Reviewed by Lexie CornerSep 25 2024
Researchers from Kyushu University have, for the first time, set a specific numerical target for global efforts to address marine plastic pollution. The study, published in the journal Marine Pollution Bulletin, found that a minimum 32 % reduction in plastic littering by 2035 is required to prevent further damage to marine ecosystems. This target was established by mapping the movement and fate of plastic debris in the oceans.
Plastic trash on the beach in Thailand. Larger plastics are easier to collect, but it will be harder to remove when if they breakdown into microplastics. Image Credit: Kyushu University/Isobe Lab
Globally, marine plastic pollution is becoming worse, and this trend will continue unless significant action is taken. Professor Atsuhiko Isobe from the Research Institute for Applied Mechanics at Kyushu University has been monitoring this issue for several years. A 2022 study by his research team estimated that about two-thirds of the 25.3 million metric tons of plastic debris that have entered the oceans remain untraceable.
My research focuses on tracking where plastic waste goes after being released into water sources such as rivers and oceans. We use computer models to track how plastics move and break down over time.
Chisa Higuchi, Study First Author and Post‐doctoral Fellow, Kyushu University
Plastic debris in the ocean eventually breaks down into smaller particles, but larger plastics take longer to degrade. While larger pieces can be more easily removed, once they break down to less than 5 mm in size, they become microplastics, which are harder to collect and more likely to be ingested by marine life. Even if littering stopped today, the number of microplastics would continue to grow.
In response to this issue, the Osaka Blue Ocean Vision was introduced at the 2019 G20 Osaka Summit. This initiative aims to halt the increase of marine plastic waste by 2050 through global cooperation and improved waste management practices.
We wanted to figure out what would be the ideal scenario for the Osaka Blue Ocean Vision to succeed. So, we utilized computational modeling along with fieldwork studies to understand where and how plastics flow into the oceans.
Chisa Higuchi, Study First Author and Post‐doctoral Fellow, Kyushu University
Researchers examined the time it takes for different types of plastics to break into smaller pieces and collected data on how rivers and other sources contribute to ocean plastic pollution.
“What we came up with are something akin to weather forecast maps, but instead of showing when and where it will rain, these maps show different scenarios on when and where plastics will end up,” explained Higuchi.
Their projections indicate that reducing plastic waste entering the oceans by 32 %, or 8.1 million tons, by 2035 would result in over 50 % less plastic in the oceans by 2050. The impact would be even more significant in highly polluted areas like the Yellow and East China Seas, where plastic waste could be reduced by up to 63 %.
Higuchi said, “Not only does this give the Osaka Blue Ocean Vision concrete targets, but it also gives governments and businesses metric goals. Naturally, we need to go beyond cleaning existing pollution; we must cut new plastic waste entering our oceans and rivers.”
This target is attainable if we use strategies like improving waste management, promoting reusable alternatives to single-use plastics, and enhancing public awareness. Many people can be pessimistic when hearing about the ongoing plastic waste problem in our lives. But I remain optimistic that we can find our way out of this predicament.
Atsuhiko Isobe, Professor, Kyushu University
Journal Reference:
Higuchi, C., et al. (2024) Reduction scenarios of plastic waste emission guided by the probability distribution model to avoid additional ocean plastic pollution by 2050s. Marine Pollution Bulletin. doi.org/10.1016/j.marpolbul.2024.116791.