Story modified from original press release issued by CSIRO Australia
Stopping plastic from entering the ocean is a mantra now spoken worldwide as communities, businesses and governments tackle the stream of plastic entering our seas.
It may come as a surprise to you that, despite growing plastic production and lots of images of pollution, there has previously been no evidence showing if plastic in our ocean has been increasing over time.
Now, a research team from NCEAS – led by researchers at CSIRO, Australia’s national science agency, and Woods Hole Oceanographic Institute – have quantified how ocean plastic has changed over the years using the world’s longest data set of floating plastic debris. Their analysis is published in Environmental Science & Technology.
“There was no plastic in 1950 and there is 350,000 tons in the ocean now, clearly there had to be an increase” said Chris Wilcox, lead author on the study and Chief Research Scientist at CSIRO.
“Previous analyses were unable to detect a change over time, but the key difference is we used analysis methods that could deal with complex ocean dynamics,” Wilcox added. “It comes as no surprise to us that our analysis shows a growth in marine plastic particles in the ocean and that this is strongly linked to the accumulating amount of plastic that is produced globally.”
The research used data on plastic particles collected from plankton nets in the western North Atlantic between 1986 and 2015.
“Some plastic is re-used, recycled or discarded, but a substantial amount ends up in the oceans and removal mechanisms like animal consumption, coastal deposition and sinking to the seafloor are unlikely to collectively equate to how much plastic is entering the oceans,” said Wilcox.
Wilcox and colleagues estimate that 0.2 per cent of global plastic produced in 2010 ended up in the ocean, which is around 460 million kilograms for that year.
“It is hard to put this amount of plastic into perspective. It is equivalent to wrapping a 10-meter clingwrap you might use at home around the earth 31,000 times,” said Wilcox.
“Imagine the marine sea creatures like fish, birds, turtles and megafauna, who live with this much plastic and in nearly all cases accidently ingest the finer particles that have broken down,” said co-author and CSIRO Principal Research Scientist Denise Hardesty.
Authors suggest that as plastic production increases and more plastic finds its way into the ocean, there is a corresponding increase in the number of plastic particles.
“Plastic bottles break down to large plastic pieces, which then break down to smaller pieces on so on – one bottle could lead to hundreds of plastic pieces in the ocean and this is where the accumulation of plastic is coming from,” said Hardesty.
“This research shows that in the western Atlantic Ocean plastic is entering the ocean faster than it is coming out through washing ashore, sinking or being consumed.
“This means that while it may be breaking down into smaller pieces, it’s not disappearing from the world’s oceans.
“Whilst other oceans would have different plastic input rates due to differences in the surrounding countries, these results clearly point to the need to continue global efforts in addressing this transboundary problem,” said Hardesty.
“Our research is consistent with others who have shown that land-based waste control efforts have not improved rapidly enough to keep up with accelerating global plastic production,” said Wilcox.
“In fact, given that production of plastic is doubling every 11 years, our waste management quality must increase at this pace just to hold the pollution level constant, much less reduce it.
“Waste control is literally racing against the consumer-driven industrial economies - if we are to improve the plastic pollution situation our waste management must improve faster that the production of plastic grows” said Wilcox.