{"id":3513673,"date":"2025-06-11T10:07:22","date_gmt":"2025-06-11T10:07:22","guid":{"rendered":"https:\/\/www.resilience.org\/?p=3513673"},"modified":"2025-06-11T23:45:37","modified_gmt":"2025-06-11T23:45:37","slug":"all-that-plastic-in-the-ocean-is-a-climate-change-problem-too","status":"publish","type":"post","link":"https:\/\/www.resilience.org\/stories\/2025-06-11\/all-that-plastic-in-the-ocean-is-a-climate-change-problem-too\/","title":{"rendered":"All that plastic in the ocean is a climate change problem, too"},"content":{"rendered":"

“This story was originally published by Grist<\/a>. Sign up for Grist’s weekly newsletter here<\/a>.”<\/em><\/p>

When you think of plastic pollution, you might imagine ocean \u201cgarbage patches<\/a>\u201d swirling with tens of millions of plastic bottles and shopping bags. But unfolding alongside the \u201cmacroplastic\u201d pollution crisis is another threat caused by much smaller particles: microplastics.<\/p>

Microplastics \u2014 tiny plastic fragments that are less than 5 millimeters in diameter, a little less than one-third the size of a dime \u2014 have become ubiquitous in the environment. They form when larger plastic items like water bottles, grocery bags, and food wrappers are exposed to the elements, chipping into smaller and smaller pieces as they degrade. Smaller plastic fragments can get down into the nano territory, spanning just 0.000001 millimeter \u2014 a tiny fraction of the width of a human hair.<\/p>

These plastic particles do many of the same bad things that larger plastic items do: mar the land and sea, leach toxic chemicals into the food chain. But scientists are increasingly worried about their potential impact on the global climate system. Not only do microplastics release potent greenhouse gases<\/span> as they break down<\/a>, but they also may be inhibiting one of the world\u2019s most important carbon sinks<\/a>, preventing planet-warming carbon molecules from being locked away in the seafloor.<\/p>

Matt Simon, a science journalist for Wired, details the danger in his forthcoming book on microplastics, A Poison Like No Other<\/em><\/a>. He told Grist that it\u2019s still early days for some of this research but that the problem could be \u201chugely important going forward.\u201d<\/p>

To understand the potential magnitude, you first have to understand an ocean phenomenon called the \u201cbiological carbon pump<\/a>.\u201d This process \u2014 which involves a complex network of physical, chemical, and biological factors \u2014 sequesters up to 12 billion metric tons of carbon at the bottom of the ocean each year<\/a>, potentially locking away one-third of humanity\u2019s annual emissions<\/a>. Without this vital system, scientists estimate that atmospheric CO2<\/sup> concentrations, which recently hit a new record high of 421 parts per million<\/a>, could be up to 250 parts per million higher<\/a>.<\/p>

\u201cThe biological carbon pump helps to keep the planet healthy,\u201d said Clara Manno, a marine ecologist at the British Antarctic Survey. \u201cIt helps the mitigation of climate change.\u201d<\/p>

The pump works like this: First, carbon dioxide from the atmosphere dissolves into water at the surface of the ocean. Using photosynthesis, tiny marine algae called phytoplankton then absorb that carbon into their bodies before passing it onto small ocean critters \u2014 zooplankton \u2014 that eat them. In a final step, zooplankton excrete the carbon as part of \u201cfecal pellets\u201d that sink down the water column. Once these carbon-containing pellets reach the ocean floor, the carbon can be remineralized into rocks \u2014 preventing it from escaping back into the atmosphere.<\/p>

So where do microplastics come in? Unfortunately, at every step of the process.<\/p>

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Troubled Waters: How Microplastics Are Impacting Our Oceans and Our Health<\/a><\/h3>\n\n
<\/path> <\/path> <\/path> <\/path> <\/svg><\/span>June 24, 2025 \u2022 10:00am US Pacific<\/strong><\/span><\/div>\n\n

Join Dr. Britta Baechler<\/strong> (Ocean Conservancy), Christy Leavitt<\/strong> (Oceana), Emily Penn<\/strong> (ocean advocate & skipper), and Madeline Kaufman<\/strong> (Debris Free Oceans) on an exploration of this topic and what we can do in response.<\/p>\n<\/div><\/div>\n\n

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\"Gyre<\/a><\/figure>\n<\/div><\/div>\n<\/div>\n\nFREE REGISTRATION<\/a>\n<\/div>

Perhaps most concerning to scientists is the way microplastics may be affecting that final stage, the sinking of zooplankton poop to the bottom of the seafloor. Once ingested, microplastics get incorporated into zooplankton poop and can cause fecal pellets to sink \u201cway, way more slowly,\u201d said Matthew Cole, a senior marine ecologist and ecotoxicologist at the Plymouth Marine Laboratory in the U.K. In a 2016 paper<\/a> he published in Environmental Science & Technology, he documented a 2.25-fold reduction in the sinking rate for the fecal pellets of zooplankton that had been exposed to microplastics. Other research has shown that plastic-contaminated krill fecal pellets<\/a> can sink about half as quickly as their purer counterparts.<\/p>

This reduced sinking rate is a result of microplastics\u2019 buoyancy \u2014 especially those made of low-density polymers like polyethylene, the stuff used in grocery bags and likely the most common polymer in the surface ocean. Slower sinking rates mean fecal pellets may spend up to two or even three days more than usual drifting through the water column, presenting more opportunities to be intercepted.<\/p>

\u201cThey\u2019re more likely to break apart, they\u2019re more likely to be eaten by other animals,\u201d Cole said, making it less likely that the carbon will reach the seafloor and become permanently sequestered.<\/p>

There are other worries too, about the way microplastics can affect phytoplankton and zooplankton health \u2014 potentially compounding the stresses already posed by rising carbon dioxide concentrations, which are making the oceans warmer and more acidic<\/a>, and are contributing to the expansion<\/a> of oxygen-depleted \u201cdead zones<\/a>.\u201d High concentrations of microplastics in water are toxic to phytoplankton<\/a>, and lab experiments have shown they can cause up to a 45 percent reduction<\/a> in some species\u2019 growth. Cole\u2019s experiments on copepods<\/a>, a common kind of zooplankton, have shown that ingested microplastics take up space in copepods\u2019 guts, causing them to eat less real food, produce smaller eggs that are significantly less likely to hatch, and live shorter lives.<\/p>

Researchers are still trying to come to grips with what all these laboratory observations could mean on a global scale. But the worry is that a planet-wide population of smaller, shorter-lived ocean algae and zooplankton may not be able to take up as much carbon as their ancestors \u2014 exacerbating the problems associated with buoyant fecal pellets.<\/p>

\u201cThere is something there that we should worry about,\u201d Manno said, stressing the need for more research. To that end, she\u2019s working on a multiyear field study<\/a>, with research expeditions planned for the microplastics-laden Mediterranean Sea and the moderately cleaner Southern Ocean. Manno said she\u2019s hoping to collect real-world plastic and fecal pellet samples and get a better look at how microplastics interact with zooplankton in the open ocean.<\/p>

The goal, Manno explained, is to quantify the decline in carbon sequestration related to microplastics and translate that into a dollar cost to society. \u201cThe ocean provides us this ecosystem service,\u201d she said. \u201cIf something stresses these processes \u2026 this is a kind of social benefit that we cannot use anymore.\u201d<\/p>

If her hypothesis is correct \u2014 that microplastics are inhibiting the biological carbon pump \u2014 it will add even more weight to a growing recognition of plastic and microplastics as a major climate disrupter. Scientists already know that plastic production and incineration cause massive greenhouse gas emissions<\/a>, and in A Poison Like No Other,<\/em> Simon notes emerging research on the way microplastics release exponentially increasing amounts of planet-warming methane<\/span> and ethylene as they break down.<\/p>

\u201cThey continue emitting forever,\u201d said Sarah-Jeanne Royer, the oceanographer and postdoctoral researcher at the Scripps Institution of Oceanography who is conducting that research.<\/p>

To mitigate their damage to ecosystems and the climate, Royer called for policymakers to double down on removing microplastics from the ocean. But that\u2019s a tall order. Despite some early-stage experiments involving plastic-eating mussels and bacteria, Simon said there are currently no viable, scalable ways to remove all the microplastics that have already accumulated in the environment.<\/p>

\u201cWe have so much microplastic and nanoplastic in so many places on the planet \u2014 in the air and the land and the sea \u2014 that there\u2019s just no way to pull it all out,\u201d Simon said. \u201cI wish there was a nice, happy solution like a magnet that you could drag through the environment and attract all the microplastics, but unfortunately that just doesn\u2019t exist.\u201d<\/p>

Instead, he called for people to take steps to limit the release of microplastics into the environment \u2014 like by installing a filter on their washing machine \u2014 as well as government-mandated caps on plastic production. \u201cWe have to stop producing so much goddamn plastic,\u201d he said. \u201cIt is out of control at this point.\u201d<\/p>

<\/p>

This article originally appeared in Grist<\/a> at https:\/\/grist.org\/science\/all-that-plastic-in-the-ocean-is-a-climate-change-problem-too\/<\/a>. Grist is a nonprofit, independent media organization dedicated to telling stories of climate solutions and a just future. Learn more at Grist.org<\/a><\/em><\/p>","protected":false},"excerpt":{"rendered":"

When you think of plastic pollution, you might imagine ocean \u201cgarbage patches\u201d swirling with tens of millions of plastic bottles and shopping bags. But unfolding alongside the \u201cmacroplastic\u201d pollution crisis is another threat caused by much smaller particles: microplastics.<\/p>\n","protected":false},"author":128238,"featured_media":3513685,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[79718,213530,252051],"tags":[],"class_list":["post-3513673","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","category-environment-featured","category-troubled-waters"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/posts\/3513673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/users\/128238"}],"replies":[{"embeddable":true,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/comments?post=3513673"}],"version-history":[{"count":7,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/posts\/3513673\/revisions"}],"predecessor-version":[{"id":3513722,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/posts\/3513673\/revisions\/3513722"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/media\/3513685"}],"wp:attachment":[{"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/media?parent=3513673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/categories?post=3513673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.resilience.org\/wp-json\/wp\/v2\/tags?post=3513673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}