Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138.
Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, NM 87545.
Proc Natl Acad Sci U S A. 2023 Apr 25;120(17):e2209615120. doi: 10.1073/pnas.2209615120. Epub 2023 Apr 17.
The first records of Greenland Vikings date to 985 CE. Archaeological evidence yields insight into how Vikings lived, yet drivers of their disappearance in the 15th century remain enigmatic. Research suggests a combination of environmental and socioeconomic factors, and the climatic shift from the Medieval Warm Period (900 to 1250 CE) to the Little Ice Age (1250 to 1900 CE) may have forced them to abandon Greenland. Glacial geomorphology and paleoclimate research suggest that the Southern Greenland Ice Sheet readvanced during Viking occupation, peaking in the Little Ice Age. Counterintuitively, the readvance caused sea-level rise near the ice margin due to increased gravitational attraction toward the ice sheet and crustal subsidence. We estimate ice growth in Southwestern Greenland using geomorphological indicators and lake core data from previous literature. We calculate the effect of ice growth on regional sea level by applying our ice history to a geophysical model of sea level with a resolution of ~1 km across Southwestern Greenland and compare the results to archaeological evidence. The results indicate that sea level rose up to ~3.3 m outside the glaciation zone during Viking settlement, producing shoreline retreat of hundreds of meters. Sea-level rise was progressive and encompassed the entire Eastern Settlement. Moreover, pervasive flooding would have forced abandonment of many coastal sites. These processes likely contributed to the suite of vulnerabilities that led to Viking abandonment of Greenland. Sea-level change thus represents an integral, missing element of the Viking story.
格陵兰岛维京人的最早记录可以追溯到公元 985 年。考古证据提供了有关维京人生活方式的深入了解，但他们在 15 世纪消失的原因仍然是个谜。研究表明，这是环境和社会经济因素的综合作用，从中世纪暖期（约公元 900 年至 1250 年）到小冰期（约公元 1250 年至 1900 年）的气候转变可能迫使他们离开格陵兰岛。冰川地貌学和古气候研究表明，在维京人占领期间，格陵兰岛南部的冰盖再次前进，在小冰期达到顶峰。反常的是，由于对冰盖和地壳下沉的引力增加，冰盖的再次前进导致了冰缘附近的海平面上升。我们使用地貌学指标和前人文献中的湖泊核心数据来估计格陵兰岛西南部的冰增长。我们通过将我们的冰史应用于格陵兰岛西南部分辨率约为 1 公里的海平面地球物理模型，来计算冰增长对区域海平面的影响，并将结果与考古证据进行比较。结果表明，在维京人定居期间，海平面在冰川带以外上升了约 3.3 米，导致海岸线后退了数百米。海平面上升是渐进的，涵盖了整个东定居点。此外，广泛的洪水将迫使许多沿海遗址被遗弃。这些过程可能导致了一系列导致维京人放弃格陵兰岛的脆弱性。因此，海平面变化是维京人故事中不可或缺的、缺失的一环。
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