Atmospheric ionization and cloud radiative forcing

Henrik Svensmark*, Jacob Svensmark, Martin Bødker Enghoff, Nir J. Shaviv

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Atmospheric ionization produced by cosmic rays has been suspected to influence aerosols and clouds, but its actual importance has been questioned. If changes in atmospheric ionization have a substantial impact on clouds, one would expect to observe significant responses in Earth’s energy budget. Here it is shown that the average of the five strongest week-long decreases in atmospheric ionization coincides with changes in the average net radiative balance of 1.7 W/m2 (median value: 1.2 W/m2) using CERES satellite observations. Simultaneous satellite observations of clouds show that these variations are mainly caused by changes in the short-wave radiation of low liquid clouds along with small changes in the long-wave radiation, and are almost exclusively located over the pristine areas of the oceans. These observed radiation and cloud changes are consistent with a link in which atmospheric ionization modulates aerosol's formation and growth, which survive to cloud condensation nuclei and ultimately affect cloud formation and thereby temporarily the radiative balance of Earth.

Original languageAmerican English
Article number19668
JournalScientific Reports
Issue number1
StatePublished - 11 Oct 2021

Bibliographical note

Funding Information:
JS is funded by the Carlsberg Foundation and the Danish council for independent research under the project “Fundamentals of Dark Matter Structures”, DFF-6108-00470, and thanks them both for their support. NJS wishes to thank the generous support of the Israel Ministry of Energy.

Publisher Copyright:
© 2021, The Author(s).


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