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Abstract

While the role of long-term sea ice decline in shaping Arctic climate change is well-established, the contribution of short-term sea-ice variability remains insufficiently explored. Here we present observational evidence that since 2007, sea ice fluctuations in Arctic marginal ice zone have remained at a high level. The annual-mean daily variability of sea ice concentration rose by 11.4%, with high-variability days becoming more frequent, especially in summer and autumn. Composite analyses reveal enhanced net heat uptake in summer (+11.9%) and greater ocean-to-atmosphere heat release in winter (+45.3%), both of which intensify after 2007. Causal analyses reveal a feedback, with higher sea ice variability being closely linked to and reinforced by anomalous net heat fluxes. These findings highlight the increasing short-term variability of the Arctic sea-ice and its key role in regulating local air–sea heat exchange.