Land gets all the attention. If I were a betting man, (I’m both not a man and too afraid to gamble on anything) I’d say that’s because it’s where we live. But the defining feature of our planet, and what makes it hospitable to life itself is, of course, water. Life, most likely, emerged from the deep ocean; freshwater sustained life as it emerged from the sea.
About 70 percent of Earth’s surface is covered with ocean, which accounts for about 97 percent of all the water on the planet. Of the remaining 3 percent that is freshwater, most of it is locked up in polar ice sheets or sea ice (though rapidly becoming part of the ocean), or too deep underground to be easily drawn upon. After all that, there is (proportionally) a tiny bit of freshwater on the surface or in shallow aquifers, which is available for use by people and living things. And about 20 percent of those remaining few drops are in the Great Lakes. 1 in 5 gallons of available water on earth! I find this absolutely staggering!
The Great Lakes are both precious and easy to take for granted — looking out over Lake Michigan is like (though not the same as!) looking out over the ocean. How could its resources be anything but infinite? But the Great Lakes are not an ocean, regardless of how we treat them — they are even more suggestible to human influence because they are contained.
As Dan Egan wrote in The Death and Life of the Great Lakes, about Lake Erie (the second-smallest of the Great Lakes) but could likely be written about a few (if not all) of them, “Lake Erie suffered immensely throughout the late 19th and 20th centuries as a receptacle for human, industrial and agricultural wastes. But nothing compares to what is happening today. Those millions of acres of destroyed wetlands, the overapplication of farm fertilizer, an increase in spring deluges and a lakebed smothered with invasive mussels have all conspired to create massive seasonal toxic algae blooms that are turning Erie’s water into something that seems impossible for a sea of its size: poison.”
Putting the pollution crisis aside (if such a thing is possible), as well as the invasive species question (again, hard to do), today I’m going to focus on the crazy anomalous warming this winter in the Great Lakes.
This has been a winter of extremes in the U.S., mostly fueled by one of the five strongest El Niños on record against a backdrop of overall warming. We’re experiencing historic heat in the ocean (365 days of “off-the-charts” increase in sea temperature), and on land, with the warmest January and February, coming after a year (2023) which was the warmest year ever since record-keeping began.
But in the Great Lakes, extreme barely begins to capture what has happened. Normally, by mid-March, the Great Lakes are covered in their maximum extent of ice. They’re not frozen solid across, but the ice coverage of the five lakes together reaches its normal peak of about 40 percent around now or a bit earlier. This year, the Great Lakes were about 1 percent frozen — only bays and sheltered areas had ice, and “virtually no part of the interior has ice on it,” Steve Vavrus, Wisconsin’s state climatologist and senior scientist at the Center for Climatic Research at University of Wisconsin-Madison, told me last week. Even in January, during one of this winter’s few cold-shots of Arctic air, the ice’s maximum extent only reached about half of its normal — about 20 percent.
El Niño typically blocks cold Arctic air from traveling south to the Midwest and Great Lakes region by effectively shunting the jet stream to Canada. The jet stream is the boundary, usually, between cold Arctic air and mild middle latitude air. “It was definitely surprising that there was so little cold air,” Vavrus said, “We had the standard forecast with strong El Niño, which is a mild winter, but I didn’t hear people saying this is going to be the warmest winter on record.”
Climate scientists have thought that climate change may be altering the path of the jet stream, making it wavier, periodically sending cold Arctic air farther South — this phenomenon is responsible for the “polar vortex” that sometimes swirls down into the U.S. — and Vavrus is one of the people studying this question, particularly the effects of El Niño. “When you get an El Niño that’s this strong, it can grab the steering wheel and help to dictate the winter regardless of what’s happening in the Arctic,” he said.
There are plenty of disconcerting consequences for such small amounts of lake ice coverage: water levels could be lower, since warmer water evaporates faster, which will start to happen now that it’s spring; stratification of the lakes’ layers, where colder water sinks below, could happen sooner, making the surface of the lake exceptionally warm, and it could happen sooner than usual. These are the kinds of conditions that can contribute to harmful algal blooms Dan Egan described above in Lake Erie. It will depend on the amount of runoff the lakes get, but the conditions will be ripe for algal blooms, which can be harmful to human health and fatal to animals, particularly worrisome when you remember that the Great Lakes provide drinking water for 40 million people in the U.S. and Canada. Ice cover also prevents against shoreline erosion, by buttressing the coasts from strong winter storms. A lack of ice is also possibly altering competition patterns and population dynamics between fish species.
One mild winter might make a season, but it doesn’t make a climate. However, Vavrus said, we can definitely anticipate that this is where we’re headed: “This was a sneak preview of what future winters are going to be more like, Not every winter will be this mild, but it’s trending in this direction, and there are certainly lessons to be learned.”
What are the lessons? Or more aptly, what are the questions we should now be asking? “How did ecosystems respond? How quickly did the lakes warm up? How did lake effect snow happen with no ice cover?”
“There are things we can learn and help us prepare for the future in terms of how warm it was. If I could place a bet, I’d bet for every single winter from now on that it will be warmer than the long-term average,” Vavrus said.
Something I’m interested in is the cultural effects of climate change, and what it will mean for people all over the world, and the ways that they make meaning in their lives — from traditions and rituals and stories. How might these practices shift as a warming planet scrambles the rough calendar of seasons?
The first time I spoke with Vavrus was last year, for my article about the American Birkebeiner, a cross-country ski race in Wisconsin, which I’m happy to brag about at any opportunity. Last year, I was able to compete in it and write about it (emphasis MINE; actual results less impressive) as skiers have done for decades. This year, for the 50th anniversary, the race was shortened, and instead of skiers making their way through the woods from Cable to Hayward, they competed on a 10km loop near the starting line. It was possible at all because of a recent purchase of a snow-making machine.
He seemed to feel the cultural effects of a lost winter acutely: “With all of the talk about climate change, the cultural part doesn’t get talked about enough.
“Winter is such a big part of Wisconsin culture, and we pride ourselves on being hardy,” he said. “This year, there were hardly any elements to feel hardy about. If we no longer have harsh winters, that does affect our identity as a cold-loving people.
“You can fully prepare that you’re heading into a different world or culture, but it’s not the same as really being there.”
This was originally posted on Tatiana’s Substack News from a Changing Planet, a free twice-monthly newsletter about what on Earth is happening, with articles and essays about climate change and the environment.
Header image: All five great lakes seen from a satellite in April 2004. Credit Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC.