Sea level changes, coastal erosion and storm surge flooding key concerns for many parts of Canada: federal government report

Sea level changes will vary greatly across Canada this century and beyond, and these changes, together with coastal erosion and storm surge flooding, represent key concerns for many areas, according to a report released earlier this week by Natural Resources Canada.

Canada’s Marine Coasts in a Changing Climate, a Government of Canada scientific report released on Tuesday, assesses how climate change is increasingly affecting the country’s coastal regions and highlights the potential impacts on communities, economies and ecosystems. The report synthesizes over 1,300 scientific publications into a “definitive and accessible” resource on climate change sensitivity, risks, opportunities and adaptation along Canada’s marine coasts, Natural Resources Canada said in a statement.

“Where relative sea level is rising, the frequency and magnitude of storm-surge flooding will increase in the future,” according to the 280-page report, which includes more than 60 authors from Canadian universities, federal departments, other levels of government, industry and professional organizations. “A range of adaptation measures will be needed in most settings to address the complex array of changes. Alternatives to hard coastal-protection structures can be effective in addressing coastal erosion and flooding in many areas.”

From an insurance standpoint, the risk of catastrophic losses due to storm-surge flooding increases with sea-level rise and increasing severe weather in Canada, the report said, noting that it is estimated, by the 2020s, annual economic damages to Canada’s coast from sea-level rise and storm surges could be in the range of $2.6 to $5.4 billion. This will increase to an estimated $48.1 billion by 2080.

For Canada’s west coast region, storm surge flooding presents a greater threat to coastal communities than sea-level rise alone, the report said. Coastal communities are already coping with extreme water levels associated with climate variability (such as El Niño/La Niña Southern Oscillation) and storm surge flooding, and the risks associated with these events are expected to increase as sea level rises. “Residential, commercial, institutional and municipal property and infrastructure in the region are vulnerable, and communities have begun to take action to reduce the risk through adaptation measures such as shoreline protection,” the report noted. [click image below to enlarge]

In Canada’s east coast region, experience has shown that “mechanisms such as setbacks, which control or prohibit coastal development, can be challenging to implement. “However, it is often even more difficult to remove and relocate buildings from an eroding coastline or flood-susceptible area,” the report said. “Selection of appropriate adaptation options may be particularly challenging in unincorporated areas where summer cottages, secondary homes or principal dwellings are established parallel to the shore in a ribbon fashion.”

According to the report, Canada’s northern coast is a “hotspot” for global climate change. “The region has experienced some of the most rapid climate change anywhere on the globe, and projected future climate changes for the northern coastline will continue to be significant. Impacts on the physical environment include declining sea-ice concentration, earlier ice break-up and later freeze-up, a lengthening of the ice-free open-water season, permafrost warming and thaw, coastal erosion, sea-level rise and changing weather patterns, including wind and waves.”

Northern coastal communities, ecosystems and economic activities are being affected by climate change impacts, which will exacerbate existing vulnerabilities. While northern coastal communities and industries are adapting, “the effectiveness and sufficiency of the existing responses have not been evaluated, although barriers to adaptation, including limited resources, institutional capacity and a lack of ‘usable’ research, have been limited,” the report said.

The report concludes that “it is imperative that future development be undertaken with an understanding of the dynamic nature of the coast and changing coastal risks. Monitoring and assessment of the effectiveness of actions taken to date, as well as research to fill data and knowledge gaps, would help inform sustainable planning and development.”