Researchers who study ice cover on the Great Lakes, and the mysterious happenings beneath, have a problem: There’s precious little of it. And that’s thwarting their ability to understand what declining ice cover means for everyone else throughout the region.
“This is one of the lowest years for ice cover on the Great Lakes,” said Marguerite Xenopoulos, a biology professor at Trent University. She has worked on Lake Superior and Lake Erie previously, but was unable to conduct field work this year.
“There was no way we could get out there. There’s no ice.”
Ice concentrations on the Great Lakes are typically highest in mid-February, in the dead of winter. The Canadian Ice Service, a division of Environment and Climate Change Canada that monitors ice in navigable waters, said combined ice cover stood at just 13 per cent in early February, less than one-third of the long-term average. For the week of Feb. 12-19, it was 6.8 per cent – a tie with 1998 for the lowest ice cover for that week, and well below the long-term average of 40 per cent.
Ice on the Great Lakes is highly variable; it waxes and wanes mainly because of air temperature, with cloud cover, wind and other factors playing supporting roles. There have been ice-abundant years even in the recent past: According to NASA, ice cover peaked above 80 per cent in both 2014 and 2015, a relatively rare occurrence.
The overall trend, though, is unambiguous: less ice, less often. George Karaganis, an ice-forecasting meteorologist at the CIS, said something changed fundamentally around 1998. After that, the frequency of low ice years greatly increased – a change that’s obvious in many charts based on historical ice data.
“If you look at the longer trends of ice cover on the Great Lakes over the past 50 years, it’s clear,” concurred Mike McKay, executive director and professor at the Great Lakes Institute for Environmental Research at the University of Windsor.
“The lakes as a whole are trending lower – a 75-per-cent decline in ice cover.”
Researchers expect continued declines in ice cover will have significant implications throughout the region, including for drinking water quality, extreme weather and fish populations. But the usual uncertainties around such projections are compounded by the fact that until recently, many Great Lakes researchers overlooked winter conditions.
This reality stems partly from practical considerations. Most vessels available to researchers are not reinforced to operate in ice, so they’re pulled from the water each fall. Sometimes researchers can work in nearshore areas by taking snowmobiles out on the ice, or even walking, but in low-ice years the dangers are often prohibitive. Another contributing factor was that many researchers assumed little was occurring in the frigid darkness.
For Prof. McKay, that changed in 2007 when he was invited on a week-long expedition aboard an icebreaker on Lake Erie. His research focuses on bacterial blooms and algae on the Great Lakes. McKay and his colleagues gladly accepted, but assumed they’d see nothing noteworthy.
“Really, we thought it was a bit of a laugh, an adventure,” he recalls. But on the first day out of Amhertburg, Ont., they noticed brown water churned by the icebreaker’s propeller wash. It was brown algae, and it changed the course of his career.
Ever since, Prof. McKay has sought to collect samples during winter, in part by partnering with Coast Guard officials in both Canada and the U.S. Icebreakers are not research vessels, he notes, but crews can collect samples when opportunities present themselves. In recent weeks two Canadian icebreakers, the Samuel Risley and Griffon, collected samples on his behalf.
According to some forecasts, the Great Lakes could be almost completely ice-free by the end of this century. One concern is the impact that might have for regional weather patterns.
“We are in so much trouble,” Prof. Xenopolous said. “We’re gonna have more intense storms, we’re going to have more rain, we’re going to have more lake-effect snow.
“I know winter drags on and on, but it’s better for the lakes to have ice than not to have ice. They’re big bodies of water, and they play a role in controlling the climate.”
And since shorelines are locked in ice for less of the year, they’re more exposed to winter storms. That spells trouble for coastal properties and roads.
“Shoreline erosion, we see that loud and clear, in a year like this year when there’s no ice cover to protect our shorelines from being battered by waves,” Prof. McKay said.
More difficult to understand is the impact on ecosystems. Prof. McKay said that while there’s insufficient evidence at present, low ice cover could lead to longer periods of harmful blue-green algal blooms in the summer. Agricultural runoff pollution causes frequent blooms in Lake Erie, one of which led to a drinking water advisory for half a million citizens of Toledo, Ohio in the summer of 2014. According to the International Joint Commission, a body that manages transborder water issues between Canada and the U.S., the Great Lakes provide drinking water to more than 38 million people.
There will inevitably also be benign, or even welcome, impacts. Water bodies with any freezing are sometimes referred to as “ice-infested,” an indication of the esteem in which ice is held in the shipping industry.
In November, the IJC’s Great Lakes Science Advisory Board issued a science strategy for the next decade. Its report noted a lack of consistent winter data from the Great Lakes – a result of “minimal” funding and an inability to do the work safely or effectively. The IJC’s plan prioritizes more research on winter limnology and meteorology – part of a broader increase in interest on Great Lakes winter research.
“There is more research going on,” Prof. Xenopoulos said. “There is also a greater request from stakeholders and managers to have this information.”
The Great Lakes have endured plenty of abuse over the last century; at one point, Lake Erie was even declared deceased. Prof. McKay said that they’ve often surprised with their resilience: “They seem to rebound.”
But they are also permanently changed. And as ecosystems shift again with continued climate warming, yet another “new normal” may take hold.
“What that looks like, really, nobody knows.”
The Globe and Mail, March 12, 2023