Is the Plastic Soup smaller than we thought?

Researchers from Utrecht University, with Mikael Kaandorp as lead author, came up with a new estimate on the size of the plastic pollution in the oceans, for this they analyzed over 20,000 scientific studies on plastic pollution. The conclusion, the amount of plastic in the ocean is a lot lower than estimates from previous studies. Kaandorp estimates that there are 3.2 million tons of plastic in the ocean and that half a million tons of plastic is added to this every year. This is a lot lower than studies that did run as high as 50-300 million tons. 

 

The news was presented by multiple media outlets as very good news. Unfortunately, the reality is a lot less rosy. Kaandorp himself emphasizes that the numbers do not change reality, there is still far too much plastic in the ocean, animals are harmed by this and plastic enters the food chain. 

Also 3.2 billion kilograms of plastic in the ocean is a gigantic amount. Especially when you consider that plastic in the ocean mostly degrades into many small pieces of plastic, microplastics (pieces of plastic smaller than 5 cm). You have to collect a lot of microplastics to get to one kilogram of plastic. 

Expressing plastic pollution by weight gives a distorted picture of the impact of plastic pollution in the ocean anyway. The most common plastic applications are for single use plastics, mostly thin films for food packaging and disposable products (FMCG) such as plastic bags, about half of the annual plastic production of 440 million tons. These very applications quickly disintegrate into microplastics when they enter the environment and spread over vast areas. 

The larger plastic items on the ocean consist mainly of fishing nets and ropes. This is not so surprising since these objects are precisely designed for use at sea, they can withstand the harsh conditions such as UV light, salt, wind much better. As a result, you find them in a reasonably intact condition at sea. And one fishing net adds up nicely in kilograms, especially when compared to microplastics that you have to catch with a plankton net.

You can also express the amount of plastic in the ocean in numbers of microplastics instead of weight. This is what American researcher Markus Eriksen of the 5Gyres Institute has done. Eriksen showed in a study also released this year, “A growing plastic smog,” that the trend of microplastics in the sea has been increasing sharply just since 2005. He estimates that the number of plastic particles floating in the ocean has now reached 170 trillion pieces, and he calls for urgent action. By the way, Eriksen also did an estimate by weight and arrives at 1.1 to 4.9 million tons of plastic present in the ocean. This is quite similar to Kaandorp’s estimate (3.2 million tons on average). 

The estimate of plastic disappearing into the sea annually that Plastic Soup Foundation cites on its website is 5-13 million tons of plastic per year. This is a 2015 study by Jenna Jambeck published in Science. At the time this publication came out there was also considerable discussion about this, both far too low and at least 10x more was a common comment. Yet for years this study was used as a reference by policy makers and organizations working to stop plastic pollution of the earth. Estimating the amount of plastic dumped into the ocean is complex, there are no neat reports and statistics for this and mostly it is done illegally.

The evidence that plastic pollution is vastly out of control is piling up, going far beyond “just” ocean pollution. Plastic has now been found everywhere on Earth, even in very remote and virtually inaccessible places on Earth such as the peaks of the Himalayas and the deepest bottoms of the ocean the Mariana Trench. It is also becoming increasingly clear that plastic poses a risk to our own health. Plastic has now been found in our own blood and heart. 

Plastic Soup Foundation is going to add the new studies to our “Facts and Figures” section on our website. Content will not change our mission and goal of stopping plastic pollution at its source. The predicted doubling of our plastic use over the next 20 years, particularly for disposable applications, is not the future path we should choose. It is high time to curb our plastic addiction and move away from disposable plastics.