Increasing snow accumulation over the Antarctic Ice Sheet may mitigate future sea level rise. However, current estimates of mitigation potential are poorly constrained due to limited records of past variability. We present an annually resolved reconstruction of Antarctic snow accumulation from 1801 to 2000 CE, employing a paleoclimate data assimilation methodology to integrate ice core records with a multi-model ensemble of climate simulations. Our reconstruction correlates well with instrumental reanalysis, and we find that Antarctic accumulation rates increased over the 20th-century, resulting in a modest amount (∼1 mm) of sea level mitigation. Mitigation is primarily driven by an accelerating trend since around 1970. Our results contrast with previous mitigation estimates of ∼10–12 mm; this discrepancy is due to poorly constrained baseline estimates of 19th-century accumulation in East Antarctica. Our reconstruction suggests that the uncertainty of future sea level mitigation from increasing Antarctic accumulation has been underestimated.

中文翻译：

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不确定的南极东部堆积历史驱动的 20 世纪南极海平面减缓

南极冰盖积雪的增加可能会减缓未来海平面的上升。然而，由于过去变化的记录有限，目前对缓解潜力的估计受到很大限制。我们提出了对公元 1801 年至 2000 年南极积雪的年度重建，采用古气候数据同化方法将冰芯记录与气候模拟的多模型集合相结合。我们的重建与仪器再分析有很好的相关性，我们发现南极洲的堆积率在 20 世纪有所增加，导致海平面适度减缓（~1 毫米）。减缓主要是由 1970 年左右以来的加速趋势驱动的。我们的结果与之前约 10-12 毫米的减缓估计形成鲜明对比；这种差异是由于对 19 世纪东南极洲积累的基线估计缺乏约束所致。我们的重建表明，南极积聚增加导致未来海平面减缓的不确定性被低估了。