Beach drones: how tech will be keeping Britain's shores clean this summer

Ellie MacKay is co-director of the Plastic Tide
Ellie MacKay is co-director of the Plastic Tide Credit:  Christopher Pledger

It’s a drizzly, wind-whipped day on Kingsdown beach in Kent. A muddy sky hugs the sea, as waves hammer the shoreline. The beach is empty; no one is stoic enough to brave these conditions.

No one, that is, apart from two figures standing next to an orange launch pad. A young woman holds a white remote control, while a man points into the middle distance. On the pad sits a drone: a £4,000 DJI Phantom Professional Quadcopter, to be precise. It takes off, gliding away over the shingle beach, buzzing angrily, snapping pictures as it goes.

Welcome to the new frontier of conservation. Far from road-testing a birthday present, these two - Peter Kohler, 33, founder of The Plastic Tide, and co-director Ellie Mackay, 28  - are on a mission to push back against the rising tide of plastic on Britain’s beaches.

Britain's beaches are being combed by drones to pick up discarded plastic Credit: Christopher Pledger

This month they begin a groundbreaking project. The organisation has developed a revolutionary algorithm that will scan aerial images, taken by drones, and identify plastic to produce an accurate map of the worst polluted parts of our coastlines.

Over five weeks from the end of this month, the duo will comb Britain’s beaches, surveying 30 seashores from John O’Groats to Cornwall using drone technology to collate more than 30,000 photographs.

Kohler, who works as a location analytics expert for Chelsea and Kensington council, wants to answer an important question.  

“We can only account for about one per cent of the total plastic that is going into the ocean,” he says. “We don’t know where the other 99 per cent is. It could be on the seabed, in marine life or washing up on beaches. Until now, there hasn’t been an accurate way to measure this.”

The Plastic Tide want to gather 30,000 images of Britain's beaches Credit: Christopher Pledger

Kohler is not a lone wolf either; a growing body of scientists are behind his quest.

Dr. Erik van Sebille, an oceanographer at Imperial College London, is one. “The reason this is so important is, once we do this with drones, there’s no reason we can’t do it with satellites. The opportunities are limitless.”

NASA and the European Space Agency are already looking into identifying plastics from space, although they’ve yet to manage what The Plastic Tide’s algorithm is promising.

"The goal is to pinpoint where the plastic comes from,” says Dr van Sebille, “What happens to plastic that leaves the Thames estuary? Does it cross to the Dutch coast or does it wash up in Norfolk? We don’t know. That means we can’t put the blame anywhere.”

Plastic tide found on beach in Cornwall Watch | Plastic tide found on beach in Cornwall
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Once they’ve gathered the 30,000 images, The Plastic Tide will upload them onto Zooniverse, a website where scientists ask volunteers for help in processing large amounts of data.

The public will be asked to tag the plastic they spot. This will train the algorithm to differentiate between a stone and, say, a bottle top. “It is like teaching a dog how to sniff out plastics,” says Kohler.

Who would chose to spend time circling plastic over watching Netflix? Kohler laughs.

“It’s strangely addictive. It helps people have an impact from home. At the end of the process we’ll have a computer programme that you can run on any image of a beach and it will pick out all the plastics down to 1.5 cm in size. That has never been done before.”

Once trained, the system will be made free to anyone, anywhere in the world. An online database could be used in schools to help children get involved in the science of monitoring beaches. Drone owners will be invited to contribute images for instant analysis in a team effort to map our planet.

At this, Dr van Sebille gets excited. “Brighton council could log in the morning after a storm, do a quick survey of how much plastic is on the beaches and then decide how many rubbish trucks they need to send out.”

But how accurate can it really be? What’s to say it won’t confuse glass with a plastic?

“At the moment, you will never get it 100 per cent perfect,” admits Ellie Mackay, a drone pilot and filmmaker with a Cambridge degree. “It might miss the odd piece, in the same way beach cleaners do. But it is infinitely more accurate than human eyesight.”

'A black bin bag is filled within 10 minutes' Credit: Christopher Pledger

After the drone demonstration, Kohler takes me on a beach clean, pulling out plastic fragments from tangles of seaweed. We find Nespresso capsules, plastic cutlery, shampoo bottles, a chunk of beach ball and a Savlon tube. A black bin bag is filled in 10 minutes. Once, Kohler found a Japanese yoghurt pot with a 1984 sell by date. Given plastic takes about 450 years to degrade, we can be sure to see a lot more arriving on our shores.

Some 8 million tonnes is thrown away each year and washed out to sea, an amount that has increased by 250 per cent in the past decade. By 2050, it is thought the plastic in the sea could weigh more than all the fish combined. The impact this is already is having on our oceanic ecosystems is immense.

But Kohler believes there’s time to stem the flow. And with better funding and high-powered drones he also has Britain's roads, parks, rivers and rail lines in his sights.

“This is a new way of doing science,” says Dr Van Sebille. “We can’t rely on governments and big institutions any more. They will always have a role but more and more science will have to be done by the rest of us.”

For more information go to The Plastic Tide or to help CrowdFund the campaign click here.