An international research team has uncovered how climate change and sea-level rise contributed to the collapse of Nan Madol, a medieval city and capital of the Saudeleur Dynasty, located on the eastern coast of Pohnpei Island, Micronesia. Known as the “Venice of the Pacific,” Nan Madol is a remarkable site consisting of over 100 artificial islets built with nearly a million tons of basalt and coral. New findings suggest that environmental pressures forced the city’s abandonment 600 years ago, offering important lessons for the modern world.
Led by Chuan-Chou Shen from National Taiwan University, the research team analysed coral rubble from the site to establish a precise timeline for Nan Madol’s construction and decline. The study reveals that subsidence-related sea-level rise and extreme climate oscillations made it increasingly difficult to maintain the city. These environmental challenges ultimately contributed to the collapse of the Saudeleur chiefdom and the city’s abandonment in the 15th century.
New Timeline for a Medieval City
Nan Madol, capital of the Saudeleur Dynasty, built with nearly a million ton of columnar basalt and coral rubbles. Photo courtesy National Taiwan University
The study identifies two major construction phases, both significantly earlier than previously thought. The first phase, during the 10th to 12th centuries CE, marked the rise of the Saudeleur Dynasty, while the second, from the late 12th to early 15th centuries, aligns with the chiefdom’s decline. By the second phase, rising sea levels had already submerged parts of the site, creating immense challenges for its inhabitants.
Nan Madol’s volcanic foundation added to these difficulties. Over millennia, the cooling and contraction of Pohnpei’s volcanic landmass caused the island to sink at a rate of 1 millimeter per year, exacerbating the effects of rising seas. Intense climate oscillations, particularly during La Niña years, brought violent storm surges and significant seawater intrusion, further damaging the city’s infrastructure. These environmental strains likely fueled public unrest, leading to the eventual overthrow of the Saudeleur Dynasty.
Lessons from the Medieval Pacific
Dr. Chuan-Chou Shen of the Department of Geosciences, National Taiwan University (front) and Dr. Felicia Beardsley, an archaeologist of the University of La Verne (back), collecting coral samples from the outer wall of the royal tomb complex. Photo courtesy National Taiwan University
Nan Madol’s history mirrors the vulnerabilities faced by many island nations today. Rising sea levels, combined with the increasing frequency of extreme weather events, continue to threaten coastal and island communities. The study highlights the pressing need for global action to combat climate change, warning that the world could see a sharp rise in climate refugees in the coming decades.
The article, “Links between climatic histories and the rise and fall of a Pacific chiefdom,” by 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 and Mark D McCoy, appears in PNAS Nexus. Click here to read it.
Article courtesy National Taiwan University / Asia Research News. Top Image: A conceptual rendering of a reconstructed Nan Madol. Photo courtesy National Taiwan University
An international research team has uncovered how climate change and sea-level rise contributed to the collapse of Nan Madol, a medieval city and capital of the Saudeleur Dynasty, located on the eastern coast of Pohnpei Island, Micronesia. Known as the “Venice of the Pacific,” Nan Madol is a remarkable site consisting of over 100 artificial islets built with nearly a million tons of basalt and coral. New findings suggest that environmental pressures forced the city’s abandonment 600 years ago, offering important lessons for the modern world.
Led by Chuan-Chou Shen from National Taiwan University, the research team analysed coral rubble from the site to establish a precise timeline for Nan Madol’s construction and decline. The study reveals that subsidence-related sea-level rise and extreme climate oscillations made it increasingly difficult to maintain the city. These environmental challenges ultimately contributed to the collapse of the Saudeleur chiefdom and the city’s abandonment in the 15th century.
New Timeline for a Medieval City
The study identifies two major construction phases, both significantly earlier than previously thought. The first phase, during the 10th to 12th centuries CE, marked the rise of the Saudeleur Dynasty, while the second, from the late 12th to early 15th centuries, aligns with the chiefdom’s decline. By the second phase, rising sea levels had already submerged parts of the site, creating immense challenges for its inhabitants.
Nan Madol’s volcanic foundation added to these difficulties. Over millennia, the cooling and contraction of Pohnpei’s volcanic landmass caused the island to sink at a rate of 1 millimeter per year, exacerbating the effects of rising seas. Intense climate oscillations, particularly during La Niña years, brought violent storm surges and significant seawater intrusion, further damaging the city’s infrastructure. These environmental strains likely fueled public unrest, leading to the eventual overthrow of the Saudeleur Dynasty.
Lessons from the Medieval Pacific
Nan Madol’s history mirrors the vulnerabilities faced by many island nations today. Rising sea levels, combined with the increasing frequency of extreme weather events, continue to threaten coastal and island communities. The study highlights the pressing need for global action to combat climate change, warning that the world could see a sharp rise in climate refugees in the coming decades.
The article, “Links between climatic histories and the rise and fall of a Pacific chiefdom,” by 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 and Mark D McCoy, appears in PNAS Nexus. Click here to read it.
Article courtesy National Taiwan University / Asia Research News. Top Image: A conceptual rendering of a reconstructed Nan Madol. Photo courtesy National Taiwan University
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