The Great Pacific Garbage Patch contains as much as sixteen times more plastic than previously estimated, with pollution levels increasing exponentially.
1.8 trillion pieces of plastic weighing 80,000 metric tons are currently afloat in the area which is rapidly growing, according to a three-year mapping effort conducted by an international team of scientists affiliated with The Ocean Cleanup Foundation, six universities and an aerial sensor company.
The Great Pacific Garbage Patch (GPGP), located halfway between Hawaii and California, is the largest accumulation zone for ocean plastics on Earth. In order to analyze the full extent of the GPGP, the team conducted the most comprehensive sampling effort of the GPGP to date by crossing the debris field with 30 vessels simultaneously, supplemented by two aircraft surveys.
Although most vessels were equipped with standard surface sampling nets, the fleet’s mothership RV Ocean Starr also trawled two six-meter-wide devices, which allowed the team to sample medium to largesized objects. To increase the surface area surveyed, and quantify the largest pieces of plastic a C-130 Hercules aircraft was fitted with advanced sensors to collect multispectral imagery and 3D scans of the ocean garbage. The fleet collected a total of 1.2 million plastic samples, while the aerial sensors scanned more than 300 km2 of ocean surface.
The results reveal that the GPGP, defined as the area with more than 10 kg of plastic per km2, measures 1.6 million square kilometers, three times the size of continental France. These figures are four to sixteen times higher than previous estimates. 92% of the mass is represented by larger objects, while only 8% of the mass is contained in microplastics, defined as pieces smaller than 5 mm in size.
“We were surprised by the amount of large plastic objects we encountered,” Dr. Julia Reisser, Chief Scientist of the expeditions, said, adding that they used to think most of the debris consists of small fragments.
By comparing the amount of microplastics with historical measurements of the GPGP, the team found that plastic pollution levels within the GPGP have been growing exponentially since measurements began in the 1970s.
“To be able to solve a problem, we believe it is essential to first understand it. These results provide us with key data to develop and test our cleanup technology, but it also underlines the urgency of dealing with the plastic pollution problem. Since the results indicate that the amount of hazardous microplastics is set to increase more than tenfold if left to fragment, the time to start is now,” Boyan Slat, Founder of The Ocean Cleanup and co-author of the study, concluded.