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World leaders agree to draw up ‘historic’ treaty on plastic wasteUN environment assembly resolution is being hailed as biggest climate deal since 2015 Paris accord World leaders, environment ministers and other representatives from 173 countries have agreed to develop a legally binding treaty on plastics, in what many described a truly historic moment.The resolution, agreed at the UN environment assembly in Nairobi, Kenya, calls for a treaty covering the “full lifecycle” of plastics from production to disposal, to be negotiated over the next two years. It has been described by the head of the UN Environment Programme (UNEP) as the most important multilateral environmental deal since the Paris climate accord in 2015.Approximately 7bn of the estimated 9.2bn tonnes of plastics produced between 1950 and 2017 are now waste. About 75% of that waste is either deposited in landfills or accumulating in terrestrial and aquatic environments and ecosystems.“Against the backdrop of geopolitical turmoil, the UN environment assembly shows multilateral cooperation at its best,” said Espen Barth Eide, the president of UNEA-5 and Norway’s minister for climate and the environment. “Plastic pollution has grown into an epidemic. With today’s resolution we are officially on track for a cure.”Inger Andersen, the director of the UN Environment Programme, tweeted: “We have just gavelled the resolution paving the way for global action to #BeatPlasticPollution. The most important environmental deal since the Paris accord.”“The work starts now!” she added.Andersen described the agreement as a “triumph by planet Earth over single-use plastics” but warned that the mandate did not grant stakeholders a “two-year pause”.“In parallel to negotiations over an international binding agreement, UNEP will work with any willing government and business across the value chain to shift away from single-use plastics, as well as to mobilise private finance and remove barriers to investments in research and in a new circular economy,” Andersen said.UN nations, which have been holding talks in Nairobi this week to discuss the terms for a treaty, agreed it should cover the production and design of plastic, not just waste. The resolution established an intergovernmental negotiating committee, tasked with drafting and ratifying the treaty. It will start work this year and aims to finish by 2024.The resolution introduces provisions to recognise waste pickers, a “groundbreaking development” that would affect millions of people, according to NGOs, and the acknowledgment of the role of indigenous peoples. It is the first time waste pickers, low-paid workers in developing nations who scavenge for recyclable plastic and other goods, have been recognised in an environmental resolution.NGOs described the resolution as a critical shift in international policymakers’ approach, which previously focused on plastic as a marine litter issue. The mandate recommends measures to tackle plastic production, predicted to almost quadruple by 2050 and take up 10-13% of the global carbon budget. They urged world leaders to show even more resolve in developing and finalising the details of the treaty over the next two years.“We stand at a crossroads in history when ambitious decisions taken today can prevent plastic pollution from contributing to our planet’s ecosystem collapse,” said Marco Lambertini, director general of WWF International. “But our work is far from over – world leaders must now show even more resolve in developing and implementing a treaty which addresses our current plastic pollution crisis and enables an effective transition to a circular economy for plastic.”Christina Dixon, the deputy ocean campaign lead at the Environmental Investigation Agency, said: “This resolution finally recognises that we cannot begin to address plastics in our ocean and on land without intervening at source. “Fundamentally, the plastics tap must be turned off if we are serious about tackling the problem,” she said.Dixon said the world was at the “start of a journey” towards securing a legally binding treaty.Niven Reddy, the Africa coordinator at the Global Alliance for Incinerator Alternatives, said: “This milestone could not have happened without a global movement pushing decision-makers every step of the way.”Joanne Green, a senior policy associate at Tearfund, said: “Today marks the first step towards justice for communities impacted by the burning and dumping of plastic waste. The recognition of waste pickers and the vital role they play in stopping plastic pollution is long overdue; governments must now ensure that they are given a prominent seat at the negotiating table.”The treaty will be accompanied by financial and technical support, including a scientific body to advise it, and the possibility of a dedicated global fund.The resolution was adopted with the conclusion of the three-day UNEA-5.2 meeting, attended by more than 3,400 delegates in person and 1,500 online participants from 175 UN member states, including 79 ministers and 17 high-level officials.There is growing public concern over plastic pollution. More than 60 countries already have implemented bans and levies on plastic packaging and single-use waste, aimed at reducing use and improving waste management.Plastic consumption in developed countries is 2.5 times higher per capita than in developing countries, according to the Planet Tracker thinktank.TopicsPlasticsSeascape: the state of our oceansPollutionUnited NationsEnvironmental activismGreen politicsnewsReuse this content

The UN has just signed a landmark agreement to reduce plastic pollution, in what some are calling the most important international environmental deal since the 2015 Paris agreement that targeted climate change.On Wednesday, marked by a gavel made from recycled plastics, representatives from 175 nations endorsed the agreement, which will act as the framework for discussions over the next two years. Worldwide, we produce 400 million tons of plastic a year, and that’s expected to double by 2040. If countries can stick to their commitments, it could lead to a massive reduction in single-use plastics, production levels, and ocean pollution.That’s a big “if”—while a lot of groups are cautiously optimistic, just like the Paris agreement, there are loopholes that countries could exploit. Here’s what you need to know about the agreement. What did the 175 countries actually agree to? “End plastic pollution: Towards an international legally binding instrument” is a series of loose resolutions promising to address the full life cycle of plastic products.It creates an intergovernmental negotiating committee, which will spend the next two years hashing out exactly how to tackle the plastic problem. Resolutions called for promoting sustainably designed products and materials, environmentally sound waste management, and financial support for developing countries.At the next UN Environment Assembly in 2024, the committee will finalize the agreement. “What we laid out was, in the easiest terms, a plan for a plan,” said Erin Simon, head of plastic waste and business at the World Wildlife Fund. But, she warned, “There could be plenty of time for countries to back off what they committed to.” What can we expect to see in the treaty? A lot could happen over the next two years. Right now, similar to the Paris agreement, the deal allows for countries to take voluntary approaches—meaning it will likely not be mandatory for them to meet their commitments. It also contains an open mandate that allows the intergovernmental negotiating committee to change the treaty before it’s signed, potentially watering it down. While the open mandate could present a potential loophole, Jane Patton, the plastics and petrochemicals campaign manager for the Center for International Law, said it allows the committee to improve the draft’s language, making issues like plastic’s toxicity to human health more explicit. “It’s about setting up a framework that countries feel empowered to take action on,” Simon said. “They are likely to take action if they have the opportunity to inform the process.”What can possibly go wrong?Just like with the Paris climate agreement, if the U.S. doesn’t uphold its end of the bargain, the rest of the world could follow suit. The U.S. is the largest plastic waste producer in the world, shipping off its unwanted garbage to developing nations.Plastic policy can sometimes gain bipartisan support, however. Even well-known environmental curmudgeon Donald Trump signed the Save Our Seas 2.0 Act, designed to fight coastal plastic debris, into law in 2020. Fortunately, the fact that plastic pollution is so visible is speeding up efforts to address it. “It’s something a bit more tangible as a problem than climate, because you can’t see greenhouse gases in the air, but I can see plastic pollution in the streets outside my house,” Patton said. Are the worst culprits finally going to be held to account? We’ll see. Plastics are derived from fossil fuels and chemicals, and, unsurprisingly, oil and chemical industries have been less enthusiastic about the treaty.Their strategy focuses on recycling, which diverts the conversation away from reducing plastic production and usage. With a recycling approach, consumers who lack access to proper recycling resources are held responsible for their plastic waste, while plastic producers can continue business as usual. Plus, if the resolution’s terms aren’t mandatory for governments, companies might not face meaningful restrictions, either.Perhaps surprisingly, companies that have been ranked as the world’s top plastic polluters, including PepsiCo, Nestlé, and Coca-Cola, have joined with dozens of others in a pre-UNEA statement supporting the treaty, using snazzy buzzwords that called for “a holistic, coordinated international response,” a “circular economy for plastics,” and a “robust governance structure to ensure countries’ participation and compliance.” Although the global agreement doesn’t enforce plastics restrictions yet, some companies have already made sustainability pledges. Nestlé commits that 100 percent of packaging will be recyclable or reusable by 2025. It may sound like progress, but environmental experts are skeptical.“Recycling doesn’t get to the root of the problems with plastic production,” said Jim Walsh, policy director at Food and Water Watch. “When you focus simply on issues of recycling and packaging management, you ignore all of the impacts of the petrochemical development and pollution that comes along with that.”The companies’ support could be due in part to a growing anti-plastics movement over the past two years. A 2021 Ipsos poll of more than 20,000 people in 28 countries found that 88 percent of respondents believe a global plastics treaty is important and 85 percent want manufacturers and retailers to be held responsible for plastic packaging. Over 2 million people signed WWF’s petition for a global plastics agreement ahead of negotiations.What’s so bad about plastic?Plastic pollution is an environmental nightmare. Annually, reports estimate that between 9 to 11 million metric tons of plastic are tossed into oceans, the equivalent of dumping a garbage truck full of plastic every minute. Forty percent of plastic produced is single-use, and disturbingly, after over a hundred years of production, only 9 percent of plastics has ever been recycled.Plastic garbage doesn’t really decompose—rather, it breaks down into smaller and smaller pieces, eventually becoming microplastics the size of sesame seeds. These synthetic crumbs act like magnets for surrounding chemical pollutants, attracting floating environmental contaminants and depositing them to unsuspecting hosts.That’s a major problem for humans. Besides the health effects from eating the plastic itself, humans are getting exposed to a host of hormone disruptors, carcinogens, and pollutants in our food, water, salt, beer, and seafood dinners. These toxins lead to serious health issues, including cancer, birth defects, cardiovascular diseases, diabetes, auto-immune conditions, neuro-degenerative diseases, and stroke. Fifth UN Environment Assembly President Espen Barth Eide told the committee on Monday his blood tests showed plastic compounds and chemicals in his body.Plastics also fuel climate change. A 2021 report from environmental group Beyond Plastics found that plastic is currently slated to outpace coal’s greenhouse gas emissions in the U.S. by 2030.“The fact that that isn’t addressed right now in any of the global multilateral environmental agreements is a significant issue,” Patton said. What happens next? Signing the treaty was a major step for taking some plastic out of the equation. “I wanna say I have all the hope,” Simon said. “The fact that we have come to consensus on the draft resolution so far showcases a collective desire to solve the plastic pollution crisis together.”But nations, companies, NGOs, and consumers shoulder greater responsibility to make good on its promises over the next few years. Several of the member nations have already started to take action. In 2019, the European Union began limiting certain single-use plastics, restricting their sale when sustainable alternatives were easily available. Kenya, the UN host country, banned single-use plastics in protected natural areas in 2020. “This is a problem that the world cannot ignore,” Patton said. “It is a problem that has urgent implications for human health and the environment, and we have to move quickly on this issue.”

It’s Thursday, March 3, and world leaders have agreed to write a binding treaty on plastic pollution.

World leaders concluded the fifth United Nations Environment Assembly on Wednesday with a promise to the world: By 2024, delegates will broker a binding, international treaty addressing the full life cycle of plastics — including its production and design.
“We made history today,” Espen Barth Eide, Norway’s minister of climate and environment and president of the Assembly, told delegates.
The United Nations conference in Nairobi, Kenya, has been branded the most significant international environmental negotiation since 2015, when world leaders met to broker the Paris Agreement. For years, scientists, policymakers, and environmental advocates have urgently called for a comprehensive solution to the plastic pollution crisis, which — like climate change — is already exerting a hefty toll on people and the natural world.
Delegates at this week’s U.N. conference agreed to address the problem through a holistic “life cycle” approach, meaning the treaty they negotiate over the next two years could limit the amount of plastic the world is allowed to produce. There are some caveats: Although the treaty itself will be binding, the resolution contains language allowing for binding and non-binding elements, and nations may have a lot of discretion over how they adhere to the treaty’s terms.
Still, the treaty may prompt U.N. member states to adopt far-reaching measures to curb plastic pollution, potentially including national production caps or market-based mechanisms, like extended producer responsibility laws that force plastic manufacturers to pay for the pollution they create. This overall approach is in line with what scientists and environmental advocates have long stressed is the best way to curb pollution from plastics.
An intergovernmental negotiating committee still has to hammer out most of the treaty’s important details, but environmental advocates the world over applauded the U.N. resolution.
“It is a monumental and inspiring act,” Graham Forbes, plastics global project leader for Greenpeace, told me. “They’ve set out a powerful intention to tackle the pollution crisis — that’s what the world needs.”
Editor’s note: Greenpeace is an advertiser with Grist. Advertisers have no role in Grist’s editorial decisions.
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In biology, there is a rule of thumb that upholds food webs: the 10% rule, meaning animals are generally good at converting energy from their food into body weight at a rate of about 10%.

For example, a cow might eat 100 pounds of grass, but only grows by 10 pounds. This rule sustains life on Earth and determines the pyramidal structure of the food chain. However, new research shows that plastic pollution and warming oceans could threaten to upend this rule, possibly creating unwelcome consequences for marine species as well as the global food supply.

Researchers on the study, published in January in the Proceedings of the Royal Society, studied zebrafish in the lab and determined that warmer water and bisphenol-A (BPA) — a chemical used in many plastics — together make fish metabolisms less efficient at converting food into energy and body weight.

In the study, zebrafish exposed to these two stressors needed more energy to grow and reached a much smaller size at adulthood than their counterparts who had not been exposed.

The global food web “depends on a certain rate of energy from one level being transferred to the next. If you disrupt that, you can disrupt whole ecosystems,” Frank Seebacher, an author on the study and a professor of biology at the University of Sydney, told EHN.

BPA, one of the most abundantly used plastic additives in the world, affects fish — and human — endocrine systems by disrupting the ability of hormones to signal important body processes like growth and development. BPA contaminates fish via plastic pollution in the ocean and through plastic materials used in aquaculture (fish farming operations). While BPA is a prevalent endocrine-disrupting chemical, others are present in plastics, too, like phthalates and polyfluoroalkyl substances (PFAS). Such chemicals have been shown to affect fish growth on their own.

Research shows that fish hormones and endocrine systems are also impacted by temperature: in warmer water, fish metabolisms speed up, making the energetic cost of growth much higher. Both warming and endocrine-disrupting chemicals impact fish growth and development, making fish less efficient at converting their food into biomass. When fish are exposed to both at once, said the researchers, the problem is worse, and could lead to population-level impacts.

While the study was done on zebrafish within the lab, changes in fish size have already been observed in the wild, said Nicholas Wu, an author on the study and a PhD student at Western Sydney University in Australia.

“This is a growing problem,” he told EHN.

Population level impacts

Less efficient fish metabolisms spell trouble for marine ecosystems — especially those animals at the top levels of the food chain, the researchers said. Smaller fish at lower levels of the food chain mean that there’s less food to go around, which could cause a decrease in populations of animals like sharks, whales, or other large predators.

Additionally, said Seebacher, when prey fish are found at lower numbers — and therefore are spread further apart in the water — predators like sharks and whales must spend more time and energy searching for food. That can be stressful for the animals and threatens their populations as well.

Wu also said that fish are not the only marine organisms for which this is a problem; the metabolisms of some crustaceans, plankton, aquatic insects, and marine mammals have also been shown in other studies to be sensitive to endocrine-disrupting chemicals from plastic pollution. These chemicals disrupt processes critical to the survival of these organisms, like body size, development, and reproduction.

After determining that warming water and plastic pollution disrupted fish growth, researchers created maps to identify “problem areas,” or areas of the world with many fisheries, high levels of plastic pollution, and faster-than-average ocean warming.

They determined that, under the RCP 8.5 warming scenario (one commonly used climate model that assumes rising emissions continuing through the 21st century), many fisheries in southeast Asia, Central America, and equatorial Africa would be at high risk of changes in fish growth within the next hundred years.

The study comes as the latest Intergovernmental Panel on Climate Change report warns that marine heat waves are already becoming more common, longer, and more intense. The report further warns that climate change will threaten marine life through habitat loss, population decline, increased risks of extinctions, and the rearrangement of marine food webs.

Impacts on global food production

Fishing nets. Some areas of the world with extremely warm waters and high levels of pollution may need to stop fishing for human consumption altogether, said Seebacher. (Credit: Hanson Lu/Unsplash) This wouldn’t just impact marine fisheries: As a result of this growth effect, said the researchers, aquaculturists who grow fish for human food production may have to spend more money on feeding their fish for the same quantity of fish harvested. Predatory fish like tuna, salmon, and marlin all require other fish as food — if those other fish are smaller and less abundant, it becomes less efficient and more expensive to grow predatory fish for human consumption.“Successful aquaculture operations rely on food and energy transfer efficiency,” Seebacher said. “If that’s out, and it’s not commercially viable anymore, it produces more pollution because it’s just inefficient.” According to the Food and Agriculture Organization of the United Nations, fish provide, on average, 7% of the protein in a person’s diet; for 3.3 billion people, however, fish provide more than 20% of the protein they eat. Global demand for fish as food is expected to rise, making it even more critical for those managing fisheries to attend to warming and plastic pollution concerns.

Future for fish 

Seebacher said he hopes that the findings of this research will inform management strategies for fisheries, possibly leading to an adjustment in fish quotas to help combat the potential decline in fish abundance. Aquaculturists, he said, could benefit from replacing materials containing BPA that are used in their aquaculture ponds, such as plastic tubing, liners, or containers.The problem of marine plastic pollution is only getting worse: according to one 2020 study, 11% of all plastic waste produced enters aquatic ecosystems, and global waste management systems likely will not be able to keep up as the amount of plastic produced each year continues to rise. Some areas of the world with extremely warm waters and high levels of pollution may need to stop fishing for human consumption altogether, said Seebacher.“The results were really quite an eye opener,” he said. “This could have really important implications.”Banner photo: Sebastian Pena Lambarri/UnsplashFrom Your Site ArticlesRelated Articles Around the Web

In front of the United Nations African headquarters in Nairobi, a 30-foot-high artwork featuring a faucet “spewing” a long stream of plastic waste dramatically illustrates the worsening flow of plastic fouling the world. Inside the main hall, 175 UN delegates took the first formal steps on Wednesday to turn off the tap. They agreed to negotiate the first comprehensive global treaty to curb plastic pollution—a move hailed as the most significant environmental agreement since the Paris climate accord in 2015.The framework of the agreement was hammered out last week ahead of the delegates’ vote. It creates a road map for treaty negotiations that are set to begin in May. Inger Andersen, who heads the UN Environment Program, told the delegates: “This is a historic moment.”This 30-foot monument themed “Turn off the plastics tap” by Canadian activist and artist, Benjamin von Wong, uses plastic waste retrieved from Nairobi’s largest slum, Kibera. It stands outside the UN African headquarters in Nairobi.Photograph by Tony Karumba, AFP/GettyPlease be respectful of copyright. Unauthorized use is prohibited.Plastic waste flowing into the oceans is forecast to triple by 2040, so the vote came not a moment too soon. Or did it? The effort to construct an international agreement to gain control of mounting plastic waste took almost five years just to get to the starting line. How can the UN, slow-moving by design, possibly come up with a solution in time to stave off an environmental disaster? Below is a guide to what’s involved, and why a binding global treaty may be the world’s best hope to contain a plastic waste crisis that knows no international boundaries.Q: How might a global treaty help solve the plastic waste crisis?A:  It would address the crux of the problem by requiring nations to commit to cleaning up their plastic waste. Because the treaty would be legally binding, it could pack more punch than the Paris accord, which requires nations to voluntarily commit to reducing greenhouse gas emissions. “This is like ‘Paris Plus,’” says Chris Dixon, the deputy ocean campaign lead at the U.K.-based Environmental Investigation Agency. “The devil is in the details, but this makes sure the ambition of the mandate is carried through. This is the beginning of the journey, not the end.”Q: Can this process be fast-tracked?  A:  Negotiators say they plan to reach an agreement within two years, astonishingly quick for the UN. The UN began exploring solutions to plastic waste in 2017. In 2019, the United States, which produces more plastic waste per capita than any other nation, was blamed for thwarting efforts to begin treaty talks, as the Trump administration opposed such a treaty. Last November, the U.S. reversed course and, along with France, announced support for a legally binding treaty. The approach is based on the treaty to end mercury pollution—known as the Minamata Convention which was finalized in just over three years. And it could take less time than the agreement to address climate change took.Q: What changed to allow this to move forward?A: Plastic waste has proliferated in recent years, and has been documented in every part of the world. As plastic production has increased—growing faster than production of any other material—the waste issue has taken on a greater urgency. That, in turn, has drawn wide support from all quarters for a global treaty. The American Chemistry Council, an industry trade group that opposed a legally binding treaty in 2019, now supports one. As two proposals were circulated—one by Peru and Rwanda, the other by Japan—support snowballed. By the time negotiators convened in Kenya’s capital city last month, those publicly backing a global treaty included more than 300 scientists, more than 140 nations, and nearly 100 leaders of multinational companies, including some of the largest plastics users: the Coca Cola Company, PepsiCo, and Unilever.Q: What’s on the table?A:  The framework’s language is only a guide for the actual treaty talks. Consequently, the language is basic in many places. For example, negotiators had to define what the plastic lifecycle entails. Should the treaty focus on when plastic becomes waste? Solutions in that case would revolve around expansion of reuse programs, recycling, and enhanced and better-funded waste management. Or is the plastic lifecycle more expansive, meaning the treaty would include every step along the way—from production of virgin plastic to packaging design, product distribution, and disposal after use? The industry focused on waste management, but the negotiators opted to recommend the broader definition. Tackling the problem from multiple angles provides more opportunities to intervene along the way, and that could reduce the amount of packaging that becomes waste or eliminate it altogether.Q: Why do we need an international treaty? Aren’t many nations already addressing the problem?A: It’s a global problem, and we need a global solution to solve it. About eight million tons of plastic are estimated to spill into the seas every year, and is known to travel across oceans. One nation’s regulations do not prevent another nation’s waste from reaching its shores. Bag bans in one country don’t stop neighboring countries from smuggling in bags for a tidy profit. Plastic waste is also traded internationally; that involves international agreements. More importantly, there are no uniform global standards or policies that guide the industry. Definitions of biodegradable plastics vary, depending on the manufacturer. And virtually no one can sort out the varying rules on what plastics can go into the recycle bin. Meanwhile, multinational corporations selling in multiple nations can find themselves sorting through hundreds of regulations affecting such issues as product design or packaging thickness. These companies strongly support harmonizing definitions, reporting metrics, and methodologies that will simplify industry practices and improve management of waste.Q: How serious is the plastic waste problem?A:  Forty percent of all plastics manufactured today is for packaging, most of it disposed of within minutes of opening it. Globally, just 9 percent of plastics get recycled. Both waste and production are on the rise: Between 1950 and 2020, production of plastic, which is made from fossil fuels, increased from roughly two million tons annually to just over 500 million tons. Production is projected to further increase to one billion tons by 2050. Consensus is growing among scientists, activists, and elected officials that to truly curtail the growth of plastic waste, plastic production must be reduced. The industry disagrees.Q: Does the framework call for a cap or reduction in production of virgin plastic? A:  No, it does not. The framework also does not include a requirement that production numbers be reported along with other statistics. Collection of production data represents the first step before any regulations could be written—and it’s a step that industry would like to avoid. On this subject, the framework contains a single sentence, instructing negotiators to “specify national reporting as appropriate”—not a strong directive, but one that does leave the door open to sharper language during the treaty talks.The framework has drawn universal praise from the parties involved. The International Council of Chemical Associations said in a statement it was “pleased with the outcome and fully supports a legally binding agreement… .”Ellen MacArthur, founder of the nonprofit Ellen MacArthur Foundation, is a proponent of creating a “circular economy” to reduce waste of any kind through reuse and recycling. She called the mandated agreement key to dealing with “the root of causes of plastic pollution, not just the symptoms.”In Nairobi Wednesday, Anderson told the delegation at the UN that reaching agreement to proceed toward a treaty “would have been unthinkable just a few years ago. But today … you are taking a crucial step to turn the tide on plastic pollution.” He then recalled how his mother eavesdropped on a pair of American businessmen in a cafe in Denmark a few years before he was born. The men laid out colorful blocks made of a strange new material in front of them, and she heard them say: “This is plastic. This is the future.”“Look—in the space of one lifetime, we have created a massive problem…,” Anderson said. “Now we must make the wrong-headed way we manufacture and use plastic the past.”

In biology, there is a rule of thumb that upholds food webs: the 10% rule, meaning animals are generally good at converting energy from their food into body weight at a rate of about 10%.

For example, a cow might eat 100 pounds of grass, but only grows by 10 pounds. This rule sustains life on Earth and determines the pyramidal structure of the food chain. However, new research shows that plastic pollution and warming oceans could threaten to upend this rule, possibly creating unwelcome consequences for marine species as well as the global food supply.

Researchers on the study, published in January in the Proceedings of the Royal Society, studied zebrafish in the lab and determined that warmer water and bisphenol-A (BPA) — a chemical used in many plastics — together make fish metabolisms less efficient at converting food into energy and body weight.

In the study, zebrafish exposed to these two stressors needed more energy to grow and reached a much smaller size at adulthood than their counterparts who had not been exposed.

The global food web “depends on a certain rate of energy from one level being transferred to the next. If you disrupt that, you can disrupt whole ecosystems,” Frank Seebacher, an author on the study and a professor of biology at the University of Sydney, told EHN.

BPA, one of the most abundantly used plastic additives in the world, affects fish — and human — endocrine systems by disrupting the ability of hormones to signal important body processes like growth and development. BPA contaminates fish via plastic pollution in the ocean and through plastic materials used in aquaculture (fish farming operations). While BPA is a prevalent endocrine-disrupting chemical, others are present in plastics, too, like phthalates and polyfluoroalkyl substances (PFAS). Such chemicals have been shown to affect fish growth on their own.

Research shows that fish hormones and endocrine systems are also impacted by temperature: in warmer water, fish metabolisms speed up, making the energetic cost of growth much higher. Both warming and endocrine-disrupting chemicals impact fish growth and development, making fish less efficient at converting their food into biomass. When fish are exposed to both at once, said the researchers, the problem is worse, and could lead to population-level impacts.

While the study was done on zebrafish within the lab, changes in fish size have already been observed in the wild, said Nicholas Wu, an author on the study and a PhD student at Western Sydney University in Australia.

“This is a growing problem,” he told EHN.

Population level impacts

Less efficient fish metabolisms spell trouble for marine ecosystems — especially those animals at the top levels of the food chain, the researchers said. Smaller fish at lower levels of the food chain mean that there’s less food to go around, which could cause a decrease in populations of animals like sharks, whales, or other large predators.

Additionally, said Seebacher, when prey fish are found at lower numbers — and therefore are spread further apart in the water — predators like sharks and whales must spend more time and energy searching for food. That can be stressful for the animals and threatens their populations as well.

Wu also said that fish are not the only marine organisms for which this is a problem; the metabolisms of some crustaceans, plankton, aquatic insects, and marine mammals have also been shown in other studies to be sensitive to endocrine-disrupting chemicals from plastic pollution. These chemicals disrupt processes critical to the survival of these organisms, like body size, development, and reproduction.

After determining that warming water and plastic pollution disrupted fish growth, researchers created maps to identify “problem areas,” or areas of the world with many fisheries, high levels of plastic pollution, and faster-than-average ocean warming.

They determined that, under the RCP 8.5 warming scenario (one commonly used climate model that assumes rising emissions continuing through the 21st century), many fisheries in southeast Asia, Central America, and equatorial Africa would be at high risk of changes in fish growth within the next hundred years.

The study comes as the latest Intergovernmental Panel on Climate Change report warns that marine heat waves are already becoming more common, longer, and more intense. The report further warns that climate change will threaten marine life through habitat loss, population decline, increased risks of extinctions, and the rearrangement of marine food webs.

Impacts on global food production

Fishing nets. Some areas of the world with extremely warm waters and high levels of pollution may need to stop fishing for human consumption altogether, said Seebacher. (Credit: Hanson Lu/Unsplash) This wouldn’t just impact marine fisheries: As a result of this growth effect, said the researchers, aquaculturists who grow fish for human food production may have to spend more money on feeding their fish for the same quantity of fish harvested. Predatory fish like tuna, salmon, and marlin all require other fish as food — if those other fish are smaller and less abundant, it becomes less efficient and more expensive to grow predatory fish for human consumption.“Successful aquaculture operations rely on food and energy transfer efficiency,” Seebacher said. “If that’s out, and it’s not commercially viable anymore, it produces more pollution because it’s just inefficient.” According to the Food and Agriculture Organization of the United Nations, fish provide, on average, 7% of the protein in a person’s diet; for 3.3 billion people, however, fish provide more than 20% of the protein they eat. Global demand for fish as food is expected to rise, making it even more critical for those managing fisheries to attend to warming and plastic pollution concerns.

Future for fish 

Seebacher said he hopes that the findings of this research will inform management strategies for fisheries, possibly leading to an adjustment in fish quotas to help combat the potential decline in fish abundance. Aquaculturists, he said, could benefit from replacing materials containing BPA that are used in their aquaculture ponds, such as plastic tubing, liners, or containers.The problem of marine plastic pollution is only getting worse: according to one 2020 study, 11% of all plastic waste produced enters aquatic ecosystems, and global waste management systems likely will not be able to keep up as the amount of plastic produced each year continues to rise. Some areas of the world with extremely warm waters and high levels of pollution may need to stop fishing for human consumption altogether, said Seebacher.“The results were really quite an eye opener,” he said. “This could have really important implications.”Banner photo: Sebastian Pena Lambarri/UnsplashFrom Your Site ArticlesRelated Articles Around the Web