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05/18/2026 | Press release | Distributed by Public on 05/18/2026 09:52

Scientists uncover centuries of climate chaos — and human resilience

Published Date

May 18, 2026

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The climate of the ancient Eastern Mediterranean was far more turbulent than previously thought - and a new study suggests that people adapted anyway.

An international team of scientists, spearheaded by UC San Diego's Center for Cyber-Archaeology and Sustainability (CCAS) and the University of Haifa's Recanati Institute for Maritime Studies (RIMS), has developed a new way to track ancient climate and used it to decode 4,000 years of key environmental history in the ancient Mediterranean. The paper was published in Quaternary Science Reviews on May 13.

An international team of scientists, spearheaded by UC San Diego's Center for Cyber-Archaeology and Sustainability (CCAS) and the University of Haifa's Recanati Institute for Maritime Studies (RIMS), has developed a new way to track ancient climate and used it to decode 4,000 years of key environmental history in the ancient Mediterranean. The paper was published in Quaternary Science Reviews on May 13.

Focusing on a former wetland on Israel's Carmel Coast, a narrow strip of land between the Mediterranean Sea and the Carmel mountain range, the researchers examined a period known as the end of the African Humid Period, a time when the region was transforming from lush and wet to increasingly dry. Rather than a slow, steady drying, the climate lurched between wet and dry extremes, sometimes within a single human lifetime, sometimes over centuries. Yet people appear to have adapted rather than abandoned the region.

"We built a new tool for reading ancient climate from wetland sediments, combining fossils, pollen, charcoal and chemistry to track how rainfall patterns shifted over thousands of years," said the paper's first author, Gilad Shtienberg, a research scholar with the Center for Cyber-Archaeology and Sustainability (CCAS) at UC San Diego's Qualcomm Institute (QI) and Department of Anthropology. "When we applied the method to these sediments, we found that the transition out of the African Humid Period wasn't smooth. Instead, the climate fluctuated sharply over periods ranging from decades to centuries."

"People are problem solvers," said the paper's senior author Tom Levy, co-director of CCAS and distinguished professor in the UC San Diego Division of Graduate Education and Postdoctoral Affairs. "They cope with environmental stress by developing new technologies and strategies. During this period, we see the emergence of floodwater farming - an early form of irrigation, as well as new ways of managing herd animals like sheep and goats. Settlements expanded into drier areas, but people adapted."

A natural environmental archive

The team uses heavy equipment to drill down to depths of up to 16 meters, about the height of a four- to five-story building, to pull up cylinders of ancient mud in which each layer is a frozen snapshot of a different timep.

Wetlands preserve layers of sediment, plant material and microscopic organisms that accumulate over thousands of years, creating a natural environmental archive.To unlock that archive, the team drilled down up to 16 meters, about the height of a four- to five-story building, pulling up cylinders of ancient mud in which each layer is a frozen snapshot of a different era. Inside those layers, the researchers found tiny shells, pollen grains, charred plant fragments and chemical traces, each one a clue. Freshwater snails and mussels pointed to rainy, lush periods; salt-tolerant species signaled drought and a shrinking wetland. Charcoal revealed erosion and runoff patterns, while pollen and seeds showed what kinds of plants were growing nearby.

The team wove these clues together into a single climate timeline, a kind of ancient weather record stretching back 8,000 years, reconstructing how conditions along the Mediterranean coast shifted from decade to decade. The record revealed an especially wet period around 7,800 to 7,600 years ago, followed by a long-term shift toward drier conditions. It also captured repeated drought episodes around 4,200 years ago; a period linked elsewhere in the Near East to widespread social disruption.

Adaptation, not collapse

Once the climate record was in, the researchers compared it with archaeological excavation and survey evidence from ancient settlements across the region to see whether drought directly triggered migration or population decline.

The answer turned out to be no, or at least, not simply. Climate stress formed an environmental backdrop for changing settlement patterns, but ancient communities appear to have responded creatively and variably rather than simply retreating. The findings push back against the idea that climate was destiny, that a drought automatically meant collapse. People, it turns out, were far more resourceful than that.

Bringing ancient environments to life with AI

The team is using AI-driven virtual reality to reconstruct ancient environments from archaeological and geoscientific data.

Beyond its historical conclusions, the study offers one of the highest-resolution climate records yet produced for the southern Levant from approximately 6050 BCE to 2050 BCE. This time span captures the entire trajectory from late Neolithic village societies to the collapse of the Early Bronze urban system in the southern Levant.

And because wetlands around the world preserve layered environmental histories in similar ways, the researchers say the method can be adapted to ask the same questions elsewhere, wherever ancient sediments and human settlements have been left behind.

In addition, harnessing a range of tools being developed by CCAS Co-Director and QI Associate Research Scientist Neil Smith, student researchers are using AI-driven virtual reality to reconstruct ancient environments from archaeological and geoscientific data from this and other CCAS eastern Mediterranean studies. The work will enable immersive, evidence-based exploration of past landscapes and events.

In addition to Shtienberg and Levy, the paper, "Early to Mid-Holocene Climate Oscillations and Cultural Shifts in the Eastern Mediterranean," was authored by Richard D. Norris, Kendall Mahony and Kristian Plat of Scripps Institution of Oceanography, University of California San Diego; Tammy M. Rittenour of Department of Geosciences, Utah State University; Steffen Mischke of Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; Dafna Langgut of Laboratory of Archaeobotany and Ancient Environments, Institute of Archaeology, and The Steinhardt Museum of Natural History, Tel Aviv University, Israel; Assaf Yasur-Landau and Dorit Sivan of Department of Maritime Civilizations, School of Archaeology and Maritime Cultures, and RIMS University of Haifa, Israel; and Miroslav Bárta of Czech Institute of Egyptology, Prague, Czech Republic. This study was funded primarily by the Irwin Jacobs Family Foundation in an award to T.E.L. (PI) for a collaboration between UC San Diego and the University of Haifa (A. Yasur-Landau, co-PI) focused on marine and cyber-archaeology in the eastern Mediterranean.

Learn more about research and education at UC San Diego in: Climate Change

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