Sea-level and summer season orbital insolation as drivers of Arctic sea-ice (2102.02067v2)

Abstract: The sea-ice cover of the Arctic Ocean is an important element of the climate and ocean system in the Northern Hemisphere as it impacts albedo, atmospheric pressure regimes, CO2-exchange at the ocean/atmosphere interface as well as the North Atlantic freshwater budget and thermohaline circulation [1]. Due to global warming, the Arctic sea-ice cover is presently evolving at an unprecedent rate towards full melt during the summer season, driving the so-called "Arctic amplification" [2]. However, the Arctic sea-ice has also experienced large amplitude variations, from seasonal to orbital (Milankovitch) time scales, in the past. Recent studies led to suggest that whereas insolation has been a major driver of Arctic sea-ice variability through time, sea-level changes governed the development of "sea-ice factories" over shelves (Figure 1), thus fine-tuning the response of the Arctic Ocean to glacial/interglacial oscillations that is slightly out of phase compared to lower latitudes [3,4]. We discuss below how insolation and sea-level changes may have interacted and controlled the sea-ice cover of the Arctic Ocean during warm past intervals and how they could still interfere in the future.