We’ve all seen the videos. Blue-hued arctic ice melted by warmer weather weakens, breaks off and crashes into the sea.
As average global temperatures rise, cold places, like Minnesota and our neighbors to the north, are warming fastest. And while we may not have any glaciers or ice caps, we do have lots of ice on lakes and rivers in the winter, and scientists expect climate change to have effects on our ice — and our way of life, too.
Scientists have been documenting the loss of ice cover for years: a 2007 study found ice cover on water bodies in the Great Lakes region had decreased by about five days per decade since the 1970s. While there’s lots of research on what that means for the lakes themselves, less is known about the impact of that loss on humans.
That’s the subject of research led by a University of Minnesota researcher and published last year in Limnology and Oceanography Letters.
“One thing I kept coming to was, OK, we’re seeing these changes with the organisms or the water quality … but how could this affect people?” said Lesley Knoll, University of Minnesota Itasca station biologist and an author of the study.
Knoll and her colleagues studied the effects of inland ice cover — or lack thereof — on cultural institutions, like the traditional carrying of a John the Apostle statue across a lake between Switzerland and Germany during the Renaissance; ice roads in Canada; a Shinto ice ceremony in Japan and yes, ice fishing in Minnesota.
“Here in Minnesota, winter is really important to us,” Knoll said. “As we experience less reliable ice conditions, we’re probably going to see a loss to the cultural, social and economic benefits of ice-related winter activities.”
Knoll and her colleagues got data on ice fishing tournaments — when they’ve been held, when they’ve been canceled and how many people have participated — going back to 2004 in both northern and central Minnesota.
Once the average winter air temperature reached about 25 degrees Fahrenheit, there were — no surprise — more cancellations, Knoll said. In the dataset, the cancellations were limited to central Minnesota — northern Minneseota temperatures don’t tend to get that warm.
Take 2015 as an example, when temperatures were unseasonably warm and about one in six ice fishing tournaments held in central Minnesota were canceled, according to the study.
“2015-2016 was one of those El Niño winters, it was very warm,” said Kenneth Blumenfeld, a senior climatologist at the Minnesota State Climate Office. “That was the first time we really heard about hardships in the ice fishing resort community. We were really starting to hear complaints from the people who run the outfits themselves. There just wasn’t much of a winter.”
The data don’t go back far enough to analyze the impact of climate change on ice fishing, but with projections of average temperatures on the rise, the research doesn’t bode well for the sport.
Ice fishing is a cultural, social and economic phenomenon in parts of the U.S. that reliably see their lakes freeze over in the winter, Knoll said. A 2011 U.S. Fish and Wildlife study found that nearly 2 million people go out ice fishing every year, and spend a cumulative 38 million days and $178 million on ice fishing equipment annually.
“It’s a very important kind of recreational activity, but also social activity for us. Especially in our really long winters, to have something to do outdoors and to do with our friends,” Knoll said.
It’s economically important, too. Lots of Minnesota resorts depend on ice anglers for winter revenue. The Brainerd Jaycees Ice Fishing Extravaganza brings an estimated $1 million to the region each year (we’re guessing ice fishing brings economic benefit to the beer industry as well, but weren’t able to find figures).
Ice cover is a robust measure of the way the climate is changing, said John Magnuson, a director emeritus of the Center for Limnology at the University of Wisconsin-Madison and an author of the paper.
“It’s useful as a miner’s canary to point out … not just in the Antarctic or Arctic, but inside and outside the Twin Cities, this is occurring right where you live and you are already being influenced by it,” he said. “The changes are occurring, and they’re occurring rapidly (and) on water bodies people live next to, play next to, ice skate on and so on.”
It’s not as simple as warmer temperatures equals worse ice, Blumenfeld said. It also has to do with precipitation, another thing that’s becoming less predictable as temperatures warm.
“If there’s a thin layer of ice on the lake and then it’s covered by snow, that’s really, really bad for ice formation,” Blumenfeld said. “Similarly, as the ice is freezing or melting, if you have a lot of wind, that just destroys ice.”
As temperatures warm, on average, changes to ice will be gradual.
“It isn’t a nice thing, that they’re always frozen and then bang, they’re never frozen,” Magnuson said. “No ice years begin to occur and become more common, and years in between when the ice isn’t safe in the winter, but you’re also going to have some really good ice years.”
That will make it harder to plan things like ice fishing tournaments, as it will be tough to predict months out whether the ice will sustain people, snowmobiles, trucks and ice fishing houses.
“We’re going to have to learn in Minnesota to be able to deal with this variable in our lives,” Magnuson said. “Especially for those people who still want to do ice things.”