Paul Jozef Crutzen. 3 December 1933—28 January 2021

Abstract

Paul J. Crutzen was both a warm-hearted person and a brilliant scientist. His research interests were broad, encompassing topics of relevance in the mesosphere, the stratosphere and the troposphere. He made fundamental scientific contributions to a wide range of topics in the science of all these atmospheric regions. For example, he first described the NO x -driven ozone loss cycle in the stratosphere, he contributed key ideas on how to explain the ‘ozone hole’ and he made fundamental discoveries on the impact of biomass-burning on the atmosphere. Understanding and combating the origins of air pollution and climate change were driving motivations for his life's work. Further, he pioneered the concept that is known as ‘nuclear winter’, he initiated the resumption of discussion on geoengineering, and coined the term ‘Anthropocene’. In 1995, together with Mario J. Molina and F. Sherwood Rowland (ForMemRS 2004), Paul was awarded the Nobel Prize in chemistry for ground-breaking work ‘in atmospheric chemistry, particularly concerning the formation and decomposition of ozone’. With all this focus on science, he did not forget the importance of private life, regarding both his family and his colleagues and students. Finally, Paul's work had a profound influence not only on the scientific world, but also on different aspects of environmental politics throughout many countries. His works on the impact of human activities on the atmosphere and climate have been influential in the past and are influential today. They provide a beacon of knowledge for the next generations of scientists and environmental policymakers.