Climate change will cause high latitude regions, like Canada, to warm drastically. With tropical heat comes tropical illnesses, and large increases in heat-related deaths.

Heat can aggravate health problems, particularly for the old, the young and the ill. For example, Montreal currently has approximately 70 annual heat-related deaths, while Toronto has 20. According to the World Health Organization, these figures are expected to climb to 460 and 290 respectively by 2020 due to climate change.

A hotter world is a sicker world

Rising average temperatures will likely extend the ranges of disease-carrying organisms like mosquitoes, rodents and bats. In 1998, drought followed by heavy rains in western North America led to a sharp increase in the population of deer mice, which carry hantavirus.

The West Nile virus has entered the United States and is moving northwards as the continent warms.

Disease-causing tropical plants have also begun migrating northward. A tropical fungus invaded Vancouver Island in 2002, killing one and injuring 52.

Global warming may also increase the risk of respiratory diseases because grasses and allergenic pollens grow more profusely in a warmer environment. A 2002 study showed that ragweed - a potent allergen producer - grew up to 61 per cent faster under conditions expected by 2050.