Plastic pollution is a huge problem since it negatively impacts marine and human life and the toxins plastic absorbs and releases move up the food chain.
However, a group of researchers from the University of Hawaii at Manoa School of Ocean and Earth Science and Technology (SOEST) revealed in their latest study yet another potential plastic hazard. Several greenhouse gases, including methane , are emitted as plastics degrade in the environment.
The study found that some of the most used plastics under sunlight release methane and ethylene in the atmosphere. The amounts of gases released are small. However, the astonishing amount of plastic waste could still contribute to greenhouse gas emissions and climate change over time.
The discovery was accidental. The leader of the team, Dr. Sarah-Jeanne Royer, was not studying plastics. Instead, she was measuring the amount of methane produced by biological organisms. However, she found that the plastic bottle that was holding the samples was releasing more methane than the organisms themselves.
After the accidental discovery, the research team tested polycarbonate, acrylic, polypropylene, polyethylene terephthalate, polystyrene, high-density polyethylene and low-density polyethylene (LDPE). These materials are used commonly in food packaging, textile, and other plastic goods. Polyethylene, the most popular material out of plastics, was releasing the biggest amounts of greenhouse gases.
Additionally, they found out that the longer the LDPE is exposed to sunlight, the greater the emissions from it. After being exposed to sunlight for 212 days, the material’s emission increased by 176 times. The reason for this is the fact the LDPE breaks down under sunlight, exposing more plastic area to the sun. Once the process begins, the emission doesn’t even stop when there is no sun.
Royer and her team are now working on measuring the amount of plastic exposed to sun globally so they can calculate its contribution to climate change, and on possible solutions of the problem.