Researchers have proven that satellites can be used to detect plastic floating on the surface of the sea, in a discovery that represents a major boost to efforts to clean up the giant patches of plastic that are found throughout the world's ocean.
Scientists at Plymouth Marine Laboratory have developed a technique where machine-learning algorithms can parse satellite imagery and pick out patches of plastic, distinguishing the litter from natural debris such as driftwood, seafoam, and seaweed.
The hope is that the findings, published this week in the scientific journal Scientific Reports, will hasten the development of an operational method of detecting and recovering floating plastic patches across the world.
The new discovery "will hopefully provide a stepping stone for satellites and drones to be used to tackle the marine plastics problem at the end of the product lifecycle", Lauren Biermann, earth observation scientist at Plymouth Marine Laboratory, explained.
At four different study sites in Canada, Scotland, Ghana, and Vietnam, the researchers successfully detected plastics with an average accuracy of 86 per cent. Moving forward, the team intends to refine the technique to improve its accuracy in turbid and river waters.
The scientists relied on imagery captured by the European Space Agency's Sentinel-2 satellites and developed an algorithm fine-tuned to finding objects floating on the ocean surface. They then worked with the University of the Aegean to develop 'optical signatures' for floating plastics and various naturally occurring forms of debris that would allow the system to autonomously identify different materials.
Biermann warned that the discovery should not diminish attempts to curb plastic pollution. "We will only ever make meaningful progress if we also tackle the source and reduce the amount of plastics produced," she said.
An estimated eight million tons of plastic pollution enter the world's oceans every year, and plastic waste is believed to cost up to $33,000 per ton in reduced environmental value, according to 2019 figures published by the Marine Pollution Bulletin.
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