Millions in Canada face flood risks as sea levels rise, study warns

Rising sea levels are intensifying the risk of coastal flooding across Canada, threatening communities and infrastructure along the coastline.  

Data from the World Meteorological Organization (WMO) indicates that global sea levels have risen at an accelerating rate, increasing from 2.13 millimetres per year between 1993 and 2002 to 4.77 millimetres annually between 2014 and 2023.  

This trend is driven by climate change, including the thermal expansion of oceans, and melting glaciers and ice sheets.   

A study by MyChoice, an insurtech company, estimates that 3.9 million Canadians live in areas projected to face coastal flooding within the next century.  

The study, which utilised data from the National Collaborating Centre for Environmental Health and Statistics Canada, found that at least 11,814 dwellings at an elevation of one metre above sea level are at risk of flooding by 2100.  

The number could increase significantly as sea-level rises in some provinces are expected to exceed one metre.   

• British Columbia: An average sea-level rise (SLR) of 127.4 cm is projected by 2100. Approximately 3.18 million residents live in communities vulnerable to coastal flooding, with 3,190 dwellings at risk. 

• Nova Scotia: The province faces an even higher average SLR of 159.3 cm. About 508,114 residents live in at-risk areas, with 2,231 dwellings at one metre elevation threatened by flooding. 

• Quebec: Despite a smaller coastal population of 12,190 in vulnerable communities, an average SLR of 156 cm endangers at least 1,968 dwellings.   

Matt Roberts, COO of MyChoice, highlighted the financial and safety challenges associated with rising sea levels. “Our study underscores the urgent need for Canadians, especially those in coastal areas, to be aware of the risks posed by rising sea levels,” he said.  

Roberts also emphasized the financial implications, urging homeowners to review their insurance policies to ensure adequate flood coverage.  

He noted the importance of implementing preventative measures, such as installing sump pumps and backwater valves, to protect properties from potential water damage. 

In response to the risks, the Canadian government has launched an expanded coastal flooding prediction and alert system. This system, now active across the Pacific, Atlantic, and Arctic coasts, provides warnings for storm surges, large waves, and high tides.  

Previously, such alerts were limited to the Atlantic coast. The new system uses advanced modelling techniques and a coastal flood risk index. This allows meteorologists to assign risk ratings ranging from low to extreme.  

They can then issue forecasts through Coastal Flooding Risk Outlook maps, which are accessible to the public and emergency management agencies. 

Addressing the challenges of rising sea levels requires coordinated efforts from governments and individuals.  

With millions of Canadians and significant infrastructure at risk, tools like the coastal flooding alert system and proactive measures by homeowners are essential to mitigate the impacts of this growing threat.