The 2007 Bering Strait oceanic heat flux and anomalous Arctic sea‐ice retreat

To illuminate the role of Pacific Waters in the 2007 Arctic sea‐ice retreat, we use observational data to estimate Bering Strait volume and heat transports from 1991 to 2007. In 2007, both annual mean transport and temperatures are at record‐length highs. Heat fluxes increase from 2001 to a 2007 maximum, 5–6 × 10 20 J/yr. This is twice the 2001 heat flux, comparable to the annual shortwave radiative flux into the Chukchi Sea, and enough to melt 1/3rd of the 2007 seasonal Arctic sea‐ice loss. We suggest the Bering Strait inflow influences sea‐ice by providing a trigger for the onset of solar‐driven melt, a conduit for oceanic heat into the Arctic, and (due to long transit times) a subsurface heat source within the Arctic in winter. The substantial interannual variability reflects temperature and transport changes, the latter (especially recently) being significantly affected by variability (> 0.2 Sv equivalent) in the Pacific‐Arctic pressure‐head driving the flow.