Abstract

There is a lively and ongoing debate about the extent to which interannual variability in Arctic sea ice influences the midlatitude circulation, and how any such links may change with global warming. While observational data supports the existence of a teleconnection between November sea ice in the Barents-Kara region and the subsequent winter North Atlantic Oscillation, climate models do not consistently reproduce such a link, with only very weak inter-model consensus. I'll discuss recent work, using the EC-Earth3 climate model, that while a deterministic (i.e. non-stochastic) ensemble of coupled simulations shows no evidence of such a teleconnection, the inclusion of stochastic parameterizations to the ocean and sea ice component of EC-Earth3 results in the emergence of a robust teleconnection comparable in magnitude to that observed. We show that this can be accounted for by an improved ice-ocean-atmosphere coupling due to the stochastic perturbations, which aim to represent the effect of unresolved ice and ocean variability. In particular, the weak inter-model consensus may to a large extent be due to model biases in surface coupling, with stochastic parameterizations being one possible remedy.