Ice cover decreasing on Great Lakes, data shows Ice cover decreasing on Great Lakes, data shows
By Hansil Mehta The average ice cover on the Great Lakes has decreased by over 20 per cent in the last 50 years, data... Ice cover decreasing on Great Lakes, data shows

By Hansil Mehta

The average ice cover on the Great Lakes has decreased by over 20 per cent in the last 50 years, data suggests.

Data collected by the Canadian Ice Service and the U.S. National Ice Service since 1973 shows a decrease in annual ice cover on all of the five Great Lakes.

Great Lakes yearly ice cover.

Great Lakes yearly ice cover.

Frank Seglenieks, a water resources engineer at the Environment and Climate Change Canada, says the trend of increasing temperature in the past five decades has had more impact on winter temperatures rather than the summer temperatures.

“It’s going to lead to less ice ongoing,” Seglenieks says.

The running average of the ice cover on the Great Lakes at the end of 1970s was 68 per cent. It has since decreased to 53 per cent this year.

Alessandro Filazzola, a post-doctoral researcher at the University of Toronto and the York University, says the climate change has had an impact on ice cover on many lakes around the world.

“Different lakes are now becoming ice free,” Filazzola says. “When they do freeze, it’s for a much shorter period of time or they freeze much later than they used to.”

Comparing average ice cover on the Great Lakes decade-over decade poses an even dire picture.

The average ice cover for the Great Lakes in 1970s was 68 per cent whereas in the 2010s, it was only 49 per cent.

In the two years of 2020s so far, the average has been a mere 33 per cent.

Filazzola says the ice cover is important for many reasons such as regulating water temperature, reducing evaporation, impact on fish populations and especially in improving water quality.

“If we’re relying on these lakes for freshwater, and even though the water treatment plants help to clear the water for us,” Filazzola says. “The worse the water quality is, the harder it is for these water treatment plants, the more money it is for cities.”

He says lake ice is also important for recreational purposes for humans such as ice fishing, snowmobiling, ice skating, and hockey.

The decrease in ice cover on the Great Lakes has had an impact on all of these things and many other things too.

Storm hunter and meteorologist at the Weather Network, Mark Robinson says less or no ice cover means a greater likelihood of snow squall events.

“Normally by February, there (are) no snow squalls. It’s all done,” Robinson says.

“But for instance, this year, we saw one of the biggest snow squall events happen just a couple of weeks ago,” Robinson says referring to a snow squall event in southern Ontario in the first week of March this year that triggered warnings for up to 25 cm snow.

Less ice on the lakes has many long-term effects on their surroundings too.

Robinson says decreased ice cover is a big problem for the shorelines of the lakes.

“Over the winter months, the storms that we get in southern Ontario and across the Great Lakes drive some really big waves,” Robinson says.

“If you’ve got waves and storms that are continuing throughout the entire winter, there’s just that much more erosion that’s going to happen.”

The winter of 2019-20 saw very low ice cover across the lakes with just 19.5 per cent ice cover.

Seglenieks says this had its impact last year on the shorelines of Lake Michigan and Lake Huron, which are predominantly sandy.

“So, you get those big waves hitting the sand and they’re just taking out a lot of the beaches, and that of course is causing more erosion,” Seglenieks says.

Robinson notes that erosion is partly because of high water level along with decreasing ice cover.

“I’m seeing the areas of Lake Erie right now that are just beginning to slump like crazy, right into the lake,” Robinson says. “Erosion has increased considerably all along the north shore of the lakes.”

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Lake Erie has the highest average annual ice cover among the Great Lakes with 81 per cent ice cover. However, the lows in the ice cover on Lake Erie have been dramatically low such as 15.9 per cent in 2019-20.

Seglenieks says the varied range and big swings in the ice cover means Lake Erie is going to be greatly affected by this.

On the flip side, Lake Ontario freezes just 29 per cent on average every year, which Seglenieks says will thus have less impact on Lake Ontario as compared to Lake Erie when decreasing ice cover is concerned.

Filazzola says future projections of ice cover are very bad if the carbon emissions keep going the way they are.

“In one of our more recent papers, we found that if carbon emissions continue the way they are now, we could see a few 1000 Lakes become permanently ice free,” Filazzola says. “That means they’ll never freeze again within the next couple of decades.”

He further adds if the carbon emissions are cut down and with better efforts towards mitigating climate change, the number might come down to a few 100 lakes.

“It doesn’t look very great in terms of how ice cover will change in the future,” Filazzola says. “However, we actually can play a strong role in determining that and we can potentially prevent hundreds, if not 1000s of lakes from becoming predominantly ice free.”

Hansil Mehta

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