The Death and Life of the Great Lakes

by Dan Egan

At about 170 feet high, the falls that tumble over the Niagara escarpment near present-day Buffalo, New York, are nowhere near the world’s tallest or even largest by volume. But they were among the most ecologically important because they created an impassable barrier for fish and other aquatic life trying to migrate upstream from Lake Ontario into the other four Great Lakes.

Despite the upgrades, the new canal would be made obsolete later in the 20th century by trains and roads that could move goods much more quickly, and—equally importantly—do it throughout the winter months when the canal froze solid.

SHIPPING WITHIN THE GREAT LAKES AND ALONG THE SEAWAY and the North Atlantic coast remains a huge business to this day, moving some 200 million tons per year of raw industrial materials like ore, sand, salt and chemicals. And much of it travels through the Seaway locks. But the overseas component of the Seaway’s traffic, which peaked at 23.1 million tons in the late 1970s, has dropped in some recent years to less than 6 million tons. Today overseas cargo typically accounts for about 5 percent or less of the overall Great Lakes and St. Lawrence Seaway shipping industry.

In 1972, Congress overrode a President Nixon veto and approved a sweeping package of amendments to the existing federal water pollution regulations that are known today as the Clean Water Act. This turned the tables by establishing the principle that industry does not have a “right” to pollute and must therefore apply for a permit to do so.

But the Environmental Protection Agency left one huge loophole in the law the year after it was passed when it expanded an exemption for water discharges from military vessels to all ships sailing in U.S. waters. The agency was likely motivated by the notion that without a ship discharge exemption, its regulators could be on the hook to somehow police millions of recreational boats. Whatever the reason, the agency clearly did not see freighter discharges as a threat. “This type of discharge generally causes little pollution,” the EPA explained when it published the regulation creating the exemption, “and the exclusion of vessel wastes from the permit requirements will reduce administrative costs drastically.” But it would cost the Great Lakes dearly. As the zebra mussel infestation of the Great Lakes would make it abundantly clear, biologically contaminated ballast water is the worst kind of pollution because it cannot be fixed by plugging a pipe or capping a smokestack. It does not decay and it does not disperse. It breeds.

How important was this 6-foot-deep ditch to the development of Chicago? Its population was less than 5,000 in 1840, at the time the canal was under construction. Just over a decade after the canal opened in 1848, the city’s population burst to more than 100,000, and it nearly tripled again in the following decade. Barges pulled by mule across the divide were laden with so much cargo—grain, lumber, livestock and foodstuffs like fruit, sugar, salt, molasses and whiskey—that Chicago, once a swamp in the middle of the continent, had become the nation’s busiest port by 1869.

In its pristine state, the waters of Lake Erie were already primed to sustain an abundance of algae—the foundation of its food web. The warmest, shallowest and furthest south of the Great Lakes, it was naturally loaded with the building blocks of life—among them carbon, oxygen, hydrogen, nitrogen, zinc, copper, calcium and silicon. This is why Lake Erie, which holds only 2 percent of the overall volume of Great Lakes water, is home to about 50 percent of Great Lakes fish.

farm runoff, like ballast water, was left largely untouched by the Clean Water Act of 1972. The goal of the law was to go after polluters that own pipes, referred to in regulatory parlance as “point sources.”

As with the phosphorus reductions demanded of cities and industries that brought sweeping, if short-lived, algae reductions on Lake Erie three decades ago, scientists say they know how to throttle these new toxic outbreaks. It will require a 40 percent reduction in the spring phosphorus runoffs into the Maumee River watershed. This won’t completely eliminate the outbreaks, but ecologists predict it will slash them by at least 90 percent. Don Scavia, director of the University of Michigan’s Graham Sustainability Institute, notes that 40 percent also happens to be the percent of corn production in this country that goes toward ethanol. “We need,” he says with an irony that could be ripped straight from the pages of Dr. Seuss, “to stop putting food in our gas tanks.”

The air temperature increase in the Great Lakes region, however slight, has been enough to dramatically reduce Superior’s average ice cover. And without a bright white winter cap to bounce solar radiation back into the sky, the lake continues to soak up heat, even during the snow season. It turns out this jump-start on the annual warming process has a profound effect on peak surface water temperatures during the summer.

“The intuition is that a very large lake like this would be slow to respond somehow to climate change,” he said. “But in fact we’re finding that it’s particularly sensitive.”

But the temperature increase could prove disastrous for the lakes’ long-term water levels because it is driving up evaporation rates. NOAA data show that evaporation on Michigan and Huron was above average every year from 2013 dating back to 1999, when the lakes’ record long low-water era began. With little to no protective winter ice cap, chilled air whooshing over relatively warm water leads to more evaporation. The result of this thermal avalanche triggered by just a tiny blip in air temperatures: the surface of the lakes is going poof into the sky.