A Warmer, More Extreme Canadian Summer: Is Above Normal the New Normal?

By Vivian Chung, Zizzo Allan Climate Law Summer Intern

Across Canada, summer has arrived early this year with projected extreme weather making national news recently.  In a changing climate, are these weather extremes the new normal?  If so, what are the implications for our health and economy?

The Globe and Mail recently published a national weather map depicting the forecast for the summer of 2012.  The map is based on an Accuweather report released last Wednesday that predicted overall “above-normal warmth for much of Canada.”  Hot and below-normal rainfall is expected for the Prairies, while a relatively higher number of thunderstorms are expected to hit eastern Ontario and southern Quebec.  Atlantic Canada is also predicted to be more susceptible to tropical systems as a result of warmer weather.

Summer National Temperature Departures and Long-Term Trend, 1948 – 2011 – Source: Environment Canada

Climate change likely has an important role in causing the forecasted rising temperatures.  Environment Canada’s senior climatologist, Dave Phillips, has offered some insight into the steady trend of warmer-than-normal Canadian weather: “It could very well be the disappearance, the vanishing of the ice at the top of the world that is having an influence on our seasons.”  The steady disappearance of Arctic ice has meant a declining Arctic influence to offset warmer Pacific waters and air flows from the south.  Increased global climate temperatures can lead to a variety of complex changes including rising ocean temperatures, more El Niños than La Niñas and increased southern air flows.

While most Canadians are enjoying the warmer temperatures, there are a number of serious negative consequences associated with extreme weather caused by climate change.  Of particular concern is the increased risk of drought and wildfire in the Prairies.  This year’s warm, dry temperatures are reminiscent of the conditions before the devastating Slave Lake wildfire that occurred last year.  Several major wildfires have already ravaged parts of the Prairies, with Manitoba experiencing the worst thus far.  National Resources Canada has also listed southern Manitoba and northwestern Ontario as having the biggest risk of wildfires this summer.  An increase in vehicle accidents is also associated with warmer weather as speeding occurs more often in fair weather, leading to more accidents.  Finally, warm air masses trap air pollutants closer to the earth’s surface, thus negatively affecting air quality and causing air pollution episodes.

These changes can impact everything from project development in the north to incidences of asthma attacks in our cities, and it looks like they will only be getting more severe and unpredictable.