Climate Change and Health and Well-Being: A Policy Primer

First Annual Science and Policy Research Conference (March, 2001)

Sound adaptation policies should be based on sound knowledge of the impacts of climate change, the vulnerability and sensitivity of Canadians to it and existing options for adaptation that are effective in reducing the risks. If Canada is to develop effective public health policies and strategies that will help its citizens to cope with climate change, Canadian researchers and policy-makers need to assess now the likely public health implications of climate change and variability at the national, regional and local levels.

As highlighted in the above chart, Health Canada has identified eight health and well-being issues, and their related vulnerabilities which need to be assessed to protect the health of Canadians from the possible effects of climate change. As part of this effort, in March 2001, Health Canada hosted, in partnership with the Canadian Climate Impacts and Adaptation Research Network (C-CIARN) of Natural Resources Canada, the First Annual National Health and Climate Change Science and Policy Research Consensus Conference involving a wide spectrum of national and international researchers and policy analysts. By identifying current gaps in knowledge the conference produced a climate change and health research agenda to guide future scientific efforts. Additional future climate change and health & well-beingconferences on research and policy will enhance the ability of all jurisdictions in Canada to address the risks to the public associated with climate change.

To provide adequate opportunity for discussion and analysis, the Policy and Planning Conference (September 5-7, 2001) focused on a limited number of health concerns including air pollution, water and food-borne contaminants, infectious diseases and vulnerable populations. For this reason only the results from the Research Conference related to these specific issues are provided below. The other health and well-being concerns related to climate change including temperature-related morbidity and mortality, the health effects of extreme weather events, stratospheric ozone depletion and increased exposure to ultra-violet radiation, and the socioeconomic impacts on community health and well-being will be the focus of future workshops and conferences.

Research Conference Results:

Health Concern: Air pollution

In urban environments, the formation of secondary air pollutants, such as ground-level ozone is enhanced at high temperatures. Climate change could accelerate the atmospheric chemical reactions that produce secondary air pollutants. As well, smog concentrations are highest on hot, sunny days when its components (ground-level ozone, NO^x and VOCs) react in sunlight. This is due in part to higher temperatures that increase evaporation of volatile liquids such as gasoline and organic solids.

An increase in asthma, allergic disorders, and cardio-respiratory diseases could result from climate-induced changes in the formation and persistence of pollen, spores and other air pollutants. Climate change may also affect the amount of time which individuals spend indoors, thus resulting in changes in exposure to indoor air pollutants and allergens. The trend towards more tightly sealed buildings and energy conservation measures has been followed by an increase in the number of complaints related to indoor air quality.

Key research gaps related to this health concern include the need for comprehensive information on the health implications of measures to mitigate greenhouse gas emissions. (e.g., indoor air quality in energy efficient homes) and longitudinal population health studies to determine objectively the impacts of climate change and the value of mitigation strategies. We need to know whether the expected higher temperatures might help to produce more smog, or more biologic air contaminants such as pollens or mold spores, and how this might affect human health.

Health Concern: Water and food-borne contamination

Climate change and weather variability in Canada pose threats for water-borne diseases, some food-borne diseases and marine and coastal issues, including harmful algal blooms and ecological disruption. Changes in precipitation, temperature, humidity, salinity, and wind have a measurable effect on the quality of water used for drinking, recreation and commerce. Heavy rainfall has been associated with water-borne disease outbreaks in Canada such as that at Walkerton, Ontario.

Temperature also influences the occurrence of bacterial agents, toxic algal blooms (red tides), and survival of viral pathogens that cause shell-fish poisoning. In addition, any existing deficiencies in watershed protection and storm drainage systems can increase the risk of contamination events if rainfall increases as projected with climate change.

Key research gaps related to the water and food-borne contaminants health concern include the need for increased knowledge and understanding of the contaminants or pathogenic agents in food and water as well as improved knowledge of the impacts of climate change on food and water production. In addition, there is a need for identification of regions and sub-populations potentially more susceptible to food and water-related illnesses because of climate change (e.g., urban, coastal and northern areas, First Nations peoples, elderly, immuno-deficient persons). Increased communication between government agencies and other researchers to avoid duplication of effort and keep the public informed is also required.

Health Concern: Vector-borne infectious diseases

Vector-borne diseases result from infections transmitted to humans and animals by blood-feeding insects, such as mosquitoes, ticks, and fleas. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. For example, St. Louis encephalitis outbreaks in the have been associated with a pattern of warm, wet winters, cool springs, and hot dry summers.

Rodent-borne diseases are less directly affected by temperature. However, the impact of weather on disease-carrying rodent populations (for example, increased food supply or exposure during flooding) can affect transmission of diseases such as hantavirus and flea-borne plague.

Key research gaps related to this health concern include the need for a baseline of data and other information through integrated multi-disciplinary approaches to track disease trends. There is also a need for improvement of research and methods to address the identification and control of vector-borne diseases and to understand the interactions between vectors and their environment. Also, public health measures need to be enhanced for the identification of vector-borne diseases and for vector and disease surveillance and control.

Health Concern: Population vulnerabilities in cities and communities

Elderly : The elderly constitute one of the sub-populations that is increasing in sizes and that is particularly vulnerable to the effects of climate change. Aging is often accompanied by chronic illnesses that may increase susceptibility to infectious diseases or to extreme health and other environmental conditions (e.g., smog, water contamination). Poverty, which increases with age among the elderly, may add to this group';s risk from severe weather.

Children : Children are one of the sub-populations that is particularly vulnerable to the effects of climate change. (e.g., increased smog, water contamination, infectious diseases, etc). The factors that may affect children';s special vulnerability to possible future climate change include poverty, access to medical care, and children';s susceptibility to environmental hazards because of their size, behavior and the fact that they are growing and developing.

Low- Income Individuals : Poverty is a risk factor for heat-related illnesses and deaths because low-income individuals are more likely to live in urban areas (where summer temperatures are often highest), are less likely to be able to afford air-conditioning systems, and may have less access to health care.

Immuno-compromised Individuals : Many illnesses such as cancer, AIDS, and diabetes, compromise immune systems. Individuals affected in this manner may be more susceptible to water-borne and vector-borne diseases and to physical stresses, such as those experienced during heat waves or floods. Adequate protection from those stresses is important and includes access to air conditioning, sanitation, and safe drinking water.

Aboriginal Populations : Many Aboriginal people live in Canada';s North which is expected to experience great climatic changes over time. Many communities in the North may be highly vulnerable to the effects on human health & well-being from environmental disruptions such as a loss of wildlife and other resources. The needed financial, technological, institutional and knowledge based resources for rapid adaptation are quite limited for many of these communities. Such vulnerabilities are also shared by Aboriginal populations living in other locations in Canada.

Key research needs related to the issue of vulnerable populations include development of a comprehensive approach to identify and address climate change impacts and adaptation problems facing vulnerable populations. In addition, standardized data collection is needed so that a baseline can be established to determine the relationship between weather and health and who is vulnerable. Specific priority research questions also exist including: What will vulnerable communities look like in twenty to thirty years? How will future environmental changes affect the social and economic disparities that exist today? What health indicators do we need to explore the relationships between climate change and health & well-being? Who is best qualified to assess the impacts of environmental change on population health and well-being?

The results of the Climate Change Science and Policy Research Consensus Conference are being used by various research funding agencies in Canada to formulate research proposals. The products of this research will then be available to public health decision makers in Canada, in their collaborative efforts to address the risks to human health & well-being from climate change.