International Ozone Assessments: the Contributions of Susan Solomon

I will trace the history of the assessments of the scientific understanding of stratospheric ozone and the influence of these assessments on policy. I first worked with Susan Solomon on the 1985 assessment, prior to adoption of the Montreal Protocol. Susan has been at heart of the quadrennial assessments since that landmark event. These have led to a series of adjustments and amendments which have accelerated the phase-out of an increasing number of ozone depleting substances (and greenhouse gases). Thanks to the Montreal Protocol, which Kofi Annan called 'perhaps the single most successful international treaty to date', and the vigilance of the scientific community, the ozone layer is on a recovery trajectory. Susan's contribution to our basic scientific understanding and her acute sense of policy relevance have been major factors in this success.