Record-breaking 2023 fires signal a new era of smoke-driven darkening on the Greenland Ice Sheet

Abstract Boreal wildfires, intensified by warming, transport smoke aerosols to the Greenland Ice Sheet (GrIS), reducing surface albedo and accelerating melt. Using two decades (2003–2023) of aerosol model fluxes and surface observations, we identify a structural shift toward intensified smoke loading since 2019. This peaked during the record-breaking 2023 Canadian wildfire season, which contributed >20% of total deposition since 2003, with southern GrIS anomalies reaching ten times the 20-year average. Persistent "heat domes" and pyrocumulonimbus events likely facilitated this exceptionally efficient transport. We demonstrate that in 2023, smoke deposition was the primary driver of albedo variability in the ablation zone, explaining 46.4% of the variance—nearly five times the influence of air temperature. These results indicate that the record-breaking 2023 season serves as a harbinger of a new regime where smoke-driven surface darkening plays a critical role in Arctic melt-albedo feedbacks, potentially decoupling ice-sheet mass loss from traditional thermodynamic drivers.