6.2.2.e

Human Health


Human Health and the Effects of a Changing Climate

In Canada, more warm weather may sound like a pleasant change. But warming global temperatures can also change the patterns of the weather, and lead to more extreme, violent weather. With warmer temperatures, there is an increased chance of heat waves, severe cold, storms, floods or droughts. Changes in growing seasons and patterns of disease spread will require adaptation to new situations.

Different areas in Canada are affected differently by changes in temperature. The northern Arctic areas will warm faster than more southerly regions, causing the melting of polar ice and of the permafrost (the permanently frozen ground). Coastal areas will be affected by rising sea levels. Central parts of the country are more likely to experience droughts, floods, and storms. In southern cities, higher summer temperatures can increase the number of smog days and can cause heat stroke in susceptible people.

Warmer temperatures bring new conditions for new species to survive, for example the insects carrying Lyme disease.

Warmer temperatures bring new conditions for new species to survive, for example the insects carrying West Nile virus.

ACTIVITY 1

  1. What conditions allow these insects to flourish?
  2. What measures can be taken to prevent contracting these diseases?
  3. What are the percentage chances of contracting these diseases? Hint: see Ontario Health
  4. What are the symptoms of these diseases?
  5. What other tropical diseases can be expected to flourish in southern Ontario, especially with international travel?

Air Temperatures and Heat Stress

Today (2003) in Ontario, the average number of days over 35 o C is ten per year. This may increase to as many as 46 per year by the middle of the next century. This is the "urban heat island effect" - the tendency of cities to retain the sun's heat when vegetation is removed and replaced.

During extreme hot summers the death rate for the elderly increases from 7 per 100,000 to over 66 per 100,000. Under climate change the number of days that exceed the 33oC heat stress threshold could increase from between 21 to 50 days. See the graphs for predicted temperatures for Toronto.

ACTIVITY 2 Temperature and human health research:

  1. What is the average increase in Celsius degrees that indicates a fever in adult humans?
  2. What might be the effect of a 1oC fever lasting for 3 days in a newborn baby?
  3. How many degrees increase above the average human temperature generally causes humans to be admitted to hospital or lose consciousness? For example, cases of heat stroke or infection.
  4. How does the average of human temperature of 37oC compare with other animal average temperatures, such as dogs? Birds?
  5. Why do higher minimums in air temperature ranges pose more of a threat to life?

Health Concerns in Canada

Health Canada has identified 8 significant health concerns related to climate change.

  1. Temperature-related illnesses (heat and cold-caused illness, heart and lung conditions, occupational health risks)
  2. Health effects of extreme weather (injuries and illness, damaged public health services, population displacement, occupational health hazards, mental and social stress due to weather disasters)
  3. Air-pollution related effects (Asthma and other respiratory diseases, heart attacks, strokes and cardiovascular disease, changed exposure to pollutants and allergens both indoors and outdoors, cancer)
  4. Health effects from water and food-borne contamination (diarrhea/poisoning by chemical or biological contaminants)
  5. Diseases in new climate zones (changed patterns of diseases caused by bacteria and viruses carried by mosquitoes, ticks and other carrier species)
  6. Health effects from ultraviolet light exposure (skin damage and skin cancer, cataracts, disturbed immune systems)
  7. Increased vulnerability in certain population segments (seniors, children, chronically ill people, low-income and homeless people, northern residents, disabled people, people living off the land)
  8. Impacts on community health and well-being (loss of income and productivity, social disruption, increased costs for health care, health effects of mitigation technologies [e.g., use of pesticides in water to kill mosquitoes], diminished quality of life).

Source: CANADA'S HEALTH CONCERNS FROM CLIMATE CHANGE AND VARIABILITY http://www.hc-sc.gc.ca/hecs-sesc/ccho/health_story_table.htm

According to BBC News Online series Autumn 2004, humanity faces potential crises in 6 areas: food, water, energy, climate change, biodiversity, and pollution. All of these will be affected by climate change! These 6 areas of crisis will also affect Ontario and its citizens.

Impacts: increases in heat stress and air pollution, climate variability with extreme events such as storms and floods and vector, food and water borne diseases all tend to increase the number of illnesses and deaths.

Lower water levels may result in more boil water notices. Spills or small amounts of pollutants will have a greater concentration. Contamination events of pollutants that must be measured in concentrations of parts per million. See Spills - Hamilton August 2004, London August 2004

Extreme events, such as flooding, leave behind great growing conditions for moulds in buildings - whether homes or commercial or industrial complexes. Millions have been spent on solving the mould problem in school portables and homes in recent years. Insurance companies are changing their policies to deal with this new problem.

Municipalities may have to allow a sewage mix with excess runoff to lakes. Floodwaters may back up sewage lines. For example, Peterborough July 2004 had millions of dollars of damage. Infrastructures such as sewage lines and water lines in most urban centres were built around the 1950s during a period of rapid growth. They are now at capacity.

ACTIVITY 3 Research:

  1. What is the history of the St.John's Ambulance? Do you have a certificate?
  2. What emergency preparedness plans are in place in your community?
  3. Have any extreme weather related events occurred there? Hint: check the newspaper archives or ask the seniors who have lived there for decades.

A number of human health issues are associated with weather and / or climate.   Human health is closely related to weather and the many complex natural systems it affects. Projected climate change will have measurable impacts on health, both positive and negative.  Projections of potential impacts are extremely difficult to make, so the health of humans in response to climate change is highly uncertain. This means that humans should be ready to adapt, and begin planning for adaptation and ways to decrease the effects of climate change

Climate-induced health effects on water-borne diseases, effects related to extreme weather events, air pollution-related effects, heat-related illnesses and deaths, and vector- and rodent-borne diseases need to continue to be researched. Scenarios for the projected changes in climate could then be written based on the data. The precautionary principle should be applied and measures taken to adapt to or mitigate the effects.