An area of concentrated plastic pollution known as the “Great Pacific Garbage Patch” (GPGP) contains up to sixteen times more debris than previously thought, according to research published this week in the journal Scientific Reports.
The conclusion comes after a team of scientists affiliated with non-profit The Ocean Cleanup Foundation, six universities and an aerial sensor company spent three years mapping the area. It’s now believed that the GPGP contains some 1.8 trillion pieces of plastic weighing 80,000 metric tonnes.
To measure the full extent of the pollution, the team crossed the debris field with 30 vessels simultaneously and supplemented these efforts with two surveys by a C-130 Hercules aircraft.
The majority of the vessels were equipped with standard surface sampling nets, though the fleet's mothership RV Ocean Starr also trawled two six-meter-wide devices, allowing the team to sample medium to large-sized objects.
In total, the fleet collected 1.2 million plastic samples and the aerial sensors scanned over 300 square kilometres of ocean surface. Analysis of the data revealed that the GPGP measures 1.6m square kilometres when defined as a zone with more than 10kg of plastic per square kilometre. This area is three times the size of continental France.
By comparing quantities of microplastics with historical measurements in the region, the researchers discovered that plastic pollution levels within the GPGP have been growing exponentially since the 1970s.
“Although it is not possible to draw any firm conclusions on the persistency of plastic pollution in the GPGP yet, this plastic accumulation rate inside the GPGP, which was greater than in the surrounding waters, indicates that the inflow of plastic into the patch continues to exceed the outflow,” says Laurent Lebreton, lead author of the study.