The only way to solve the problem is to stop plastic even reaching our oceans
The plastic accumulating in the giant garbage patches in the middle of our oceans has been getting more and more attention from the media and the public.
But at the same time, scientists are starting to realise that this open-ocean accumulation is only a very small part of the issue. We should worry more about the plastic closer to our coastlines.
One of the less pretty sides of our huge increase in living standards over the last few years is a great increase in the amount of waste we produce. In particular, plastic waste is a burden on the environment. While plastic itself is a great and useful material, the way some of it is mismanaged at the end of its life greatly harms ecosystems.
There is now so much plastic in the environment that a group of academics led by Jan Zalasiewicz from the University of Leicester recently suggested that the appearance of plastic in the stratigraphic record could be used as a marker for the start of the new anthropocene geological epoch. Plastic is all around us, and it is the material that best defines our economic progress in the last 50 years.
Of all the places where plastic pollution has been found, the oceans have gotten the most attention. The accumulation of floating plastic in the middle of the Pacific Ocean is the poster child of our wasteful society. And indeed, there is an awful lot of plastic in the so-called garbage patch in the Pacific Ocean. Twice the size of Texas, it contains perhaps ten trillion pieces of plastic, weighing up to 70,000 metric tonnes. Once you add up the floating plastic in the garbage patches in the other four ocean basins, that number almost doubles.
Yet, the floating plastic in the garbage patches is not the whole story. In fact, it is only a very small (and I would argue almost irrelevant) part of it. For one, there’s just as much plastic floating outside the garbage patches as there is in it, so by focussing only on the centres of the ocean, we are ignoring the plastic closer to our coastlines and in our rivers, where it can reach equally high levels.
Secondly, plastic closer to our coastlines does more harm to marine life. In general, for marine life to be at risk of plastic in a certain place, there needs to be both plastic and marine life there. Now, there is fortunately hardly any life inside the garbage patches; they are among the lowest productivity zones in the ocean. There is very little fishing going on there, by vessels or seabirds, simply because there is very little fish.
The third reason why the patches of floating plastics are only a very small part of the story is that most plastic in the ocean is actually not floating at all. The two hundred thousand tonnes of plastic on the surface of the ocean is dwarfed by the ten million or so metric tonnes of plastic entering the ocean every year. More than 99 per cent of plastic is essentially missing. This could be on the seafloor, back on coastlines, or in animal guts; nobody knows how it’s distributed between these compartments.
So the plastic in the infamous Pacific garbage patch is only a small fraction of all plastic in the ocean, and it is in the area where it probably does least harm. I would argue that we should leave the patch alone for now and stop polluting first.
The Ellen MacArthur Foundation released a report showing that 32 per cent of all the plastics produced end up in the environment. This leakage should be our focus, by incentivising recycling, improving filters in wastewater treatment plants, and creating plastics that truly and quickly degrade in our environment.
If we can stop plastic reaching the ocean in the first place, we solve most of its impact. We can deal with cleaning up the garbage patches in due time.
• Dr Van Sebille is leading an exhibit on the problem of plastic in our ocean at the 2016 Royal Society Summer Science Exhibition, 4–10 July in London.