Warmer winters mean less ice on Lake Michigan, hurting trout and whitefish

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There’s hardly any ice on Lake Michigan right now. Same goes for the other Great Lakes. Without ice on the lakes, weather patterns and regional commerce could look entirely different.

As of last week, just 0.43 percent of the Great Lakes were covered with ice heading into the beginning of 2024, according to the data from the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory (NOAA GLERL).

“Usually for this date, we’d see 9 percent lake ice. However, we are very, very early in the season,” said Bryan Mroczka, a meteorologist and physical scientist with NOAA GLERL.

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It may be early in the season, but historical data going back to the early 1970s show ice coverage is beginning to slowly disappear. Maximum coverage on the Great Lakes — Michigan, Huron, Superior, Erie and Ontario — has fluctuated from as high as 90 percent to as low as nearly 12 percent in 2002. And over those 50 years, researchers identified a 5 percent decrease in ice cover per decade.

“Right now we’re seeing about 50 percent of the ice cover that we saw 50 years ago today,” Mrozka said. “So it’s a very slow decrease, but it is a statistically significant decrease in ice.”

Winters are not as cold as they used to be and they’re not as long either, which means the ice is setting in later and melting earlier.

For thousands of years, seasonal ice cover was the norm on the Great Lakes and all kinds of plants and animals evolved alongside that cycle. But less ice and more open water will mean changes, according to Richard Rood, a professor emeritus at the University of Michigan and co-investigator of the Great Lakes Integrated Sciences and Assessment Center (GLISA).

“These systems, whether they be human or ecosystems, have evolved in the presence of patterns of ice, and therefore when ice changes, all of these things will be thrown into some state of having to adapt,” Rood said.

Not only are cold water species like lake trout and whitefish destabilized by less ice cover, so too are the very borders of the lakes. According to Mroczka, the region’s largest storm occurs during the winter times and for years the ice acted as a kind of buffer between major waves and the shoreline.

“So with decreasing ice, we see more potential for shoreline erosion or shoreline infrastructure damage,” Mroczka said.

He adds that while less ice could be a boon for the shipping industry, it would have massive consequences on recreational sports that rely on the seasonal ice coverage.

Even as scientists note the decrease in ice coverage, they still point out the average time for maximum ice cover is still about a month away for most lakes during the weeks between the last week of February and the first week of March.

“And the fact that we’re so low right now, isn’t out of the norm for this time of year,” Mroczka said. “The further we get into January, if that number stays as low as it is, it becomes more abnormal.”

Still, Mroczka warns the trend of less ice could affect future generations.

“Our children and our children’s children, are going to see a much different environment in 50 years or 100 years, than we’re seeing now,” Mroczka said.

This story was originally published on January 8, 2024.