Let me give you a visual of how much plastic there is. 

Rotating ocean currents, known as gyres, pull and collect floating plastic, creating large collections of plastic. There are five gyres in the world creating five garbage patches in the world’s oceans.  

geologyin.com

These are like 5 big islands of non-biodegradable plastic. The largest is the Great Pacific Garbage Patch. 

https://www.cbsnews.com/

The Great Pacific Garbage Patch is located between CA and Hawaii and covers an area twice the size of Texas, more than three times the size of France and holds around 100,000 tons of plastic. This weight is equivalent to that of 500 Jumbo Jets. It is estimated that there are at least 1.8 trillion pieces of plastic floating in this patch – approximately 250 pieces of plastic for every human being on the planet. 

Most of the mass within this patch is from larger pieces of plastic. However, in terms of number of pieces, 94% of the pieces in this patch has been determined to be microplastics.

From the air, you won’t actually see an island but a cloudy haze of loosely grouped collections of plastic, most of which has sunk below the ocean surface or has scattered within and below as microplastics.

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