EGU General Assembly 2020
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Natural halogens buffer tropospheric ozone in a changing climate

Fernando Iglesias-Suarez1,6, Alba Badia1, Rafael P. Fernandez2, Carlos A. Cuevas1, Douglas E. Kinnison3, Simone Tilmes3, Jean-François Lamarque3, Mathew C. Long4, Ryan Hossaini5, and Alfonso Saiz-Lopez1
Fernando Iglesias-Suarez et al.
  • 1Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain
  • 2National Research Council (CONICET), FCEN-UNCuyo, UTN-FRM, Mendoza 5501, Argentina
  • 3Atmospheric Chemistry Observations and Modelling, NCAR, Boulder, CO 80301, USA
  • 4Climate and Global Dynamics Laboratory, NCAR, Boulder, CO 80301, USA
  • 5Lancaster Environment Centre, Lancaster University, Lancaster, UK
  • 6Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Germering, Germany (

Reactive atmospheric halogens destroy tropospheric ozone (O3), an air pollutant and greenhouse gas. The primary source of natural halogens is emissions from marine phytoplankton and algae, as well as abiotic sources from ocean and tropospheric chemistry, but how their fluxes will change under climate warming –and the resulting impacts on O3– are not well known. Here we use an Earth system model to estimate that natural halogens deplete approximately 13 % of tropospheric O3 in the present-day climate. Despite increased levels of natural halogens through the twenty-first century, this fraction remains stable due to compensation from hemispheric, regional, and vertical heterogeneity in tropospheric O3loss. Notably, this halogen-driven O3 buffering is projected to be greatest over polluted and populated regions, mainly due to iodine chemistry, with important implications for air quality.

How to cite: Iglesias-Suarez, F., Badia, A., Fernandez, R. P., Cuevas, C. A., Kinnison, D. E., Tilmes, S., Lamarque, J.-F., Long, M. C., Hossaini, R., and Saiz-Lopez, A.: Natural halogens buffer tropospheric ozone in a changing climate, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5355,, 2020.


Display file

Comments on the display

AC: Author Comment | CC: Community Comment | Report abuse

displays version 2 – uploaded on 05 May 2020, no comments
A typo has been fixed.
displays version 1 – uploaded on 30 Apr 2020, no comments