Abstract Marine terminating glaciers evolve on millenial timescales in response to changes in oceanic and atmospheric conditions. However, the relative role of oceanic and atmospheric drivers remains uncertain. The evolution of marine terminating glaciers under the warmer than present Holocene Climate Optimum climate can give important insights into the dynamics of ice streams as the climate evolves. The early Holocene evolution of Jakobshavn Isbrae, from the Last Glacial Maximum extent up to 8.2 ka BP is well constrained by geomorphological studies in the area. However, the Holocene minimum extent of the glacier is unknown. Here, we use a high-resolution regional ice sheet model to study the retreat and readvance of Jakobshavn Isbrae from the Mid-Holocene to the Little Ice Age. This model of Jakobshavn Isbrae accurately tracks the terrestrial ice margin and agrees with available estimates of marine grounding line evolution. We find that the Holocene minimum extent of both the terrestrial ice margin and the grounding line, reached at 6–5 ka BP, is close to the present day extent of the glacier. We also find that the glacier is currently located close to a tipping point, from beyond which readvance would require a longer and more significant cooling than the Little Ice Age. We assess the importance of the ocean forcing in explaining the Holocene evolution of Jakobshavn, and find that cooling within the fjord during the Mid-Holocene is critical for the glacier to readvance. This finding emphasizes the role of ocean forcing when trying to understand the millenial scale evolution of marine terminating glaciers.

中文翻译：

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现在的 Jakobshavn Isbræ 接近全新世最小范围

摘要 海洋终止冰川随着海洋和大气条件的变化在千年时间尺度上演化。然而，海洋和大气驱动因素的相对作用仍然不确定。在比目前更温暖的全新世气候最佳气候下海洋终止冰川的演变可以为了解冰流随着气候演变的动态提供重要的见解。Jakobshavn Isbrae 的早期全新世演化，从末次盛冰期到 8.2 ka BP，受到该地区地貌研究的很好的限制。然而，冰川的全新世最小范围是未知的。在这里，我们使用高分辨率区域冰盖模型来研究 Jakobshavn Isbrae 从中全新世到小冰河时代的退缩和再进退。这个 Jakobshavn Isbrae 模型准确地跟踪了陆地冰缘，并与现有的海洋接地线演化估计值一致。我们发现，陆地冰缘和接地线的全新世最小范围在 6-5 ka BP 时达到，接近现在的冰川范围。我们还发现，冰川目前位于临界点附近，从临界点开始，重新开始需要比小冰河时代更长、更显着的冷却。我们评估了海洋强迫在解释雅各布港全新世演化过程中的重要性，并发现全新世中期峡湾内的冷却对于冰川的重新发展至关重要。这一发现强调了海洋强迫在试图了解海洋终止冰川的千年演化过程中的作用。