Decoding the dynamics of poleward shifting climate zones using aqua-planet model simulations

Abstract Growing evidence indicates that the atmospheric and oceanic circulation experiences a systematic poleward shift in warming climate. However, complexity of climate system, including coupling between ocean atmosphere, natural variability land-sea distribution, tends to obfuscate causal mechanism underlying shift. Here, using an idealised coupled aqua-planet model, we explore shifting circulation, by isolating contributing factors from direct CO $$_2$$ 2 forcing, indirect surface warming, wind-stress feedback dynamics. We find that, contrast particular enhanced subtropical plays important role driving This emerges background Ekman convergence anomalous heat absence dynamical change. It expands tropical warm water zone, causes mid-latitude temperature gradient, hence forces corresponding associated wind pattern. The wind, turn drives circulation. Our simulations, despite being idealised, capture main features observed changes, for example, patterns near-surface sea level pressure, storm tracks, precipitation large-scale implying increase greenhouse gas concentrations not only raises temperature, but can also systematically zones poleward.