Change the climate and you change the weather

Change the climate and you change the weather

A view from the public sector
May 1, 2006

It’s been said that 2005 was the year Mother Nature was mad at the world. We started the New Year in shock from the deadliest tsunami in modern history and ended it still cleaning up after Hurricane Katrina—the costliest storm ever. We were awed by the power and force of nature and quietly thankful that we live in Canada—not immune to nature’s wrath but seemingly protected this time around.

Canadians are spared from the world’s worst weather—in fact, Canada doesn’t hold any of the world’s weather records. However, we still get our share of weather misery. For the past 10 years, I’ve put together an end-of-the-year review of Canada’s top weather stories. A decade is too short a period to detect a trend, but sufficient time to note some recurring events. What a decade it was! No part of the nation seemed to escape the whims of the weather gods. It was truly the stuff of Hollywood blockbusters. We endured flash floods, weather bombs, hailers, humongous snowstorms, burning infernos, and disastrous droughts. Coincidentally or not, it was the warmest decade on record. Six of our warmest ten years in half a century have occurred since 1998. And, it was consistently warm, with 34 of the past 37 seasons being warmer than usual.

The decade of meteorological mayhem began in Quebec in 1996 with the Saguenay flood, Canada’s first billion-dollar disaster. No one could forget the infamous ice storm of 1998, least of all the four million people in Ontario and Quebec who endured the most destructive and disruptive storm in Canadian history. Nova Scotia residents experienced three “50-year” storms in less than 12 months during 2003-2004, highlighted by Hurricane Juan’s direct hit on Halifax. Not to be outdone by the East Coast, in 2004, British Columbia featured a year-long parade of weather disasters beginning with destructive wind storms and deadly avalanches, followed by a summer of fire, an autumn of floods, and an early winter with record rains. And for Alberta, for much of the decade, it was either too much rain, leading to the province’s costliest weather disaster, or too little rain and the province’s costliest climate disaster. Add to that the Pine Lake tornado—the fourth worst killer tornado in Canadian history.

I continue to be amazed and thankful that so few Canadians die from the ravages of severe weather. It’s not that we have a gentle climate. That we have a modern weather service and a responsive emergency program across the country are important, but Canadians are also experienced in weather matters, educated about weather safety, and have a deep respect for the power of nature. A century ago, six times more Canadians died from weather than today.

Of concern to everyone should be the higher incidence of flash flooding in our cities. Our experience with flooding is mostly inundation from ice jamming and snow melting—usually giving us enough time to move out of harm’s way. Recently though, we have been swamped by “American-like” flash floods with too much rain in too short a time. In two examples from Ontario, both storms had rainfall intensities exceeding those of Hurricane Hazel, the province’s designer storm. In July 2004, a stalled weather system dumped between 100 and 240 mm of rain on Peterborough. It proved too much for the city’s drains and sewers—some built a century ago. Few cities in North America could have handled the phenomenal 14 billion litres of water in five hours that overwhelmed Peterborough’s downtown. That’s enough water to fill almost nine SkyDomes. It was one of the wettest days ever in Canada (at least, east of the Rocky Mountains) and estimated to be a one-in-200-year occurrence for Ontario. On August 19, 2005, a line of severe thunderstorms swung eastward across southern Ontario from Kitchener to Oshawa, dumping 80 to 180 mm of rain across the northern half of Toronto. In its wake, the storm left a trail of damage exceeding $500 million—the greatest insured loss in the province’s history, and the second largest loss in Canadian history, according to the Insurance Bureau of Canada.

All this meteorological mayhem; is it a fluctuation or a trend? A bit of tough-weather luck or a preview of what’s to come? Few question that climate is changing faster and greater now than in a very long time. Temperatures in Canada have risen twice as much as the Earth as a whole and in half the time. But, climate is and has always been changing! More importantly, is the change resulting in more extreme weather? The meteorological record is suggestive about that but not conclusive. Scientists can’t say with full certainty that extremes of weather are on the rise, or that they are more intense or last longer than in the past. (If that were the case it would be consistent with our expectations of climate change). However, what we do know is that the world is becoming a more dangerous place to live. The number of weather-related disasters has increased dramatically in Canada and around the world. While we don’t know for sure that the weather has changed, what we do know is that we have changed! Our attitudes, clothes, building materials, where we live, what we drive, and how we spend our leisure time have all changed. What we are now seeing in all parts of the world is that weather extremes appear to be having a much greater impact on both our society and the environment. At times, I think that we have changed more than the weather! Regardless of climate change, we are becoming more vulnerable to weather’s vagaries and its extremes. As the world’s population rises, we are crowded together more than ever. Canada’s population density of three people per square kilometre is one of the world’s lowest, yet we are among the most urbanized people, with nearly 85 percent living in communities of 10,000 or more. Not surprisingly, we are becoming greater targets for weather extremes.

Too many Canadians are living in highly exposed areas: flood plains, low-lying coastal zones, and steep mountain regions. In these places, it is not just a matter of the changing climate but also changing land use. As more development occurs, our susceptibility to severe storms increases. And at the same time, spending on infrastructure has declined as a percentage of GDP—a worrisome trend indeed. Instead of increasing our protection against a changing climate and the more volatile weather that will likely come with it, we are exposing ourselves to greater and greater risk. Even without climate change, the weather hits of the past are becoming major blows today. Our society doesn’t seem to be coping well with the climate we’ve got now, let alone the climate we will get. As soon as a disaster occurs, we move quickly to clean-up and get on with our lives. Soon, we forget what happened, comforted by the fact that we survived the “Storm of the Century” and are presumably safe for the next 99 years.

When we look back over the last 100 years, we expect the weather to be more or less what it has always been. But now, because our climate is changing so quickly, the past 10 years may serve as a better guide. This past decade provides ample warning that Canadians, rather than being immune to the ravages of weather, are instead becoming increasingly more vulnerable. Today’s weather extremes may be tomorrow’s norm.

David Phillips is a Senior Climatologist at Environment Canada.

The views and ideas expressed in this column do not necessarily reflect those of the Canada Foundation for Innovation or its Board Directors and Members.