Global Warming Enhances the impact of ENSO on Northern Hemisphere Tropospheric Ozone

The El Niño-Southern Oscillation (ENSO) is a dominant mode of climate variability, influencing not only the global climate but also atmospheric chemistry. The impact of ENSO on tropospheric ozone has been investigated in previous research, yet its influence on tropospheric ozone in a warmer world remains unclear. Here, we investigate changes in the impact of ENSO on tropospheric ozone in the Northern Hemisphere using Coupled Model Intercomparison Project Phase 6 (CMIP6) data under the SSP3-7.0 scenario. The results of linear regression indicate that the response of ozone to ENSO strengthens, with coefficients increasing significantly from the near future to the distant future. This enhancement might be associated with changes in atmospheric circulation. This study suggests that ENSO should be considered when predicting changes in Northern Hemisphere tropospheric ozone under accelerating global warming.

※ This work was supported by the Korea Environment Industry & Technology Institute (KEITI) through the “Climate Change R&D Project for New Climate Regime” funded by the Korea Ministry of Environment (MOE) (2022003560001), and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No.2022R1A2C1008858).