Degrading plastics give off harmful greenhouse gases

James Marshall
August 4, 2018

While worldwide attention is now focused on marine pollution by plastics, the team points out that reducing plastic waste is also important to curb global warming.

"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".

The findings are of considerable concern after the Met Office warned this week that our summers are getting wetter and warmer - in keeping with the predicted effects of climate change.

Study senior author Professor David Karl, of the University of Hawaii at Manoa School of Ocean and Earth Science and Technology, said: 'Plastic represents a source of climate-relevant trace gases that is expected to increase as more plastic is produced and accumulated in the environment.

This newly discovered source of methane has not been factored into global estimates and could prove to be significant in future predictions.

Mass production of plastics started almost 70 years ago, and the production rate is expected to double over the next two decades, according to a UH news release.

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

All of these plastics were found to produce the harmful emissions, including polycarbonate, acrylic, polypropylene, polyethylene terephthalate, polystyrene, high-density polyethylene, and low-density polyethylene (LDPE).

The researchers carried out tests on such common plastic products as water bottles, shopping bags and food containers. Once sunlight starts to decompose the plastic - a process called photo-degradation - emissions can continue even as the Sun starts to fade.

Moreover, it is known that smaller particles, called 'microplastics, ' are ultimately created in the environment which could further speed up the production of gas.

They also trigger storms which increase flooding, drought and erosion. Because of their durability and practical use, production rates are expected to double over the next 20 years, which could continue to release a variety of chemicals throughout their degradation.

Turtles eat plastic bags mistaking them for jellyfish.

Plastic debris can get lodged in coral and affect the health of reefs. Now environmentalists have another reason to demand urgent action. England was the last United Kingdom nation to introduce one, in 2015.

The researchers said the drop in plastic bag pollution measured from 2010 - about the mid-point of charging policies coming into force - showed the power of such levies.

Other reports by Click Lancashire

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