Mention the word “plastic” and the first images that spring to mind include beaches fouled by a soggy layer of plastic bags and bottles. Or sea creatures, dead or half-strangled from eating or getting tangled up in the stuff.
Plastic pollution has become a major aesthetic and ecological menace across the world, but there is another unseen dimension to the rapid expansion of the plastics industry: the growing cloud of climate-altering greenhouse gases that are generated from extracting and producing the material. Most plastics are derived from crude oil and other fossil fuels, leading to significant airborne emissions when they are produced, dumped or burned.
A new report titled Plastic & Climate: The Hidden Costs of a Plastic Planet, estimates that the production and burning of plastic will add another 850 million tonnes of greenhouse gases to the atmosphere this year, equal to the emissions from nearly 200 large, coal-fired power stations.
By 2050, the cumulative volume of greenhouse gases from plastic making and disposal could amount to more than 10% of the remaining carbon budget that has been set to avoid overshooting a 1.5°C increase in average global temperature.
The report, published by the United States-based Center for International Environmental Law (CIEL), draws specific attention to the incineration of packaging and other plastics considered to have little or no recycling value.
This appears to have been exacerbated by the Chinese government’s January 2018 decision to ban the importation of low-grade plastic scrap for reprocessing. As a result, increasing volumes of plastic scrap are piling up in several developed nations that formerly exported this waste to China.
Globally, the use of incineration in plastic waste management will grow dramatically in the coming decades. Emissions from plastic incineration in the US alone were estimated at nearly six million tonnes of carbon dioxide equivalent (CO₂e) during 2015.
Waste incineration and “waste-to-energy” incineration is often thought of as an easy answer to large-scale plastic pollution. But it leads to extremely high greenhouse gas emissions, along with toxic pollution to the air, water and ground, according to CIEL.
The recycling industry is promoting the conversion of plastic waste into new synthetic fuels through the use of gasification, pyrolysis and plasma arc technology.
Niven Reddy, a Pietermaritzburg-based campaigner from environmental justice group groundWork, says some plastics are burned on open fires as a result of poor municipal waste collection systems. But so far there are no municipal waste incinerators or waste-to-energy plants in South Africa.
Reddy says it is likely the cement-making industry is burning some plastic waste, but statistics have not been made available to the public.
“There have been proposals to install two waste-to-energy facilities [in Wellington in the Western Cape and Midrand in Gauteng], but these have been defeated by civil society,” says Reddy. He adds that waste incineration can emit large quantities of poisonous compounds, including nitrogen oxides, mercury, dioxins and ultra-fine particles that can cause heart and lung disease, premature death and cancer.
At a global level, only a fraction of used plastic is recycled into the products for which it was originally produced. This is the case even for readily recyclable types of plastic, such as PET and HDPE.
According to the CIEL report, recycling plastic involves several steps, from separate collection to long-distance transportation, processing and remanufacture.
“The high costs of these steps, the low commercial value of recycled plastic and the low cost of virgin material mean that plastic recycling is rarely profitable and requires considerable government subsidies. Due to these limitations, only 9% of all plastic ever discarded since 1950 has been recycled, while another 12 % has been incinerated,” it says.
There are other challenges associated with recycling. Several types of plastic are contaminated with colourants, additives and fillers.
The report says global production of plastic rose to about 380 million tonnes in 2015 from two million tonnes in 1950. If this rapid growth continues, plastic will account for nearly 20% of global oil consumption by 2050.
CIEL based its analysis largely on industry data from Europe and North America. It says the plastic pollution crisis is not simply a threat to the health of the world’s oceans but also “a significant and growing threat to the Earth’s climate”.
The report says greenhouse gases are emitted at every stage of the plastic lifecycle, starting from when fossil fuels are extracted from the ground and transported to petrochemical refineries.
At the refinery level, the largest emissions are generated during the energy-intensive “cracking” process, where feedstocks such as ethane or naphtha are heated to between 750°C and 1 100°C and mixed with steam to split the feedstock into smaller molecules.
Of the total volume of plastic produced, CIEL suggests that up to 40% is converted into single-use packaging materials that are extremely difficult to recycle.
Once dumped, plastic continues to release greenhouse gases as it degrades, or when it is deliberately burned in open fires or incinerators.
What can be done?
According to CIEL, the place to start is to halt the production of single-use, disposable plastic.
To further encourage a transition to zero-waste, plastic producers should be compelled to take responsibility throughout their product’s lifecycle.
A report published by the Organisation for Economic Co-operation and Development last year said plastic recycling rates were thought to be 14% to 18% globally. The remainder of plastic waste was either incinerated (24%) or dumped in landfills and the natural environment (58% to 62%).