The 2025 ACP Paul Crutzen Publication Award

30 April 2026

Atmospheric Chemistry and Physics has named the winner of the 2025 ACP Paul Crutzen Publication Award, plus two shortlisted articles. The award was created to recognize an outstanding publication in ACP that advances our understanding of atmospheric chemistry and physics. The annual award was created in honour of Paul Crutzen, Nobel Prize awardee and former director of the Max Planck Institute for Chemistry, who played a pivotal role in the creation of the journal 25 years ago.

This year's recipient for a paper published in 2025 is:

02 Jun 2025

Quantified ice-nucleating ability of AgI-containing seeding particles in natural clouds

Anna J. Miller, Christopher Fuchs, Fabiola Ramelli, Huiying Zhang, Nadja Omanovic, Robert Spirig, Claudia Marcolli, Zamin A. Kanji, Ulrike Lohmann, and Jan Henneberger

Atmos. Chem. Phys., 25, 5387–5407, https://doi.org/10.5194/acp-25-5387-2025, 2025

Award citation

Award citation

Ice nucleation has been studied for decades to better understand cloud evolution and to improve weather and climate predictions. Although silver iodide particles have been used extensively since the 1940s in cloud seeding projects and in weather modification, there have been no direct measurements of the ability of the particles to form ice crystals in natural clouds. In these unique experiments with a UAV in supercooled clouds, the authors show that only 0.1 to 1 percent of the particles form ice crystals. The results provide new insight into ice formation in clouds and will have implications for future cloud seeding experiments.

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The article describes unique experimental evidence for the formation of ice in supercooled clouds. Ice nucleation has been studied for decades to better understand cloud evolution and to improve weather and climate predictions. Although silver iodide (AgI) particles have been used extensively since the 1940s in cloud seeding projects and in weather modification, there have been no direct measurements of the ability of the particles to form ice crystals in natural clouds. In these unique experiments with a UAV, the authors show that only 0.1 to 1 percent of the AgI particles form ice crystals. The lead author Anna Miller at ETH Zurich said "The experimental setup we had in CLOUDLAB allowed us to uniquely quantify the ice-nucleating effects of silver iodide in real natural clouds, which has never been done before, despite AgI having been used for decades in cloud seeding projects. The results were puzzling at first, leading to many thought-provoking discussions and eventually our hypothesized ice nucleation mechanism. It was very interesting and rewarding work, and I am very proud to have been a part of it. We are delighted that our work has been recognized and chosen for this award."

Congratulations also to the authors of two further papers, which were shortlisted for the award. These articles made important advances in our understanding of how air pollution from shipping affects lightning, and how Australian bushfires can affect polar stratospheric clouds. These articles are listed on the ACP Paul Crutzen Publication Award web page.

We are grateful to the members of the independent prize committee who selected this year’s awardees: Sonia Kreidenweis (Chair, Colorado State University), SK Satheesh (Indian Institute of Science, Bangalore), Steve Sherwood (University of New South Wales), John P. Burrows (University of Bremen), Ulrike Lohmann (ETH Zurich), Ilona Riipinen (Stockholm University) and Hiroshi Tanimoto (National Institute for Environmental Studies, Japan).