Rapid ice loss from the Greenland ice sheet since 1992 is due in equal parts to increased surface melting and accelerated ice flow. The latter is conventionally attributed to ocean warming, which has enhanced submarine melting of the fronts of Greenland’s marine-terminating glaciers. Yet, through the release of ice sheet surface meltwater into the ocean, which excites near-glacier ocean circulation and in turn the transfer of heat from ocean to ice, a warming atmosphere can increase submarine melting even in the absence of ocean warming. The relative importance of atmospheric and oceanic warming in driving increased submarine melting has, however, not been quantified. Here, we reconstruct the rate of submarine melting at Greenland’s marine-terminating glaciers from 1979 to 2018 and estimate the resulting dynamic mass loss. We show that in south Greenland, variability in submarine melting was indeed governed by the ocean, but, in contrast, the atmosphere dominated in the northwest. At the ice sheet scale, the atmosphere plays a first-order role in controlling submarine melting and the subsequent dynamic mass loss. Our results challenge the attribution of dynamic mass loss to ocean warming alone and show that a warming atmosphere has amplified the impact of the ocean on the Greenland ice sheet.

自 1992 年以来，格陵兰冰盖的冰层迅速流失，这在一定程度上是由于地表融化增加和冰流加速所致。后者通常归因于海洋变暖，这加剧了格陵兰海洋终止冰川前沿的海底融化。然而，通过将冰盖表面融水释放到海洋中，这会激发近冰川的海洋环流，进而将热量从海洋转移到冰层，即使在没有海洋变暖的情况下，变暖的大气也会增加海底融化。然而，大气和海洋变暖在推动海底融化增加方面的相对重要性尚未量化。在这里，我们重建了 1979 年至 2018 年格陵兰海洋终止冰川的海底融化速率，并估计了由此产生的动态质量损失。我们表明，在格陵兰岛南部，海底融化的变化确实受海洋控制，但相比之下，大气在西北部占主导地位。在冰盖尺度上，大气在控制海底融化和随后的动态质量损失方面起着一级作用。我们的研究结果挑战了动态质量损失仅归因于海洋变暖的原因，并表明变暖的大气放大了海洋对格陵兰冰盖的影响。