Hemispheric contrast in summer season duration responses to CO2 removal

As global warming accelerates, questions arise about whether the climate system can revert to its original state as CO2 concentrations decrease. Delayed summer season recovery has important implications for heatwaves, wildfires, and socio-environmental risks. Using multiple climate models with CO2 ramp-up and ramp-down simulations, here we show that summer season duration in extratropical lands exhibits hysteretic responses, with longer summers during CO2 decrease than increase. Much stronger hy