Yellow spot indicating plastic on the blue satellite image of an otherwise pristine beach. Photo: RMIT Australia
Plastic, as you know, is everywhere these days. Big chunks floating around in the sea, medium chunks inside bellies of animals, and tiny chunks floating in our blood. Despite our knowing that we probably ought to stop creating so damn much plastic, it appears that our lust for… well, stuff is winning. Beach cleanups are a way do our part, even if it can feel like too little, too late. But a new satellite imagery technique could help in those cleanups, since it allows researchers to see plastic on beaches from space.
Plastic is an increasingly concerning issue, but in marine environments, it’s the most concerning. Somewhere between 19- and 23-million metric tons of plastic makes its way into the ocean and/or coastal environments every day, and we’re not slowing down. According to reports, that number will double by 2030 unless drastic measures are taken, and it’s unlikely that drastic measures will be taken.
“Plastics can be mistaken for food, larger animals become entangled and smaller ones, like hermit crabs, become trapped inside items such as plastic containers,” said Dr Jenna Guffogg from RMIT University, who was the lead author of a study into the satellite imagery’s usefulness.
The new technique identifies the differences in how light is reflected off different surfaces, like sand, water, and plastic. This allows researchers to find plastic from almost 400 miles above the surface of the Earth.
“Remote island beaches have some of the highest recorded densities of plastics in the world, and we’re also seeing increasing volumes of plastics and derelict fishing gear on the remote shorelines of northern Australia,” Guffogg continued. “If plastic isn’t cleaned up, it eventually fragments into smaller pieces of micro and nano plastics, which cause even more harm. While the impacts of these ocean plastics on the environment, fishing and tourism are well documented, methods for measuring the exact scale of the issue or targeting clean-up operations, sometimes most needed in remote locations, have been held back by technological limitations.”
While we have been using satellite technology to track plastics for years now, this new way of doing it is far more precise — especially when it comes to tracking plastic on beaches, which has, until now, proven to be difficult.
Guffogg and her colleagues came up with something called the Beached Plastic Debris Index (BPDI), which is “a mathematical formula that assesses patterns of reflected light picked up by satellites as they pass overhead,” that “allows them to identify the most interesting aspects of an image.”
The next step is to use the satellites in real world scenarios.
“Detection is a key step needed for understanding where plastic debris is accumulating and planning clean-up operations, which aligns with several Sustainable Development Goals, such as Protecting Seas and Oceans,” said Dr Mariela Soto-Berelov, a co-author of the study. “This is incredibly exciting, as up to now we have not had a tool for detecting plastics in coastal environments from space. The beauty of satellite imagery is that it can capture large and remote areas at regular intervals. We’re looking to partner with organizations on the next step of this research; this is a chance to help us protect delicate beaches from plastic waste.”
