The carbon-footprint study, titled "PET’s carbon footprint: to recycle or not to recycle"
has found that in communities with limited infrastructure, recycling a
plastic bottle can actually result in a bigger carbon footprint than
simply throwing it in a landfill.
"The footprint of recycling is lower than that of landfills only if at least half of the plastic ends up being valorised. That's right: only if about 50 percent or better of the used PET actually displaces production of new PET, will recycling deliver the lowest footprint," said Eric Johnson, one of the study's authors.
In typical curbside recycling programs, less than 50 percent of recovered PET eventually ends up as new plastic packaging.
However, the researchers did find that programs where bottles were taken back by the manufacturer, recycling services that required separate collection or bottle-deposits typically reported much higher displacement rates – some in the range of 75 percent.
Still, the authors say these findings aren't a reason to give up on recycling.
Instead, they hope their findings will encourage communities that already have a recycling infrastructure to increase used PET's displacement of new PET significantly above 50 percent through better collection and sorting techniques.
For communities that lack suitable recycling programs, the authors hope to dispel the common misconception that shipping plastics for recycling in other countries is just as harmful as landfilling.
"Yes, the transport adds to the footprint, but not nearly as decisively as displacement, said Johnson in The Ecologist. "If the travelling bottles end up substituting what would have been new PET, then the journey was well worthwhile."
One disappointing part of this study is that it seems to ignore the environmental impact of plastics once they do end up in the landfill.