8 millions tons of plastic in the ocean – really?

When you read about plastic pollution in the ocean you will most likely come across the figure 8 million tons. Where does this come from?

One of the sources is a study conducted in 2015 by American and Australian researchers at the National Center for Ecological Analysis and Synthesis associated with the University of California, Santa Barbara.

The researchers first calculated how much garbage one person produces every year. They studied 192 countries with coast lines. Then they estimated how much of this was plastics and then how much ended up in the ocean. The latter calculation was based on the various countries’ garbage management systems and practices. Finally they made prognoses for future emissions of plastics based on population growth.

The study was published in Science February 13, 2015. It was referred to in several international media, including National Geographic, The New York Times and BBC.

The first plastics study

The article’s abstract said:

“Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025.”

Much more plastics than this

A new study published in Nature March 22 this year found four to sixteen times more plastics in the oceans than previously reported.

It studied the sub-tropic area between California and Hawaii. This area is also coined The Great Pacific Garbage Patch. The study suggests there is far more plastics entering the oceans than the much used figure 8 million tons.