Rising CO2 Alters Upper Atmosphere Response to Stratosphere Sudden Warming

This figure shows the percentage change in the daily zonal mean electron density (latitudes vs pressure, approximate altitudes on right y-axis) during the 2008-2009 sudden stratospheric warming under doubled CO2 conditions relative to control conditions (present CO2). Credit: Kumar et al. [2026], Figure 5d Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Geophysical Research Letters Rising atmospheric carbon dioxide (CO₂) is cooling the upper atmosphere, but it is also changing how the atmosphere responds to natural disturbances. One important example is a sudden stratospheric warming (SSW), a wintertime event that disrupts atmospheric circulation from the stratosphere to the edge of space. Because SSWs can alter the ionosphere, they can affect satellite operations, radio communications, and navigation systems. Using a whole-atmosphere model, Kumar et al. [2026] investigate how the atmospheric response to strong SSW changes in a future climate with doubled CO₂. They find that CO₂-driven cooling changes upper-atmosphere winds, making the response increasingly different between the Northern and Southern Hemispheres. These changes produce larger hemispheric differences in atmospheric composition and ionospheric plasma density. The study provides new insight into how climate change could influence future space weather and its impacts on modern technology. Citation: Kumar, S., Oberheide, J., & Martinez, B. C. (2026). Impact of doubled CO2 on the response of the mesosphere, thermosphere, and ionosphere to the 2008–2009 sudden stratospheric warming. Geophysical Research Letters, 53, e2026GL121817. https://doi.org/10.1029/2026GL121817 —Huixin Liu, Editor, Geophysical Research Letters Text © 2026. The authors. CC BY-NC-ND 3.0Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.