Anthropogenic Aerosols Have Significantly Weakened Northern Hemisphere Summertime Storminess in the Satellite Era

Northern Hemisphere summertime storminess has weakened significantly in the satellite era with important implications for weather and air quality. Recent work found that Arctic amplification and sea ice loss do not significantly affect the weakening trend but did not examine the role of other forcings such as aerosols. Here we use multiple Detection and Attribution Model Intercomparison Project (DAMIP) model simulations to reveal that anthropogenic aerosols and greenhouse gases respectively contribute approximately equally to the weakening of summertime storminess in the zonal mean, suggesting that aerosols play a leading order role in summertime trends. Furthermore, aerosols dominate the weakening in the Pacific sector, with the aerosol-induced weakening trend being twice as large as that from greenhouse gases. In the Atlantic sector, greenhouse gases dominate over aerosols. We further connect the aerosol-induced changes in temperature and shortwave radiation to storminess using energetic frameworks. Our results show aerosols are a crucial contributor to recent Northern Hemisphere summertime regional climate change.