Plastic production belches out over 5% of global greenhouse gas emissions

A study from Lawrence Berkeley National Laboratory finds that, in 2019, production of virgin plastic spewed about 2.24 billion metric tons (t) of carbon dioxide equivalent into the atmosphere, or 5.3% of total greenhouse gas (GHG) emissions.

That same year, emissions from aviation and shipping came to 1.32 billion t, and emissions from landfills and wastewater treatment totaled 1.63 billion t, according to the open data site Climate Watch. If the plastics industry continues to grow, the researchers estimate, plastics production could end up contributing between 21% and 31% of total GHG emissions.

The researchers, Nihan Karali, Nina Khanna, and Nihar Shah, focused on nine types of plastic made from fossil fuels that together represent about 80% of global production. They include low-density and high-density polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride.

With their model, the scientists found that most of the emissions come from steps that happen before the starting materials go through polymerization. Creating monomers is the source of about 26%, refining hydrocarbons and producing other plastic ingredients kick out 29%, and pulling feedstock oil and gas from the ground produces about 20% of the GHG emissions from the manufacture of these plastics.

The authors note that their model does not include GHG emissions from the use or disposal of plastics.

The American Chemistry Council (ACC), an industry group, says in a statement that the supply chain must be cleaned up as quickly as possible. “We expect production will continue to increase over time as demand increases over time,” says Stewart Harris, the group’s director of global plastics policy. Harris says the future of plastics production might look different if industry switches to feedstocks other than fossil fuels. These could include biobased materials and circular feedstocks generated by mechanical and chemical recycling.

ACC spokesperson Matthew Kastner says the LBNL study examines only plastics manufacturing. He contrasts it with a 2022 study from the consulting firm McKinsey that compares plastics with alternative materials over the “entire life cycle of plastic products,” including use and disposal. When a study includes this information, “plastics almost always have lower life cycle GHG emissions compared to common alternatives,” Kastner says.

Neil Tangri, science and policy director for Global Alliance for Incinerator Alternatives, an environmental group, calls the McKinsey study flawed.

Tangri, who was a reviewer of the LBNL study, says the McKinsey study doesn’t follow global standards for life cycle assessment, does not say where the data analyzed come from, and is not reproducible. That’s why the study is only ever cited by industry, he says in an email.

In contrast, “the LBNL report does look only at the production phase, and that is by design,” Tangri says, because primary plastics production is the most important issue in reducing plastic pollution. United Nations Environmental Programme leaders are meeting in Ottawa, Ontario, April 23–29 to develop an international treaty aimed at stopping plastic pollution.