Current status of marine wastes
What is plastic in the first place?
Plastic is "synthetic resin derived from petroleum." Synthetic resins are those made of high molecular compounds. Simply put, it is a substance made by human. Processed by the application of heat and pressure, the resulting products are essential to our lives.
Macroplastic and microplastic
There are two major types of plastic that flow into the sea: macroplastics and microplastics. The visible plastic is called macroplastic, and the finer plastic (less than 5mm) is called microplastic. Microplastics can be divided into fine ones from the beginning and those that wear out after they go to the sea. Each of them has a different effect on their sources and organisms, so they are very important when thinking about marine plastics issues.
Why "do not let plastic flow into the sea"?
At present, 8 million tons of plastic is flowing into the sea every year, and it is said that plastic in the ocean will exceed the amount of fish in 2050 (by The New Plastics Economy).
So why can't plastic flow into the sea?
That's because plastic doesn't decompose naturally. Because it will exist semi-permanently somewhere on the earth. Currently, most plastics are made from petroleum. In other words, plastic is made by humans. Natural organic materials such as wood can be broken down into carbon dioxide and water because of the presence of microorganisms that can be broken down. However, microorganisms that can at least degrade petroleum-derived plastics do not exist in the natural environment. Plastics, which are high molecular compounds, are very durable. The durability, which is an advantage of the product, will be a major obstacle when it becomes garbage.
That's because plastic doesn't decompose naturally. Because it will exist semi-permanently somewhere on the earth. Currently, most plastics are made from petroleum. In other words, plastic is made by humans. Natural organic materials such as wood can be broken down into carbon dioxide and water because of the presence of microorganisms that can be broken down. However, microorganisms that can at least degrade petroleum-derived plastics do not exist in the natural environment. Plastics, which are high molecular compounds, are very durable. The durability, which is an advantage of the product, will be a major obstacle when it becomes garbage.
How much plastic is made in the world now?
The figure above shows the annual output of plastic. Compared to 2 million tons in 1950, it was 380 million tons in 2015, almost 200 times as large. According to THE NEW PLASTICS ECONOMY RETHINKING THE FUTURE OF PLASTICS, plastic production is expected to double in the next 20 years, indicating that plastic production is increasing more and more in the future.
What is plastic used for?
Inexpensive plastics that are easy to process are used in a wide range of fields. Looking at the pie chart, you can see that the proportion of packaging materials is particularly large. According to UNEP (United Nations Environment Program) "SINGLE-USE PLASTICS", Japan's per capita consumption of packaging containers is the second largest in the world after the United States. It is not somebody else’s problem. In modern Japanese society, excessive packaging has become commonplace.
What happens to plastic that you no longer need?
Combining this annual production (the world's production of plastics), as of 2015, 7.8 billion tons of plastics have been produced. Among them, 9% is recycled, 12% is incinerated, and 79% is landfill and scattered throughout the natural environment (by Single-use plastics), meaning that most of the vast amount of plastic is scattered somewhere on the earth.