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On a pristine beach in Gippsland, a team of scientists are dumping plastic rubbish.
Their littering is extremely precise.
When they're done, 14 squares of trash — each exactly 2 square metres — are arranged neatly in the sand.
This yellow spot, pictured below, is how they look to a satellite passing 617 kilometres overhead.
This yellow spot is how they look to a satellite passing 617 kilometres overhead. (Supplied: RMIT)
Spot waste from space
Jenna Guffogg led the RMIT research team behind that spot.
Her newly published algorithm uses satellite imagery to spot plastic washed up or discarded on beaches.
By identifying plastic waste from space, Dr Guffogg hopes the tool can guide clean-up work all over the globe.
"We find plastics everywhere from the Arctic to the Antarctic; from the tops of mountains to the ocean floor," she said.
Jenna Guffogg led the scientists behind a tool that uses satellites to scan for plastic waste on beaches. (Supplied: RMIT)
Satellites have long been used to track plastic in the ocean but have struggled to accurately spot pollution against a sandy background.
Dr Guffogg's algorithm – called the Beached Plastic Debris Index – was precisely calibrated to catch the small differences in how light is reflected between sand, plastic and water.
It's similar to tools used to monitor forest growth and map bushfires from above.
The squares in Gippsland were an important test: each was smaller than the satellite's pixel size of 3 square metres and made of different kinds of plastic.
The squares in Gippsland were each smaller than the satellite's pixel size of 3 square metres. (Supplied: RMIT)
The test proved the algorithm could spot the pollution.
Now it's up to humans to pick it up.
Drowning in plastic
Tens of millions of tonnes of plastic enter the Earth's oceans every year.
Fishing line, bottles, bags, wrappers. It all spreads through ocean currents to land far from where it was dropped.
As it does, Dr Guffogg said it also breaks down into smaller, increasingly harmful pieces.
"Recent estimates [suggest] there's roughly the same number of plastic items floating in our oceans now as there are stars in our Milky Way," she said.
"That number sits around 5 trillion pieces – it's really hard to comprehend."
The Great Pacific Garbage Patch – a swirling trash mass three times bigger than France – is the most famous example, but Dr Guffogg said the increasing volume of plastic waste being dumped means more hotspots will constantly pop up on land and at sea.
Ocean currents draw plastic into the Great Pacific Garbage Patch. (Supplied: The Ocean Cleanup)
Calling for help
The tiny size and enormous volume of plastic waste pieces means this tool will never be able to find it all.
Speaking on ABC News, Dr Guffogg called on other researchers and organisations to build on what her team had started.
"What we've done at RMIT is a fantastic first step — We've shown that this sort of technique can work," she said.
"The next step is to try and scale that up."
That might mean finding new ways to scan larger areas more quickly or zoom in on ever-tinier waste from space.
"The wonderful thing about satellites is they capture data all around the globe," Dr Guffogg said.
"There's no reason this couldn't be applied to another beach in another country, so that's what we're hoping for."
Of course, it will also require human effort to actually pick up the rubbish.
Starting with 14 suspiciously perfect piles in Gippsland.