The two sides of plastic and climate change

It is unlikely that you can a day in modern society without using plastic in one form or another. Plastics are marvel of material science that have enabled modern life as we know it. However, hidden behind its convenience, plastic also poses serious environmental challenges. So when it comes to addressing the biggest issue of our times, climate change, is plastic hindering our progress or helping us solve it?

Plastics emissions

David Attenborough opened our eyes globally to the challenges presented by plastic pollution and the effect it has on our marine ecosystems. In fact, we release 15 million metric tonnes of plastic every year into our oceans and that's equivalent to the mass of more than a million double decker buses. And that is not the only environmental issue with plastics. According to Judith Enck of Bennington College in the United States (US), plastics are not only a marine pollution problem but also a climate emissions problem.

A new report, published by Enck’s organisation Beyond Plastics in October 2021, finds that the emissions from the plastics industry in the US is responsible for 232 million tons of carbon dioxide emissions every year, which is equivalent to the emissions of 116 averaged sized coal-fired power plants. The report also finds that the plastics industry will exceed the emissions of the coal industry by 2030, giving the report its name: “The New Coal: Plastics & Climate Change”.

So while coal power is on the way out globally, plastics production is increasing at a rapid pace, with some projections suggesting that annual plastic production could quadruple by 2050 from their current rates of over 300 million tonnes of plastic per year. Enck suggests that this is because the fossil fuel industry sees plastics as their ‘plan B’ with demand for their plan A of using fossil fuels for transportation decreasing in recent years with the growth in electric cars.

Another reason for why the plastics industry is booming is because a relatively new type of fossil fuel extraction, which has become very popular in the US and globally, produces a waste gas that the plastics industry can readily turn into single-use plastics. While historically plastics have been made from coal and then oil, in recent years fracked natural gas has been the raw material for plastics.

Fracking is a new method of extracting natural gas (mainly methane) by injecting large amounts of water, chemicals and sand into the ground to shake it up and release the methane gas to be collected and used for energy. During this process, ethane gas is also released and this is typically piped out from fracking sites to facilities called ethane crackers, which Enck says are “the real big one”, when it comes to emissions related to plastics production.

At these cracker facilities, ethane is superheated until the molecules crack to form smaller ethylene molecules, which are a key building block of single-use plastics made from polyethylene (PE). These facilities, solely in the US, were responsible for annual greenhouse gas emissions of 70 million tonnes, and it is expected that by 2025, the emissions from ethane crackers will have grown by another 42 million tonnes due to new facilities being brought online.

While there are other ways to produce plastics in lower carbon ways, like from plant based sources such as corn, the vast majority of plastics (99%) are still produced from fossil fuels and thus it is currently impossible to separate plastics production from fossil fuel production. This is why Enck says they are “attached at the hip, you cannot have one without the other”.

Why do we have so much plastic?

If plastics are so environmentally damaging, why do we have so much of it in the first place? Everywhere you look in our modern world, you find plastics in one form or another: in tea bags, phones, computers, chewing gum, toothpaste and even in bank notes. One reason is because plastics are a hugely versatile category of materials with many beneficial properties that according to Nicola de Blasio from Harvard University, have “enabled modern life as we know it”.

Plastics are made up of synthetic polymers or repeating chains of carbon atoms, combined with other elements such as oxygen, nitrogen and sulphur. They are cheap, durable, lightweight, and can be either soft or hard, can withstand extreme temperatures and are chemically resistant. Furthermore, their properties are highly customisable through additives that add extra functionality specific to the desired application. That means we can use plastics for pretty much any application we require them for. As a result, it is not conceivable to imagine a world without plastics, as they have made our lives easier and safer in numerous ways. This became particularly prominent during the COVID-19 pandemic, when the protective equipment that was keeping us safe from the virus was largely made of single-use plastic.

Plastics helping climate

Although emissions from plastics are significant, there are even some applications of plastics where they are supporting our efforts to minimise the effects of the climate crisis. One such application are the blades of wind turbines, which are particularly essential going forward in providing renewable, low carbon energy to wind-rich regions of the world such as the UK.

The specific type of plastic used in wind turbine blades is glass-fibre reinforced epoxy plastic, and these are often referred to as reinforced plastics or composite materials. This reinforced plastic is required for wind turbines because it is a very strong and stiff material while remaining lightweight and moldable to the specific, complex aerodynamic shape of wind turbine blades. Other materials such as aluminium, steel or wood would not be up to the job and using them would mean that the wind turbine blades would have to be much smaller (producing a lot less energy) and not last as long, meaning they would have to be replaced more often.

However, while the wind turbines that use reinforced plastics can last as long as 25 years in operation, they do still present an issue when they have to eventually be decommissioned because reinforced plastics are very challenging to recycle. As a result, so called “wind turbine graveyards” have been building up across the world with more than 2.5 million tonnes of reinforced plastic waste generated from wind turbines alone every year.

According to Darshil Shah from the University of Cambridge there are two key reasons why recycling wind turbine blades is so challenging. Firstly, because these reinforced plastics are made up of both continuous glass fibres and plastics, the recycling process must be able to separate them from each other so that they can be used again and this is a challenging thing to do that requires a lot of energy. Secondly, because of the large size of blades required, these blades need to be made from a particular class of plastics called thermosets, which do not require very large heating elements during manufacture. However, these thermosets form crosslinks when cured into a solid material and thus they cannot be melted down into a liquid form again, like with the more common class of thermoplastics, making the recycling much more challenging.

Recycling of plastics

Recycling regular plastics also appears to be a challenge given that according to a study from the University of California only 9% of all plastic ever produced has been recycled, with 79% ending up in landfills. According to Lee Bell from the organisation IPEN - or the International Pollutants Elimination Network - this is because there is no market for recycled plastics given how cheap virgin plastic is currently and because the additives that are in plastic products make recycling them more challenging and costly. Similarly to the wind turbine blades, because most plastics today are not just a single type of polymer but are either multiple polymers or contain multiple additives, it is no longer possible to separate these into their constituent materials such that they could be used again. As a result, the plastics are contaminated and become essentially worthless for recycling.

The other issue with recycling plastics is that, unlike metals, they cannot be recycled infinitely as they gradually start to degrade and so practically can only be recycled a few times before they are no longer useful. As Bell notes “there is no such thing as an endlessly recycled plastic”.

There are two main ways to recycle plastics which are mechanical recycling and chemical recycling. Mechanical recycling is the most common method of recycling where the polymers are separated into each polymer type and then crushed and remelted into plastic granules, which are used in new plastic products Chemical recycling, on the other hand, uses large amounts of energy to turn mixed plastics into fuel that is then subsequently burnt for a given application. From a climate perspective, mechanical recycling produces much lower amounts of greenhouse gas emissions and should be the preferred route for plastic recycling, according to Bell.

To improve rates of recycling, Bell suggests that the production of plastics needs to be modified such that many of these additives are removed and products are designed using single polymers. Additionally, this needs to occur in conjunction with additional taxes placed on virgin plastics in order to make recycled plastic more competitive and encourage the uptake of plastic recycling infrastructure and use. Even with the implementation of these suggestions, it is unlikely that recycling can represent a solution to the plastic pollution and emissions crisis that we are facing, unless virgin plastic production is reduced.

Future of plastics

So if recycling is not sufficient on its own as a solution, where does that leave the future of plastics and what should be done about them?

Fredric Bauer from Lund University points out that it was not inevitable that we ended up in this plastics-filled society. After World War II, there was a concerted effort by the petrochemicals industry to find more and more uses for plastics, including convincing consumers that plastics are disposable materials that can be used just once before being thrown away. Thus they artificially contributed to creating the huge demand for plastics that we have today.

So while those decisions led us down this path, it is not inevitable that we need to continue down the path of more and more plastics. While we will still need plastics in certain sectors, such as healthcare, a significant number of plastic uses can be replaced with alternatives such as bioplastics, wood or metal that carry much more potential for recycling or composting and often have lower emissions associated with them, particularly over multiple uses.

What we need is to break away from this dependency on plastics and ultimately this requires reducing the volumes of plastic produced, which will then incentivise the use of alternative materials. According to Bauer, this means at the product design stage that “we need to think carefully about where we really need these properties that plastics have”. So while plastics have an essential use in wind turbines, their use as single-use bags is not warranted given that there are so many feasible alternatives such as paper or cotton bags.

This also means the increasingly unsustainable levels of consumption that we see in Western societies today. For example, the fast-fashion industry has created a huge boom in the consumption of clothes and this has been made possible largely by the availability of cheap polyester, another common type of plastic.

However, while buying fewer clothes and recycling any plastic we consume do both help somewhat, to achieve an overall reduction in production of plastics, Bauer points out that this requires system-level change and this is achieved by people putting pressure on the system. This means people need to get “organised in various ways to put pressure on policy makers, decision makers and larger firms to make the necessary changes on the higher level on how we use plastics,” says Bauer. In practice, this could be writing to your MP, joining a plastics campaign group or just raising awareness of these issues with friends and family.

So while in some instances plastics are helpful in addressing the climate crisis, due to their close link with fossil fuel production, the current rates of plastic production cannot continue if we are to have a livable planet in the decades to come. Like doughnuts, plastics can be used in moderation but for the sake of averting the worst effects of the climate crisis and marine pollution, our global addiction to plastics in all aspects of our lives must end.