Logarithmic CO2 warming reverses North Atlantic winter atmospheric circulation changes

The North Atlantic climate is strongly influenced by large-scale atmospheric circulation, including the storm track and jet stream, which shape regional precipitation, temperature, and wind patterns. Climate models project an intensification of the winter circulation through the 21st century, however, it remains unclear whether abrupt or non-monotonic changes might occur under ongoing warming. Here we show that under continued CO2 emissions beyond 2100, the intensification reverses, with both the storm track and jet stream returning toward their 20th-century states. We attribute this reversal to the logarithmic relationship between CO2 and temperature, which leads to a reduced meridional temperature gradient and weakened atmospheric circulation at high CO2 concentrations. This behavior also alters regional climate patterns, reversing storm track-induced warming and wetting at higher mid-latitudes and cooling and drying at lower mid-latitudes over eastern North America and the North Atlantic. Our findings suggest that mitigation policies should account for the pace of continued emissions as well as the potential reversals in climate impacts.