Science and Technology Daily, Beijing, August 10 (Reporter Zhang Mengran) According to a model study recently published in Nature Geoscience, 95% of the global initial floating plastic in the ocean in 2020 is composed of plastic debris larger than 2.5 cm, and its survival time may be longer than previously expected.

It has been estimated in the past that there are about 250 million kilograms (250,000 tons) of plastic pollutants on the global ocean surface, but the amount of plastic pollution that is expected to enter the ocean each year is far greater than this figure. It is thought that this discrepancy could be due to an overestimation of the amount of plastic being imported from land and rivers, unknown processes removing much of this plastic from the ocean surface, or fragmentation and degradation.

To explore the reasons for this discrepancy, scientists at the Uhlich Research Center in Germany incorporated global observations of plastic pollution into a numerical model that tracks how plastic particles migrate and transform in the ocean. The team estimated there would be 3.2 million tons of floating plastic in the ocean in 2020. Of the 470,000-540,000 tonnes of plastic entering the oceans in 2020, about half came directly from fishing activities and the rest from coasts and rivers. 95% of the floating plastic was larger than 2.5cm, with microplastics accounting for only a small proportion.

The study shows that the total amount of plastic is higher but the input is lower than previous estimates, indicating that some process of removing ocean plastic is not missing. But this type of plastic has a long lifespan, or longevity, with only 10 percent likely to degrade or sink within two years.

The team estimates that the amount of floating plastic entering the oceans is increasing at a rate of 4% per year, underscoring the need for urgent action to reduce Marine plastic pollution.

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