In several recent studies natural cork bottle stoppers are claimed to have a very favourable carbon footprint because of carbon sequestration in cork oak trees. These results have been used for promoting cork stoppers (and other cork products) as more environmentally friendly and a practical means of greening the packed product. We found part of the data, system boundaries and allocation methodologies applied in the considered LCA studies to be debatable. For example, carbon sequestration in cork oaks is probably limited to 0.95-1.25 tonne C/tonne raw cork harvested, 20-25% of what is reported. Standardized methods such as ISO 14000 and PAS 2050 do not allow taking into account carbon sequestered in vegetation in managed cork oak landscapes and other forms of managed forest in carbon footprint calculations. There is also the risk of double counting of carbon sinks in view of subsidies by EU and national states for e.g. landscape management.
The main results are presented by the authors in a short animated film: