Climate change makes winter ice more dangerous
New research on the link between climate change and winter drowning has found that reported drowning deaths are increasing exponentially in areas with warmer winters.
The study, published Wednesday in the journal PLoS One, looked at drownings in 10 countries in the northern hemisphere. The greatest number of drownings occurred when the air temperature was just below freezing, between minus 5 degrees Celsius and 0 Celsius (between 23 degrees Fahrenheit and 32 Fahrenheit).
Some of the most marked increases have occurred in areas where indigenous customs and livelihoods require extended time on the ice. In the countries studied, children under the age of 9 and adolescents and adults between the ages of 15 and 39 were the most vulnerable to winter drowning.
Sapna Sharma, associate professor of biology at York University in Toronto and lead author of the study, said people don’t always realize how global warming increases the risks of winter traditions like skating, ice fishing and snowmobiling.
“I think there is a lag between climate change and local and everyday impacts,” Sharma said. “If you think of climate change in winter, you think of polar bears and ice caps, but not those activities that are simply ingrained in our culture. “
These ingrained habits can lead to a false sense of security, Sharma said.
“It could be minus 20 degrees Celsius today and tomorrow and on weekends, but last week it was 15 degrees Celsius,” she said. “Well, we may have forgotten as individuals that it was hot and sunny last week on a Tuesday, but the ice hasn’t forgotten. “
The absence of sustained cold, which leads to more freeze-thaw events, is crucial. Every time the ice thaws and refreezes it weakens a bit – and it can stay that way for the rest of the cold season.
“Warmer temperatures mean that the ice is not as thick or as solid as it would be otherwise,” said Robert McLeman, professor of geography and environmental studies at Wilfrid Laurier University who did not participated in the study. “And so people go there and don’t realize the ice is rotten.”
The authors compared death records and temperature data from Canada, Estonia, Germany, Latvia, Finland, Russia, Sweden, Italy, Japan and the northern United States. They analyzed about 4,000 records in total over a 26-year period, although the time period varied depending on the data available in each country.
Researchers have found that more cold-weather drownings occur in the spring, when daily low temperatures rise too much to support stable ice structures. At the same time, these higher temperatures make the time outdoors more pleasant, which means more people are spending time on the ice.
Northern Canada and Alaska have higher drowning rates, even in very cold weather. Sharma said it’s probably because people there are just spending more time on the ice. Indigenous communities close to the Arctic depend on waterways for food and travel, which means more time on the ice in winter and an increased risk of drowning.
The coronavirus pandemic could also put more people at risk.
“If this winter looks a bit like this summer,” said Sharma, “a lot of people have spent time in the cottage country in Ontario because we just can’t go anywhere. “
She said ice with standing water, slush, or holes on the surface was generally dangerous.
“Snow cover is when it gets tough,” Sharma said. “People think there is so much snow on the ice, the ice must be thick,” but snow can also act as insulation, causing the ice to melt faster.
“We, as individuals, need to adapt our decision-making,” she added, and focus on how changing winters affect rivers, lakes and streams. “It may not be as secure now as it was 30 or 40 years ago.”
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