To better understand mechanisms of ice‐sheet decay, we investigate the surface mass balance of the Laurentide Ice Sheet (LIS) during the early Holocene, a period of known rapid LIS retreat. We use a surface energy‐mass balance model (EMBM) driven with conditions derived from an equilibrium atmosphere‐ocean general circulation model 9 kilo‐years ago simulation. Our EMBM indicates a net LIS surface mass balance of −0.67 ± 0.13 m yr−1, with losses primarily due to enhanced boreal summer insolation and warmer summers. This rate of loss compared to LIS volume reconstructions suggests that surface ablation accounted for 74 ± 22% of the LIS mass loss with the remaining loss likely driven by dynamics resulting in basal sliding and calving. Thus surface melting likely played a governing role in the retreat and disappearance of this ice sheet.
