The world's first carbon footprint study into the impact of closures on the environment has shown screwcaps emit four times more greenhouse gases than cork.
The study, conducted by French agency Cairn Environnement, revealed a natural cork stopper emits 2,490kg of CO2 per tonne; a Diam closure emits 4,253kg and a screwcap, made with 35% recycled aluminium, created 10,633kg.
The study was commissioned by Diam and screwcap producer Oeneo Bouchage.
Its sales director Dean Banister, said: "The research project represents the initial phase of our efforts to reduce our carbon usage. We believe we can improve the impact of Diam...by around 40%."
See next week's Harpers for more details and reaction.