Bearing witness to dying ice

The five Great Lakes, Superior, Michigan, Huron, Erie, and Ontario, with the smaller lakes and rivers that connect them, span the eastern half of the North American continent on the border between the United States and Canada. All combined, the Great Lakes system covers some 95,000 square miles of surface area, making it the largest freshwater ecosystem in the world. This ecosystem holds more than 20% of the world’s freshwater and half of that is in Lake Superior alone. In the past 50 years, Lake Superior has had 20 winters where less than half of its surface froze over, and 12 of those have been since the year 2000.

Ice has played a significant role in ecosystems around the big lake. Scientists have theorized that an ice bridge allowed the iconic moose and wolves of Isle Royale National Park to walk approximately 15-20 miles from the Canadian or Minnesota shoreline to the island. The moose arrived first in the early 1900s. There has been much debate about whether they actually walked over the ice, swam that distance, or were transported by wealthy sportsmen from Minnesota to establish a hunting population. Experts believe the wolves crossed from Minnesota during the severely cold winter of 1949-50. But no more ice bridges are likely to form, so no more wolves will be arriving without human transport.  

Lake Superior ice coverage has always varied from one year to the next, depending on the severity of winter temperatures. But over the last 20 years, the ice has fluctuated wildly more than during the twentieth century, and average ice cover has declined about 5% per decade (Johnson, 2021). In 2021 while we enjoyed a quiet spring break watching the light change across that small bay on the south shore, I did not realize that Lake Superior had peaked at only 50% ice coverage a couple weeks earlier with the help of a late February polar vortex; and then the ice disappeared as quickly as it had formed, like delicate spring flowers. This fleeting, temporary existence now appears to be the fate of all ice on Earth.

In January 2024, ice cover across the Great Lakes was only six percent, one of the lowest amounts ever recorded. For the Great Lakes ecosystem and the people who love it, this is yet another symptom of human-caused global heating. “Between 1979 and 2016, Earth has lost 87,000 square kilometers (33,000 square miles), an area about the size of Lake Superior, per year on average.” This may not seem troubling to people who do not like the cold winter season, but ice in the form of glaciers, ice sheets, and ice caps cover ten percent of Earth (or it did in the not so distant past). With seasonal snow, these white surfaces have offset global heating for many decades by reflecting a lot of sun rays back into space. Open water (unfrozen lakes and polar areas) in winter brings more rain rather than snow and that has ripple-effects across natural and human systems, such as earlier tick and insect activity, and loss of traditional winter recreation with its economic and cultural benefits. The seasonal melting of ice provides millions of people with water to drink and grow crops and nourishes many beautiful ecosystems around the world. Seasonal and multi-year ice protects ocean and lake shorelines from the erosion action of waves. 

January 2024 was the warmest winter month in human record keeping. In the Red River valley, our temperatures were 20-30 degrees Fahrenheit above traditional averages. What little snow had accumulated in November and December (maybe 10 inches) melted away by the first week of February. This winter has been like a waking dream where I have been transported back to living in Virginia. Warmer winters in the northland means more cloudy days. I am enjoying the mild temperatures, but I also miss those below zero days with their crispness and blinding bright sunshine. I can’t stop thinking about global climate disruption – this winter is preview of a future without deep snow, without starkly cold temperatures, and without ice.

From growing up in Minnesota, cold temperatures, snow, and ice are the characters in every winter story. But this is not just my heritage. Our species, homo sapiens, grew up in cool temperatures, with plenty of ice covering Earth’s poles. Seeing the heatwaves we are experiencing now, even in winter, it scares me to think of a future so warm that we may not have any polar ice. Can humans survive on an Earth with no ice?  

I wonder, how many more winters of ice-covered lakes will I experience in my lifetime. Farewell ice. We may not realize it yet, but we will miss you.