A Tribute to Paul Crutzen (1933-2021): The Pioneering Atmospheric Chemist Who Provided New Insight into the Concept of Climate Change

Abstract Paul Crutzen received his doctorate in meteorology from the University of Stockholm in 1968 and was awarded the Nobel Prize in Chemistry in 1995. In addition to chemistry and atmospheric science, however, the breadth of his accomplishments has also been recognized by biologists, Earth-System scientists, and geologists. This tribute provides some insight into Crutzen’s career and how it contributed to so many scientific disciplines. In addition, we offer a roadmap showing how these diverse contributions were woven together over the course of more than five decades of research. The citation for the 1995 Nobel Prize reads that it was given for, “…work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone.” The inclusion of the wording “formation … of ozone” applies only to him among the three laureates (Crutzen, Mario Molina and F. Sherwood Rowland). His research on tropospheric chemistry led to seminal studies of tropical biomass burning, which eventually evolved into the concept, later known as “nuclear winter,” a topic in the forefront of far-ranging popular discussions in the 1980s. Lastly, Crutzen’s proposal for the emergence of the “Anthropocene” as a new geological epoch that would terminate the 11,700-year-old Holocene is considered by the Earth-System science community to be the most pronounced trademark of his remarkable career. Crutzen also received American Meteorological Society’s Battan Award for his co-authorship of Atmosphere, Climate, and Change, recognized by the organization as the best book for general audiences. In the later years of his career, as a member of the Pontifical Academy of Sciences, Crutzen was a key player in the formulation of Laudato Si’, Pope Francis’ encyclical on climate change, which was released in advance of the Conference of Parties (COP 21) meeting that announced the formulation of the Paris Climate Accords in 2015.