Risks to health from climate change

Health risks of climate change

Climate change is affecting health, and will continue to affect health in the future. People in Canada face a wide range of risks that vary from region to region because of Canada's large land mass.

The extent of these risks depends on:

how quickly our climate changes
the level of greenhouse gases emitted into the atmosphere
how well we adapt to the new environmental conditions and risks to health

Direct and indirect health risks

Climate change poses direct and indirect health risks. Direct health risks result from climate-related exposures, often associated with hazards such as:

floods
storms
air pollution events
extreme heat events, commonly called “heat waves”

Indirect health risks are related to environmental and social factors that influence how climate change affects individuals and communities. These factors can either:

decrease the impacts of climate change, or
make the impacts of climate change worse

These environmental and social factors impact:

food yields
the erosion of cultures
stresses on housing and settlements
the distribution of infectious diseases
water flows (including quality and quantity)
patterns of population migration and displacement
impacts on economic livelihoods and impoverishment

Health risks of climate change may:

last only a short time
- for example, heat illness
last months or years
- for example, mental health effects of flooding
be multi-generational or irreversible
- for example, the decline of a culture among Indigenous Peoples

We have identified key categories of climate-related risks, and the potential effects these can have on the health and well-being of people in Canada.

Weather-related natural hazards

Climate change influences the frequency and intensity of natural hazards, including:

floods
wildfires
droughts
severe storms
coastal erosion
extreme heat events

These hazards can cause:

injury
loss of life
various health problems

If they are severe enough, they often:

damage property and infrastructure
cause disruptions to communities and the economy

The health effects of natural hazards can be serious. They include:

heat stroke
psychological impacts
cardiovascular and respiratory diseases

Factors that affect whether you and your family are affected, and how badly, include:

your ability to take protective measures
your ability to recover after an event
the policies and programs in place, including health services to reduce health risks and how easy it is for you to access them

Canada has many recent examples of severe impacts from these hazards on the health and safety of people in Canada, including:

Fort McMurray fires in Alberta in 2017
flooding in Ontario and Quebec in 2018
storms in the Maritime provinces in 2021
heat waves in British Columbia and drought in the Prairies in 2021

There are effective ways to address each specific hazard. Health authorities, community organizations, municipalities, provinces and the federal government are already using many of these actions. Health authorities can use climate change adaptation to reduce health risks to populations at highest risk of harm from climate change impacts.

Water quality and security

Climate change is expected to result in changes in precipitation and temperature resulting in:

reduced water quality
changes in water quantity
increased flood and drought risks

This will put pressures on:

natural water systems (rivers, lakes and oceans), for example through algae blooms
human drinking water and wastewater systems, thereby increasing risks to the health of Canadians

The extent and intensity of these changes will vary by region and season.

Water-related health risks associated with climate change include:

threats to drinking water and irrigation supplies
increases in water-borne diseases such as:
- giardiasis
- cryptosporidiosis
- campylobacteriosis
physical injuries and mental health impacts from extreme weather events such as floods and droughts
threats to health and well-being due to the socio-economic and environmental consequences of water insecurity
impacts of from sea-level rise and loss of ice in Canada

Not all people in Canada will experience these impacts equally. Communities at greater risk include:

First Nations, Métis and Inuit communities, many of which already face water insecurity
rural and remote communities that have only basic water and sewage infrastructure

Food safety and security

Climate change increases risks of food insecurity by:

rises in food prices
negative nutritional effects
disruptions to food systems

Precipitation, temperature, and extreme weather events are projected to increase the introduction of pathogens (living things that cause disease) to food that can cause illness. These pathogens may be viruses, bacteria or parasites.

Floods and droughts may introduce chemical contaminants that have harmful health effects into Canada's food systems.

Not all people in Canada will experience the impacts of climate change on food security and food safety equally. Communities more likely to experience the most severe effects include:

Indigenous Peoples
those in Canada's Northern region

Climate change is affecting Indigenous food systems and contributing to declining availability, accessibility and quality of traditionally harvested foods. Such foods play an important role in community and individual health and well-being. Climate change has already affected nutrition, mental health outcomes and food sovereignty in many Indigenous communities.

Indigenous food security must be understood within the context of historical and ongoing colonialism. Indigenous self-determination and the gendered and intergenerational transmission of Indigenous knowledge are central to Indigenous food security and sovereignty and needed adaptation actions.

Air quality

Climate change is closely linked to air quality. Climate change is affecting air quality in Canada, and several air pollutants contribute to climate change. Exposure to air pollution increases the risk of health problems.

A warming climate is expected to worsen air quality levels in Canada. For example, climate change will:

increase the frequency and severity of wildfires
- wildfire smoke is one of the most significant climate-related risks to air quality in Canada
affect airborne allergens such as pollen by:
- increasing pollen counts
- extending pollen seasons
- expanding the geographic distribution of plant species

Climate change can also affect indoor air quality when:

high levels of outdoor air pollutants get into buildings
mould grows following extreme weather events, such as floods

People at increased risk of health impacts related to air pollution due to climate change include:

seniors
children
Indigenous Peoples
those living in high air pollution areas
those with pre-existing conditions such as asthma or cardiac disease

Reducing greenhouse gas emissions can have health benefits related to improved air quality.

Mental health impacts of climate change

Climate change increases risks to the mental health and well-being of many people in Canada. Short-terms hazards that can affect mental health include:

floods
wildfires
hurricanes
extreme heat events

Longer-term events that can affect mental health include:

drought
sea-level rise
melting permafrost

Knowledge and awareness of climate change threats can also affect mental health, resulting in emotional and behavioural responses such as:

fear
grief
anger
worry
anxiety
hopelessness

Mental health impacts of climate change may include:

worsening of existing mental illness such as psychosis
new-onset mental illness such as post-traumatic stress disorder
mental health stressors such as grief, worry, anxiety and vicarious trauma
a lost sense of place, which refers to the perceived or actual detachment from community, environment or homeland

Impacts can also include:

lack of community cohesion
disruptions to psychosocial well-being and resilience
disruptions to a sense of meaning in a person's life

These impacts can result in:

distress
higher rates of hospital admissions
increased suicide ideation or suicide
increased negative behaviours such as:
- violence
- aggression
- substance misuse

Specific groups at higher risk for the mental health impacts of climate change include people experiencing health inequities based on:

age
race
ability
culture
gender
geographic location
socio-economic status

Page details

Date modified:: 2022-11-07

Language selection

Search