The amount of ice covering the Great Lakes has declined a whopping 71% over the past 40 years, with only about 5% of the surface freezing over this past year, according to a study by the American Meteorological Society.
The study was conducted by scanning U.S. Coast Guard reports and satellite images taken between 1973 and 2010, finding that ice coverage was down a massive 88% on Lake Ontario, and falling 79% on Lake Superior. Ice on Lake St. Clair was only down about 37%.
Chequamegon Bay, located near Lake Superior, has also been strangely free of ice. It’s normally frozen to the point where trucks drive on it, but this past winter the local Madeline Island ferry was forced to stay open all season, something that’s only happened once before.
Lead researcher Jia Wang of the National Oceanic and Atmospheric Administration lab in Ann Arbor, MI attributes this to several factors, climate change obviously being one (see Arctic Ice: Near Record Low, Melt Accelerating), as well as climate patterns such as La Nina and El Nino. According to his reports, diminishing ice levels can accelerate wintertime evaporation, causing water levels to fall for larger portions of the year and exposing more shorelines to waves. This could also lead to increased algae, which results in damaged water quality.
As a Detroiter who grew up on Lake St. Clair, I can say this isn’t really surprising at all. I’ve noticed significant changes in winters on the water now from when I was a kid, and considering the fact that it’s March and we have 80 degree Fahrenheit temperatures when we’d normally still have 3 feet of snow, something definitely isn’t right (see recent post March Heat Wave Is One Of The Most Extreme Heat Events In US History).