Fig. 4: Occurrence probabilities of temperature jumps under additional global warming.

a Median occurrence probabilities for temperature jumps of varying magnitude across CMIP6 models. A lower bound of -10 is applied to likelihood values. Contour lines indicate constant probability levels. The white cross marks the September 2023 jump; the white circle shows the same event after adjusting the shortwave radiation contribution. The corresponding GWLs of each year are based on the CMIP6 ensemble mean GMT. b Change in magnitude of temperature jumps with the same likelihood as the 2023 event by 2100 under SSP5-8.5. Boxplots and grey markers represent individual model simulations. Boxplots show the median, quartiles, and whiskers extending to 1.5 × the IQR. Red markers denote best estimates based on the pooled simulations when multiple simulations are available. Positive values imply that a jump in 2100 would need to be more intense than the 2023 event to have the same probability, indicating increasing temperature variability in September under higher warming levels.