Comment les changements climatiques modifieront-ils notre santé?

Les sécheresses dans certaines parties du Canada pourraient bien causer de sérieuses répercussions sur l'agriculture locale ainsi que sur le mode de vie et les ressources des personnes affectées.  De telles perturbations ont des effets à la fois sur la santé physique et mentale. Et ceci n'est qu'un exemple parmi d'autres. 

La compréhension de ces effets sur la santé et le développement de nouvelles politiques pour nous protéger des vagues de chaleur, des tempêtes de verglas, ainsi que des nouvelles maladies devraient être des composantes essentielles de notre système de santé. 

Bien que le Canada ait planifié que la production des émissions des gas à effets de serre serait réduite, notre climat va continuer à changer et présentera encore des défis pour de nombreuses années.

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can carry
West Nile Virus  

How Will a Changing
Climate Affect our Health?

Barbara MacKinnon
Director of Environmental Research
New Brunswick Lung Association
April 2003

e have had a long, cold, snowy winter here in New Brunswick, and you may have heard at least one person say, "What about Global Warming? Bring it on!"

(photo: NB Lung)

Although the globe as a whole is expected to get warmer, a few places might even get cooler. The reality is that a change in our normal climate is likely to give us unusual weather, such as more severe and more frequent storms, more droughts, and unusually cold or unusually mild winters. These changes will have effects on our health.

In over-simplistic terms, climate change is expected to increase illness and death from familiar causes and increase the likelihood of unfamiliar health outcomes.

Heat waves

Many parts of Canada are predicted to have more hot days (technically, days over 30 C) each summer. This will have serious consequences for infants, the elderly and people with lung and heart diseases. The number of heat-related deaths is expected to increase. People living in urban areas, especially in houses with inadequate air conditioning, are vulnerable because buildings and pavement trap heat. The positive side of temperature change is that winters may become warmer in some locations, reducing the number of deaths from hypothermia.

Air Pollution

Most of our production of greenhouse gases is from the burning of coal, oil and gas in our power plants, industries and vehicles. These actions also produce thousands of tonnes of other pollutants that go into the air every year. Even though you often cannot see these pollutants, they can seriously affect your health. Exposure to these pollutants decreases the ability to breathe for people who have lung and heart diseases. It can trigger asthma attacks, cause heart attacks, lead to cancer, and it can cause premature mortality. A study conducted by the Toronto Department of Public Health indicated that almost 2000 people a year die in Toronto from air pollution (Basrur, S.V. 2000. Illness Costs Of Air Pollution. Toronto Public Health.) could put this reference below in a list of references, in which case you would put (Basrur, 2000).

In many locations in Canada, hot weather goes hand in hand with elevated levels of air pollution. In New Brunswick, our warm winds blow to us from the central United States and Ontario regions. These regions also have the most power plants and heavy traffic routes so our warm winds carry pollution. As climate change results in more hot days, we will also have more days with high levels of pollution. Hotter temperatures also increase the chemical reactions that form some air pollutants such as ground-level ozone. As well, it is likely that people will turn up their air conditioners, thus increasing the emissions from power plants. These factors combine to mean that we can expect more air pollution during hotter days in the summer.

(Source: Gordon McBean, Institute for Catastrophic Loss)

Changes in the distribution of plants and animals

A warming climate and changes in precipitation patterns will also affect the distribution of plant and animal species other than humans. These changes in geographical distribution could have a variety of effects on humans, from changing the types of plants that can be grown for food or for commercial uses, to increasing our exposure to certain diseases (West Nile virus, Lyme's Disease) carried by animals extending their range northward.

Storms and droughts

Climate change is expected to result in more frequent and more violent storms. In the winter, severe ice storms can result in injuries and death from hypothermia, carbon monoxide poisoning from using inappropriate heating sources indoors or heart attacks from over exertion while removing ice or snow. Hurricanes can cause injury from damage to homes or falling trees, or even from drowning during sudden flooding. Although certain areas may receive increased annual rainfall, this rain may fall during more extreme storms and wash away valuable topsoil, causing more damage than benefit.

According to the Institute for Catastrophic Loss at the University of Western Ontario, "more than four million Canadians have been affected by natural disasters in the last three years. The loss of life and property from events like the 1996 Saguenay flood, the 1997 Red River flood and the 1998 ice storm in Quebec all warn about Canada's growing vulnerability."

Droughts in certain parts of Canada may seriously impact local agriculture and thus peoples' livelihood and food resources. Both physical and mental health are directly impacted by these factors.

(Source: Gordon McBean, Institute for Catastrophic Loss)

Rising sea levels

Sea levels in eastern Canada may rise by about half a meter over the next century, in part due to melting ice caps and in part because the land mass is very slowly sinking. Higher sea levels together with more frequent and severe storms may cause low-lying areas to be inundated with water and coastal erosion to occur. Fresh water resources of coastal communities may be contaminated by salt water. Health impacts related to this include increased risk of drowning and stress from loss of income from coastal investments and businesses.

Population displacement

Changes in temperature and precipitation patterns as well as rising sea levels may make certain parts of the world uninhabitable. People now living in places expected to be impacted by rising water or drought may see New Brunswick as a safer place to live. An increasing immigrant population may tax our health care system.

Northern Canada is particularly vulnerable to impacts of climate change. Already the melting ice cap is causing homes to sink into the softening permafrost and winter roads to be impassable. The resulting socioeconomic impacts may well have significant impacts on the mental and physical health of aboriginal communities.

According to the Intergovernmental Panel on Climate Change, it is important to recognize that certain factors can modify the vulnerability of a particular population to the health impacts of climate change or variability. The sensitivity of a population depends on factors such as level of urbanization, access to air conditioning, and overall health status of the population. The federal government is encouraging research on the impacts of climate change on Canadians by supporting research networks across the country, called the Climate Change Impacts and Adaptation research Networks (C-CIARN). The Health networks are coordinated by the Climate Change and Health Office of Health Canada. Although Canada has plans to reduce our production of greenhouse gases to help slow down climate change, our climate is expected to continue to change and present challenges for many years. Understanding the health impacts, and developing new policies to protect us from heat waves, ice storms, and new diseases are essential components of the new health care system.

More detailed information on all of these topics can be found on the website of the Intergovernmental Panel on Climate Change, www.ipcc.ch.