Predicting the Unpredictable

Lake Michigan water levels are low right now, but they might not always be that way.

Lake levels are controlled primarily by precipitation, runoff and evaporation. Those things are caused by climate, and the climate is changing. The National Oceanic and Atmospheric Administration’s National Climate Data Center (NCDC) found that 2012 was the hottest year on record by 3.2 degrees. It was also one of the driest years on record, with most of the country suffering from abnormally dry conditions and much of it, including Eastern Wisconsin, in drought. On Nov. 27, 2012, the U.S. Drought Monitor reported 62.7 percent of the continental U.S. was experiencing moderate to exceptional drought.

That’s not all. The NCDC found that 2012 also had the second most extreme weather events on record. While the epicenters of those events were far away from Wisconsin, like fires in the western states and Hurricane Sandy on the East Coast, that doesn’t mean they always will be. (Although we did get some Sandy-related windy weather.)

The hot, dry, extreme year wasn’t a fluke. It was part of a trend. Jia Wang, ice climatologist for the Great Lakes Environmental Research Laboratory, said the region’s air temperature is about three to four degrees warmer now than it was 40 years ago.

We can assume the climate will continue to change, that future years will look more like 2012. That may mean the lakes stay low, but not necessarily. More extreme weather events could cause Great Lakes water levels to change, too, which could lead to extremely high or extremely low water.

In October, surface water hydrologist and University of Wisconsin-Madison doctoral student Evan Murdock presented on climate change to a group of Door County residents and municipal board members. He explained climate modeling and predictions for the Great Lakes region.

Murdoch said most climate models suggest future water levels will be lower than average and the region will experience more summer storms, more heat waves and more snow.

There was only one takeaway point from that presentation: uncertainty is the only certainty.

That point doesn’t help shoreline residents decide whether or not to extend their docks, or comfort marina owners paying for dredging year after year.

Instead, Murdoch suggested designing shoreline homes and communities to be adaptable to a changing climate. Marinas should install floating docks to avoid dredging, towns should require new developments be set back farther from the water in case of floods, landscapers should plant heat-tolerant vegetation and everyone should create emergency response plans in case of extreme weather.

University of Wisconsin Sea Grant scientists are working on projects that could guide shoreline communities into an unpredictable future. Gene Clark is building a tool that will show the potential economic impacts to navigation, ports, harbors and marinas that could result from climate change, and David Hart is building a tool to visualize the shoreline and water level change for three Great Lakes harbors.

Whatever comes with the future, whether it’s high water or low, the ability to deal with unpredictable weathers will be shoreline communities’ greatest asset.