We know there’s a profusion of plastic in the ocean; floating at the surface, accumulating on the seafloor, making its way into the bellies of organisms and even becoming incorporated into rocks. We also know that a worrying amount of the plastic seeping into our oceans is unaccounted for, with some studies suggesting that as much as 99% is missing. But working out how much of the stuff is actually journeying from land to the marine environment each year has been tricky, and largely well-educated guesswork. Now, scientists have come up with a figure, and it’s not pretty.
Around 8 million metric tons of plastic waste entered the ocean in 2010, and the vast majority of it is underwater. To put that into perspective, that would leave you wading ankle-deep in trash across an area 34 times the size of Manhattan. That’s also around the same amount of plastic that the entire world produced in 1961. What’s worse, if we don’t clean up our act, 10 times as much could be bound for the oceans annually by 2015.
Plastic is a very useful material, but it’s also an environmental disaster. It was first introduced to the consumer market in the ‘30s, but it wasn’t until the ‘70s that scientific studies started reporting the problem of plastic pollution in the ocean. Back then, scientists estimated that around 0.1% of plastic produced globally is dumped, blown or washed out into the marine environment. Now, according to a new Science study, we know the problem is far more depressing, with as much as 4.5% of the world’s total plastic production entering the ocean.
For the investigation, scientists pooled international data on population, waste production and management to calculate how much plastic the world’s 192 coastal countries produce. Next, they modelled different scenarios to estimate how much could potentially find its way to sea, for example due to leaky landfills or littering.
In 2010, these countries generated an impressive 275 million metric tons of plastic waste, and between 4.8 and 12.7 million metric tons of this spilled into the sea. That’s as much as 1,000 times more than the mass of floating plastic that scientists have found in our oceans so far. Interestingly, the top 10 offenders, which includes many countries in south-east Asia, generally have low rates of plastic waste production per person. China, number one on the list, adds as much as 3.5 million tons of plastic to the oceans each year, but the average person produces half as much as someone in the U.S., who ranked 20 on the chart.
But we can’t go around pointing the finger because many of those at the top of the list are developing nations with high coastal populations and no formal waste management systems, and hence low rates of recycling. That’s because waste management comes fairly low on the list of priorities during a country’s development, with clean drinking water and sewage treatment understandably coming first.
So we know the problem, what’s the solution? Trying to mop it all up from the ocean is likely unfeasible at this stage, so we need to focus on stopping it getting in there in the first place. That means reducing the consumption of single-use plastic items and improving waste management practices.