Plastic that is mismanaged and thrown by humans as waste in the environment does not stop the emissions there, but releases even more gases as it disintegrates in nature. As a result, this is caused by solar radiation that generates greenhouse gases both in the air and in the water. Efforts to measure these emissions are still in the early stages, but the first study to be done demonstrates only plastic in the oceans (excluding the amount we throw on the ground) and shows how it continuously releases greenhouse gases into the oceans such as methane and these emissions only rise higher as it dissolves in water. Current estimates address only 1% of the plastic found on the surface of the oceans, while 99% of the plastic emissions found in the deep ocean cannot yet be accurately measured. Significantly, research shows that plastic on beaches, riverbanks or landscapes releases greenhouse gases at staggering rates.

Petrochemical industries plan to expand plastic production and threaten to worsen the climate impact of plastic by breaking the limit of global warming up to 1.5 degrees. If production, disposal and combustion continue to grow on this trajectory as they have been, by 2030 these emissions will reach 1.34 gigatons per year, equivalent to 295 five-hundred-megawatt coal-fired power plants. But by 2050, production and combustion could emit 2.8 gigatons of carbon per year, releasing as many emissions as 615 five-hundred-megawatt coal-fired power plants.

LANDFILLS

In a modern landfill tightly compacted piles of waste are sealed under rubber and clay barriers with a liner on top that prevents liquid from flowing out through channels and pipes that collect the contaminated liquid and allow it to flow out of the pit. Before being released, this strained and toxin-laden liquid is collected in ponds and treated in a special way. When the waste pit exceeds its carrying capacity, it gets covered with mud and a plastic shield on top.

In general, landfills are not designed to degrade waste, they are simply designed to store and contain it. Some biodegradable waste (such as food) decompose very slowly in an oxygen-free environment. Due to the lack of oxygen, the bacteria produce methane gas, an extremely dangerous gas that can easily ignite and catch fire. Not only is methane one of the greenhouse gases which is contributing to global warming but if too much methane gets collected underground, because of its highly flammable characteristics, it can also explode easily. Modern landfills have systems that collect this gas in pipe layers that are placed above the solid waste layer. According to NYSDEC (New York State Department of Environmental Conservation), some of the landfills allow this gas to escape into nature, while some of them sell it or burn it as a source of energy. Landfills and the natural environment are the final destinations for more than ¾ of non-degradable plastic waste according to a new global assessment.

According to a report by scientists in Science Advances, if current trends in plastic production and waste management continue, the amount of plastic waste in landfills and natural environments — currently 4.9 billion metric tons — will double by 2050. To understand how much plastic we've produced globally, researchers measured global plastic production from trade associations and market research companies. In 2015 the total of all plastic ever produced since 1950 is 8.3 billion metric tons. Production has become so fast that of all the plastic produced in 1950, 50% of it was produced in the last 13 years alone. 

In other words around 400 million metric tons has been stable for 50 years, but since 2002, we have doubled this yield. According to research only 30% (2.5 billion metric tons) of all plastic ever produced is still in use. Part of this trend is that half of polymer plastic is converted into packaging material. A large amount of plastic packaging is thrown away the same year it is purchased. The average use of a plastic bag is 12 minutes compared to its lifespan which is estimated to be 1000+ years. In 2015, 146 million polymer plastics were used for packaging and 141 billion metric tons were thrown away. In contrast to fibre-free plastics of which 65 million metric tons are consumed in construction because they are used for long-term purposes, only 12 million metric tons or 5% of all waste ever made is caused by construction. Global plastic pollution has doubled from 2000 to 2019 to 353 million tons. Almost ½ of all plastics come from those that have had a lifespan shorter than 5 years, of which 40% is packaging, 12% consumer goods and 11% textiles and clothing.

The world is producing twice as much plastic waste than 2 decades ago, of which 50% ends up in landfills, 19% is burned, 22% is thrown away in nature (land, rivers, oceans, seas, lakes, etc.), while only 9% of it is recycled. Almost half of all plastic that is produced is collected inadequately, and the disposal of large plastics known as macroplastics is transformed into microplastics (polymers with a diameter of less than 5 mm) from things such as industrial ones, synthetic textiles, car parts, etc. OECD countries (Organization for Economic Co-operation and Development) are behind 14% of total plastic waste. Within it, they are responsible for 11% of macroplastic pollution and 35% of microplastic pollution.

SLOW DECOMPOSITION OR NONE?

Plastic is a broad term for many materials belonging to different categories (PET, PVC, LDPE, etc.). All these materials contain the same problem: "natural degradation".

Under normal natural conditions, plastic bottles (Category (1) PET/PETE) take 500 to 700+ years to decompose, a very slow process, while plastic bags start the decomposition process after 1000+ years. Decomposition rates are further reduced when manufacturers add antioxidants that increase the plastic's resistance to acidic contents.

The reason for the slow degradation is very simple. The chemical compounds contained in the plastic material are not commonly known for nature's bacteria and such materials are called “xenobiotics” (:xenobiotics: /noun/ - substances unknown to the body or ecological system, a chemical that is found in an organism but is not produced or not normally expected to be part of that organism).

Since this material does not exist in a natural form in nature (such as sugar cane, cotton, etc.) as a consequence, there is not even one natural organism that has the right information or capacity to dissolve this man-made material effectively in the soil or at all. Also, because of the fact that plastics have only been around for the last 50 years, there is no experiment or research that contains data on the disposal of this material, and there’s no assurance that it will ever decompose after 450-1000+ years. After all, it has a longer life-span than a human being and no one has lived that long to know the consequences.