Scientific projections indicate that climate change could affect the health and well-being of Canadians both directly and indirectly.

• There are two types of direct health effects of climate change. The first are those caused by projected higher temperatures. Examples include increases in illness and death from heat stroke and dehydration. The second are injury, illness and death caused by projected increases in extreme weather, such as tornadoes, floods and winter storms.
• Climate change could also have significant indirect health effects, as changes in climate trigger other changes that could affect health. An example would be the transmission of infectious diseases such as malaria, dengue and yellow fever as insects carrying diseases migrate northward into the Canadian climate.
• Another potential indirect health effect of climate change is increased illness related to air pollution. Fossil fuel use produces two main greenhouse gases (GHGs): carbon dioxide and methane, neither of which directly cause air pollution. However, fossil fuel use also produces other by-products which do cause air pollution, such as smog. As well, increasing temperatures anticipated with climate change can serve to magnify the effects of pollutants already in the air.
• Children, the elderly, and people suffering with cardio-respiratory problems, are at highest risk of experiencing adverse health effects due to air pollution even at today's levels. Projections of more frequent and severe heat waves due to future climate change indicate that this air pollution problem may worsen.
• It is projected that many larger Canadian cities could expect to experience a significant rise in the number of very hot, smoggy days, with more and longer heat waves. This increase in hot weather, combined with an aging population, is expected to result in an increase in heat-related deaths in urban centres.
• Projections of more frequent and severe heat waves and humidity could lead to increases in smog and air pollution advisories. Increases in pollens and mold spores would compound the situation and affect those with cardiovascular disease, respiratory disorders such as asthma, emphysema and chronic bronchitis, and allergy problems.
• Trees and other vegetation that give rise to allergenic pollens grow more profusely in a warmer climate. When combined with smog and other atmospheric pollutants, illness from allergic respiratory disease, particularly asthma, could increase.
• Projections of frequent and extreme weather events such as floods, droughts, hurricanes, and tornadoes are of concern as these could increase deaths, injuries, infectious diseases (with contaminated run-off affecting water supplies) and stress-related disorders associated with social disruption and environmentally forced migration.
• The quality and the quantity of drinking water could decrease as water sources in some areas become threatened by drought. Health disorders related to environmental and water contamination by bacteria, viruses, protozoa and parasites could also increase.
• Many Aboriginal communities that follow a traditional diet based on hunting, fishing and other resource-based activities, could be vulnerable to health problems due to predicted changes in the amount and distribution of wildlife, fish and vegetation.
• The projected health-related effects of climate change and the need for various adaptation strategies, such as expanded vigilance and medical services, health monitoring, environmental management, disaster preparedness and improved water and pollution control, could add to Canada's health care costs. With research, planning and preparation, some projected impacts of climate change can be minimized.
• The consideration of costs/benefits related to the health of Canadians is an important component in developing the federal government's strategy on climate change and needs to be an integral part of the decision-making process undertaken by governments and stakeholders.
• Improved health can be one of the benefits of taking action to mitigate climate change and there are tangible ways for Canadians to help reduce GHG emissions. At times, it means changing our lifestyle. Driving less is one part of the solution. By walking or cycling more often instead of driving, we reduce greenhouse gas emissions, benefit from more physical activity and eliminate stress in a healthy way.

1 Various sources, including Health Canada, Environment Canada and the David Suzuki Foundation.

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