What are the climate costs of plastic?

This article is the first of a two-part series on plastic and climate change.

Found from the peaks of Mount Everest to the depths of the ocean and inside every organ in our body, plastic is all around us, in us and will outlive us.

Ubiquitous, versatile and disposable, plastic has shaped the modern age in a way that few other materials have. Plastic is used in virtually every industry in a staggering range of forms: packaging, clothes, electronic components, consumer products and construction, to name only a very few. 

Nowadays it is also infamous for its tendency to clog waterways and beaches, get eaten by turtles or accumulate in gigantic landfills. And, it’s developing a reputation as a driver of global warming. A study published last year in Nature Sustainability calculated the carbon footprint of the plastic industry to be 2 gigatonnes of greenhouse gas emissions, or 4.5 percent of the world’s total emissions, in 2015.

But how exactly does humanity’s addiction to plastic contribute to climate change? In this article, we’ll look at the ways we produce and dispose of plastic and how these lead to emissions. Then, in the next article in this series, we’ll dive into the climate change impact of plastic that ends up in our oceans as well as what we can do next.

The birth of plastic

Broadly speaking, plastics are materials composed of man-made “polymers” – large molecules built from repeating chains of small molecules called “monomers.” 

Humans have used naturally moldable materials for thousands of years. The use of rubber, for example, dates back to the ancient Olmec civilization. But new substances started to be developed during the 19th century, and the following century saw an explosion of plastic development and mass production. Given its low production cost and many useful applications, plastic has boomed over recent decades. In 2020, the world created an estimated 367 million tonnes of plastic.

It is, however, likely to leave an increasingly large climate footprint, according to a 2019 report by the Center for International Environmental Law (CIEL), which estimates that plastic production could in total emit 56 gigatonnes of greenhouse gas emissions by 2050. This equates to more than 10 percent of the entire remaining carbon budget set out by Intergovernmental Panel on Climate Change (IPCC) to try and limit warming to 1.5 degrees Celsius since the Industrial Revolution.

Every step of the plastic production chain emits greenhouse gases. Nearly all plastic resins are derived from fossil fuels – mainly natural gas and oil, but also some from coal. Other than the emissions generated from using these fossil fuels as the feedstock for plastic, extracting fossil fuels can also lead to greenhouse gas emissions in various other ways, including through flaring, methane leakages, and the energy used to drill and extract oil or gas. Carbon is also released when forests and vegetation is cleared to construct pipelines and wellpads.

After oil and gas is extracted, they are sent to “cracking” plants, where they are broken down into monomers before being stitched together in long chains to create polymers, the building blocks of plastic. Afterwards, plasticizers or other chemicals may be added to the plastic before it is cooled and shredded into tiny pellets called nurdles, which are then shipped to manufacturers to be formed into bags, textiles and other goods. 

This process emits an intense amount of greenhouse gases. Just within the U.S., plastic manufacturing is thought to add 114 million U.S. tons (103.4 million tonnes) of carbon dioxide equivalent every year, according to a report released last year by Beyond Plastics, a U.S.-based group that aims to end plastic pollution. The report states that this number is expected to grow, with at least 42 more plastics facilities coming under operation, construction or the permitting process in the country since 2019.

Judith Enck, the president of Beyond Plastics, says that most cracker facilities within the U.S. are proposed in low-income areas, especially around communities of color. “It’s as if we’ve created ‘sacrifice zones,’ where there are entire neighborhoods that are battered with air pollution and water pollution that’s making a lot of people sick,” she says.

“I think it’s really troubling that the phrase ‘Cancer Alley’ [the 85-mile stretch of land containing 25 percent of the U.S.’s petrochemical production] just flows off our tongues. But that’s what that stretch of the Mississippi River is called. Cancer Alley.”

Natural gas is the main plastic feedstock used in the U.S., due to an abundant supply as a result of the shale gas boom of recent years. But oil is a major feedstock in the rest of the world. The World Economic Forum estimates that roughly 4 to 8 percent of oil extracted globally is then used for plastic, half of which is used as material feedstock and the other half used to provide energy for the production process, leading to the CIEL report authors to roughly estimate that, outside the U.S., producing plastic from oil releases 108 million tonnes of carbon dioxide equivalent every year. 

However, the role of coal in plastic production is rapidly growing – especially as global plastic production is increasingly reliant on coal-dependent countries like China, Indonesia and South Africa. The aforementioned study published in Nature Sustainability found that this trend has doubled the carbon and health footprint (as relates to particulate matter) of plastic production since 1995.

“One factor might be that in wealthy countries we have more strict environmental guidelines, and this can even lead to this shift – we also call it ‘outsourcing’ – of the dirty steps like plastic production to other countries where we don’t have these strict guidelines,” says Livia Cabernard, a post-doctoral researcher at ETH Zürich and one of the authors of the study. She added that a consumer preference for cheaper products and increasing Western imports of commodities like electronics and machinery might also explain this trend.

The research found coal to be the source of 44 percent of plastic production emissions, mainly for electricity generation and for resin production and manufacturing. Even though 88 percent of the carbon emissions and 93 percent of the health impacts from plastic production occurred in countries outside Europe and the U.S., Western countries enjoyed 80 percent of the economic value of these plastics.

Cabernard added that outsourcing plastic production to these coal-dependent countries meant that it is harder for them to achieve their climate commitments to reduce greenhouse gas emissions, because “what counts in these climate agreements are our domestic emissions, which indeed in many high-income regions have decreased. But on the other hand, when we look at our consumption-based impacts, they actually have increased…we just cause the impacts somewhere else.”

The difficult disposal of plastic

The wonderful qualities of plastic when in use are also its environmental downfall. Its resistance to water and durability means that it degrades very slowly, and depending on the type of plastic and environment, it can take decades or even centuries to break down. In fact, the bulk of most plastic’s existence happens after it is disposed , typically after being used only once. It is after we throw plastic away that its life begins to diverge into a variety of paths – and emit carbon in various ways.

Plastic is usually landfilled, incinerated or recycled. Ideally, all plastic would be recycled in perpetuity, but in reality, only about 9 percent of all plastic ever produced has been recycled just once. The costs of recycling compared with the cheapness of making new plastic results in much of the world’s used plastic, even when cleaned and thrown into the recycling bin, being landfilled or incinerated. Infinite reuse is also impossible, because plastic’s quality degrades each time it is repurposed.

So around 60 percent of all plastic made since 1950 has been either sent to landfills – where it emits methane and carbon dioxide and can lead to soil, groundwater and smell pollution for nearby communities – or discarded in the natural environment.

The most emissions-heavy way to manage plastic waste is to burn it. From 1950 to 2015, around 12 percent of all discarded plastic was incinerated. Facilities that incinerate waste (which usually includes both plastic and other disposed material) for energy can now be found around the world. The logic is to take various types of waste material and burn it into fuels to be reused as power. Many municipalities have adopted this technology in order to reduce the waste that ends up in landfills while displacing some fossil fuel dependency. 

But according to the CIEL report, for every tonne of plastic burned, 0.9 tonnes of carbon dioxide equivalent are still released, even after accounting for the fossil fuel use it displaces. This means that plastic incineration, including when it is burned for energy use, emits far more greenhouse gas emissions than both landfilling or recycling.

And the fossil fuel “offset” will become less valid as economies decarbonize and switch to using renewable energy. According to Janek Vähk, the Climate, Energy, Air Pollution programme coordinator at Zero Waste Europe, waste incineration could come to occupy 7 percent of the total European carbon budget in a future that keeps global warming to 1.5 degrees Celsius. 

“A lot of waste which is currently incinerated actually is recyclable, but it ends up incinerated because it’s the simplest thing to do,” Vähk says. “It’s just something to do with economics: waste incineration is cheaper than recycling. Why bother with all the separate collection, recycling and so on if you could just simply burn it and get a little bit of energy out of it?”

The emissions from incineration waste for energy can vary, depending on the type of energy used to power the incinerator and the type of waste burned. It is often not simply pure plastic that is incinerated but mixed municipal waste, which could require more energy for the incineration process. For example, more energy is needed to burn plastic mixed with food or other organic material that could contain more moisture, which then reduces the fossil fuel offset. The U.S. Environmental Protection Agency estimated that the emissions from waste-to-energy incineration in 2016 from the U.S. alone was 11 million tonnes of carbon dioxide equivalent.

According to a recent report by Zero Waste Europe, these incineration facilities can contaminate surrounding communities with persistent organic pollutants, also known as “forever chemicals,” as was found with the waste incinerators the authors studied in Spain, the Czech Republic and Lithuania. These pollutants gradually accumulate within living things in the environment and can harm human health over time. For example, they found that most of the chicken eggs from communities surrounding the incineration facilities had higher levels of toxins than permitted for sale or consumption. 

Yet the plastic waste generated in many countries is often overwhelming, to the point that many export it to be managed elsewhere. The primary destination was once China, until it banned most plastic waste imports in 2018. This resulted in the trade being diverted to other Asian countries – either legally or illegally – including Malaysia, which was the top importer of plastic waste in 2020. A report by the Environmental Investigation Agency last year found that despite only having a recycling capacity of 515,009 tonnes, Malaysia imports roughly 835,000 tonnes of foreign plastic waste each year – even while producing 2.4 million tonnes domestically. 

Mageswari Sangaralingam, a senior research officer with Friends of the Earth Malaysia, said that after China banned plastic imports, communities near Port Klang (a major port in Malaysia) began to experience breathing difficulties. After investigating on their own, they detected some illegal recycling plants near their agricultural areas.

“[The recycling plants] were just dumping it. And sometimes [plastic dumps] catch fire, so it’s in flames. Or sometimes they intentionally burn it,” says Sangaralingam. She said that Friends of the Earth Malaysia and other groups then assisted the communities in appealing to the authorities to address the problem by reaching out to international media to bring attention to this issue. “Thailand, Vietnam and Indonesia, they all became a dumping ground for this waste from developed countries.”

Batches of plastic waste that contain a mix of resins or that are contaminated with non-plastic material are often difficult to recycle and are thus often illegal to import, but shipping containers holding imported waste might be mislabeled to obscure this. The Basel Convention, an international treaty that aims to reduce the trade in hazardous waste, was amended in 2019 to also include plastic.

Nevertheless, the waste trade continues. Since many countries lack the capacity to manage such large quantities of plastic waste or because the plastic is unrecyclable, it is often dumped, openly burned or lost into the environment, at which point its climate impact becomes more difficult to measure. Every year, between 5 and 12 million tonnes of plastic waste are thought to be leaked into waterways before ultimately ending up in the ocean.

Read on in part 2 of this series on plastics.