This large “natural discharge” concentrates 80,000 tons of plastic on an area equivalent to three times that of France.
It does not have much to do with a continent as it was read in many media a few years ago, but still. In the middle of the Pacific, between Hawaii and California, a large area concentrates huge amounts of plastic waste. A new study was published in Scientific Reports can measure the extent.
On a territory as big as three times France, nearly 2 trillion plastic waste floats freely, according to researchers at The Ocean Cleanup, a non-profit organization founded by a young Dutchman, Boyan Slat, who dreams to clean the oceans. This represents nearly 80,000 tons of plastic, which is 4 to 16 times more than previous estimates.
“We must not imagine a sea of plastic,” warns Laurent Lebreton, oceanographer and first author of this publication. “The concentrations vary between 1 and 100 kg per square kilometer. This is not noticed at first glance. But when you take a closer look, it’s still a lot of waste for such an isolated place, in the middle of nowhere. “The waste is concentrated here by the currents that come around this area. calmer.
The researchers conducted the first expedition with fifteen boats in 2015 to sample the waste in several hundred locations. The nets used were nevertheless too small to give a good idea of the distribution of the largest waste (above 50 cm). They returned with a LIDAR-equipped aircraft, an infrared camera and high-resolution cameras in 2016. And that changed everything.
“Micro-plastics (size less than half a centimeter, Ed) are the majority in number – 94% of waste – but they represent only 8% of the total mass,” says Laurent Lebreton. Waste of more than 10 cm represents three-quarters of this mass of floating plastic. “It’s a big surprise. Rather a nice surprise in a way because the biggest waste will be the easiest to remove. “
Another surprise, almost half comes from fishing boats. It is most often buoys or nets, often deadly for many species, starting with sea turtles. “We do not want to point the finger at fishermen, this situation is a collective responsibility,” warns Laurent Lebreton. “It’s our way of life and consumption, the society at all disposable as a whole that needs to be questioned.”
This year, The Ocean Clean Up will test a first 600m long curved floating dam. Objective: “rake” this large patch to concentrate the waste of more than one centimeter and allow their collection by boat. In the long term, it would take 60 “barriers” of one to two km long to collect 90% of this waste by 2040, the organization predicts. Their unit cost is estimated at € 5 million (including the three-year transaction costs). The price to pay for cleaning the oceans as long as it is time: little by little, plastics break up to form micro-plastics which will be much more difficult to get rid of.