2. Where does the plastic waste come from?

Image of marine debris, washed ashore at the west coast of Jutland, Denmark. (Photo: Kathrin Brockmann)

Global plastic production has increased several-fold over the past few decades, rising by 620 per cent between 1970 and 2013, and the amount of marine litter has experienced similar growth. Many sources estimate that roughly 80 per cent of marine plastic litter originates on land. But according to a recent Australian study, how much litter from the world’s various coastal regions finds its way to the oceans primarily depends on how advanced the different countries’ waste collection and recycling systems are.

Waste recycling is particularly poor in China and Southeast Asia, where a tremendous amount of plastic litter ends up in the ocean. If waste recycling isn’t significantly improved, thanks to increasing production the amount of litter worldwide will continue to rise until at least the year 2100.

In contrast, the amount of plastic waste dumped into the sea by ships will most likely have decreased: for decades now, the International Convention for the Prevention of Pollution from Ships (MARPOL) has outlawed dumping plastic waste. But of course, some waste still finds its way off board, whether intentionally or not.