Every year, 8 million tons of plastic enter the ocean. That’s equivalent to one truckload dumped into the sea every minute of the day. From there, it goes on a long and destructive journey. “The plastic that enters the ocean can be carried vast distances by currents to all parts of the world, including remote Antarctica and the Mariana trench, the deepest place on Earth,” says Winnie Lau, senior officer for The Pew Charitable Trusts’ Preventing Ocean Plastics campaign. Along the way, it infiltrates ecosystems and causes untold harm to marine life.
What’s the problem with plastic?
Plastic is almost inescapable in our daily lives. It’s used to make everything from food packaging to toiletries, clothing, furniture, computers and cars. This ubiquitous material is designed to be very durable – and as a result much of it doesn’t biodegrade. Depending on the type, plastic can take between a few decades to potentially millions of years to disintegrate in landfill. Consequently, unless it’s burned, which itself causes pollution, nearly every piece of plastic ever manufactured still exists today – and when it enters the ocean, its effects can be felt for centuries.
Where does waste come from?
Globally, we produce more than 300 million tons of plastic waste each year, and that number is rising. Yet of all the plastic waste ever created, only 9% has been recycled, while the rest has been incinerated or discarded, mainly ending up in landfills. A big reason for this is that 50% of the plastic we produce is single use, meaning it’s intended to be thrown away immediately after it has served its purpose – like straws, plastic carrier bags and water bottles. Because it’s so frequently produced and so rapidly discarded, single-use plastic increases the amount of waste entering landfills, and in turn, that increases the amount that inevitably escapes into the environment.
Why is the ocean so badly affected by plastic?
Incredibly vast and deep, the ocean acts like a huge sink for global pollution. Some of the plastic in the ocean originates from ships that lose cargo at sea. Abandoned plastic fishing nets and longlines – known as ghost gear – is also a large source, making up about 10% of plastic waste at sea. Marine aquaculture contributes to the problem, too, mainly when the polystyrene foam that’s used to make the floating frames of fish cages makes its way into the sea.
But the vast majority of waste enters the water from land. Extreme weather and high winds brings it there, and pollution along coastlines gets swiftly hauled out by the tides. The ocean is also the endpoint for thousands of rivers, which carry tonnes of loose litter and waste from landfills, ultimately depositing it into the sea. In fact, just 10 rivers worldwide, eight of them originating in Asia, are responsible for the bulk of river-borne plastic that enters the oceans: China’s Yangtze is the biggest source, contributing 1.5 million metric tonnes each year. That’s mainly because several countries outsourced their plastic waste management to China. Until January 2018, when it banned the trade, China imported almost half of the world’s plastic trash.
What’s the impact on marine life?
Hundreds of thousands of marine animals get entangled in plastic waste each year – especially in ghost gear – which limits their motion and their ability to feed, and causes injuries and infections. Less visible is the devastation that occurs through the ingestion of plastic: seabirds, turtles, fish, and whales commonly mistake plastic waste for food, because some has a similar colour and shape to their prey. Floating plastic also accumulates microbes and algae on the surface that gives it an odour that’s appetising to some sea animals. Once animals consume it, ingested plastic can pierce internal organs or cause fatal intestinal blockages; it also leads to starvation, because a stomach crammed with plastic gives an animal the illusion of being full.