Shen Chuan-Chou, Beardsley Felicia, Gong Shou-Yeh, Kataoka Osamu, Yoneda Minoru, Yokoyama Yusuke, Hu Hsun-Ming, Huang Chun-Yuan, Liu Sze-Chieh, Chiang Hong-Wei, Wei Hsin-Lin, Chung Yun-Chuan, Jiang Leilei, Lin Albert Yu-Min, Fox James, David Mordain, Lebehn Jason, Barnabas Jason, Kohler Gus, Richards Zoe T, Hobbs Jean-Paul A, McCoy Mark D
Department of Geosciences, High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), National Taiwan University, Taipei 10617, Taiwan, ROC.
Research Center for Future Earth, National Taiwan University, Taipei 10617, Taiwan, ROC.
PNAS Nexus. 2024 Oct 1;3(10):pgae399. doi: 10.1093/pnasnexus/pgae399. eCollection 2024 Oct.
Sea level rise and climate change are shaping present societies, particularly those on oceanic islands. Few historical examples could serve as references for these changes. One such potential model is the Saudeleur Dynasty with its capital Nan Madol on the Pacific Island of Pohnpei. However, the timing of its construction, as well as the dynasty's fluctuations and potential environmental influences, has remained unresolved. Through the analyses of Th ages on 171 dates on corals fragments used as building materials and charcoal C ages from excavations, 2 major construction phases spanning from the 10th to the 15th century CE can be discerned. The results show that the first phase of the site's construction, spanning the 10th-12th century, marked the dynasty's rise. The second period, spanning from the late 12th to the early 15th century, provides the most substantial evidence for the demise of the island-scale chiefdom and a significant societal reorganization. The phases are centuries earlier than previously believed. With this new evidence, we propose the hypothesis that variations in the El Niño-Southern Oscillation and subsidence-related sea level rise presented major challenges for building and maintaining Nan Madol, and thus, influenced the course of the island's history. This case serves as a compelling example of how adverse climatic conditions can spur investments-in this case, in seawater defense under high sea levels-yet ultimately may contribute to abandonment. It offers lessons for island nations, showcasing coastal resilience in the face of worsening catastrophic events that unfolded over generations.
海平面上升和气候变化正在塑造当今社会，尤其是那些位于海洋岛屿上的社会。很少有历史实例能为这些变化提供参考。一个这样的潜在模型是位于太平洋波纳佩岛、以楠马多尔为首都的绍德雷尔王朝。然而，其建造时间以及该王朝的兴衰及其潜在的环境影响一直没有定论。通过对用作建筑材料的珊瑚碎片上171个年代测定数据以及挖掘出的木炭碳年代的分析，可以辨别出公元10世纪至15世纪的两个主要建设阶段。结果表明，该遗址建设的第一阶段，即10世纪至12世纪，标志着该王朝的兴起。第二阶段，即从12世纪末到15世纪初，为岛屿规模的酋邦的衰落和重大的社会重组提供了最有力的证据。这些阶段比之前认为的要早几个世纪。有了这一新证据，我们提出一个假设，即厄尔尼诺-南方涛动（El Niño-Southern Oscillation）的变化和与沉降相关的海平面上升给楠马多尔的建设和维护带来了重大挑战，因此影响了该岛的历史进程。这个案例有力地说明了不利的气候条件如何能刺激投资——在这种情况下，是在高海平面下的海水防御方面的投资——但最终可能导致被遗弃。它为岛国提供了经验教训，展示了面对几代人以来不断恶化的灾难性事件时的海岸复原力。
