Planet Ooze

One million species of plants and animals—one in eight of all known species—are currently at risk of extinction. Air pollution kills eight million people each year, accounting for an eighth of all deaths worldwide. Levels of carbon dioxide, methane, and nitrous oxide in the atmosphere reached record highs in 2023, as did fossil fuel consumption and global average surface temperatures. Now 2024 has been confirmed as the hottest year since pre-industrial times, and it is likely to exceed those other climate milestones from 2023, too. In the US, per- and polyfluoroalkyl substances—aka PFAS, the toxic “forever chemicals” used in nonstick pans and many other consumer and industrial goods—have made their way into everyone’s bloodstreams and almost half of all tap water. Microplastics were found in every human placenta examined in one recent study and in each human testicle examined in another; they can also be found suspended in an ocean gyre dubbed the Great Pacific Garbage Patch that is twice the size of Texas. In the Gulf of Mexico, there is an oxygen-starved “dead zone” the size of Connecticut that sometimes swells to New Jersey proportions.

What should we do with all this overwhelming information? One response: organize it all into one Earth-encompassing dashboard. That’s what the cross-disciplinary and transnational team of scientists behind the Planetary Boundaries project has done in a series of papers, starting with a groundbreaking 2009 article in Nature that was followed by updates in 2015 and 2023. These researchers have attempted to define a “safe operating space for humanity” by delineating nine global processes that are “critical for maintaining the stability and resilience of the Earth system as a whole” and setting safety thresholds for each. Transgress those boundaries, they warn, and we risk a breakdown of our planet’s fundamental life-enabling systems.

In the researchers’ latest report, nearly all the dashboard lights are blinking red. Of the nine processes, we’ve already crossed into the danger zone for six: climate change, biodiversity loss, land use change, freshwater use, nutrient flows into the environment, and “novel entities” (a catchall term for radioactive waste, plastics, and chemical pollution). We are accelerating toward the boundaries of two more: air pollution and ocean acidification. Only one—the still-healing ozone layer—is trending in the right direction.

The boundary we have overshot the furthest is the one that arguably gets the least attention: nutrient flows. That is the term these scientists use for the spillage of nitrogen and phosphorus from our agricultural and industrial processes into our ecosystems. Both nitrogen and phosphorus are “limiting factors” essential for plant growth. For billions of years, the rates at which those two elements cycled through the world’s food chains were relatively stable. Then the twentieth century brought industrial-scale phosphorus mining and scientific breakthroughs that unlocked the atmosphere’s nitrogen for fertilizer manufacturing.

We waste a staggering amount of both critical nutrients. Nitrogen and phosphorus are now flowing into the environment at up to three times the rate at which they can be absorbed. Farmers apply far more synthetic fertilizer and manure to their fields than is necessary as a kind of insurance policy to boost crop yields, and much of it washes into waterways instead of being taken up into stalks of corn or soybeans. Runoff fuels toxic algal blooms downstream. This cascading phenomenon—life-enabling nutrients becoming an engine for death—can be found all over the world, but the most glaring example is the Gulf’s dead zone, which chokes off aquatic life and the fisheries that anchor the region’s economy.

Art Cullen, the editor of The Storm Lake Times Pilot in Iowa, wrote about what he saw on a road trip in the spring of 2024, including heavy rains turning the Raccoon, Des Moines, and Mississippi Rivers into nutrient superhighways:

About 30 percent of the nitrogen applied for raising corn is lost to water, and much of it right now is draining off in the spring rise. All that detritus, the tons upon tons of soil with phosphorus mixed in, float downstream past St. Louis, Baton Rouge and New Orleans, suffocating the Gulf of Mexico for the sake of corn, wheat, cotton and rice…. Methane is cheap in the gulf, where oil and gas derricks line the horizon. We ship the gas upstream to Iowa, where it is processed into anhydrous ammonia for fertilizer. Farmers inject it in the soil to feed the corn that feeds the hogs that create the phosphorus in their manure. It flushes down the Raccoon all over again.

Phosphorus is much harder to come by than nitrogen. It can be found in dilute quantities in plants and soil, and in higher concentrations in animal manure. But the primary sources for modern agriculture are deposits of ancient sedimentary phosphate rock scattered around the globe, from central Florida to Morocco to China.

“No phosphorus, no life on Earth,” as the journalist Dan Egan explains in The Devil’s Element, his account of how this confounding element helps to keep the plates of modern civilization spinning—and how some plates may be starting to wobble and crash to the floor. Without steady supplies of phosphorus, there can be no mass production of corn, soy, wheat, vegetables—all the staples that feed eight billion people and counting. One ton of phosphate is needed to produce 130 tons of grain. Egan quotes Isaac Asimov’s blunt assessment in 1974: “Life can multiply until all the phosphorus is gone and then there is an inexorable halt which nothing can prevent.”

Phosphorus is a global commodity that’s also a fundamental building block of life. Our helical DNA strands are woven from it, and it’s the primary ingredient in ATP, the molecule that delivers energy between our cells. Our bones and teeth are mostly built out of calcium and phosphorus. But an excess of it in the environment can crowd out another life-giving element: oxygen. Phosphorus and nitrogen carried to sea by the Mississippi fertilize plumes of algae that die, sink, and suck up oxygen as they decompose, creating that hypoxic expanse in the Gulf of Mexico.

In the Great Lakes and smaller bodies of water around the country, excess phosphorus fuels a particularly deadly kind of bloom: blue-green algae. Egan offers vivid descriptions of these Twilight Zone–ish blobs—made up of cyanobacteria that produce a range of toxins (including one scientists have dubbed “Very Fast Death Factor”)—that are taking over America’s shorelines, threatening local fishing and tourism industries, and even gumming up municipal water supplies.

The Devil’s Element is a tale of folly, waste, greed, and excess, which Egan unspools with a light touch and a brisk pace. He opens the book with a police foot chase; the unfortunate suspect is eventually fished out of an algae-choked canal and hospitalized in Cape Coral, Florida. In its final pages he describes a pilot project to capture phosphorus from the pee of residents of Brattleboro, Vermont, and its use of an educational video featuring a talking drop of urine named Uri Nation. Along the way we meet Hennig Brand, an alchemist who first succeeded in isolating pure phosphorus from urine in 1669 while searching for the philosopher’s stone, the mythical substance that could turn lead to gold. Others quickly discovered that while the waxy, glowing stuff did not produce gold, it was poisonous, extremely unstable as a solid at room temperature, and prone to exploding. These properties earned it the moniker “the Devil’s element,” which in turn presaged its other modern application as an ingredient in some of the most horrendous weapons that humans use on one another. (Egan writes about a German beachcomber whose leg began to melt and char after a small orange rock he had collected exploded in his pants—a pebble-size legacy of the Allied firebombing of Hamburg in 1943 washed up on a Baltic shore.)

At the outset of the Industrial Revolution many nation-states figured out that they couldn’t feed their fast-growing populations without finding a lot more phosphorus than was available from manure and crop residues and naturally occurring in soils. Egan gives a grim global tour of the various predatory lengths to which imperial powers and modern multinational firms have gone to secure phosphorus. Soon after the Battle of Waterloo the British dug up their own fallen soldiers’ phosphorus-rich bones, shipped them home, then heated and ground them up as fertilizer to grow food for the living. In the middle of the nineteenth century, European and American farmers became reliant on imports of guano (bird poop) strip-mined from Peruvian islands by indentured Chinese laborers. When those reserves were exhausted in the 1890s, they turned elsewhere. Thus began the century-long ordeal of the Banaba Islanders, displaced from their Pacific homeland by the voracious English-owned, Australia-based Pacific Phosphate Company. After a company agent discovered vast reserves of phosphorus-laden rock on Banaba one day in 1900, the firm’s miners carved up the island chunk by chunk. The rocks were carried by conveyor belt to ships that ferried them onward to fertilize fields around the world. Banaba’s destruction helped Australia and New Zealand boost the productivity of their soils and become wealthy agricultural exporters. After the late 1970s Banaba’s phosphate reserves were largely depleted—by that point, mining firms had stripped 90 percent of the island’s land surface and removed 22 million tons of material. In the process, they also ruined many of the sacred caves where the islanders had collected water to survive periods of drought.

The case of Western Sahara is also instructive. Today it is on the United Nations’ list of “non-self-governing territories”—in other words, nations without a nation. Western Sahara was occupied by Morocco in 1975 in a very short war, soon after Spain had relinquished its colonial claims on the country. The Western Saharans were forcibly resettled; most still live in tent camps in Algeria. Their plight has one proximate cause: Morocco’s desire to maintain its grip on the global phosphate market. Morocco holds more than 70 percent of the world’s phosphate rock reserves. Its state-owned fertilizer producer accounts for a fifth of the country’s total export revenue and is the biggest employer. Western Sahara has significant deposits of phosphate—not nearly as large as Morocco’s, but large enough to potentially undermine its ability to set prices for a commodity that is essential for human survival.

As one expert tells Egan, “Phosphorus is a hell of a lot more critical than oil.” Each year about 250 million tons of phosphorus are dug out of sedimentary rocks around the world to be turned into fertilizer. Egan warns that the pace at which humans are extracting—and wasting—phosphorus cannot be sustained. Some experts see the US running out of its domestic reserves, most of which are in Florida and North Carolina, well before the end of the century. Estimates for the life span of known global phosphate reserves range from a few decades to four hundred years, depending on the rate at which we continue to let it spill into rivers, seas, and lakes.

Whether that happens or not, looming shortages will lead to higher food prices, unless and until new reserves are found or new ways to economically recover dilute sources of phosphorus are devised. Unlike some other Malthusian prophecies that never came to pass, this one looks harder to dodge. “The idea of energy security for three hundred million people suddenly looks like an easy problem to solve, at least compared to food security,” Egan writes.

Egan has become one of our most skillful chroniclers of unintended consequences. His first book, The Death and Life of the Great Lakes, is a masterful account of two centuries’ worth of reckless interventions in the world’s largest freshwater ecosystem. The book reads like a deadly serious blooper reel, in which people (usually overconfident white men) radically remake a supremely complex ecosystem they only dimly understand, and disaster after disaster unfolds for the native species of the lakes. Toward the end of that book, Egan writes about the most persistent and visible problem plaguing the Great Lakes, the one that led him to his next subject: toxic algal blooms caused by agricultural runoff.

Much of that pollution can be traced to industrialized cattle and hog farms. Farmers overuse chemical fertilizers on fields of corn and soybeans, much of which is turned into animal feed. Those animals produce huge volumes of manure, which then becomes an additional source of phosphorus pollution. As one farmer in Ohio’s Maumee River Basin tells Egan of his neighboring pig and dairy farmers, who spread manure on their fields that leaches into Lake Erie during the next downpour, “They’re trying to get rid of their shit.” It’s cheaper, after all, than hauling it away or building more manure storage lagoons. But the downstream effects are costly—and go far beyond swimming restrictions for beachgoers. In 2014 algal cyanobacteria toxins contaminated and shut down the entire water supply for 500,000 residents in and around the city of Toledo. National Guard troops trucked in bottled water until the city’s water treatment facility could be upgraded to deal with it.

Time and again, Egan’s reporting reminds us, we heedlessly tinker with systems we barely comprehend. Now, of course, we are doing that at a global scale and breakneck pace. Egan doesn’t put it this way, but the implicit question posed by both of his books is this: Can our civilization mature quickly enough to stop shitting where we eat?

On a local level, we know the answer is yes. In The Death and Life of the Great Lakes, Egan writes about the origins of the Chicago Sanitary and Ship Canal. Cholera outbreaks in Chicago caused by residents basically drinking their own sewage drove the city to build the canal in 1900, reversing the flow of the Chicago River and vastly improving local sanitation—by dumping waste into the southward-flowing Mississippi River instead. That’s long been humanity’s answer to pollution: just send it somewhere else. But as the cellular biologist Barry Commoner once observed, everything goes somewhere. And ecologically, there’s no such thing as a free lunch. Sometimes—and lately, more and more—our effluent oozes its way back to us.

Egan visits communities that have popped up in recent decades near Lake Okeechobee, the largest freshwater lake in Florida. These booming towns have drawn retirees from other parts of the US like moths to the porch light. But phosphorus from agricultural operations in surrounding counties is flowing into the lake at ten times the rate it can handle. Egan meets residents who became severely ill from inhaling airborne toxins released by cyanobacteria left baking in the sun. What’s the point of living canal-side in the sunshine, they wonder, if you can’t even go outside?

In his 2012 essay “State of the Species,” Charles Mann wrote:

As a relatively young species, we have an adolescent propensity to make a mess: we pollute the air we breathe and the water we drink, and appear stalled in an age of carbon dumping and nuclear experimentation that is putting countless species at risk including our own.

One way of thinking about phosphorus: it’s the clearest, most damning indicator that our civilization has yet to reach adulthood.

James Elser, a University of Montana ecologist and phosphorus expert, tells Egan that we’ll have to grow up in a hurry. “By 2050, nine, ten billion people will need to be fed and they are becoming more affluent as well, which is great, but that also means more meat production, and that puts more pressures on the phosphorus system,” he says. “We have to do that at the same time that we don’t forget people need to drink water as well…. We have to make these two things happen at the same time. That’s a challenge.”

Egan points out that phosphorus—essential for life but available in finite quantities unevenly distributed around the globe—just “isn’t nature-designed to be used once and then flushed away.” Yet that is exactly what we do with it. We are absurdly profligate with this precious element. He notes that as much as 80 percent of phosphate mined for food production is wasted—dispersed during mining and refining, washed away when rains hit fertilized fields, lost whenever uneaten food is tossed into the trash.

Egan shies away from offering grand “prescriptions,” but toward the end of The Devil’s Element he does have some modest suggestions for “steps we can take to pull some of that nuisance phosphorus back into the agricultural cycle, which could check burgeoning algae outbreaks and extend the life-expectancy of the Earth’s phosphorus reserves.”

He mostly focuses on tweaking the rules. One thing that would help, he says, is to close the waste loops: incentivize the capture and use of dilute phosphorus that currently escapes into the environment from human and animal waste and runoff. Another: close the loopholes in the Clean Water Act that let farmers off the hook for their phosphorus pollution. In the US, many farmers apply too much manure and fertilizer in a slapdash way, because they pay no penalty for the nutrients that escape their fields to pollute water bodies downstream. There are available technologies to improve the timing and precision of that application, but their use depends on policies that monitor and reward or punish agribusinesses.

The power of the farm lobby and the politics of corn ethanol subsidies already made that unlikely. Now that the Supreme Court has struck down Chevron deference to agencies’ interpretations of congressional statutes—and with it much of the administrative law precedent holding up the federal regulatory apparatus—it’s even less plausible that any future administration’s executive tweak to the Clean Water Act could survive legal challenges, absent further (also unlikely) action by Congress. As one legal expert told The Washington Post, “The real goal of the interest groups on the right that are backing this litigation is to enfeeble the federal government’s ability to deal with the problems that the modern world throws at us”—thereby freeing them from the costs of complying with water quality rules and other bothersome regulations. Just as the dashboard lights are blinking brighter and faster, the Court’s conservative majority has locked the steering wheel and cut one of the brake lines. (In early March, the Court issued a ruling that weakened the Environmental Protection Agency’s authority to limit how much sewage cities and counties can discharge into water bodies.) The new Trump administration is now moving rapidly to disable other key safety mechanisms: in February the president issued an executive order directing the Army Corps of Engineers to expedite permitting for new fossil fuel projects, which will weaken water quality protections across the country.

At a journalism conference in April 2024, I listened to the former Environmental Protection Agency administrator Michael Regan dodge two questions in a row about the dead zone in the Gulf, and when and whether the EPA might make it a priority. “It is a tough issue,” he told the first questioner. “What I can do is have some of my staff spend a little more time with you on some of the specific issues.” He made the same offer to the second questioner and said something about the need to “design more creative and rewarding voluntary programs” with the “agricultural community.” A few days later, the EPA announced the first-ever regulations limiting levels of certain PFAS in drinking water. Given their ubiquity, cleaning up PFAS will be devilishly difficult. Still, it’s easier to tackle pollution from single “point sources” like factories or within facilities like sewage and water treatment plants than it is to send inspectors out to examine ditches and drain tiles in farm fields all across the country. And due to the almost unmatched influence of the agribusiness lobby, forever chemicals may also prove to be a more politically tractable problem than phosphorus runoff.

The good news is that phosphorus flows don’t have to function as the hourglass marking our inexorable approach to civilization’s collapse. We can avoid Asimov’s dead end, if we choose, by making our food systems more efficient and getting better at capturing and recycling phosphorus from waste and effluent. Improved farming techniques such as planting cover crops and integrating livestock and crop production can reduce the need for chemical fertilizers, and new technologies can help farmers time and target their application more precisely. Shifting our diets away from meat and dairy and toward, say, legumes would also reduce fertilizer use for the growth of animal feed crops.

Such changes will require both cultural shifts and carefully designed policies. In her seminal essay “Leverage Points: Places to Intervene in a System,” the environmental scholar and systems theorist Donella Meadows described nine leverage points that can be used to change systems run amok. Some of the most powerful, she argued, are information flows, the rules of the system (e.g., incentives and penalties), and the goals of the system.

Egan’s books are an attempt to improve information flows, to shove all the repellent evidence right under our noses. The Planetary Boundaries project is another—an effort to quantify just how badly humanity is fouling its own nest. Critics of that approach point out that it’s impossible—hubristic, even—to precisely locate such thresholds. The choices are arbitrary, and the boundaries are all interconnected to boot, so how can we possibly quantify these limits with any confidence? What’s more, no element exists in isolation: perturb one, and you’ll have knock-on effects on the others.

On the other hand, if you start solving one problem then it’s possible you’ll make progress on solving others, too, in ways you might not predict. There’s a lesson to be found in the one planetary process that’s heading in the right direction: ozone. The Montreal Protocol, which enforced the phaseout of ozone-destroying chemicals, is widely viewed as the most effective environmental treaty ever signed. It represents nearly two hundred countries coming together to act in their collective self-interest, and it has done exactly what it was intended to do: patch the hole in the ozone layer.

And although its architects did not have climate change in mind, it has also turned out to be the world’s single most effective climate policy measure. By some estimates the treaty has averted a potential additional degree Fahrenheit of global warming by 2100 by banning ozone-depleting chlorofluorocarbons that also happen to be potent greenhouse gases. In trying to stave off one planetary disaster, the signatories bought us some time on another one. If we get more efficient with our finite phosphorus stores, we will also reduce our dependence on the fertilizers that are the primary drivers of the global surge in emissions of nitrous oxide, the greenhouse gas of most concern after carbon dioxide and methane. The same steps that would help solve our nutrient leakage crisis would go a long way toward reducing agriculture’s climate footprint. Sometimes concerted collective action has unintended consequences, too—but the good kind.