The extent of polar stratospheric ozone loss – often referred to as the “Ozone Hole” – is significantly influenced by climate change, and in turn, stratospheric ozone has been recognized as an important component in the climate system. To accurately quantify the effects of climate change on stratospheric ozone and the related feedback mechanisms, as well as to make reliable predictions of future ozone loss and the so-called recovery date, a correct representation of all relevant processes is indispensable. However, a number of gaps in the understanding of these processes still exist. The issues where the lack of understanding is most palpable are (a) the catalytic ClOx/BrOx chemistry, (b) chlorine activation on cold stratospheric aerosol, (c) NAT nucleation mechanisms, and (d) mixing and transport of processed air to lower latitudes. The RECONCILE project sets out to address all these issues using a comprehensive approach that includes laboratory and field experiments together with microphysical and chemical transport modelling. RECONCILE will produce and test reliable parameterisations of the key processes in Arctic stratospheric ozone depletion and bridge these to large scale chemistry climate models (CCMs), thereby greatly enhancing their ability to realistically predict the future evolution of Arctic stratospheric ozone loss and the interaction with climate change.