Fig. 1: The mean NAO index and its response to increased CO2.
From: More positive and less variable North Atlantic Oscillation at high CO2 forcing
Results with preindustrial control runs from models and ERA5 (years 1979–2023) are shown for (a) winter (DJF) and (b) summer (JJA). The response from the model preindustrial values is show in (c) for DJF and (d) for JJA. The empty circles denote individual models (13 models for 2 × CO2, 55 models for 4 × CO2, and 6 models for 8 × CO2). All individual models are listed in Table S1. The error bars show the 95% confidence interval on the mean, obtained by bootstrapping.
