Seven-thousand years ago, Neolithic settlers in the ancient village of Tel Hreiz in Israel became the first known society to build a wall to protect their settlement from rising sea levels. Today, their work is providing new insights into how societies battled against climatic threats, lending deeper insight into how modern society may similarly respond.

Writing in PLOS ONE, an international team of researchers from the University of Haifa, Flinders University in Australia, the Israel Antiquities Authority, and the Hebrew University analyzed the 100-meter-long (328-foot) remains of an ancient coastal defense system constructed by boulders sourced from riverbeds as far as 2 kilometers (1.2 miles) from the main village. Though Tel Hreiz was initially built at a safe elevation of 3 meters (nearly 10 feet) above the sea line, post-glacial sea levels began to rise at a rate of 7 millimeters each year.

"During the Neolithic, Mediterranean populations would have experienced a sea-level rise of 4 to 7 millimeters a year," Dr Ehud Galili from the Zinman Institute of Archaeology at the University of Haifa said in a statement. "This rate of sea-level rise means the frequency of destructive storms damaging the village would have risen significantly." 

"The environmental changes would have been noticeable to people, during the lifetime of a settlement across several centuries," Dr Galili added. "Eventually, the accumulating yearly sea-level necessitated a human response involving the construction of a coastal protection wall similar to what we're seeing around the world now."

It is believed that the seawall was built in response to increasing sea levels and served as temporary relief before the village was ultimately abandoned.

"There are no known or similarly built structures at any of the other submerged villages in the region, making the Tel Hreiz site a unique example of this visible evidence for human response to sea-level rise in the Neolithic,” said study co-author Dr Jonathan Benjamin from Flinders University. Dr Benjamin notes that studying ancient civilizations that faced sea-level rise and intensified storm systems may inform how modern society responds to issues related to climate change, though the magnitude varies between the two.

If current greenhouse gas emission trends continue, it is expected that more than 300,000 homes in the US alone will face some sort of flooding. A study published earlier this year found that global sea-level rise associated with climate change could reach 2 meters (6.5 feet) by the end of the century.

"Many of the fundamental human questions and the decision-making relating to human resilience, coastal defense, technological innovation and decisions to ultimately abandon long-standing settlements remain relevant," said Dr Galili.