https://news.climate.columbia.edu/2025/11/06/what-really-happened-on-easter-island-ancient-sediments-rewrite-the-ecocide-story/Columbia Climate School
November 6, 2025
A
new study led by researchers at the Lamont-Doherty Earth Observatory offers the clearest evidence yet that a centuries-long drought transformed life on Rapa Nui (Easter Island) beginning around the year 1550. The scientists collected sediment cores from two of the island’s few freshwater sources: Rano Aroi, a high-elevation wetland and Rano Kao, a crater lake. By analyzing the hydrogen isotope composition of plant leaf waxes within those cores, the team reconstructed a continuous, 800-year record of past rainfall trends, showing that annual precipitation declined and remained low for more than a century. The findings challenge long-held narratives of societal “collapse,” instead showing that Rapanui communities were resilient to profound climate stress. We spoke with lead author
Redmond Stein about how the team uncovered this history and what it means for understanding the links between climate and culture.
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Sediments in lakes and wetlands accumulate slowly over time and preserve lots of information about the climatic and environmental conditions under which they were deposited. Many scientists have previously studied sediments from Rapa Nui and have inferred past environmental changes by looking at things like elemental abundances, pollen and plant macrofossils, and changes in how quickly the sediment accumulated. These proxies are incredibly valuable, but they can often respond in complex ways to multiple climate and environmental variables—for example, temperature, precipitation, and changes in human land use. Conversely, we think leaf waxes on Rapa Nui are only recording information about local rainfall and aridity. By measuring the composition of leaf waxes preserved in wetland sediments— the ratio of “heavy” to “light” hydrogen in these waxes varies in tandem with the ratio of hydrogen in the water that plants absorb from rain—we were therefore able to put a rough estimate on the magnitude of drought that occurred on Rapa Nui in the 16th century for the first time.
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The ecocide narrative suggests that people on Rapa Nui destroyed their island by way of deforestation, eventually leading to a period of societal conflict and population collapse prior to European contact in the 18th century. This story has been popularized as a parable for global overconsumption, presenting the people of Rapa Nui as architects of their own destruction. Although it’s true Rapa Nui was gradually deforested and that this represented a major ecological transition on the island, many studies have cast doubt on the ecocide hypothesis. Perhaps most importantly, there is no strong evidence of a demographic collapse prior to European arrival.
Our study and others now suggest that the people of Rapa Nui were dealing with drought beginning in the 16th century, which would have significantly impacted life on the already freshwater-poor island. Importantly, our hypothesis is not simply that regional climate changed, and that social and political hierarchies must have shifted in tandem, or that deforestation was unimportant, but rather that climate provides an important context for the human history of Rapa Nui. The exact mechanism by which a decrease in rainfall could have led to challenging circumstances is still unclear—for example, if this would have exacerbated soil erosion issues, led to a decline in drinking water, pushed people to find new freshwater resources, or impacted the ability of the vegetation to grow. Regardless, our study makes clear the history of Rapa Nui is much more nuanced than the ecocide narrative implies.
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Stein, R., Curtin, L., Balascio, N.L.
et al. Prolonged drought on Rapa Nui during the decline of megalithic monument construction.
Commun Earth Environ 6, 865 (2025).
https://doi.org/10.1038/s43247-025-02801-4
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