Above average temperatures, coupled with diminishing blasts of Arctic air have lessened ice in the region; El Nino also responsible for this winter
Satellite photo shared by NOAA and NASA The five storied lakes of North America—Superior, Michigan, Huron, Erie and Ontario—the largest freshwater ecosystem on Earth, have recorded significantly below average ice cover for the second consecutive year in a row, according to United States government agencies.
The Great Lakes are covered with a thick layer of ice in late February or early March usually. That is when the ice cover reaches its peak. But that has not been the case during the winter of 2023-24.
“As of February 11, total ice coverage across all lakes measured a mere 2.7 per cent. Lakes Erie and Ontario are basically at—or tied with—their respective historic lows for this time of year, making both essentially ice-free,” a note on the website of the National Oceanic & Atmospheric Administration (NOAA) dated March 1, stated.
The lakes have been consistent in that their maximum basin-wide annual ice coverage has been 53 per cent since reliable satellite data collection began in 1973.
But over the last five decades, “the amount of ice has dropped about 5 per cent each decade, amounting to a 25 per cent decrease,” NOAA added.
In addition, the ice season on the Great Lakes has shortened in duration by approximately 27 days on average over these 50 years, it noted.
“Lake Superior typically sees peak ice cover mid-February to early March. With the forecast looking much warmer than average for the next few weeks, it’s unlikely that we’ll see a significant increase in ice cover this season,” according to NOAA.
The Great Lakes are the largest freshwater ecosystem on Earth. But according to the Fifth National Climate Assessment, they are also among the fastest-warming lakes in the world.
NOAA said global warming was largely responsible for the lack of ice this winter. El Nino, the warmer phase of the El Nino-Southern Oscillation, had been declared since the middle of last year.
2023 was declared as the hottest year on record and January 2024 the hottest January on record, largely because of El Nino.
But it is not just about El Nino. Much of the ‘Lower 48’ (Continental US excluding Alaska and Hawaii) has been seeing a warming trend during the winter months. Among them, the upper Midwest/Great Lakes regions have seen some of the most dramatic warming.
“In recent years, numerous Decembers have exhibited above-average temperatures, with this winter notably featuring significantly warmer conditions. The delayed formation of ice due to the lack of cold air early in the season makes ice concentration harder to achieve,” said the NOAA note.
Most of the US states on the shores of the Great Lakes have seen above average winter temperatures.
The Midwestern states of Minnesota, Wisconsin and Michigan are experiencing their warmest meteorological winter (December through February) to date.
“Meanwhile, New York, Pennsylvania, and Ohio are experiencing their second, third, and fourth warmest meteorological winters,” said NOAA.
It added that January 2024 “did see some periods of cold, but they were not sustained long enough to allow ice coverage to increase, peaking at 15-20 per cent during the third week of the month”.
Fewer and generally shorter intrusion of blasts of cold air from the Arctic exacerbates the situation and results in diminishing ice cover.
“Ice plays an important role in the ecosystems, economy, and coastal resilience of the Great Lakes. It is a natural part of the yearly cycle of the Great Lakes, upon which many animal species, ranging from microbial to larger fauna, rely on for protecting their young and harboring eggs,” NOAA said.
It noted that the lakes also saw most of their significant storms and large wave events during the colder months of late fall through winter.
“The ice sheets along the shore act as an important buffer against these waves, protecting the coast from erosion and damage to shoreline infrastructure. In years with very low ice cover, such as the current one, the coast becomes more susceptible to the full force of wave energy,” the US agency said.
The lack of ice is also affecting tourism and recreational activities. “Last month, the John Beargrease Sled Dog marathon, one of the most beloved dog sled competitions in the Midwest, was canceled due to lack of snow,” according to NOAA.
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