The health effects of climate change

Climate change is a shift in weather patterns that is directly or indirectly caused by human activity. Climate change has an impact on the health of the population, notably by changing the composition of the air we breathe and influencing the temperature and frequency of certain weather events. They are in addition to natural climate change. 

Numerous effects of climate change can already be seen in Québec:

• An increase in the frequency of extreme weather events:
  • Heat waves (such as those experienced in southern Québec during the summer of 2010)
  • Periods of drought
  • Heavy rainfall
  • Floods (such as those experienced in the Montérégie in 2011)
  • Tornados
  • Forest fires
• The disappearance of permanent sea ice in the Arctic Ocean during summer
• The thawing of frozen subsoil (permafrost) in northern Québec, causing soil instability and numerous problems with buildings and infrastructure

Some effects of these climate changes are already observable in Québec and affect the public health. However, there are many steps that can be taken to prevent health problems associated with climate change.

Climate change can worsen chronic diseases:

• Diabetes
• Respiratory illnesses
• Cardiovascular disease
• Cerebrovascular disease
• Kidney disease
• Neurological disease
• Mental illness

It can also cause death due to complications. 

Heat waves are more frequent with climate change and can cause several health problems, varying from discomfort to dehydration.

These problems particularly impact:

• Children
• Seniors
• People with reduced autonomy
• People with chronic diseases

To learn more, read The effects of oppressive and extreme heat.

Floods caused by a significant accumulation of rain can increase the risk of injury and drowning. They can also cause various health problems: 

• Carbon monoxide poisoning due to poor use of combustion appliances when there is no electricity
• Gastroenteritis due to the consumption of contaminated food and water
• Respiratory problems due to mould
• Psychological problems:
  • Stress for victims, but also for the volunteers and workers who support them
  • Depression and post-traumatic stress disorder

In times of drought, some basic foods can be hard to find and therefore more expensive. Given the increased cost of groceries, it can be difficult for some people to buy the nutritious foods needed to maintain good health. Severe droughts are also a significant source of stress for agricultural workers.

Polluted air that accumulates over cities (smog) can affect many people, even if they are healthy, including children and joggers and other athletes.

Smog can cause:

• Irritation of the respiratory tract
• Cough
• Shortness of breath
• Breathing problems 

Climate change causes a rise in temperature and humidity, which increases the concentration of pollen in the air. Pollen is an allergen that causes seasonal rhinitis (hay fever). This allergic reaction can lead to several complications:

• Chronic sinusitis
• Symptoms of allergic asthma, such as coughing
• Difficulty breathing
• Wheezing

Climate change fosters the displacement of populations of animals, insects and ticks that carry diseases that are transmissible to humans. In Québec, such displacement increases the number of cases of:

• Rabies
• West Nile virus (WNV)
• Lyme disease

The increase in average temperatures in Québec caused by climate change also influences our behaviour. By spending more time outdoors, many people are increasingly exposed to the sun’s ultraviolet (UV) rays. This can lead to the following consequences:

• Sunburns
• Burns, sometimes up to second degree
• Premature aging of the skin (wrinkles)
• Brown spots on the skin
• Damage to eyes, such as cataracts
• Weakening of the immune system
• Skin cancer

• Mon climat, ma santé  (My Climate, My Health)
  Institut national de santé publique du Québec (in French only)
• Mon climat et moi  (My Climate and I)
  Fondation Monique-Fitz-Back (in French only)