Can we predict health impacts in a changing climate?

Canada’s climate is changing. We’re observing shifting air temperature, variations in air quality, increasing water-, food- and vector-borne diseases, an increasing number of heat waves, and more impactful natural weather events such as flooding, wildfires and storms. Communities across urban, rural, coastal and northern regions of Canada vary in their susceptibility to climate-related hazards. As such, it is important to understand the factors that make communities vulnerable, so that protective measures can be identified and implemented to help develop resilience.

An important tool for building that resilience is the environmental impact assessment. This assessment is used to evaluate the potential contribution of proposed mining projects to climate change. However, the regional and national processes are not consistent in the methods applied to assess project contribution to climate change and impact on health. As one of the top five global producers of potash, uranium and niobium, nickel and other minerals, Canada’s mining industry faces extensive implications from climate change, including significant risks that could affect all facet of the mining cycle – from exploration, planning, transportation and operations to decommissioning. One obvious consequence of climate change is water management, a major expense of most mining operations. However, many mining companies consider climate change a low to medium risk to their business operations.

The increasing frequency of climate-related hazards is already affecting Canadians’ health and well-being.

Health outcomes from exposures to flooding include exposures to sewage and contaminants in water, exposures to mould, spread of disease, and food and water insecurity. Health outcomes from exposures to wildfires include burns, mortality, post-traumatic stress disorder as well as respiratory effects resulting from exposures to air pollution. Increased incidences of asthma and use of bronchodilators, an increase in hospital visits and/or physician visits for asthma, obstructive pulmonary disease, bronchitis and pneumonia have also been observed and are considered contributing factors to a significant rise in mortality worldwide. Smoke exposures among pregnant women have also been associated with reduced average birth weight among infants.

A recent review of the federal environmental impact assessment (EIA) process recommended that proposed projects should be evaluated based on sustainability pillars founded on environmental, health, social, cultural and economic considerations. For example, increasing temperatures are expected to increase heat-related illnesses, such as heat stroke and exhaustion, and may further worsen existing respiratory, circulatory, and nervous system medical conditions. The impact of increasing temperatures on the mining workforce and nearby communities have typically not been evaluated in impact assessments.

Communities’ susceptibilities to climate change hazards need to be considered in the EIA process to ensure that they can respond and adapt to both climate- and project-related impacts. One way to assess community health is through the conduct of health impact assessments (HIAs), as required by some Canadian provinces. HIAs identify and examine, in a balanced way, both positive and negative impacts of the proposed project on human health.

HIAs evaluate not only environmental factors, but also consider other factors that may affect the overall health of individuals and communities, including social, cultural and economic determinants of health. These health indicators are typically combined to produce a description of overall health that encompasses a more holistic approach. HIAs can be integrated into the federal IA process to identify and assess determinants of health that are vulnerable to both project- and/or climate-related impacts. HIAs are typically a collaborative process that hinges on stakeholder engagement. The findings of HIAs will help guide decision-makers and stakeholders through the process of review, monitoring and development of adaptive strategies to mitigate health risks.

HIAs require an understanding of baseline health and community well-being prior to project development. Baseline health may be significantly influenced by climate-dependent hazards and as such, the conduct of HIAs will require a dynamic understanding, rather than a constant one, of study area baseline conditions and project risks and impacts. More importantly, the HIA process will identify climate change impacts on the health, safety and security of susceptible groups within communities. HIAs can consider additional project design buffers that address climate variability and extreme weather events, and can also consider adaptation measures that conserve biodiversity, the natural ecosystem and habitat to reduce risk.

There is much debate about how to address climate change impacts on community health. It is very challenging to coordinate roles and responsibilities among stakeholders which include the project sponsor, varying levels of government, public health units and Indigenous communities. However, the HIA process can provide a platform for project sponsors to establish collaboration and partnership with stakeholders that not only develop adaptive measures, but also look for opportunities to strengthen community resilience in the face of changing climate.