Degrading plastics 'release greenhouse gases', study shows

James Marshall
August 5, 2018

Methane emissions, mainly caused by burning fossil fuels, are a major driver of global warming, putting them in the crosshairs of the global fight against climate change.

Plastic food packaging decaying in parks, on beaches and in the sea have been linked to climate change in eye-opening new research.

Polyethylene, which is used in shopping bags, is the most produced and discarded synthetic polymer across the globe.

The research, carried out by the University of Hawaii's Manoa School of Ocean and Earth Science and Technology (SOEST), discovered that methane was released as the plastic is broken down.

About 6.3 billion tons of plastic have been generated since it was first mass produced about 70 years ago.

The production rate of plastic is expected to double over the next two decades, and the degradation of plastic is already known to release a variety of chemicals that can have a negative impact on ecosystems.

The team behind the discovery described what they found as "unexpected".

Additionally, the team found that the emission rate of the gases from virgin pellets of LDPE increased during a 212-day experiment and that LDPE debris found in the ocean also emitted greenhouse gases when exposed to sunlight.

Plastic drinking straws are the latest target of activists, who say they are used once and discarded because most can not be recycled. Once sunlight starts to decompose the plastic - a process called photo-degradation - emissions can continue even as the Sun starts to fade. "However, for the other hydrocarbon gases with much lower global emissions to the atmosphere compared to CH4, the production from the plastics might have more environmental and global relevance". When these plastics are further broken down or cracked, the study authors say the rate of gas production can further accelerate. Microplastics - smaller pieces of plastic particles found to move up the food chain and in almost every corner of the world, including Antarctica - may further accelerate GHG production.

They also trigger storms which increase flooding, drought and erosion.

"Considering the amounts of plastic washing ashore on our coastlines and the amount of plastic exposed to ambient conditions, our finding provides further evidence that we need to stop plastic production at the source, especially single use plastic", said Sarah-Jeanne Royer, lead author of the study.

Sir David Attenborough revealed during Blue Planet 2 that "we dump eight million tonnes of plastic into the sea every year" which is killing and harming marine life.

Other reports by Click Lancashire

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