As Microplastics Amass, Our Planet’s Plastic Problem Is Getting Personal

How the “forever” remnants of our plastic pollution are now threatening the integrity of key ecosystems we rely on to live and jeopardizing our health.

A floating “island” in the Pacific Ocean twice the size of Texas, the conglomerate of plastic trash known as the Great Pacific Garbage Patch bobs in the breeze, filled with straws that can lodge in the noses of turtles and six-pack rings and bottle caps that can strangle and choke sea creatures. It conjures a compelling visual—even if it falsely implies that the plastic-waste issue is contained, harming only the animals unlucky enough to brush up against the mass.

But what recent research suggests is that such easily visible garbage is “just the very tip of the iceberg” when it comes to the world’s plastic problem, says Matt Simon, science reporter at Wired and author of A Poison Like No Other: How Microplastics Corrupted Our Planet and Our Bodies. Beneath the surface, both literally and figuratively, is a massive number (in the trillions) of tiny microplastics and even tinier nanoplastics that are “accessible to the entire tree of life,” he says.

Occurring in a variety of shapes and colors, these mini plastics are unified by their size. Scientists refer to any plastics smaller than five millimeters (about the size of a sesame seed) as microplastics and have recently differentiated the very smallest of these pieces, smaller than 100 nanometers, as nanoplastics, which are not visible to the naked eye. The particular trouble that these tiny plastics pose is two-fold: It’s very tough to clean them up, and it’s very easy for them to pollute our ecosystems, as they can be either ingested or inhaled, or both, by all living things.

As for where they originate? Like any large plastic object, called a macroplastic, microplastics can, in some instances, be manufactured intentionally. Think: glitter, foam balls for bean bags, and microbeads in exfoliating cleansers of the 2010s. (After those microbeads were deemed a hazardous pollutant in 2015, a U.S. law banned the production of rinse-off cosmetics containing them, foreshadowing the crisis to come.) Also in this category are what’s known as pre-production nurdles or pellets, plastics created in the size of rice grains that are then transported to manufacturers, where they’re melted down to create things like shampoo bottles and chip bags. And in transit alone, these pellets have been known to spill in mass quantities.

But where the real core of the microplastics issue lies is a far more familiar source: the macroplastics—plastic bottles, bags, containers, even synthetic clothing (which is a type of plastic)—we use on a daily basis. Though these products are often proclaimed to last forever, it’s more accurate to say that they degrade forever, breaking down into tinier and tinier pieces (aka microplastics, and eventually, nanoplastics) that pollute our environment, compromising the balance of our planet’s ecosystems and creating ripple effects for our own well-being. “I like to think of macroplastics as microplastic pollution just waiting to happen,” says Anja Brandon, PhD, associate director of U.S. plastic policy at Ocean Conservancy.

To that end, any single macroplastic can disintegrate into a theoretically infinite number of micro- and nanoplastics over the course of its endless existence—and starting right away, when it encounters water, heat, or physical friction. In fact, one of the biggest contributors to microplastic pollution is a process that includes all of the above: washing clothes in the washing machine, which sends millions of microfibers into water-treatment facilities, where they can easily slip through filters and wind their way into waterways and the ocean.

The urgency of the microplastics crisis comes from its mega size: Humans around the globe currently produce roughly 300 million tons of plastic each year, more than ever in our history, and all of it will spend eternity breaking down, meaning the problem is a compounding one. As a result, microplastics are now everything, everywhere, all at once: Researchers have identified them not only in the ocean but in all compartments of the environment, from the air to freshwater systems and soil. “There’s nothing and nowhere on Earth that isn’t impacted by microplastics,” says Janice Brahney, PhD, associate professor at Utah State University's Watershed Sciences department.

How the effects of microplastics on ecosystems pose a threat to global well-being

Microplastics in the ocean

Of all environmental spaces, the ocean is where scientists have conducted the most microplastics research, largely because they happened upon them there first, identifying “plastic particles” floating atop the Sargasso Sea in the Atlantic Ocean in the 1970s. It wasn’t until 1997 that Captain Charles Moore discovered plastics were accumulating in the ocean en masse—cue the plastic island—and 2004 that Richard Moore coined the term “microplastics” to refer to the tiniest offenders.

Now, with the prevalence of microplastics and nanoplastics in the ocean, the issue of animals eating plastics extends to the smaller fish and microorganisms that can’t take down a full-sized macroplastic, says Dr. Brahney. And as nanoplastics and microplastics accumulate up the food chain—through even the tiniest zooplankton that accidentally eat them with algae, that are then eaten by larger fish that also eat nanoplastics and microplastics, and so on—they can cause direct harm at every stage. “These small plastics can lodge in the guts and gills [of fish], blocking their digestive tracts and leading them to feel full without absorbing key nutrients, and to stop eating,” says Dr. Brahney, “which eventually causes death.”

But these physical blockages aren’t the only threat to sea creatures; the breakdown of microplastics can cause chemical fallout, too. Manufacturers add a variety of chemicals to plastics—a set that includes upwards of 10,000 different options, some of them known toxins—to make them malleable, flameproof, waterproof, durable, or any number of other qualities. And these aren’t chemically bound to the actual plastic molecules, “so they can leach out like water from a sponge as the plastic breaks down,” says Dr. Brandon. The composition of plastic also creates room for the microplastic molecules to pick up other chemicals in the environment, like heavy metals and pesticides, and even bacterial pathogens, and transport these toxic hitchhikers up the food web. This, again, threatens the continued availability of the fish that we eat and the gentle balance of the ecosystem of which they’re all a part.

Climate research also points to a few ways that microplastics can interfere with the ocean’s helpful ability to trap carbon in its depths; this process is essential for cooling our planet by drawing a huge amount of carbon dioxide out of the atmosphere. Usually, it works like this: Carbon dioxide dissolves into water at the ocean’s surface, at which point algae absorbs it, and then zooplankton eat algae, eventually releasing the carbon as part of their poop, which sinks down to the ocean floor (for good). But now, that zooplankton poop is laden with the tiny plastics that they’re eating, too, which is causing it to sink more slowly. At the same time, microplastics may be toxic to zooplankton, shortening their lives and thus reducing their overall ability to trap carbon—again, a process we rely on to draw carbon out of the air and keep the planet cool.

Microplastics in the air and atmosphere

Microplastics suspended in the air we breathe pose a relatively new threat to the health of the planet and its inhabitants. Only in the past five years have scientists begun to identify and quantify airborne microplastics, and it wasn’t until 2020 research by Dr. Brahney’s team that it became clear how extensively these little particles are circling the atmosphere.

“Ten years ago, I was like, ‘Microplastics are a marine problem, and I don’t work in the marine environment.’ But we’ve polluted the ocean for so long with plastic [and to such a large extent in recent years] that now, microplastics are being aerosolized off the surface of the ocean and are traveling back, through wind, into the terrestrial environment,” says Dr. Brahney. Not to mention the mass amounts of microplastics being whipped directly into the air by car tires wearing down on roads. Indeed, the concentration of airborne microplastics is so large now (exact numbers are tough to come by, but thousands of tons is a ballpark estimate), they’re detectable even in regions of very high altitudes, hundreds of miles from urban centers.

Certainly, that means we’re breathing in microplastics. But from an ecological standpoint, the breakdown of plastics in the air also signals the release of potent greenhouse gasses like methane, says Simon. “It’s important to remember that 99 percent of plastics are still made out of fossil fuels—oil and gas,” he says, “and once they’re out in the environment and hit with sunlight, they release quantities of that carbon back into the atmosphere.” More carbon in the air just contributes, again, to rising temperatures by way of the greenhouse effect.