Paul Crutzen, who left us last month, on 28 January 2021, aged 87, was certainly one of the most important Earth system scientists of the Anthropocene.
Paul’s work covered a wide range of topics. His earliest work focused on stratospheric ozone chemistry, through which he helped develop an understanding of the potential effects of human activities, including supersonic aircraft, on the Earth’s ozone shield. His work also provided a basis for understanding the Antarctic ozone hole, for which he was awarded the Nobel Prize in Chemistry in 1995, together with Mario Molina and Sherry Rowland.