Scientists estimate that perhaps 8m tonnes of plastic waste enters the ocean each year, discharged by rivers or shed from ships. Plenty stays close to shore. Some, though, is carried by currents to mid-ocean gyres.
The biggest of these is located halfway between California and Hawaii—and so littered with flotsam that it has been nicknamed the Great Pacific Garbage Patch.
A study published in Scientific Reports by Laurent LeBreton of the Ocean Cleanup, a Dutch charity, and colleagues, found that it contains between 45,000 and 129,000 tonnes of plastic debris spread over an area roughly the size of Alaska.
The idea of sweeping it all up might sound fanciful. To Boyan Slat it seemed merely ambitious. What if, he wondered in 2012 (then aged 18), you could build a massive bow-shaped floating barrier, anchor it to the seabed and let currents shuffle the litter into the scoop? Despite his youthful age and madcap scheme, Mr Slat set up the Ocean Cleanup to put it into practice.
In 2018, €20m ($23m) and several prototypes later, the device set sail from San Francisco on September 8th, escorted by a Coast Guard vessel, a shipload of camera crews and a flotilla of curious boaters.
System 001, as the contraption has been christened, is a hollow cylinder 600 metres long and 1.2 metres in diameter, itself made of plastic (polyethylene). It was moulded together into a seamless whole from 12-metre segments at a shipyard across the San Francisco Bay in Oakland.
A three-metre-deep skirt (made of sturdy polyester) dangles beneath the boom to prevent litter from escaping under it; buoyant plastic tends to float within a metre of the water’s surface
Ocean Cleanup now has System 002 to fish out the collected rubbish, which the charity sells to recyclers.
The system can do little about plastic microscopic particles that make up just 8% of plastic in the gyre
Modeling predicts they need around 10 full-size systems to clean up the Great Pacific Garbage Patch alone
BUT after fleets of systems are deployed into every ocean gyre, combined with source reduction, the aim is to remove 90% of floating ocean plastic by 2040
Rivers are the main source of ocean plastic pollution. Research found that 1000 rivers are responsible for roughly 80% of riverine pollution
The Interceptor is The Ocean Cleanup’s answer for river plastic waste. It is the first scalable solution to prevent plastic from entering the world’s oceans from rivers
It is 100% solar-powered and extracts plastic autonomously
The ocean’s plastic problem cannot really be solved without better waste management on land and I know a man who is planning to tackle that problem!
Do you pick up litter when you walk on a beach?