Effects of climate change on human health in Canada

Climate change in Canada has contributed to a rise in temperatures and extreme weather events that affect human health.[1][2] Some health outcomes include heat-related illnesses and respiratory conditions, which disproportionately affect populations, particularly low-income communities.[2] The affected groups are mainly influenced by age, socio-economic conditions and pre-existing health conditions.[2]

Background

Climate change has contributed to increases in droughts, floods, and wildfires in Canada.[1] Globally, human activities (anthropogenic activities) have contributed to climate change and have been associated with a 1.7 °C increase in Canada's surface air temperature since 1948.[2] Climate change has impacted multiple areas across Canada and its adjacent oceans, with higher temperatures observed in the northern regions.[3] Future climate projections indicate that temperatures will increase during the winter season.[4] It is also projected that there will be an increasing demand for cooling in Canada for the next 50 years.[4]

Climate change disproportionately affects Canadians, as it varies based on factors such as geographic context, socioeconomic status, and standard of living.[5] Climate change has been associated with economic impacts, contributing to job losses in some regions.[5] Reduced income can limit workers from purchasing their essentials, including water and food.[5] These factors are associated with poor diet and health outcomes.[5] The heavy reliance on fossil fuels has contributed to the presence of greenhouse gases in the atmosphere, which is linked to the spread of infectious diseases among the public.[6] Health outcomes include heat strokes, dehydration, pregnancy issues, allergies, Lyme disease, foodborne illnesses, and physical and mental health impacts.[6] Poverty has also been linked to the environmental and health risks among low-income communities.[2]

Extreme weather events in Canada have been associated with increased heat-related morbidities and mortalities.[7] In 2021, there were 619 deaths in British Columbia during a heatwave event.[7] In Canada, thousands of hospital admissions and emergency visits occur annually, mostly during the summer season.[7] Mortalities resulting from extreme heat exposure are expected to increase by approximately 10.7% by 2090.[7] The temperature is also projected to become warmer within the region, especially during the months of May and September.[7] The warm season (May-September) has a high probability of becoming longer, resulting in more intense and frequent heat.[7]

During the period 2004-2023, there were approximately 38,398 emergency department (ED) visits.[7] There were two extreme weather events that occurred in Canada in 2018 and 2021.[7] In 2018, there were 8.6 hospitalizations per million population, and in 2021, 32.2 hospitalizations per million population were reported.[7] Heat disproportionately affects certain communities in Canada, and adults aged 80 years or older were reported to have the highest annual rates of hospitalizations.[7] Hospitalization rates were higher among males and increased among those who are 12 years and older.[7] Female hospitalizations occurred mostly for those aged 45 and older.[7] On average, males had higher hospitalization rates, as compared to females aged 12 years or older.[7] Health Canada reported that the data does not cover all the provinces within Canada, which may underestimate the overall impacts on the vulnerable communities.[7] The gender-based hospitalization rates varied among individuals with different age groups.[7] The highest heat-related illnesses were found in older adults aged 80 years and older.[7]

Air quality and respiratory health

The heavy reliance on fossil fuels has contributed to the increase in greenhouse gas concentrations in the atmosphere, polluting the air we breathe.[6] There are approximately 15,300 premature deaths and health impacts related to air pollution are estimated to be worth $114 billion.[6] Ozone is associated with lung irritation, hospital admissions and early deaths.[6] Long-term exposures to the fine particulate matters in the air have been linked to 570 to 2,700 premature deaths annually.[6] Wildfire smoke has been identified as a major contributor to premature deaths in Canada.[6]

Food and water systems

Food quality, safety, and security are affected in the prairie provinces such as Alberta, Saskatchewan, and Manitoba.[6] These provinces account for more than 80% of the agricultural land in the region.[6] Canada is considered among the top 5 largest exporters of agricultural products.[6] Extreme weather events like floods can significantly impact the crop yields, food production and distribution across the country.[6]

Water quality, security, and safety have also been affected by climate change, impacting the health of populations.[6] The rise in sea levels, rapid snowmelt, and heavy precipitation can pollute the water systems, reducing the overall supply.[6] These water sources are used for eating and drinking, which can lead to waterborne diseases among the vulnerable communities.[6] In Canada, approximately 14% of the population resides in a rural community and depends on small water sources serving fewer than 300 individuals.[6] Indigenous communities are disproportionately affected by the limited access to clean and safe drinking water.[6] The rapid change in weather events, such as flooding, can result in bacterial contamination within the water systems, which may impact the health of Indigenous groups.[6]

Health system impacts

The health sector in Canada is a source of greenhouse gas (GHG) emissions per capita.[8] The health sector emits 30 to 50 times more GHG emissions per capita compared to India.[8] The affected members may require hospitalization depending on the severity of the heat-related symptoms.[8] Assessing the impacts of climate change from the health sector in Canada has been a challenge due to limited resources.[8] This can limit the development of proper mitigation measures since addressing climate-related impacts requires coordinated efforts.[8] Climate change is associated with a high risk of cardiovascular and respiratory diseases.[8] Globally, it has been documented that more than 4 million asthma cases resulted from poor air quality.[8] When heat waves intensify and lead to extreme weather events, this places pressure on the health care infrastructure, which in turn affects health care supply chains.[8] In the past, flood events have prevented proper health care delivery services across provincial and territorial jurisdictions in Canada.[8] In 2021, the flood in British Columbia damaged health care sectors and roadways, which prevented access to some areas.[8] The health sector encountered a shortage in medical supplies and were unable to deliver medications.[8] Sick patients were unable to receive the needed treatments due to the floods, which blocked roads.[8] Pollution from the healthcare sector in Canada has resulted in an annual loss of approximately 23,000 disability-adjusted life years, which range between 4,500 and 610,000.[8]

Vulnerable populations

Vulnerable groups in Canada include children, older adults, chronically ill individuals, visible minorities, racialized populations, and marginalized populations.[5] Children and older adults in Canada have weaker immune systems and are at a higher risk of contracting heat-related illnesses due to the extreme heat events.[5] Poverty is one of the indicators that can increase exposure to climate change.[2] The dimensions of poverty include low income, access to healthcare, homelessness, housing and food security.[2] Low-income groups may also lack resources, which may limit their capacity to effectively respond to extreme weather events like floods.[2] The limited access to resources is also linked to risk of increased illnesses and fatalities for older adults.[2] Pregnant individuals are also impacted since the exposure to heat can affect the fetus.[2]

Métis and Inuit communities depend on the environment for their way of life.[9] Indigenous communities are among the vulnerable populations in Canada that are impacted by the elevated temperatures.[10] Additionally, the Indigenous communities that are impacted by climate change may face barriers due to the limited support from the public health sector in some regions.[10] The Public Health Agency of Canada reported that the Nunavut communities have low GHG emissions per capita.[10] These communities experience global warming at a rate approximately four times higher than the rest of the Canadian population.[10] Inequities are also seen in a global context, as the countries that mostly emit greenhouse gas emissions are least affected by climate change impacts.[10]

The research conducted on climate change focuses on morbidity and mortality rates arising from heat exposure.[11] Climate change is also associated with economic impacts on health.[11] Quebec is composed of 18 regions and represents approximately 22% of the Canadian population.[11] In this context, the historical period represents 1990-2019 and the future projections range from the years 2040-2069.[11] Quebec's historical average temperature during the summer (May-September) was approximately 15.5 °C and is projected to increase by 2.5 °C-3.5 °C between 2040 and 2069.[11] Future projections indicate that hot summers in Quebec are projected to affect 10.5 million residents during 2050-2070.[11] Heat has historically (1990-2019) resulted in 410 fatalities, 200 hospitalizations, 31,900 emergency department visits and 6,100 ambulance transport each summer in Quebec.[11] In the years of 2040-2069, mortality rates and hospital admissions are predicted to increase by 118% and 230%, respectively, including a 65% increase in morbidity rates.[11] These projections are estimated under the normal circumstances of climate change under a threefold increase, without accounting for the potential socioeconomic changes during that period.[11]

By 2050, costs are expected to double due to climate change, with estimates of 85%-135% compared to the historical period (1990- 2019).[11] Population growth is one factor that has been associated with the increase of health risks.[11] Healthcare costs include the direct, indirect, and intangible costs.[11] Direct costs include emergency medical teams, emergency department visits, and hospitalizations.[11] The emergency medical services accounted for 30% of the direct costs due to the increased heat waves and operations.[11] By 2050, the intangible costs are expected to increase due to the losses in well-being that is associated with the increase in population and heat waves.[11] Indirect costs accounted for a greater loss in productivity during 2040-2069.[11] In the years of 1990-2019, Quebec's total annual heat-related health costs were $3.6 billion.[11] Health costs attributed to extreme heat for the projected period are expected to result in a 5-8.5 fold increase.[11] Even under more optimistic climate scenarios, heat waves are predicted to result in significant costs related to heat exposure in 2050.[11] The data on health-related costs can inform adaptation strategies such as reducing urban heat island effects, improving health systems and increasing urban greening strategies.[11]

Interventions and adaptation strategies

Climate change affects public health in numerous ways. The available health data is used to guide adaptation and mitigation strategies.[12] HealthADAPT, which is managed by Health Canada, receives funding to conduct numerous health assessments related to climate change.[12] Public health assessments have been conducted in northern Ontario and the city of Guelph in Waterloo.[12] These areas were assessed due to the high-intensity heat waves and were associated with negative health outcomes.[12]

Health Canada has established an iterative process to manage health risks.[13] This includes the implementation of health monitoring plans, including assessments involving Indigenous communities.[13] Data are collected and integrated into the adaptation and monitoring plans, which may help in reducing morbidities.[13] Proper indicators are then developed to have an effective monitoring plan.[13] This is done through collaboration with stakeholders to ensure that their concerns are addressed in the monitoring plan.[13] This process also includes documenting and evaluating the effectiveness of monitoring and adaptation successes to share the information and lessons learned with the stakeholders and partners.[13] This strategy supports the existing health authorities to implement appropriate strategies within the jurisdiction.[13] The Direction de santé publique de la Montérégie conducted Health Impact Assessments (HIAs) to assess health impacts of projects that are not directly related to the health.[10] These assessments support and encourage municipalities to consider projects that can positively contribute to public health in the decision-making process.[10]

Engaging with other sectors to implement and adjust proposed adaptation and mitigation strategies may improve health outcomes.[13] Green roofing has environmental benefits through the management of stormwater, which may have neutral to positive effects on public health.[13] Reducing carbon dioxide emissions in industrial processes is another method that has been linked with reduced human exposure to hazardous materials.[13] Greenhouse gases are the primary drivers of climate change and can be mitigated by planting more trees, which can reduce carbon dioxide levels.[13]

Heat alert and response systems can be implemented across all provinces in Canada, including the rural areas where Indigenous groups reside.[14] These systems enable the residents to take early precautions like staying hydrated, reducing heat-related health risks.[14] Quebec has implemented a heat warning system, which resulted in fewer medical appointments made by chronically ill seniors in the region of Montérégie.[14] Environment and Climate Change Canada (ECCC) rates the risk and provides health protection measures that vulnerable groups can follow.[15] Indigenous-led actions to develop climate change strategies may support the identification of health-related risks at a community level.[15] The Government of Canada has committed to working in partnership with First Nations, Inuit, and Métis on appropriate climate change and adaptation measures.[15]

References

  1. 1 2 Slonosky, Victoria (2025-12-10), "Droughts and Floods in Nineteenth Century Canada", Proceedings of Proceedings of the Corfu Summer Institute 2024 "School and Workshops on Elementary Particle Physics and Gravity" — PoS(CORFU2024), vol. 490, SISSA Medialab, p. 356, doi:10.22323/1.490.0356, retrieved 2026-03-31
  2. 1 2 3 4 5 6 7 8 9 10 Bezgrebelna, Mariya; Aliyev, Emil; Amoah, Yaa S. A.; Atkinson, Donna; Chiblow, Susan Bell; Daley, Mardi; Drolet, Julie L.; Fletcher, Amber; Harper, Sherilee; Kenny, Glen P.; Lacap, Leanne M.; McKenzie, Kwame; Sachal, Abhay; Valois, Pierre; Wolbring, Gregor (2024-11-01). "Climate change, poverty, and health: A scoping review of the Canadian context". The Journal of Climate Change and Health. 20 100348. Bibcode:2024JCCH...2000348B. doi:10.1016/j.joclim.2024.100348. ISSN 2667-2782. PMC 12851359. PMID 41647115.
  3. ↑ NRCAN; NRCan; RNCan (2024). "NRCAN Open Science and Technology Repository". ostrnrcan-dostrncan.canada.ca. Retrieved 2026-03-31.
  4. 1 2 Chidiac, Samir E.; Yao, Lan; Liu, Paris (2022-04-02). "Climate Change Effects on Heating and Cooling Demands of Buildings in Canada". CivilEng. 3 (2): 277–295. doi:10.3390/civileng3020017. ISSN 2673-4109.
  5. 1 2 3 4 5 6 Pue, Kristen; Morningstar, Sarah; Painter, Carla Valle; Désilets, Caroline (2025-11-27). "Scoping Review: Examining the Vulnerability of Canadians to Climate Change and the Role of the Social Protection System in Supporting a Socially Just Response". Government of Canada. Retrieved 2026-03-31.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Public Health Agency of Canada (2022-10-25). "Mobilizing Public Health Action on Climate Change in Canada". Government of Canada. Retrieved 2026-03-31.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Health Canada (2025-07-14). "Health-related morbidity and mortality in Canada". Government of Canada. Retrieved 2026-03-31.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 Barber, B.; Rainham, D. G.; Tyedmers, P.; Vandertuin, T.; Ritcey, G.; Christie, S. D. (2024). "Sage Journals: Discover world-class research". Healthcare Management Forum. 37 (5): 395–400. doi:10.1177/08404704241252032. PMC 11348628. PMID 38739689.
  9. ↑ National Collaborating Centre for Indigenous Health (2022). "Climate Change and Indigenous Peoples' Health in Canada" (PDF). National Collaborating Centre for Indigenous Health. Retrieved 2026-03-31.
  10. 1 2 3 4 5 6 7 Castleden, Heather; White, Isaac; Otaodese, Jennifer (2023). "What We Heard: Perspectives on Climate Change and Public Health in Canada". Government of Canada. Retrieved 2026-03-31.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Boudreault, Jérémie; Campagna, Céline; Lavigne, Éric; Chebana, Fateh (2025-01-01). "Projecting the overall heat-related health burden and associated economic costs in a climate change context in Quebec, Canada". Science of the Total Environment. 958 178022. Bibcode:2025ScTEn.95878022B. doi:10.1016/j.scitotenv.2024.178022. ISSN 0048-9697. PMID 39674157.
  12. 1 2 3 4 Health Canada (2025-10-09). "HealthADAPT". Government of Canada. Archived from the original on 2026-03-31. Retrieved 2026-03-31.
  13. 1 2 3 4 5 6 7 8 9 10 11 Health Canada (2022-09-12). "Climate Change and Health Vulnerability and Adaptation Assessments: Workbook for the Canadian Health Sector". Government of Canada. Retrieved 2026-03-31.
  14. 1 2 3 Health Canada (2022). "Health of Canadians in a Changing Climate" (PDF). Government of Canada. Retrieved 2026-03-31.
  15. 1 2 3 Environment and Climate Change Canada (2023). "Canada's National Adaptation Strategy: Building Resilient Communities and a Strong Economy". Government of Canada. Retrieved 2026-03-31.
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