The Ocean's Plastic Problem: An Enormous Threat

Plastic pollution is a pressing issue, with an estimated 1 to 2 million tonnes of plastic entering the oceans annually. This figure equates to 0.5% of the world's plastic waste, which, in 2010, was the weight of nearly 90 aircraft carriers. The OECD Global Plastics Outlook estimates that 1.7 million tonnes of plastic end up in the oceans each year, with 1.5 million tonnes remaining close to the shoreline, 0.2 million tonnes sinking to the seabed, and less than 0.1 million tonnes being transported offshore on the surface.

How much plastic waste ends up in the ocean?

It is estimated that between 1 and 2 million tonnes of plastic enter the oceans annually. This equates to around 0.5% of the world's plastic waste.

The OECD Global Plastics Outlook estimates that 1.7 million tonnes of plastic end up in the oceans, with 1.5 million tonnes remaining close to the shoreline, 0.2 million tonnes sinking to the seabed, and less than 0.1 million tonnes being transported offshore on the surface. A recent study by Meijier et al. (2021) estimates that the figure is around 1 million tonnes.

Scientists think that about 8 million metric tons of plastic entered the ocean in 2010, and the problem continues to grow. Nearly one-quarter of the world's plastic waste is mismanaged or littered, meaning it is not stored in secure landfills, recycled, or incinerated. This makes it vulnerable to polluting the environment, with some of it eventually making its way to the ocean.

More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean. The probability that mismanaged plastic waste enters the ocean varies across the world, depending on factors such as the location and length of river systems, proximity to coastlines, terrain, and precipitation patterns.

What are the sources of plastic in the ocean?

It is estimated that between 1 and 2 million tonnes of plastic enter the oceans annually. This plastic comes from a variety of sources, including littering, mismanaged waste, and industrial activities. One of the major sources of plastic in the ocean is riverine plastic emissions. More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean. This means that the plastic that ends up in the ocean comes from a variety of land-based sources, including littering, improper waste management, and industrial activities.

Another source of plastic in the ocean is mismanaged waste. Nearly one-quarter of the world's plastic waste is mismanaged or littered, which means it is not stored in secure landfills, recycled, or incinerated. This mismanaged waste can be leaked into the environment and eventually make its way into the ocean. The probability that mismanaged plastic waste enters the ocean varies depending on factors such as the location and length of river systems, proximity to coastlines, terrain, and precipitation patterns.

In addition to riverine plastic emissions and mismanaged waste, plastic in the ocean can also come from industrial activities, such as manufacturing and shipping. Plastic pellets, known as "nurdles", are often used in industrial processes and can be accidentally spilled or released into the environment, eventually making their way into the ocean.

Once plastic enters the ocean, it can be transported by ocean currents and accumulate in certain areas, such as gyres or coastal regions. It can also be ingested by marine life, leading to health issues and even death. Some plastic sinks to the seabed, while other pieces are washed up, buried, and resurfaced along shorelines. This shows that plastic in the ocean comes from a variety of sources and has a significant impact on the marine environment.

How does plastic waste reach the ocean?

It is estimated that between 1 and 2 million tonnes of plastic enter the oceans annually. This is around 0.5% of the world's plastic waste. While it's tough to say exactly how much plastic is in the ocean, scientists think about 8 million metric tons of plastic entered the ocean in 2010.

There are several ways in which plastic waste reaches the ocean. One of the main ways is through littering. When plastic is thrown away, it can easily be blown away by the wind or washed away by rainwater into streams, rivers and drains, which all lead to the ocean. Careless and improper waste disposal is a big contributor to this, with illegal dumping of waste adding greatly to the plastic surge in our seas.

Another way plastic ends up in the ocean is through landfill sites. When rubbish is being transported to landfill, plastic is often blown away because it's so lightweight. From there, it can eventually clutter around drains and enter rivers and the sea.

Plastic can also enter the ocean through drains in our homes. Despite growing awareness, objects containing plastic are still being flushed down toilets instead of being disposed of in waste bins. Wet wipes, cotton buds and sanitary items that are inadequately disposed of find their way into the ocean via this route. Even if you don't flush these items, microfibres are released into waterways when we wash our clothes, which can end up in the ocean.

Finally, human activity at sea is another important source of plastic pollution. A 2019 report by Greenpeace revealed that 50,000 double-decker bus-loads' worth of discarded plastic fishing equipment is left in the oceans each year.

How much of the world's plastic waste is mismanaged?

It is difficult to say exactly how much plastic is in the ocean, but scientists estimate that around 8 million metric tons of plastic entered the ocean in 2010. A more recent study estimates that between 1 and 2 million tonnes of plastic enter the oceans annually, with 0.5% of plastic waste ending up in the ocean.

The OECD Global Plastics Outlook estimates that 1.7 million tonnes of plastic enter the oceans, with 1.5 million tonnes remaining close to the shoreline, 0.2 million tonnes sinking to the seabed, and less than 0.1 million tonnes being transported offshore on the surface.

While we might think that much of the world's plastic waste is recycled, only 9% is. Half of the world's plastic goes straight to landfill, and a further fifth is mismanaged, meaning it is not recycled, incinerated, or kept in secure landfills. This puts it at risk of being leaked into rivers, lakes, and the ocean.

A 2017 study found that 80% of mismanaged plastic in the ocean came from just five Asian countries: China, Thailand, Vietnam, Indonesia, and the Philippines.

What are the impacts of plastic in the ocean?

It is estimated that between 1 and 2 million tonnes of plastic enter the oceans annually. This is around 0.5% of the world's plastic waste. While it is difficult to say exactly how much plastic is in the ocean, scientists believe that about 8 million metric tons of plastic entered the ocean in 2010.

Plastic in the ocean has a devastating impact on marine life and ecosystems. It has been found to injure and kill fish, seabirds and marine mammals. It has impacted at least 267 species worldwide, including 86% of all sea turtle species, 44% of all seabird species and 43% of all marine mammal species. The impacts include fatalities as a result of ingestion, starvation, suffocation, infection, drowning, and entanglement. In 2010, a California grey whale washed up dead on the shores of the Puget Sound. Autopsies indicated that its stomach contained a pair of pants, a golf ball, more than 20 plastic bags, small towels, duct tape and surgical gloves.

Plastic pollution is undoubtedly an issue that requires worldwide cooperation. Its consequences affect the whole planet and its inhabitants: it threatens ocean health, the health of marine species, food safety and quality, human health, coastal tourism, and contributes to climate change. It is estimated that the yearly economic costs of plastic in the ocean are between $6-19bn USD.

Billions of pounds of plastic can be found in swirling convergences that make up about 40% of the world's ocean surfaces. At current rates, plastic is expected to outweigh all the fish in the sea by 2050. Thousands of seabirds and sea turtles, seals and other marine mammals are killed each year after ingesting plastic or getting entangled in it. Endangered wildlife like Hawaiian monk seals and Pacific loggerhead sea turtles are among nearly 700 species that eat and get caught in plastic litter.

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