Blog Redux: What Less Lake Ice Means for Ecology, Economy and Ourselves

A warmer-than-average January created interesting ice on Lake Mendota. Photo: Gavin Dehnert

NOTE: This post originally ran on January 17, 2012. In the four of the five years since this post, Lake Mendota has frozen over well after its “median” freeze date, and in three of the five years it has thawed much earlier.

A few days before Christmas, I was headed down John Nolen Drive on a last-minute shopping excursion when I noticed a couple of fishermen out on Lake Monona – in a boat.
Now, it’s January 4th, and there’s still no snow on the ground in Madison and most of our lakes are dominated by open water.
Curious about what such late freezes might mean for both lake inhabitants and shoreline residents, I sat down for a talk with the Center for Limnology’s director emeritus, John Magnuson. Turns out that the biggest consequence of shorter ice cover on our northern lakes might mean a lot more to humans on the shoreline than the organisms that call the water home.
That’s not to say nothing in the lake feels the effect of later ice on and earlier ice off. For example, certain species of algae have evolved to take advantage of the still waters that occur once a lake has iced over. While present in the lake most of the year, these tiny algae float to the surface when the frozen lake’s waters still.  In winter, they become the dominant class of plankton.
“It’s a survival mechanism that works pretty well for them,” says Magnuson, “but in current conditions, these algae aren’t doing so well. At this time of the year when the lake is still open, the slightest bit of wind is enough to mix the lake from top to bottom. They’re not hurt by mixing, but they out compete a lot of the other algae when the water’s really still under the ice.”
Magnuson admits the ecological impacts are subtle. The more obvious effects are on human use of the lakes.
“Right now, when it’s cold [outside] but the lake’s not frozen, is not a great recreational use time on Lake Mendota,” he notes.
Usually this time of year, I would pass cross-country skiers and ice fishermen on any pre-Christmas drive past Lake Monona. And these outdoor pursuits are part of Wisconsin’s winter economy. Sure, ice fishing and snow shoeing may not be big drivers in Madison’s economic engine, but, says Magnuson, “In the northern part of the state, winter recreation is an economic subsidy for the area.”
Despite all of this, perhaps the biggest problem we have with an open-water Lake Mendota in January is less tangible. An ice-less Lake Mendota in January just doesn’t “feel right.”
“Human beings have a strong sense of place,” says Magnuson. “They get homesick or long for the country they immigrated from, and in Wisconsin, our sense of place includes the four seasons and that includes winter. And in our area, that sense of place includes lakes. And these are important to us. This sense of place affects how we see ourselves and what we do in their lives and what we hope our children will get to do in their lives.”
But, says Magnuson, our sense of place may need to shift to accommodate the new normal. And that means greater variability and a shorter lake ice season. “Historically [in the mid-1800’s] Lake Mendota had about 4 months of ice. And right now we’re averaging about three.”
Maybe the ecological or economic impacts of that change aren’t catastrophic, he says, but “on the other hand, I’m unhappy. I’m actually sad that we’re losing winter as we knew it.”