Study reveals up to 11 million tons of plastic polluting ocean floors

The amount of plastic waste littering the Earth's ocean floors could be up to 100 times the quantity floating on the surface, according to a study published this week.

Researchers at the Commonwealth Scientific and Industrial Research Organization (CSIRO)—an Australian government agency—and the University of Toronto in Canada found that up to 11 million tons of plastic are polluting the planet's ocean floors, including microplastics and larger objects like fishing nets, cups, and bags.

"We know that millions of tons of plastic waste enter our oceans every year but what we didn't know is how much of this pollution ends up on our ocean floor," CSIRO senior research scientist and study co-author Denise Hardesty said in a statement. "We discovered that the ocean floor has become a resting place, or reservoir, for most plastic pollution, with between 3 to 11 million tons of plastic estimated to be sinking to the ocean floor."

Study leader Alice Zhu, a doctoral candidate at the University of Toronto, said that "the ocean surface is a temporary resting place of plastic so it is expected that if we can stop plastic entering our oceans, the amount would be reduced."

"However, our research found that plastic will continue to end up in the deep ocean," Zhu stated. "These findings help to fill a longstanding knowledge gap on the behavior of plastic in the marine environment."

“Understanding the driving forces behind the transport and accumulation of plastic in the deep ocean will help to inform source reduction and environmental remediation efforts, thereby reducing the risks that plastic pollution may pose to marine life," she added.

The study is part of CSIRO's Ending Plastic Waste program, whose goal is "an 80% reduction in plastic waste entering the Australian environment by 2030."

Humans produce approximately 440 million tons of plastics annually, or roughly the combined weight of every person on the planet. Plastic pollution harms not only the environment and ecosystems, but also human health and economies.

Plastic use is expected to double by 2040. Negotiations on a global plastics treaty have made little progress amid lobbying by the fossil fuel and petrochemical industries.