Chicago was built on the swampy land at the shores of Lake Michigan. The city has been able to exist because the water has been controllable -- until now. Due to climate change, Lake Michigan's shoreline has been wildly fluctuating with higher highs and lower lows. Over a number of years, the lake's water levels would shift a couple of inches. However, in the past seven, it's shifted by six feet. As the New York Times reports, the swings between the two [high and low levels] show signs of happening faster than any time in recorded history." (Dig Deeper: Read the full story, complete with 3D maps.)

Why This Matters

The wildly shifting water levels of Lake Michigan's shores mean Chicagoans have endured impacts of both the lake coming into the city, smashing apartment windows and flooding streets, and shrinking away, which threatens the drinking water supply. The city's old sewer system is especially an issue on the city's South Side, where increasing big rains frequently flood basements. Chicago's infrastructure -- like many cities across the country -- simply isn't built for the rapidly changing climate.

The Climate Science Behind The Shifts

Warmer air holds more moisture, which in turn leads to more rainfall during storms. The average air temperature is up by 1.2 degrees Fahrenheit, creating wetter weather. Hotter air can also increase evaporation, especially coupled with the increase in water temperature: the Great Lakes are an average of 1.5 degrees Fahrenheit warmer than they were about 15 years ago.

And according to a recent report from NOAA, the lake's temperature changes reach to its depths, indicating a longer-term, more fundamental shift in the ecosystem and weather patterns.

"This is a big lake," Craig Stow, a NOAA Great Lakes Environmental Research Laboratory scientist and author of the study, told the Chicago Tribune. "That's a lot of water. That's a lot of change."

Planning For The Chicago Of The Future

For the city of Chicago and Lake Michigan more broadly, it's unclear what the future holds, making it difficult to plan. Since 2020, the city has installed thousands of feet of jersey barriers and sandbags to keep roads safe from flooding. There may also be federal funding for an offshore barrier. What is certain -- is that the lake is profoundly changing.

"From the conversations I have with colleagues, the consistent message I hear is that we can expect extremes on both ends," John Allis, chief of the Army Corps of Engineers' Great Lakes Hydraulics and Hydrology office told the New York Times.