Ice cover for inland lakes and rivers in the Northern Hemisphere has steadily declined for the past 150 years, putting people’s cultural and spiritual practices at risk — and potentially their livelihoods, says a recent University of Minnesota study published in Limnology and Oceanography Letters.

Researcher Lesley Knoll and colleagues write that warmer winters are causing events of socioeconomic and cultural importance — such as ice fishing tournaments, cross-country skiing and ice-skating races — to increasingly be canceled.

Like many Midwestern states, Minnesota has a long history of ice fishing and is home to dozens of ice fishing tournaments each year that draw participants and tourism dollars to local communities.

Researchers found a higher number of tournament cancellations in the central part of the state when average winter air temperatures reached 24.8 degrees Fahrenheit or warmer.

“Reduced ice fishing during warmer winters has the potential to influence the economy and social network of northern communities. There is often a very social aspect to ice fishing,” said Knoll, station biologist at the College of Biological Sciences’ Itasca Biological Station and Laboratories. “In addition, lakes in Minnesota with long-term ice records show similar declining ice cover trends to those documented worldwide.”

Newsletter signup for email alerts

Further north, ice roads that serve remote areas are also imperiled, the study found. And in Germany, Catholic priests have carried a statue of John the Apostle across a frozen Lake Constance to a church in Switzerland since the 15th century as a sign of friendship. Lake Constance last froze in 1963, marking the last procession between the two countries.

“While each of these issues may seem like only a local concern, for the millions of people living in places where winter ice is in retreat it adds up to a major shift in their relationship to winter,” said Sapna Sharma, an associate professor at York University and study co-author. “It’s time that freshwater ice loss is included in the list of major climate change impacts.”