Climate change is affecting lakes in the northern hemisphere, new research has shown.
Study, published in the journal Geophysical Research Letters, examined 122 lakes from 1939 to 2016 in North America, Europe, and Asia and found that ice-free years became more than three times more common than 1978.
This year, ice-free not only threaten the livelihoods of people who depend on them, but also have the potential to cause profound environmental impacts.
“Ecological ice acts as a reset button,” said Sapna Sharma, co-author of the study and associate professor in the Department of Biology at York University in Toronto.
“In years when you don’t have an ice cover, water temperatures are warmer in the summer. Algae are more likely to bloom, some of which may be toxic. And that can really affect spawning time and affect fish populations under ice.”
There are also concerns in the Arctic, where warming is happening three times faster than anywhere else in the world. And with more warming, there is more and more melting of permafrost, which can affect water quality in northern communities.
“One has an impact on the hydrology of the region,” said Claude Duguay, a professor at the University of Waterloo and university chair for the cryosphere and hydrosphere from space who was not involved in the study.
“When you get to the catastrophic drainage of these lakes, they naturally disappear. And they won’t necessarily reform when we get to higher temperature conditions. The impact of communities can be on food safety. So you think about traps, hunting, fishing, and water availability for communities. “
Of the world’s millions of lakes, the study suggests that more than 5,000 of them could be ice-free by the end of the century.
The authors found that ice-free years were more common in the second half of their study period. Although before 1978 there were only 31 events without ice, and after that year there were 108.
One of the oldest records of lake ice is that of Lake Suwa near Nagano in Japan, dating from 1443 and guarded by Shinto priests. The study found that instead of freezing annually, it now freezes on average twice a decade.
“In the next 10 years, it may be the last time the lake will ever freeze again,” Sharma said.
The authors say these changes in the lakes will continue for decades as the planet warms due to the continuous release of greenhouse gases into the atmosphere.
The most endangered are lakes that are deep because they find it harder to create ice, especially the Great Lakes, Sharma said.
And it’s not just a matter of water quality; it is also about quantity, she noted. Ice helps reduce the rate of evaporation, so without this essential ice cover the rates of evaporation can increase and decrease the amount of fresh water available.
Alex Mills, a professor at York University who studies ice phenology and was not involved in the research, has seen the change himself, especially on Lake Simcoe in Ontario.
“The overall trend is pretty clear and it’s been around 1850, the lake is now freezing about two weeks later than it used to be, and melting about a week earlier than it was before,” he said. “And if you add them up, the ice here on the lake is about three weeks less a year than it used to be. So that’s a pretty dramatic change.”
Mills said Barrie, a town lying on the shores of Lake Simcoe, had an annual carnival in Kempenfelt every winter until the 1970s. Then someone failed “and that was it,” he said. “We’ve never had a carnival on the lake since.”
While more lakes are likely to see more ice-free winters, Sharma said she believes there is still hope with more research and solutions.
“I was on [United Nations climate change conference] meeting, and there are just so many young people who care about climate change who dedicate their working lives to doing something about it. And people have very creative solutions, ”she said.
“I think we will be able to find out that support in the next 20 or 30 years [the] the climate is changing and it’s affecting us now and we need to do something about it now – if we have people for that, I think we can change things. “