The Supreme Court just shriveled federal protection for wetlands, leaving many of these valuable ecosystems at risk

Many ecologically important wetlands, like these in Kulm, N.D., lack surface connections to navigable waterways. USFWS Mountain-Prairie/Flickr, CC
Many ecologically important wetlands, like these in Kulm, N.D., lack surface connections to navigable waterways. USFWS Mountain-Prairie/Flickr, CC

By Albert C. Lin, The Conversation

The U.S. Supreme Court has ruled in Sackett v. EPA that federal protection of wetlands encompasses only those wetlands that directly adjoin rivers, lakes and other bodies of water. This is an extremely narrow interpretation of the Clean Water Act that could expose many wetlands across the U.S. to filling and development.

Under this keystone environmental law, federal agencies take the lead in regulating water pollution, while state and local governments regulate land use. Wetlands are areas where land is wet for all or part of the year, so they straddle this division of authority.

Swamps, bogs, marshes and other wetlands provide valuable ecological services, such as filtering pollutants and soaking up floodwaters. Landowners must obtain permits to discharge dredged or fill material, such as dirt, sand or rock, in a protected wetland.

This can be time-consuming and expensive, which is why the Supreme Court’s ruling on May 25, 2023, will be of keen interest to developers, farmers and ranchers, along with conservationists and the agencies that administer the Clean Water Act – namely, the Environmental Protection Agency and the U.S. Army Corps of Engineers.

For the last 45 years – and under eight different presidential administrations – the EPA and the Corps have required discharge permits in wetlands “adjacent” to water bodies, even if a dune, levee or other barrier separated the two. The Sackett decision upends that approach, leaving tens of millions of acres of wetlands at risk.


The Sackett case

Idaho residents Chantell and Mike Sackett own a parcel of land located 300 feet from Priest Lake, one of the state’s largest lakes. The parcel once was part of a large wetland complex. Today, even after the Sacketts cleared the lot, it still has some wetland characteristics, such as saturation and ponding in areas where soil was removed. Indeed, it is still hydrologically connected to the lake and neighboring wetlands by water that flows at a shallow depth underground.

In preparation to build a house, the Sacketts had fill material placed on the site without obtaining a Clean Water Act permit. The EPA issued an order in 2007 stating that the land contained wetlands subject to the law and requiring the Sacketts to restore the site. The Sacketts sued, arguing that their property was not a wetland.

In 2012, the Supreme Court held that the Sacketts had the right to challenge EPA’s order and sent the case back to the lower courts. After losing below on the merits, they returned to the Supreme Court with a suit asserting that their property was not federally protected. This claim in turn raised a broader question: What is the scope of federal regulatory authority under the Clean Water Act?

What are ‘waters of the United States’?

The Clean Water Act regulates discharges of pollutants into “waters of the United States.” Lawful discharges may occur if a pollution source obtains a permit under either Section 404 of the act for dredged or fill material, or Section 402 for other pollutants.

The Supreme Court has previously recognized that the “waters of the United States” include not only navigable rivers and lakes, but also wetlands and waterways that are connected to navigable bodies of water. But many wetlands are not wet year-round, or are not connected at the surface to larger water systems. Still, they can have important ecological connections to larger water bodies.

In 2006, when the court last took up this issue, no majority was able to agree on how to define “waters of the United States.” Writing for a plurality of four justices in U.S. v. Rapanos, Justice Antonin Scalia defined the term narrowly to include only relatively permanent, standing or continuously flowing bodies of water such as streams, oceans, rivers and lakes. Waters of the U.S., he contended, should not include “ordinarily dry channels through which water occasionally or intermittently flows.”

Acknowledging that wetlands present a tricky line-drawing problem, Scalia proposed that the Clean Water Act should reach “only those wetlands with a continuous surface connection to bodies that are waters of the United States in their own right.”

In a concurring opinion, Justice Anthony Kennedy took a very different approach. “Waters of the U.S.,” he wrote, should be interpreted in light of the Clean Water Act’s objective of “restoring and maintaining the chemical, physical, and biological integrity of the Nation’s waters.”

Accordingly, Kennedy argued, the Clean Water Act should cover wetlands that have a “significant nexus” with navigable waters – “if the wetlands, either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’”

Neither Scalia’s nor Kennedy’s opinion attracted a majority, so lower courts were left to sort out which approach to follow. Most applied Kennedy’s significant nexus standard, while a few held that the Clean Water Act applies if either Kennedy’s standard or Scalia’s is satisfied.

Regulators have also struggled with this question. The Obama administration incorporated Kennedy’s “significant nexus” approach into a 2015 rule that followed an extensive rulemaking process and a comprehensive peer-reviewed scientific assessment. The Trump administration then replaced the 2015 rule with a rule of its own that largely adopted the Scalia approach.

The Biden administration responded with its own rule defining waters of the United States in terms of the presence of either a significant nexus or continuous surface connection. However, this rule was promptly embroiled in litigation and will require reconsideration in light of Sackett v. EPA.

The Sackett decision and its ramifications

The Sackett decision adopts Scalia’s approach from the 2006 Rapanos case. Writing for a five-justice majority, Justice Samuel Alito declared that “waters of the United States” includes only relatively permanent, standing or continuously flowing bodies of water, such as streams, oceans, rivers, lakes – and wetlands that have a continuous surface connection with and are indistinguishably part of such water bodies.

None of the nine justices adopted Kennedy’s 2006 “significant nexus” standard. However, Justice Brett Kavanaugh and the three liberal justices disagreed with the majority’s “continuous surface connection” test. That test, Kavanaugh wrote in a concurrence, is inconsistent with the text of the Clean Water Act, which extends coverage to “adjacent” wetlands – including those that are near or close to larger water bodies.

“Natural barriers such as berms and dunes do not block all water flow and are in fact evidence of a regular connection between a water and a wetland,” Kavanaugh explained. “By narrowing the Act’s coverage of wetlands to only adjoining wetlands, the Court’s new test will leave some long-regulated adjacent wetlands no longer covered by the Clean Water Act, with significant repercussions for water quality and flood control throughout the United States.”

The majority’s ruling leaves little room for the EPA or the Army Corps of Engineers to issue new regulations that could protect wetlands more broadly.

The court’s requirement of a continuous surface connection means that federal protection may no longer apply to many areas that critically affect the water quality of U.S. rivers, lakes and oceans – including seasonal streams and wetlands that are near or intermittently connected to larger water bodies. It might also mean that construction of a road, levee or other barrier separating a wetland from other nearby waters could remove an area from federal protection.

Congress could amend the Clean Water Act to expressly provide that “waters of the United States” includes wetlands that the court has now stripped of federal protection. However, past efforts to legislate a definition have fizzled, and today’s closely divided Congress is unlikely to fare any better.

Whether states will fill the breach is questionable. Many states have not adopted regulatory protections for waters that are outside the scope of “waters of the United States.” In many instances, new legislation – and perhaps entirely new regulatory programs – will be needed.

Finally, a concurring opinion by Justice Clarence Thomas hints at potential future targets for the court’s conservative supermajority. Joined by Justice Neil Gorsuch, Thomas suggested that the Clean Water Act, as well as other federal environmental statutes, lies beyond Congress’ authority to regulate activities that affect interstate commerce, and could be vulnerable to constitutional challenges. In my view, Sackett v. EPA might be just one step toward the teardown of federal environmental law.

This is an update of an article originally published on Sept. 26, 2022.

Are gas stoves bad for your health? Here’s why the federal government is considering new safety regulations

Gas stove. Photo by Andrea Piacquadio.
Gas stove. Photo by Andrea Piacquadio.

By Jonathan Levy, The Conversation

Cooks love their gadgets, from countertop slow cookers to instant-read thermometers. Now, there’s increasing interest in magnetic induction cooktops – surfaces that cook much faster than conventional stoves, without igniting a flame or heating an electric coil.

Some of this attention is overdue: Induction has long been popular in Europe and Asia, and it is more energy-efficient than standard stoves. But recent studies have also raised concerns about indoor air emissions from gas stoves.

Academic researchers and agencies such as the California Air Resources Board have reported that gas stoves can release hazardous air pollutants while they’re operating, and even when they’re turned off. A 2022 study by U.S. and Australian researchers estimates that nearly 13% of current childhood asthma cases in the U.S. are attributable to gas stove use.

Dozens of U.S. cities have adopted or are considering regulations that bar natural gas hookups in new-construction homes after specified dates to speed a transition away from fossil fuels. At the same time, at least 20 states have adopted laws or regulations that prohibit bans on natural gas.

On Jan. 9, 2023, the U.S. Consumer Product Safety Commission announced that it will consider measures to regulate hazardous emissions from gas stoves. The agency has not proposed specific steps yet, and said that any regulation will “involve a lengthy process.” On Jan. 11, CPSC Chair Alexander Hoehn-Saric further clarified that the agency was looking for ways to reduce indoor air quality hazards, but did not plan to ban gas stoves.

As an environmental health researcher who does work on housing and indoor air, I have participated in studies that measured air pollution in homes and built models to predict how indoor sources would contribute to air pollution in different home types. Here is some perspective on how gas stoves can contribute to indoor air pollution, and whether you should consider shifting away from gas.

Natural gas has long been marketed as a clean fuel, but research on its health and environmental effects is calling that idea into question.

Respiratory effects

One of the main air pollutants commonly associated with using gas stoves is nitrogen dioxide, or NO₂, which is a byproduct of fuel combustion. Nitrogen dioxide exposures in homes have been associated with more severe asthma and increased use of rescue inhalers in children. This gas can also affect asthmatic adults, and it contributes to both the development and exacerbation of chronic obstructive pulmonary disease.

Nitrogen dioxide in homes comes both from outdoor air that infiltrates indoors and from indoor sources. Road traffic is the most significant outdoor source; unsurprisingly, levels are higher close to major roadways. Gas stoves often are the most substantial indoor source, with a greater contribution from large burners that run longer.

The gas industry’s position is that gas stoves are a minor source of indoor air pollutants. This is true in some homes, especially with respect to exposures averaged over months or years.

But there are many homes in which gas stoves contribute more to indoor nitrogen dioxide levels than pollution from outdoor sources does, especially for short-term “peak” exposures during cooking time. For example, a study in Southern California showed that around half of homes exceeded a health standard based on the highest hour of nitrogen dioxide concentrations, almost entirely because of indoor emissions.

How can one gas stove contribute more to your exposure than an entire highway full of vehicles? The answer is that outdoor pollution disperses over a large area, while indoor pollution concentrates in a small space.

Ventilation is an essential tool for improving indoor air quality in homes.

How much indoor pollution you get from a gas stove is affected by the structure of your home, which means that indoor environmental exposures to NO₂ are higher for some people than for others. People who live in larger homes, have working range hoods that vent to the outdoors and have well-ventilated homes in general will be less exposed than those in smaller homes with poorer ventilation.

But even larger homes can be affected by gas stove usage, especially since the air in the kitchen does not immediately mix with cleaner air elsewhere in the home. Using a range hood when cooking, or other ventilation strategies such as opening kitchen windows, can bring down concentrations dramatically.

Methane and hazardous air pollutants

Nitrogen dioxide is not the only pollutant of concern from gas stoves. Some pollution with potential impacts on human health and Earth’s climate occurs when stoves aren’t even running.

A 2022 study estimated that U.S. gas stoves not in use emit methane – a colorless, odorless gas that is the main component of natural gas – at a level that traps as much heat in the atmosphere as about 400,000 cars.

Some of these leaks can go undetected. Although gas distributors add an odorant to natural gas to ensure that people will smell leaks before there is an explosion risk, the smell may not be strong enough for residents to notice small leaks.

Some people also have a much stronger sense of smell than others. In particular, those who have lost their sense of smell – whether from COVID-19 or other causes – may not smell even large leaks. One recent study found that 5% of homes had leaks that owners had not detected that were large enough to require repair.

This same study showed that leaking natural gas contained multiple hazardous air pollutants, including benzene, a cancer-causing agent. While measured concentrations of benzene did not reach health thresholds of concern, the presence of these hazardous air pollutants could be problematic in homes with substantial leaks and poor ventilation.

Methane leaks from natural gas at all stages of production and use. UC Santa Barbara, CC BY-ND
Methane leaks from natural gas at all stages of production and use. UC Santa Barbara, CC BY-ND

Reasons to switch: Health and climate

So, if you live in a home with a gas stove, what should you do and when should you worry? First, do what you can to improve ventilation, such as running a range hood that vents to the outdoors and opening kitchen windows while cooking. This will help, but it won’t eliminate exposures, especially for household members who are in the kitchen while cooking takes place.

If you live in a smaller home or one with a smaller closed kitchen, and if someone in your home has a respiratory disease like asthma or chronic obstructive pulmonary disease, exposures may still be concerning even with good ventilation. Swapping out a gas stove for one that uses magnetic induction would eliminate this exposure while also providing climate benefits.

There are multiple incentive programs to support gas stove changeovers, given their importance for slowing climate change. For example, the recently signed Inflation Reduction Act of 2022, which includes many provisions to address climate change, offers rebates for the purchase of high-efficiency electric appliances such as stoves.

Moving away from gas stoves is especially important if you are investing in home energy efficiency measures, whether you are doing it to take advantage of incentives, reduce energy costs or shrink your carbon footprint. Some weatherization steps can reduce air leakage to the outdoors, which in turn can increase indoor air pollution concentrations if residents don’t also improve kitchen ventilation.

In my view, even if you’re not driven to reduce your carbon footprint – or you’re just seeking ways to cook pasta faster – the opportunity to have cleaner air inside your home may be a strong motivator to make the switch.

This article has been updated to reflect the Jan. 11, 2023 statement from the Consumer Product Safety Commission that the agency has no plans to ban gas stoves.

Ants – with their wise farming practices and efficient navigation techniques – could inspire solutions for some human problems

Photo by Kumar Kranti Prasad

By Scott Solomon, The Conversation

King Solomon may have gained some of his famed wisdom from an unlikely source – ants.

According to a Jewish legend, Solomon conversed with a clever ant queen that confronted his pride, making quite an impression on the Israelite king. In the biblical book of Proverbs (6:6-8), Solomon shares this advice with his son: “Look to the ant, thou sluggard, consider her ways and be wise. Which having no guide, overseer, or ruler, provideth her meat in the summer, and gathereth her food in the harvest.”

While I can’t claim any familial connection to King Solomon, despite sharing his name, I’ve long admired the wisdom of ants and have spent over 20 years studying their ecology, evolution and behaviors. While the notion that ants may offer lessons for humans has certainly been around for a while, there may be new wisdom to gain from what scientists have learned about their biology.

Ants have evolved highly complex social organizations.

Lessons from ant agriculture

As a researcher, I’m especially intrigued by fungus-growing ants, a group of 248 species that cultivate fungi as their main source of food. They include 79 species of leafcutter ants, which grow their fungal gardens with freshly cut leaves they carry into their enormous underground nests. I’ve excavated hundreds of leafcutter ant nests from Texas to Argentina as part of the scientific effort to understand how these ants coevolved with their fungal crops.

Much like human farmers, each species of fungus-growing ant is very particular about the type of crops they cultivate. Most varieties descend from a type of fungus that the ancestors of fungus-growing ants began growing some 55 million to 65 million years ago. Some of these fungi became domesticated and are now unable to survive on their own without their insect farmers, much like some human crops such as maize.

Ants started farming tens of millions of years before humans.

Ant farmers face many of the same challenges human farmers do, including the threat of pests. A parasite called Escovopsis can devastate ant gardens, causing the ants to starve. Likewise in human agriculture, pest outbreaks have contributed to disasters like the Irish Potato Famine, the 1970 corn blight and the current threat to bananas.

Since the 1950s, human agriculture has become industrialized and relies on monoculture, or growing large amounts of the same variety of crop in a single place. Yet monoculture makes crops more vulnerable to pests because it is easier to destroy an entire field of genetically identical plants than a more diverse one.

Industrial agriculture has looked to chemical pesticides as a partial solution, turning agricultural pest management into a billion-dollar industry. The trouble with this approach is that pests can evolve new ways to get around pesticides faster than researchers can develop more effective chemicals. It’s an arms race – and the pests have the upper hand.

Ants also grow their crops in monoculture and at a similar scale – after all, a leafcutter ant nest can be home to 5 million ants, all of which feed on the fungi in their underground gardens. They, too, use a pesticide to control Escovopsis and other pests.

Yet, their approach to pesticide use differs from humans’ in one important way. Ant pesticides are produced by bacteria they allow to grow in their nests, and in some cases even on their bodies. Keeping bacteria as a living culture allows the microbes to adapt in real time to evolutionary changes in the pests. In the arms race between pests and farmers, farming ants have discovered that live bacteria can serve as pharmaceutical factories that can keep up with ever-changing pests.

Whereas recent developments in agricultural pest management have focused on genetically engineering crop plants to produce their own pesticides, the lesson from 55 million years of ant agriculture is to leverage living microorganisms to make useful products. Researchers are currently experimenting with applying live bacteria to crop plants to determine if they are effective at producing pesticides that can evolve in real time along with pests.

Improving transportation

Ants can also offer practical lessons in the realm of transportation.

Ants are notoriously good at quickly locating food, whether it’s a dead insect on a forest floor or some crumbs in your kitchen. They do this by leaving a trail of pheromones – chemicals with a distinctive smell ants use to guide their nest mates to food. The shortest route to a destination will accumulate the most pheromone because more ants will have traveled back and forth along it in a given amount of time.

In the 1990s, computer scientists developed a class of algorithms modeled after ant behavior that are very effective at finding the shortest path between two or more locations. Like with real ants, the shortest route to a destination will accumulate the most virtual pheromone because more virtual ants will have traveled along it in a given amount of time. Engineers have used this simple but effective approach to design telecommunication networks and map delivery routes.

Photo by Carlos Pernalete Tua

Not only are ants good at finding the shortest route from their nests to a source of food, thousands of ants are capable of traveling along these routes without causing traffic jams. I recently began collaborating with physicist Oscar Andrey Herrera-Sancho to study how leafcutter ants maintain such a steady flow along their foraging paths without the slowdowns typical of crowded human sidewalks and highways.

We are using cameras to track how each individual ant responds to artificial obstacles placed on their foraging trails. Our hope is that by getting a better understanding of the rules ants use to respond to both obstacles and the movement of other ants, we can develop algorithms that can eventually help program self-driving cars that never get stuck in traffic.

Look to the ant

To be fair, there are plenty of ways ants are far from perfect role models. After all, some ant species are known for indiscriminate killing, and others for enslaving babies.

But the fact is that ants remind us of ourselves – or the way we might like to imagine ourselves – in many ways. They live in complex societies with division of labor. They cooperate to raise their young. And they accomplish remarkable engineering feats – like building structures with air funnels that can house millions – all without blueprints or a leader. Did I mention their societies are run entirely by females?

There is still a lot to learn about ants. For example, researchers still don’t fully understand how an ant larva develops into either a queen – a female with wings that can live for 20 years and lay millions of eggs – or a worker – a wingless, often sterile female that lives for less than a year and performs all the other jobs in the colony. What’s more, scientists are constantly discovering new species – 167 new ant species were described in 2021 alone, bringing the total to more than 15,980.

By considering ants and their many fascinating ways, there’s plenty of wisdom to be gained.