Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
Proc Natl Acad Sci U S A. 2011 Jun 14;108(24):9765-9. doi: 10.1073/pnas.1101708108. Epub 2011 May 31.
West Greenland has had multiple episodes of human colonization and cultural transitions over the past 4,500 y. However, the explanations for these large-scale human migrations are varied, including climatic factors, resistance to adaptation, economic marginalization, mercantile exploration, and hostile neighborhood interactions. Evaluating the potential role of climate change is complicated by the lack of quantitative paleoclimate reconstructions near settlement areas and by the relative stability of Holocene temperature derived from ice cores atop the Greenland ice sheet. Here we present high-resolution records of temperature over the past 5,600 y based on alkenone unsaturation in sediments of two lakes in West Greenland. We find that major temperature changes in the past 4,500 y occurred abruptly (within decades), and were coeval in timing with the archaeological records of settlement and abandonment of the Saqqaq, Dorset, and Norse cultures, which suggests that abrupt temperature changes profoundly impacted human civilization in the region. Temperature variations in West Greenland display an antiphased relationship to temperature changes in Ireland over centennial to millennial timescales, resembling the interannual to multidecadal temperature seesaw associated with the North Atlantic Oscillation.
过去 4500 年来，格陵兰岛西部经历了多次人类殖民和文化变迁。然而，这些大规模人类迁徙的原因多种多样，包括气候因素、适应能力、经济边缘化、商业探索以及敌对邻里关系等。由于在定居点附近缺乏定量古气候重建，以及格陵兰冰盖上的冰芯得出的全新世温度相对稳定，评估气候变化的潜在作用变得复杂。在这里，我们根据格陵兰岛西部两个湖泊沉积物中烯酮不饱和度，提供了过去 5600 年的高分辨率温度记录。我们发现，过去 4500 年中的主要温度变化是突然发生的（在几十年内），与萨卡克、多塞特和挪威文化的定居和废弃的考古记录同时发生，这表明突然的温度变化深刻影响了该地区的人类文明。格陵兰岛西部的温度变化与爱尔兰的温度变化呈反相关关系，在百年至千年时间尺度上，类似于与北大西洋涛动相关的年际至数十年温度跷跷板。
