A handful of plastic washed up on Hawaii’s Kamilo Beach
The 5 Gyres Institute, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
Concentrations of microplastics in the oceans have skyrocketed over the past 18 years, with researchers estimating that there are now 2.3 million tonnes floating in the world’s oceans.
Microplastics are defined as plastic particles less than 5 millimeters in length and are commonly found in sea turtles, whales and fish. Research has tracked microplastic pollution in the oceans since the 1970s, but it wasn’t until 2005 that plastic concentrations began to increase rapidly and consistently.
Marcus Eriksen, Lisa Erdle, and colleagues at the 5 Gyres Institute in Santa Monica, California, examined data on surface plastic pollution collected between 1979 and 2019. major marine regions.
No clear trends in plastic concentrations could be identified from 1979 to 1990, but plastic concentrations from 1990 to 2004 showed fluctuations without a clear trend.
However, the team found that marine plastic concentrations have risen sharply over the past 18 years, reaching more than 10 times their 2005 levels.
In a press release, Eriksen said: “We have found an alarming trend of exponential growth in microplastics in the world’s oceans since the millennium, reaching more than 170 trillion plastic particles.
Erdle says the sharp rise in concentrations since 2005 may be due to the recent boom in plastic production. According to the OECD and Our World in Data, global plastic production nearly doubled from 263 million tons to 460 million tons between 2005 and 2019.
It could also be the result of a failure to introduce mandatory measures to reduce pollution, despite the accumulation of waste as new plastics enter the ocean and old debris breaks down into microplastics. says Erdle. “With no binding international policy in recent years, plastic pollution in the world’s oceans has increased rapidly,” she says.
Erdle said the study was unique in its geographic breadth and 40-year time span, looking only at data through 2019. .
Since then, several countries, including the UK, have introduced legislation to address microplastic pollution, including banning the use of plastic straws and reducing demand for single-use carrier bags.
But Erdle believes that actually lowering ocean pollution levels will require more radical action across the global plastics industry.
In 2022, countries will agree to develop a global treaty to tackle plastic pollution, with a draft due by 2024. Erdle said the treaty is binding and enforceable and should address the entire lifecycle of plastics.
The agreement should include a cap on overall plastic production, she said, describing the measure as an “effective tool” to reduce the concentration of microplastics in the oceans.
By 2040, the amount of plastic in the world’s oceans could be 2.6 times higher than it was in 2016, a study warns if policies on plastics do not change broadly.
Other scientists have also supported calls for a global cap on plastic production, but such a move would be highly controversial and likely to be fiercely resisted by the petrochemical industry.
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