Does Plastic Contribute to Global Warming?

As if we needed any more reasons to be concerned about the alarming scale of plastic pollution, it has now been discovered that this unbiodegradable substance can contribute to global warming, as well. A study conducted by the University of Hawaii has demonstrated that when plastic is exposed to direct sunlight, it can react to produce the harmful greenhouse gases (GHG) methane and ethylene.

With global concern about methane emissions already sky high, and environmentalists all over the world already lobbying to limit the amount of plastic that ends up in landfill and our oceans, the new findings represent yet another reason to take action immediately. Only by reining in our production of plastic and ensuring that as much of it as possible is recycled can we limit the deleterious effects of this ubiquitous substance.

A catalogue of crimes

In addition to clogging up our rivers, seas and oceans and jeopardising animal life on both land and water, plastic appears to also have a detrimental impact on the environment itself. The ground-breaking new study, published in the journal Plos One, looked at the amount of emissions produced by plastic when exposed to sunlight over a 212-day period.

They found that virgin pellets of polyethylene – the most common form of plastic – released the harmful gases once it came into contact with solar radiation. This occurred when the plastic was housed in water or air (although it happened more rapidly in the latter) and perhaps most troublingly of all, the reaction continued even after darkness had returned.  

“We attribute the increased emission of greenhouse gases with time from the virgin pellets to photo-degradation of the plastic, as well as the formation of a surface layer marked with fractures, micro-cracks and pits,” explained Sarah-Jeanne Royer, lead author on the paper. “With time, these defects increase the surface area available for further photo-chemical degradation and therefore contribute to an acceleration of the rate of gas production.”

Kicking our plastic habit

Plastic was first invented around the turn of the 19^th century, though it has only reached production on a mass scale in the last 50 years. However, experts have predicted that a rising global population and the attendant spike in demand will lead to plastic production increasing twofold over the next 20 years. This will result in even more emissions of GHGs into our atmosphere, exacerbating the already difficult problems posed by climate change.

While scientists are pursuing a variety of innovative solutions to fight against plastic pollution – including the unlikely marriage of forensic science and artificial intelligence – the best course of action would be to cut down on our addiction. Plastics are seen everywhere we go and form part of everything we use and consume, but they must be phased out if we want to avoid the most serious environmental effects associated with them.

“Considering the amounts of plastic washing ashore on our coastlines our finding provides further evidence that we need to stop plastic production, especially single-use plastic,” said David M Karl, another author of the study. If we don’t, we’ll give ourselves virtually zero chance of meeting the climate goals outlined at the COP21 summit in Paris three years ago.