Impacts of regional sea ice loss – a global response

Climate model studies have shown a wide range of responses in the northern hemisphere to reduced sea ice loss in the Arctic. The most robust is the thermodynamic response with local warming in the region of the sea ice loss. Many studies also find a shift in the tropospheric jet towards the equator and a tendency towards the negative phase of the North Atlantic Oscillation. However, these mid-latitude dynamic responses seem somewhat dependent on the extent and location of sea ice loss as well as model differences. We use new atmosphere-only experiments from the Polar-Amplification-MIP of CMIP6 to further explain how the dynamic responses in the atmosphere relate to the pattern of sea ice loss in the Arctic on multi-decadal time-scales. We find exciting new results that suggest that Arctic sea ice loss can also impact the southern hemisphere, while Antarctic sea ice loss can impact the northern hemisphere, and we propose possible atmospheric mechanisms to explain this linkage. We also highlight the importance of large ensembles to differentiate between robust responses and atmospheric noise