Scientists warn of ‘alarming’ increase in ocean microplastic pollution

A plastic handful washed up on Kamilo Beach, Hawaii

The Institute of 5 Gyres, CC-BY 4.0 (

Concentrations of microplastics in the oceans have increased over the past 18 years, with researchers now estimating that there are 2.3 million tonnes floating in the sea globally.

Microplastics – defined as plastic particles less than 5 millimeters long – are usually found in the bodies of sea turtles, whales and fish. Studies have tracked microplastic pollution in the oceans since the 1970s, but it wasn’t until 2005 that plastic concentrations began to rise rapidly and steadily.

Marcus Eriksen And Lisa Erdle at the 5 Gyres Institute in Santa Monica, Calif., and their colleagues looked at ocean surface plastic pollution data that had been collected between 1979 and 2019. This data came from more than 11,000 collection stations spanning most major ocean regions.

Patchy data made it impossible to identify clear trends in plastic concentrations between 1979 and 1990, while between 1990 and 2004 plastic concentrations showed fluctuations without a clear trend.

But the team found that over the past 18 years, plastic concentrations in the oceans have risen sharply, up to more than 10 times their 2005 levels.

“We have seen an alarming trend of exponential growth of microplastics in the global ocean since the millennium, reaching over 170 trillion plastic particles,” Eriksen said in a press release.

The sharp rise in concentrations since 2005 may be due to a boom in plastic production at that time, Erdle says. Global plastic production almost doubled between 2005 and 2019, from 263 million tons to 460 million tons, according to the OECD and Our World in Data.

It could also be the result of a failure to introduce mandatory measures to reduce pollution, Erdle says, even as litter piles up as new plastics enter the oceans and older parts break down into microplastics. “In recent years, there have been no binding international policies, and we are seeing a rapid increase in plastic pollution in the world’s oceans,” she says.

The study, which Erdle says is unique in its geographical scope and four-decade span, only looked at data up to 2019. That was partly because the researchers needed to define a “point boundary clear” for analysis, Erdle says. .

Since then, some countries, including the UK, have introduced laws to tackle microplastic pollution, such as banning the use of plastic straws and reducing demand for single-use carrier bags. unique.

But Erdle believes more sweeping action targeting the entire global plastics industry will be needed to truly reduce marine pollution levels.

In 2022, countries agreed to develop a global treaty to tackle plastic pollutionwith draft text expected by 2024. Erdle says the treaty must be binding and enforceable, and address the full life cycle of plastics.

The agreement should include a cap on overall plastic production, she says, describing the measure as an “effective tool” to reduce microplastic concentrations in the oceans.

Without a widespread change in plastic policy, the rate at which plastic is pouring into the world’s oceans could be 2.6 times higher by 2040 compared to 2016, the study warns.

Other scientists have also backed calls for a global cap on plastic productionbut such a decision would be extremely controversial and is likely to be strongly resisted by petrochemical industries.


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