James A. Screen

We investigate the response of surface temperature persistence, quantified using a lagged autocorrelation, to imposed Arctic sea‐ice loss in coupled model experiments. Sea‐ice loss causes increases in persistence over ocean in midlatitudes and the low‐Arctic, which are of a similar magnitude to the total response to climate change in these regions. Using an idealized model, we show that sea‐ice loss induces a slowing of meridional wind anomalies, which can drive the midlatitude persistence increase obtained in coupled models. Sea‐ice loss should induce persistence increases in the Arctic, through its effect on the surface heat capacity. However, in coupled models with imposed sea‐ice loss, persistence increase in the Arctic is essentially absent. We suggest that methods used to constrain sea‐ice in coupled models may spuriously reduce the effects of sea‐ice loss on persistence.