Plastic 'fingerprints' spotted from space on remote Aussie beach
A new development in satellite technology will help researchers seek out garbage accumulating across the planet.
Looking down at the Earth from space, signs of humankind are everywhere. The cooling ponds at the Chernobyl nuclear power plant, the open-cut Bingham Canyon Mine in Utah, and of course the Great Wall of China all stand out against the natural environment.
However until now, one of the most abundant creations of humankind has been hard to spot — plastic. While satellite technology had been able to survey it in the oceans, tracking it on beaches proved more difficult as computers were misclassifying shadows and water as plastic.
But by analysing how sand and plastic reflect light differently, scientists from RMIT University have discovered how to detect it on land. Study lead author Dr Jenna Guffogg explained to Yahoo News beaches covered in 5 to 10 per cent plastic are now identifiable.
“Everything on the surface of the Earth has a unique fingerprint, and that fingerprint is made out of light,” she said.
“When we look at trees, they're green because that's how they interact with light. We can see some of that light, but we can't see all of it. And satellites can see a lot more than we can.”
How is the plastic detected?
Guffogg’s team taught computers to differentiate between the “fingerprints” of plastic and sand. Concentrations of plastic are then highlighted with colour in images taken by satellites. The idea builds upon research that RMIT led on the detection of bushfires and forest monitoring.
“Scientists think that there's almost the same number of individual pieces of plastic in our oceans that there are stars in our Milky Way. And that number is around 5 trillion. So it's a huge problem we're facing,” she said.
Pictures supplied to Yahoo News by the research team show tests undertaken by the team at Shallow Inlet, close to Wilsons Promontory National Park, in Victoria’s Gippsland region.
Taken on the beach, they show plastic patches lined up on the sand for the experiments. A high-definition image was taken by the WorldView-3 satellite as it flew overhead at an altitude of 617 km and the plastic was picked up as a bright spot against the sand.
In scientific terms, the work is still in its infancy as Guffogg has only been researching the issue for four years. As the technology improves, the goal will be to trace plastic in remote environments and send out teams of garbage collectors to clean it up.
“Researchers around the world have found plastic everywhere from the Arctic to the Antarctic. We see it at the tops of mountains all the way to the ocean floor,” she said.
“Unfortunately, islands tend to accumulate a lot of plastic because ocean currents push them around. Not a single person lives on Henderson Island in the middle Pacific and it has some of the highest concentrations of plastics on its beaches in the world.”
The advancement has been published in the journal Marine Pollution Bulletin.
Love Australia's weird and wonderful environment? 🐊🦘😳 Get our new newsletter showcasing the week’s best stories.