Scientists warn of ‘alarming’ rise in ocean microplastic pollution

The concentration of microplastics in the oceans has increased dramatically over the past 18 years, and researchers estimate that there are currently 2.3 million tons of plastic floating in the sea worldwide.

Microplastics, defined as plastic particles less than 5 millimeters long, are commonly found in the bodies of sea turtles, whales and fish. Research has been tracking microplastic pollution in the oceans since the 1970s, but it wasn’t until 2005 that plastic concentrations began to increase rapidly and consistently.

Markus Eriksen and Lisa Erdl of the 5 Circle Institute in Santa Monica, California, and their colleagues studied ocean surface plastic pollution data collected between 1979 and 2019. These data came from over 11,000 collection stations covering most of the major ocean regions.

Scattered data did not reveal any clear trends in plastic concentrations between 1979 and 1990, while between 1990 and 2004 plastic concentrations fluctuated without a clear trend.

But the team found that over the past 18 years, the concentration of plastic in the ocean has increased dramatically, more than 10 times its 2005 level.

“We have detected an alarming trend of exponential growth of microplastics in the world’s oceans since the turn of the millennium, reaching over 170 trillion plastic particles,” Eriksen said in a press release.

The spike in concentration since 2005 could be linked to the boom in plastic production around that time, Erdl said. According to the OECD and Our World in Data magazine, global plastics production nearly doubled between 2005 and 2019, from 263 million tons to 460 million tons.

It could also be the result of a failure to enforce mandatory pollution reduction measures, Eardle says, even as waste accumulates as new plastic enters the oceans and old pieces break down into microplastics. “There has been no binding international policy in recent years and we are seeing a rapid increase in plastic pollution in the oceans,” she says.

The study, which Erdle says is unique in its geographic latitude and four-decade span, only looked at data up to 2019. This was partly because the researchers needed to establish a “clear cut-off point” for the analysis, Erdle says. .

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

But Eardle believes more drastic action, targeting the entire global plastics industry, will be needed to really reduce marine pollution.

In 2022, countries agreed to develop a global treaty to combat plastic pollution, with draft text expected by 2024. Erdle says the treaty should be binding and legally binding, and cover the entire life cycle of the plastic.

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 ocean.

The study warns that without a wide-ranging change in plastic policy, the rate at which plastic enters the world’s oceans could increase 2.6 times by 2040 compared to 2016.

Other scientists have also backed calls for a global cap on plastic production, but such a move would prove extremely controversial and likely to generate strong opposition from the petrochemical industry.