The Center for International Environmental Law and partner organisations compiled emissions data across the full plastic lifecycle, from gas and oil extraction through refining, manufacturing, use, incineration and degradation in the environment.
They estimated lifecycle emissions of about 850 million tonnes of greenhouse gases in 2019, measured as the amount of carbon dioxide (CO2) that would have the same warming effect. That is equal to 189 coal plants, rising to 1.34 billion tonnes a year by 2030 (295 coal plants). Cumulatively, plastic could emit more than 56 billion tonnes by 2050, consuming 10–13% of the remaining carbon budget for staying below 1.5 °C.
The report was the first to frame plastics as a climate problem for a general audience and remains widely cited by campaigners.
It is a non-governmental organisation (NGO) synthesis and its 2019 figure is much lower than the later Lawrence Berkeley National Laboratory (LBNL) (2.24 billion tonnes for production alone) and Cabernard (2 billion tonnes lifecycle) estimates, reflecting different scopes and data. Pair it with the peer-reviewed studies rather than citing it alone.