The researchers examined the production and transportation of glass bottles and found that light-weight glass bottles produced just as much greenhouse gas as light-weight PET bottles. Although the production process of PET bottles releases more CO2, the transport process releases less gas. Rebecca Cockin, Recycling Manager at UK Glass, said: "We are very encouraged by the findings of the report, which helps us to dispel some of the criticisms and negative influences of the glass packaging industry and promote the development of the glass packaging industry." WRAP chairman Richard Swannell said: "This proves that the recycling rate of lightweight glass bottles is a positive factor for the environment. In this study, 75cl glass bottles were compared with PET bottles. Bottle types include 45g PET non-cycle bottles, glass bottles with a typical 496g cycle rate of 81% and light glass bottles with a 365g cycle rate of 81%.

At the same time, the study also included glass bottles with a 365g cycle rate of 92% and PET bottles with a cycle rate of 50% and 100% of the same mass. The study found that the gas release from 54g PET bottles was within the range of 365g glass bottles.