Links between climatic histories and the rise and fall of a Pacific chiefdom

Chuan-Chou Shen; Felicia Beardsley; Shou-Yeh Gong; Osamu Kataoka; Minoru Yoneda; Yusuke Yokoyama; Hsun-Ming Hu; Chun-Yuan Huang; Sze-Chieh Liu; Hong-Wei Chiang; Hsin-Lin Wei; Yun-Chuan Chung; Leilei Jiang; Albert Yu-Min Lin; James Fox; Mordain David; Jason Lebehn; Jason Barnabas; Gus Kohler; Zoe T Richards; Jean-Paul A Hobbs; Mark D McCoy

doi:10.1093/pnasnexus/pgae399

Links between climatic histories and the rise and fall of a Pacific chiefdom

PNAS Nexus. 2024 Oct 1;3(10):pgae399. doi: 10.1093/pnasnexus/pgae399. eCollection 2024 Oct.

Authors

Chuan-Chou Shen^{1

2}, Felicia Beardsley³, Shou-Yeh Gong⁴, Osamu Kataoka⁵, Minoru Yoneda⁶, Yusuke Yokoyama^{7

8

9

10}, Hsun-Ming Hu^{1

2}, Chun-Yuan Huang^{1

2}, Sze-Chieh Liu^{11

12}, Hong-Wei Chiang¹¹, Hsin-Lin Wei^{1

2}, Yun-Chuan Chung^{1

2

13}, Leilei Jiang¹⁴, Albert Yu-Min Lin^{15

16}, James Fox¹⁷, Mordain David¹⁸, Jason Lebehn¹⁸, Jason Barnabas¹⁸, Gus Kohler¹⁹, Zoe T Richards^{20

21}, Jean-Paul A Hobbs²², Mark D McCoy²³

Affiliations

¹ Department of Geosciences, High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), National Taiwan University, Taipei 10617, Taiwan, ROC.
² Research Center for Future Earth, National Taiwan University, Taipei 10617, Taiwan, ROC.
³ Anthropology Program, College of Arts and Sciences, University of La Verne, La Verne, CA 91750, USA.
⁴ Department of Geology, National Museum of Natural Science, Taichung 40419, Taiwan, ROC.
⁵ Department of Global Communication and Language, Kansai Gaidai University, Osaka 573-1001, Japan.
⁶ Laboratory of Radiocarbon Dating, The University Museum, University of Tokyo, Tokyo 113-0033, Japan.
⁷ Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan.
⁸ Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
⁹ Graduate Program on Environmental Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-00419, Japan.
¹⁰ Research School of Physics, The Australian National University, Canberra, ACT 0200, Australia.
¹¹ Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan, ROC.
¹² Advanced Geological Research Task Force, Sinotech Engineering Consultants, Inc., Taipei 114065, Taiwan, ROC.
¹³ Department of Geosciences and Geography, University of Helsinki, 00014, Finland.
¹⁴ Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Centre of China, School of Marine Sciences, Guangxi University, Nanning 530004, China.
¹⁵ Qualcomm Institute, University of California, San Diego, CA 92093, USA.
¹⁶ National Geographic Society, NW Washington, DC 20036, USA.
¹⁷ Department of Chemistry, State University of New York, Stony Brook, NY 11794, USA.
¹⁸ Pohnpei State Historic Preservation Office, Kolonia, Pohnpei 96941, Federated States of Micronesia.
¹⁹ National Historic Preservation Program, Palikir, Pohnpei 96941, Federated States of Micronesia.
²⁰ Coral Conservation and Research Group, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia.
²¹ Collections and Research Centre, Western Australian Museum, Welshpool, WA 6016, Australia.
²² School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
²³ Department of Anthropology, Florida State University, Tallahassee, FL 32304, USA.

Abstract

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 ²³⁰Th ages on 171 dates on corals fragments used as building materials and charcoal ¹⁴C 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.

Keywords: ENSO; Nan Madol; Saudeleur Dynasty; coral 230Th dating; subsidence-induced sea level rise.