Ocean plastic pollution set to double within 30 years – and clean-up technology won’t solve problem, study shows

Devices that collect floating waste from the surface of the ocean will not solve the problem of plastic pollution, a study shows.

Researchers found river barriers could be a more effective method of reducing pollution “significantly” if used in tandem with surface clean-up technology.

They compared estimates of current and future plastic waste with the ability of floating clean-up devices to collect it, and discovered the impact of such devices was “very modest”.

The researchers, from the University of Exeter, the Leibniz Centre for Tropical Marine Research, the Leibniz Institute for Zoo and Wildlife Research, Jacobs University and Making Oceans Plastic Free, estimated that the amount of plastic reaching the ocean will peak in 2029.

They also warned surface pollution would reach more than 860,000 metric tonnes, more than double the current estimates of 399,000, by 2052 — the date when previous research suggested the rate of plastic pollution might reach zero.

“The important message of this paper is that we can’t keep polluting the oceans and hoping that technology will tidy up the mess,” said Dr Jesse F Abrams, of the Global Systems Institute and the Institute for Data Science and Artificial Intelligence, both at the University of Exeter.

“Even if we could collect all the plastic in the oceans — which we can’t — it’s really difficult to recycle, especially if plastic fragments have floated for a long time and been degraded or bio-fouled.

“The other major solutions are to bury or burn it — but burying could contaminate the ground and burning leads to extra CO2 emissions to the atmosphere.”

The study, published in the journal Science of the Total Environment, analysed the efficacy of private initiatives that propose collecting plastic from oceans and rivers, which have recently gained widespread attention.

It looked at one scheme called the Ocean Cleanup which aims to clean the “Pacific garbage patch” in the next 20 years using 600m floating barriers to collect surface plastic for recycling on incineration or land.

The researchers analysed the impact of deploying 200 such devices, running constantly for 130 years from 2020 to 2150, and found global floating plastic debris would be reduced by 44,900 metric tonnes, just over 5 per cent of the estimated global total by the end of that period.

“The projected impact of both single and multiple clean up devices is very modest compared to the amount of plastic that is constantly entering the ocean,” said Dr Sönke Hohn, of Leibniz Centre for Tropical Marine Research.

“These devices are also relatively expensive to make and maintain per unit of plastic removed.”

The researchers said a “complete halt” of plastic pollution entering the oceans via rivers could prevent most of the waste they predict over the next three decades.

However, they point out that due to the importance of large rivers for global shipping, such barriers are unlikely to be installed on a large scale.

As such, given the difficulty of recycling and negative impacts of burying or burning plastic, the study says reducing disposal and increasing recycling rates are essential to tackle ocean pollution.

“Plastic is an extremely versatile material with a wide range of consumer and industrial applications, but we need to look for more sustainable alternatives and rethink the way we produce, consume and dispose of plastic,” said Professor Agostino Merico, of Leibniz Centre for Tropical Marine Research and Jacobs University.