She is the author of a widely cited study which estimates that the glass bottle accounts for around half of the CO2 footprint of a bottle of wine. Dr Helena Ponstein has been working as an independent expert and consultant in the field of sustainability and climate protection for wineries since 2009. She is a graduate of Heilbronn University and Humboldt University in Berlin, where she completed a Master's degree in sustainable resource management. She went on to complete her PhD there on the topic of "Avoiding greenhouse gas emissions from the global wine value chain" with case studies from Germany and Finland.