The Rideau Canal Skateway in Ottawa, the world's largest natural frozen skating rink, had to close before March 1 this year, making its skating season a short 28 days; Flickr photo courtesy National Capital Commission
The Rideau Canal, which runs through Ottawa, is one of the Canadian capital's biggest attractions. During the winter, the canal becomes the world's largest naturally frozen skating rink. At nearly 5 miles, the size of 90 Olympic-sized skating rinks, it draws hundreds of thousands of skaters every year, especially during the city's Winterlude Festival, an annual three-weekend celebration in February.
But this year, the Rideau Canal closed early. Warmer temperatures meant the canal was only open for 28 days of skating this year; in the 1980s the canal averaged 40 skating days a season. It had to close before the festival concluded on Feb. 20.
"It was a shorter season than usual," said Jean Wolff, senior media relations manager with National Capital Commission. To ensure safety on the skateway, the city requires 10 to 15 consecutive days of temperatures below 0 degrees Fahrenheit to make sure there is a safe layer of ice.
"We never had that this winter. I'm not even sure we had a stretch of five days," Wolff said.
The early closure was a disappointment to festival-goers, he said. The skateway is an icon -- an important part of their cultural tradition of outdoor ice sports.
But the canal's short season is not an anomaly to Canadians. In a paper published Monday in the Institute of Physics' Environmental Research Letters, researchers determined that climate change across Canada has already had a negative impact on the outdoor skating season, and if that trend continues, the viability of outdoor skating in Canada will be threatened for future generations.
Pond hockey and outdoor skating is a popular pastime in Canada. It's not just playing on frozen lakes and canals; many families will create rinks in their own backyards. Hockey legend Wayne Gretzky first learned how to skate on a rink his father made in their backyard when he was 3 years old.
Study authors Nikolay Damyanov, Damon Matthews, and Lawrence Mysak studied data from Canadian weather stations stretching from 1951 to 2005. They interviewed city officials who managed skating rinks and other outdoor rink builders and determined that an outdoor skating rink requires at least three consecutive days of temperatures at minus 5 degrees Celsius or lower to start a skating season. They compared those requirements with the weather data to determine the number of viable skating days in each region.
The found a 20 percent to 30 percent decrease in the length of skating seasons over the past 50 years, with the biggest drops in Alberta, eastern British Columbia, and the southern Prairie regions.
It's indicative of just how hard climate change is hitting northern countries like Canada, said Matthews, assistant professor of geography at Concordia University in Montreal. Canada has experienced a warming in winter temperatures of about 2.5 degrees Celsius over the last 50 years -- that's three times the global average.
"Here it's manifesting faster and earlier. Canadian winters are vulnerable to climate change, and it's being felt at the level of a backyard rink," Matthews said.
Simon Donner, an assistant professor of geography at University of British Columbia, has also been looking at the effects of climate change on lake freezes over time. He says this new study is a simple but clever way to take existing data and combine it with our experiences to show that climate change is not just all raw data and calculations. A born-and-raised Canadian he's seen the changing winters threaten his own family's New Year's ice hockey tradition.
"One of the things about climate change is we get this impression that it's going to affect everyone else, but not us. It's happening at home too," said Donner. "The iconic tradition of pond hockey is seriously threatened."
Peter Jackson, professor of atmospheric sciences at the University of Northern British Columbia, questioned how the team defined the start of skating season.
But even among rink builders, the required temperature to start and maintain a safe layer of skating ice is debated. Because the seasonal starting temperature were determined by anecdotes instead of a controlled study, it's not clear how precisely this study can determine the length of the outdoor skating season, Jackson said.
If this trend continues, outdoor skating days in southwestern Canada could even reach zero by mid-century, although the authors of the study point out that climate model data is necessary to make more accurate predictions about the future of the outdoor skating season across Canada.
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