Extended Data Fig. 4: Drivers of \({{\boldsymbol{p}}}_{{{\bf{CO}}}_{{\bf{2}}}}\) do not exhibit crossover in any CMIP model despite large changes in sea ice.

Seasonal evolution of \({p}_{{{\rm{CO}}}_{2}}\)-related drivers in the CMIP models for their timing of a, d, sea-ice retreat and regrowth (see Methods), b, e, annual high of net primary production, and c, f, annual low and high of temperature are shown for both a–c, CMIP5 RCP8.5 and d–f, CMIP6 SSP5-8.5. Curves indicate Arctic domain averages for each model, while red points are for the observation-based product of sea-ice concentration (Methods). Plot characteristics are as in Fig. 3 and Extended Data Fig. 3.