Both PET plastic bottles and returnable glass bottles have their own environmental benefits and drawbacks. While it's true reusable glass bottles have a global warming potential than R-PET and PET, health and environmental costs of marine litter waste is an externalized cost by society/packaging industry and is generally not taken into account when comparing their environmentally friendliness.

In Belgium the recycling rates for plastics are at 44.7% and glass 96.9%. Currently the best option would be to focus on recycling and reducing the waste generated and not the type of packaging.