As Great Lakes water levels inched up this spring, perhaps headed toward record highs, a right-wing website crowed that environmentalists had been foiled. The greens’ forecast of plummeting levels under the influence of climate change was proving a wild inaccuracy.
But it was the wingers who were foiled. Apparently failing to read the fine print, they didn’t notice that environmental groups have become more nuanced in their predictions as recent modeling has suggested climate change could contribute to a decline in water levels (heat and extended drought) or rising water (frequent intense rainstorms). Or levels could remain roughly the same.
That the models pointed in various directions is testimony not only to the complexity of predicting the future generally, but also to the surprises the Great Lakes have in store for anyone who pretends to understand completely how they work. If there’s any sure lesson the Great Lakes teach, it’s this: the more we know, the more we know that we don’t know much.
It’s this reality that helps foster the dreaded refrain from scientists: more research is needed. It’s also this reality that should keep government officials humble and cautious in attempting to manage resources related to the Great Lakes.
One case in point is the recent decision by the Great Lakes states to permit the city of Waukesha, Wisconsin, to divert an average of approximately 8 million gallons a day from Lake Michigan to serve as its drinking water supply. The city would return an equivalent amount of water to the lake. Regardless of the merits of the decision, flat statements by some officials that the diversion would have little or no effect on Lake Michigan were unwise. The historical record demonstrates that a flip of the coin has sometimes been as accurate as supposedly expert, sage opinions like this one.

Another illustration of the need for humility is the fouling of western Lake Erie since the turn of the century. After suffering global embarrassment as an algae-choked dead lake in the 1960s, Erie made a rapid comeback in the 1970s and 1980s, thanks to strict environmental laws and a changing ethic in the citizenry.
In the early 1990s Lake Erie was celebrated as a success story for the ages. Thanks largely to strict concentration limits in laundry detergent and tougher discharge limits on sewage plants, phosphorus levels in the lake had fallen dramatically, eliminating most of the ugly algae that had served as a filthy green banner of pollution in the 1960s.
Determined to bray about the cleanup, governments went beyond what the scientists told them, proclaiming the job done. “Getting Better All the Time” was the title of a document on the lake’s progress put out by Ohio officials in the early 1990s.
But in 2002 news media surrounding Lake Erie once again pronounced it a water body in crisis.  The symptoms of the sickly patient began with a slow and worsening suffocation. The central basin of the lake, also the site of anoxia in the 1950s and 1960s, was nearly devoid of oxygen. The expansion of the “dead zone,” as many reporters called it, a natural phenomenon in the lake but now out of control, was alarming in part because it was seemingly inexplicable.

Scientists had multiple hypotheses. A warming climate, including a series of winters in which little or no ice blanketed Erie, might be depriving the central basin of oxygen. Algae that normally produce oxygen might, for some reason, no longer are doing so. Decaying wastes, including sewage and algae, might be consuming oxygen.

A so-called cousin to the zebra mussel, the quagga mussel, also introduced to the Great Lakes system through ballast water, might be the problem, said an Ohio State University professor. Releasing far more phosphorus as waste than the zebra mussel, the quagga might be fueling algae growth, and the decomposition of the algae might in turn be gobbling up critical oxygen.
It might have been easier to discern the cause of the sudden decline if overconfidence had not robbed governments of an important tool. In 1994, with the Lake Erie phosphorus goals of the early 1970s achieved, both nations discontinued monitoring of phosphorus dumping, or loadings, to the lake. “By not having the loading data, we cannot tell exactly what is happening these days in Lake Erie,” said an Ohio State University researcher.
The dead zone was less alarming and repulsive to the eye than the severe summertime algae blooms that began to dominate the western basin of Lake Erie around the same time. In August 2014, toxic blue-green algae tainted the water at the City of Toledo’ s Lake Erie intake, resulting in a public health advisory not to drink the water. In the summer of 2015, the western basin suffered its worst bloom in memory.
Not a single person – politician, bureaucrat, scientist, advocate – saw Lake Erie’s renewed decline coming. Nor did anyone forecast that runoff of the soluble fraction of phosphorus, mostly from farms, would be the culprit. Only now, more than a dozen years into the Third Battle of Lake Erie, are serious potential solutions beginning to emerge.
These Great Lakes are complicated systems with far too many variables for models to plot accurately. Fact- and data-averse politicians invest too few research dollars in them. Until we become far more sophisticated in our science, and more consistently fund the tools we need to monitor the Lakes, the mantra of not only government but private citizens must be “first do no harm.” And second, go respectfully about the business of learning more about them, so we can better steward them.
Dave Dempsey