to this growing threat, the Canadian government has activated a new coastal flooding prediction and alert system to warn of storm surges, large waves, and high tides across the Pacific, Atlantic, and Arctic coasts. Previously, such alerts were only issued on the Atlantic coast. This expanded system employs advanced modelling techniques and a coastal flood risk index to evaluate the likelihood and expected impact of flooding events. Meteorologists can now assign risk ratings ranging from low to extreme and issue forecasts through Coastal Flooding Risk Outlook maps available to the public and emergency management partners.

The threat of rising sea levels and increased coastal flooding is a complex challenge that requires action from both governments and individuals. With significant portions of Canada’s population and infrastructure at risk, it’s imperative to utilize tools like the new coastal flooding alert system and to take preventative measures to protect homes and communities.

See below for a list of Canadian communities that are highly vulnerable to coastal flooding.

Source: The National Collaborating Centre for Environmental Health