Recent slowing of Arctic sea ice melt tied to multidecadal NAO variability

The reduction of Arctic sea ice concentration (SIC) is a key indicator of global warming. In September 2012, SIC reached its lowest recorded value. Since then, sea ice melt has slowed down, showing a linear trend of only -0.4±6.8%/decade from 2012 to 2023, compared to -11.3±3.3%/decade from 1996 to 2011. Here, we demonstrate that the recent slowdown in September sea ice melt is closely coupled with the multi-decadal variability of the preceding summer North Atlantic Oscillation (NAO), which has transitioned from the lowest point of its negative phase in the early 2010s to a positive phase. During this shift, decreased heat and moisture, along with reduced downward longwave radiation, have contributed to offsetting the long-term decline, leading to a slowdown in Arctic sea ice melting. Additionally, the Atlantic Multidecadal Oscillation plays a primary role in driving the interdecadal variability of the NAO and Arctic sea ice by modulating wave-mean flow interactions.