Where is the ice? Great Lakes ice cover reaches 50-year record low
(CNN) — A warm start to the winter season has left the Great Lakes virtually ice-free and with their lowest ice cover to kick off a new year in at least 50 years.
On New Year’s Day, only 0.35% of the Great Lakes were covered in ice, the lowest on record for the date, and well below the historical average of nearly 10% for this point in winter, according to data from the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory (GLERL).
This year’s missing ice in the Great Lakes adds to a growing trend of winter ailments plaguing the US, from dwindling snowpacks in the West to an ongoing snow drought in the Northeast, all becoming more common due to warming temperatures from the climate crisis.
Since record-keeping began in 1973, researchers have found the Great Lakes have been experiencing a massive decline in ice, with the peak coverage dropping by about 5% each decade.
“It’s certainly very low for this time of year,” James Kessler, a physical scientist at NOAA’s GLERL, told CNN.
Air temperature matters when it comes to ice cover on the Great Lakes, said Kessler. Cold air is needed to cool the water so the lakes can freeze. But with the climate rapidly heating up, records show warmer than average temperatures in the region are melting the chances for Great Lakes ice to form.
“We’ve had consistently above average air temperature in the region, and we haven’t had consistently cold days,” Kessler said. “That’s really what you need. You need a consistent number of days below freezing.”
Average December temperatures in the Upper Midwest states surrounding the Great Lakes soared 8 to 12 degrees Fahrenheit above normal for the month. It was the warmest December on record for several cities along the Great Lakes, including Chicago, Detroit, Green Bay, Wisconsin, and Duluth, Minnesota.
It was a similar story on the eastern side of the lakes as well, with Cleveland; Erie, Pennsylvania, and Buffalo, New York, all seeing one of the warmest Decembers on record. As a result, Lake Erie is currently completely ice-free.
It’s an ongoing trend. Lake Erie has seen a decline in ice coverage of about 5% each decade, according to Kessler, while Lake Superior is seeing the most rapid rate of ice cover loss of about 7% every 10 years. Recent studies have shown that Lake Superior is among the fastest warming lakes in the world, thanks to planet-heating pollution.
It is still early in the season, Kessler cautioned. One prolonged blast of Arctic air in the coming weeks could cause ice coverage to increase exponentially. And peak ice in the Great Lakes typically occurs in late February or early March.
Kessler said that while there is year-to-year variability, the Great Lakes are trending toward a future with less ice cover.
“First of all, (the data) is very noisy,” Kessler said. “But if you fit a trend line to this data, you do get a decreasing trend, so we do see that (ice cover) is going down.”
Low ice cover in the Great Lakes has serious ramifications for industries and the environment.
Less ice could extend shipping season. Shipments by water along the Great Lakes could grow with the ice-free waters giving way to more vessels, according to researchers at the University of Wisconsin-Superior looking into how reduced ice cover could directly affect navigation there.
“The commercial shipping industry is like a multibillion-dollar industry, and so less ice cover is good for them,” Kessler said. “Often, the freighters get stuck when it’s a high year, and the US Coast Guard has to go rescue them and it’s a huge undertaking. So, from that perspective, low ice is good economically.”
On the flip side, he said there’s also an economic benefit when the lakes are frozen: coastal towns benefit through recreational activities such as ice fishing competitions or ice hockey games.
Ice cover also protects the shorelines of the lakes. Without it, high waves can cause severe flooding, coastline erosion and damage. A dearth of ice coverage can also lead to more severe snowstorms like the one that paralyzed Buffalo, New York, and surrounding towns in 2022, Kessler said.
When very cold, windy conditions form over an unfrozen lake, it sets the stage for “lake-effect” snow. And the Great Lakes are the only place in the US where this phenomenon occurs, except occasionally at the Great Salt Lake in Utah.
Kessler said that while the first couple days of January have been notable for low ice cover on the Great Lakes, daily lows are not as significant as month-long lows.
“If the month of January as a whole is on average lower than past Januarys, that will be more remarkable to me,” he said.
It’s impossible to know exactly how the rest of winter’s temperatures will play out around the Great Lakes. But a strong El Niño winter like this year’s typically means a greater chance for warmer than average temperatures there, meaning it could continue to be an uphill battle for the lakes’ ice.
