Too few farmers are curbing pollution in Lake Erie. Should they be forced?

As the cyanobacteria die, they settle to the bottom of the lake, creating a feast for microbes that consume oxygen as they devour the remains. That has caused a massive dead zone — an area without enough oxygen for marine life to thrive — in the lake’s central basin. To avoid suffocating, fish are forced to swim to less-desirable habitats.

Today, Lake Erie has the Great Lakes’ most abundant fish population, in part because it is so nutrient-rich. In Ohio alone, recreational fishing for the lake’s prized walleye, perch and other species brings in more than $1 billion a year. But scientists believe a worsening dead zone could bring major long-term consequences for the food web.

While it’s not yet clear how climate change will alter the forces at play in the lake, said Laura Johnson, director of the National Center for Water Quality Research at Ohio’s Heidelberg University, one thing is evident: “The lake is going to get more susceptible to blooms.”

That’s in large part because toxic algae thrive in warm water. The Great Lakes are already warming, and are expected to get still warmer as the climate changes. One EPA study found Lake Erie, already the warmest and shallowest Great Lake, gained .74 degrees between 1995 and 2015.

A study last year found that a 2 degrees Celsius temperature increase — which scientists expect to see in Lake Erie by 2050 if climate change continues unabated — would cause blooms to start 10 days earlier and grow 23 percent more intense. 

Meanwhile, climate change also brings wetter springs to the Great Lakes. The region has experienced a 10 percent increase in precipitation since 1901, and 2019 was Michigan’s wettest on record.

It’s not clear how those changes will affect agriculture. When heavy rain falls after farmers have fertilized their fields, it can send more nutrient-laden runoff gushing into Lake Erie despite farmers’ efforts to reduce overall fertilizer use. On the other hand, warmer temperatures could offset the impacts of heavier rain, hastening evaporation to reduce runoff.

A complex set of factors drives the blooms, from the lake’s shallow warmth, to its artificially-inflated nutrient loads, to the invasive mussels that give cyanobacteria a competitive advantage by devouring other types of algae.

But none is more significant than the heavy loads of phosphorus that pour into the lake from farms, feedlots, lawns and wastewater pipes, providing a ready source of fuel for cyanobacteria. So-called “non-point” sources, such as fertilizer and manure runoff, are responsible for the bulk of those nutrients.

Yet environmental regulators have long hesitated to get tougher on farmers by requiring (and not just asking) them to reduce pollution loads, even as they ratcheted up regulations on factories and sewage treatment plants that are far smaller contributors to the bloom.

The Great Lakes Water Authority, for instance, has spent millions on upgrades at its Detroit wastewater treatment facility in recent years, reducing phosphorus discharges into the Rogue River, which drains into the Detroit River and on to Lake Erie, by 60 percent. The reductions are a point of pride, said Majid Khan, the authority’s director of wastewater operations. But “in order to see a larger impact (on algae blooms), you need to address the … contribution coming from other sources,” referring to the region’s vast farming operations. 

State environmental regulators agree. Reducing farm runoff will be key to meeting the 2025 goal, said Michelle Selzer, Lake Erie coordinator for the Michigan Department of Environment, Great Lakes and Energy.

“Our focus now,” Selzer said, “is how do we get there?” 

The voluntary conservation paradox

At the root of the question lies the Clean Water Act, a revolutionary federal environmental law that has triggered dramatic improvements to water quality in U.S. lakes and streams since the 1970s. 

Landmark revisions in 1972 imposed pollution controls on industries that formerly dumped sewage freely into the nation’s waterways, triggering environmental disasters such as the 1969 Rouge and Cuyahoga river fires and polluting Lake Erie so badly that some declared it “dead.”

The Clean Water Act tamped down so-called “point source pollution” from factory drains and sewer pipes. But Congress chose not to regulate pollution from less-direct sources, such as fertilizer that seeps from farms and lawns. That left states and Native American tribes to decide how best to control these “non-point” sources.

Most, including Ohio, Michigan and Indiana, shy away from regulation in favor of promoting programs that pay farmers to voluntarily rein in pollution. Ontario’s plan for Lake Erie also emphasizes voluntary cooperation.

The programs are popular, but underfunded, which means that plenty of farmers willing to participate are left out. One, the federal Environmental Quality Incentives Program,…