Higher boreal summer insolation in the early to middle Holocene drove thousands of years of summer warming across the Arctic. Modern-day warming has distinctly different causes, but geologic data from this past warm period hold lessons for the future. We compile Holocene temperature reconstructions from ice, lake, and marine cores around Greenland, where summer temperatures are globally important due to their influence on ice sheet mass balance, ocean circulation, and sea ice. Highlighting and accounting for some key issues with proxy interpretation, we find that much of Greenland experienced summers 3 to 5°C warmer than the mid-twentieth century in the early Holocene—earlier and stronger warming than often presumed. Warmth had dramatic consequences: Many glaciers disappeared, perennial sea ice retreated, plants and animals migrated northward, the Greenland Ice Sheet shrank rapidly, and increased meltwater discharge led to strong marine water stratification and enhanced winter sea ice in some areas.

全新世早期至中期较高的北方夏季日照导致整个北极地区经历了数千年的夏季变暖。现代变暖有明显不同的原因，但过去温暖时期的地质数据为未来提供了经验教训。我们从格陵兰岛周围的冰、湖泊和海洋核心编译全新世温度重建，其中夏季温度对冰盖质量平衡、海洋环流和海冰的影响具有全球重要性。通过代理解释强调并解释一些关键问题，我们发现格陵兰岛的大部分地区在全新世早期经历了比 20 世纪中叶高 3 至 5°C 的夏季——比通常假设的更早且更强烈的变暖。温暖产生了戏剧性的后果：许多冰川消失，常年海冰消退，植物和动物向北迁移，