Fig. 2: Changes in winter mean temperature and Tstd under different CO2 pathways.

Changes in the mean winter temperature (contours) and Tstd (shading) relative to the mean of the piControl (CTL) run for (a) L1%, b M1%, c H1%, and d H2% experiments (Unit: K). The horizontal lines for each experiment indicate the time of peak CO2 concentration (violet) and the end of the ramp-down (blue). 45˚-65˚N is defined as the mid-latitude of the Northern Hemisphere (red dashed box). The stabilization period is defined as 150 years after the ramp-down period, after which it is masked. The results for the full integration period are presented in Fig. S2; e Time series of the standard deviation of the daily mean temperature (Tstd; green) in winter over 45˚-65˚N and the Arctic Amplification strength (AAF; blue) during the CO2 pathway (Unit: K). They are smoothed using a 15-year running mean.