Something is happening to our beloved Lake Michigan.
Scientists aren't sure what it is, but some experts believe the symptoms point to further evidence of radical climate change and alarming drops in lake levels.
We are all too familiar with the site of a frozen lake during our long Chicago winter. But experts say rising air temperatures may be to blame for decreases in ice cover every year.
NOAA, the government's main climate agency, says between 1972 and 2008, Lake Michigan ice cover declined by about 30 percent. That allows the lake to evaporate year-round. And with a growing population actually drinking that lake, scientists are concerned of a larger threat than ever of dramatic drops in the actual water level of the Great Lakes.
The Army Corps of Engineers says Lake Michigan is almost a full foot below its long-term average water level. But picture this: last year, the University of Rhode Island said Great Lakes water levels fluctuated by only seven feet for thousands of years. There is evidence that 8,500 years ago, water levels dropped by more than 60 feet due to climate change, and its theorized that's what cut the lakes off from each other.
The graphics above indicate levels of ice coverage on the Great Lakes. On the right, levels in 1977 were predominantly frozen solid (shown in black) and the least amount of ice is found along the west shore of Lake Michigan in teal blue. On the left, the graphic shows ice coverage in 2002. Light blue indicates no ice coverage and royal blue indicates 95 percent coverage.
Some believe a new, dramatic shift could occur again. Illinois
Congressman Mark Kirk points to a University of Michigan study which suggests the Great Lakes could drop eight feet this century.
"Our current Great Lakes climate forecasting ability remains very limited," said Kirk. "The Army Corps of Engineers only forecasts water levels six months out, with NOAA using one-year models. While invaluable, this is not enough to determine systemic changes to our lakes."
Kirk is seeking action which would require NOAA to conduct long-term ice cover and water level outlooks for the Great Lakes. Last year, Great Lakes states ratified a Water Compact which restricted further diversions of lake water.