A synthesis of project findings: Sea level rise and public health implications

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This project considered the potential direct and indirect health impacts of sea level rise on coastal communities, and how better to incorporate health considerations into adaptation planning. The outputs of this project can be used to inform future adaptation measures and in turn, to consider how adaptation decisions could affect health.

The project outputs are presented in four reports: Report 1 identifies geographic areas of Canada’s coastline that are most exposed to impacts from sea level rise. Report 2 presents a literature review of the potential physical and mental health impacts resulting from exposure to sea level rise. Report 3 reviewed current community-based adaptation approaches to sea level rise and health, and Report 4 considered how health could be better considered in community-based adaptation planning for sea level rise.

Key messages from the overall project findings include the following:

• Projections for relative sea level rise across Canada differ due to regional variation in vertical land movement. Sea level rise will thus affect coastal communities in Canada differently, with the most significant geographic impacts occurring in Atlantic Canada, but the largest population affected in British Columbia.
• The direct impacts of sea level rise on health are difficult to parse out from the varied and broad impacts of climate change and are intertwined with other climate change hazards such as coastal flooding, erosion, and extreme weather events, whose impacts may be exacerbated. Sea level rise may also have direct impacts on saltwater intrusion, and water and soil contamination.
• Sea level rise impacts on health could be wide ranging, including increased potential for drowning and physical injuries near the sea; reduced access to safe drinking water; increased exposure to vector-borne diseases and mould; mental health impacts from loss of cultural land, livelihoods, and displacement; and compromised social determinants of health.
• Some communities may be at higher risk of experiencing health impacts due to heightened geographical exposure to the effects of sea level rise, or due to heightened sensitivity to risks based on cultural, historic, or systemic inequities.
• The majority of coastal communities at risk of exposure to sea level rise have developed community-based adaptation documents and acknowledge sea level rise as a significant hazard, usually in the context of the gradual long-term impacts rather than exacerbation of events that are already increasing in frequency such as coastal flooding, erosion, and extreme weather events.
• Most community-based adaptation documents focus on the impacts of sea level rise on infrastructure and the built environment but almost never consider health impacts directly.
• Protection measures are the most common adaptation approach to sea level rise, followed by accommodation measures (e.g., nature-based solutions), which are considered to have the most co-benefits for communities.
• Health impacts of sea level rise may be considered indirectly in the context of coastal flooding effects on impaired access to emergency services, damaged water or wastewater infrastructure, salinization of agricultural land and drinking water supplies, and mental health impacts.
• Adaptation plans for Indigenous communities were more likely to consider impacts on health and the social determinants of health in vulnerability assessments and adaptation activities.
• Communities may benefit from greater integration of public health considerations in adaptation planning for climate change more generally, and sea level rise specifically, but may need assistance to understand the possible health impacts and implications of any adaptation measures, particularly as health is a provincial jurisdiction and typically out of scope for local land use planning activities.
• Communities need access to meaningful data and assistance in applying for climate change funding for adaptation and assistance in identifying how best to use funding to implement solutions that align with land use planning and development priorities.
• Public health, local government, land use planners and provincial/territorial partners can use these project resources as a starting point for working together to better integrate health considerations into climate adaptation planning for coastal communities throughout Canada.

 Knowledge gaps and areas for further study

For communities that include and consider health in their adaptation approaches, further study is needed to identify if, and how, health outcomes are measured during implementation. There was little information available on the health co-benefits or potential maladaptations that could arise from various adaptation approaches to sea level rise. Further study may be needed to understand how adaptation approaches themselves will impact communities. For coastal cities that are more advanced in their planning efforts, collecting data on health outcomes before and after implementation of adaptation measures could help identify whether benefits or unexpected consequences are occurring, and inform continued use of adaptation strategies of protection, accommodation, retreat, and avoidance. Exchanging knowledge and sharing good practice between communities and across Canada could help build community capacity to adapt.

Recognizing that sea level rise and climate change generally are global issues, continued observation of the impacts of sea level rise on communities at an international scale will help inform ongoing Canadian adaptation actions. There may be unexpected consequences of sea level rise on health or new adaptation approaches that have not been considered in the Canadian context at this time.