The Plastic Tide

The Problem

Water and air, the two fluids on which all life depends, have become global garbage cans.
— Jacques Cousteau
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The Plastic Tide is rising, swamping the ocean and everything and everybody that uses it.

 
The vision of the future if nothing is done (Source: Ellen Macarthur Foundation)

The vision of the future if nothing is done (Source: Ellen Macarthur Foundation)

The Plastic Tide is growing by 8 million metric tonnes a year. If nothing is done, it is estimated that this figure will rise to 80 million metric tonnes a year by 2025.  

 

This tide does not recede. It consists of all sizes of plastics, with larger pieces taking at least 400 years to break down, into fragments known as microplastics.  These and other tiny pieces of plastic, like microbeads, accumulate, forming an oceanic soup that recent estimates put at 15 to 50 trillion pieces. 

 

 

Where Does Plastic Pollution Come from?

Around 80% of the 8 million tonnes of plastics come from land-based sources, with the remainder coming from shipping and the fishing industry.  Major land-based sources are broken down into two sources:

- Primary sources are the waste plastics from the manufacturing industry - known as 'nurdles' or 'mermaid's tears' - these small beads are transported in large volumes into the marine ecosystem. A recent beach clean in Cornwall found 127,000 nurdles in a single clean.

- Secondary sources are plastic litter - bottles, food packaging, polyester clothing, fishing line - which is brought to the beach by wave action, river deposits, sewage outlets and storm drains, as well as being directly deposited by beach users.

 

UNEP - Marine Litter Vital Graphics

Where does it go?

One of the major problems with tackling the plastic pollution problem is identifying where the plastics end up once they enter our oceans and seas. So far we can only account for 1% of the total plastic in our oceans today, which begs the question; where is the missing 99%?

Answering this question is becoming a major concern and focus for scientists.  Without this knowledge, it is impossible to identify trends, support legislation, monitor improvement, or develop strategies to reduce plastic pollution if we don’t have evidence of when, where and how the plastics are distributed.

What are the types?

List of types of Plastics in everyday use (Source: Ellen Macarthur Foundation)

Impacts on Marine Life

The impact of this synthetic tide is pervasive. Increasing evidence shows how quickly our oceans are becoming swamped. From clogging the deepest depths before we have even explored them, to starving the birds that soar above the ocean surface, this is a problem that affects all marine life. But it also has increasing impact on human life too, from toxicity to rising economic costs.

It's estimated that 100,000 marine creatures die each year through starvation due to eating plastic that stays in their stomach making them feel full. A paper in the Proceedings of the National Academy of Sciences estimates that 90% of seabirds carry around 10% of their body weight in plastics - a similar proportion to airline hand luggage allowance for humans. This figure is expected to increase to 99% by 2050. 

Impacts on Marine Life

At the other end of the scale, deep in the Mariana Trench - 7 miles below the ocean surface - tiny shrimp-like amphipods were found to have very high or extraordinarily high levels of plastic and industrial contaminants. These levels are only usually seen in marine life in some of China's most polluted river estuaries. 

The extent of the plastics pollution is clear and shocking - reaching the wildest and most remote areas of our planet - areas we haven't even fully explored yet. These supposedly pristine frontiers of our globe are being destroyed before we have even seen them - the impact of humankind reaches far beyond our own territory, and without full knowledge of the extent of our pollution, we have very limited ability to act.

Is Plastic Toxic to Marine life?

Yes, perhaps devastatingly so. Plastics act as a sponge, soaking up other toxic chemicals and pollutants in the ocean. As they break down, they release these into the environment as well as the additives used to give them their properties, such as colour, which in turn can be highly toxic. Whilst this has been known for some time, scientists have been unable to quantify the impact on marine life until recently. Studies are now confirming prior concerns; a study recently demonstrated that fish larvae exposed to microplastics not only inhibits hatching,  stunts growth and alter feeding patters but, shockingly, altered their behavioural responses to predators!

Are we eating our own Plastic waste?

Again, yes. It is estimated that average consumers of seafood ingest around 11,000 pieces of microplastics per yearwith over a third of all fish caught in the English Channel containing microplastics. There is increasing concern that this could adversely affect humans - although this is still being studied and debated.

This recent BBC News video shows the moment that the plastic enters our foodchain and starts its journey towards our own dinner plates.

A good place to read more is this recent Greenpeace report on Plastics in Seafood.

How much does this all cost?

The World Economic Forum report estimates that food wrapping alone, around a third of all plastic produced, loses 95% of its value after its first use which can be for just seconds. This translates to an estimated loss of £65-£100 billion annually to the global economy.  Further, the report estimates that by 2050 20% of global oil production will be consumed by the production of plastics generating 15% of global carbon dioxide gas production. 

The Missing 99%

Despite these growing concerns, whilst we can estimate how much plastic is already in, and is entering, our ocean, we can't say for certain where it goes.

This presents a huge problem to scientists, as it is a major missing piece of understanding telling us how plastic impacts both the oceans and our lives.  So far we can only say with certainty where 1% ends up - on the ocean surface.  The remaining 99% is unaccounted for - we are unsure how much ends up on our sea floor, in the water column, in sea creatures or on our beaches.