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Attributed and Expected Effects of Global Warming

The predicted effects of an increase in global average temperature for the environment and for human life are numerous and varied. Some phenomena are already being attributed at least in part to global warming, such as glacier retreat, ice shelf disruption (e.g. Larsen Ice Shelf), rise in sea level, changes in rainfall patterns, increased intensity and frequency of hurricanes and extreme weather events. Other possible eventual effects include: reductions in the ozone layer, spread of diseases such as malaria and dengue fever and mass extinction events.

Canadian Consequences

The full eventual impact of global warming on Canada is of course still uncertain and speculative at this point, but here are some possible consequences of global warming on the individual provinces:

  • British Columbia and the Yukon may see a rise of sea levels along the north coasts. The result may be increased sedimentation and coastal flooding. Low-lying homes, docks and port facilities will be at risk. Summer droughts along the south coast and southern interior of British Columbia may result in decreased stream flow, lower fish survival, and a reduction of water supplies in the dry summer season.
  • The Prairies could see increased air temperatures and decreased soil moisture, as well as an increase in the frequency and length of droughts in semi-arid regions, and average potential crop yields could fall by 10-30%. However, higher temperatures could lengthen the growing season and increase crop production in northern regions.
  • Ontario could see a 3-8C average annual warming by 2100, resulting in fewer weeks of snow, a longer growing season, less moisture in the soil, and an increase in the frequency and severity of droughts, and an increase in the frequency and severity of forest fires as a result.
  • The province of Quebec could also see temperature increases, and lower water levels in the St. Lawrence River which would affecting shipping, navigation and the marine environment. Initial positive effects on agriculture would be a longer growing season and the extension of agriculture further north.
  • Rising sea levels in the Atlantic provinces could result in greater risk of floods, coastal erosion, coastal sedimentation, and reductions in sea and river ice. Loss of fish habitat and changes in the range, distribution and breeding success rates of seabirds.
  • In the Canadian Arctic, future winter temperature increases of 5-7C over the mainland and much of the Arctic Islands and modest cooling in the extreme eastern Arctic are projected. Summer temperatures are expected to increase up to 5C on the mainland, and 1-2C over marine areas. The Arctic could witness a decline of the tundra and taiga/tundra ecosystems and more than one half of the discontinuous permafrost area could disappear resulting in short term surface instability. Many species of fish and streams may shift northward, and High Arctic Peary caribou, muskoxen and polar bears run the risk of extinction.
Polar bear on ice floe

In 2005, scientists found - for the first time - evidence that polar bears are drowning because climate change is melting the Arctic ice shelf.

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