"It is extreme events that will be the biggest impact on Canadians from climate change."
Dr. Gordon McBean, Assistant Deputy Minister, Meteorological Service of Canada

Most Canadians would happily take the edge off a bitter January night by raising the temperature a few degrees. In that light, global warming sounds fine - what harm could it cause, besides a decline in thermal underwear sales?

As it turns out, plenty.

Severe winter storms:
Since the mid 1970s, the frequency of severe winter storms in Canada has nearly doubled. Models predict that future winters will boast fewer weak storms, but increasing numbers of very severe storms. This means more travel disruptions, more property damage and more accidental deaths.

Downpours:

In the USA, heavy one-day rainfalls have become 20% more common over the past 90 years. These cause flooding of city streets, sewer overflows, erosion, flash floods and landslides, without the benefits of recharging reservoirs or alleviating drought. Canadian models suggest that within 50 years, heavy one-day rainfalls will become twice as common as they are today, and are also likely to become 50% more intense.

Heat Waves:
Both the frequency and length of heat waves are expected to increase in most parts of Canada. Temperatures which have been "extreme" for generations will become "normal".

As an example, the number of days with temperatures over 30ºC in London, Ontario is expected to rise from 10 days per summer to about 50 days per summer by 2050. August in the Toronto of the future will probably be much like that of Kentucky today.

These periods of intense heat will amplify smog, already a significant cause of death (see Pollution Worsens) and heat-related death tolls will spiral upwards.

Hail:
In Calgary the average frequency of large hailstorms (hailstones greater than 20 mm) has increased eightfold, from one every four years in the 1980s to two per year in the 90s. As the frequency of hail-generating thunderstorms is expected to increase dramatically, so will the damage to cars, buildings, and agricultural crops.

Tornadoes:
An increase in warm, moist lower atmosphere conditions will spawn large tornadoes more frequently - such as the recent event that devastated Pine Lake, Alberta. Central Alberta, southern Ontario and the Ontario/Quebec border will probably experience the strongest rise in these violent events.

Wildfires:
Over the past several decades, the area of Canadian boreal forest affected by fire and insects has doubled. Although there are complex factors involved, the greatest increases so far have been in the regions of greatest warming. Continued warming will produce greater seasonal contrasts which, in concert with an expected 44% increase in lightning strikes, is expected to increase the area burned by 78% in the next 50 years.

 

 

Unconventional Catastrophes:
The Ice Storm of 1998 was a taste of the nasty surprises climate change could hold in store for Canada. It was not a severe storm in normal terms - in fact, the scene on the ground was a peaceful, gentle drizzle. It was the incredible duration and extent of the drizzle that made it, at a total of $3 billion, the most costly natural disaster in Canadian history.

Why would global warming make an ice storm?

There is good reason to believe that the Ice Storm, which generated ice twice as thick as had ever been recorded before in the region, would not have been possible without the 1997-98 El Niño The El Niño Connection. This unprecedented El Niño, in turn, was probably born of climate change.

The El Niño produced an unusually strong jetstream across the southern US, which then swung up to carry a long train of warm, moist air masses to eastern Canada. At the same time, a shallow layer of cold air crept down from Labrador and stalled in the St. Lawrence Valley. The warm air rode up on top and dropped rain into the cold surface air, so that it froze on contact with the ground. The stability of the El Niño-driven jetstream maintained what would normally have been a shortlived scenario for many days - turning a rainy afternoon into a week-long multi-billion dollar disaster.


As global weather patterns continue to change, bizarre weather - like that which caused the ice storm - will become more common. New weather patterns, combined with other climate change impacts (such as sea level rise and rapid snowpack melts), will generate unexpected new types of disasters.

And as the disasters mount, so do their price tags.

Extreme Economic Impacts