A 7,000-year-old seawall has been discovered off the Israeli coast, and it's now the oldest-known defence against rising sea levels. The seawall eventually failed, and the village had to be abandoned, in what's serving as an ominous lesson from the past.
     The Tel Hreiz archaeological site is located off the Carmel coast of Israel and once hosted a vibrant Neolithic community. This Mediterranean settlement thrived for hundreds of years, as its villagers hunted gazelle and deer, farmed cows and pigs, fished for tilapia, raised their dogs, and manufactured copious amounts of olive oil. But with each passing generation, the villagers noticed something rather frightening: The waters of the Mediterranean were getting higher and higher.
     The rising sea levels would have been noticeable across a person's lifespan, as they rose at an alarming rate of 4 to 7 mm each year, or around 70 cm (28 inches) every 100 years. Reluctant to leave their settlement, and to protect against the increasingly powerful waves and the destructive effects of erosion, the Tel Hreiz villagers decided to take matters into their own hands by constructing a 100 m long (330-foot) seawall that ran parallel to the shore.
     The seawall, as the new research suggests, was nothing too fancy, having been built by piling large boulders atop each other. The seawall's length, the use of big boulders sourced from outside the community, and its careful arrangement on the shore "reflect the extensive effort invested by the Neolithic villagers in its conception, organisation and construction," wrote the authors in the study. The seawall may have helped for a while, but it ultimately failed, and the village - after nearly 500 years of continuous occupancy - had to be abandoned.
     This recent study involved scientists from the University of Haifa, Flinders University in Australia, the Israel Antiquities Authority, and the Hebrew University. The seawall, which is today submerged under 3 metres of water, was constructed some 7,000 years ago, and it's now the oldest known coastal defence system in the archaeological record. It's an exceptional find, as infrastructure improvements such as these didn't start to appear in the region until the Bronze and Iron Ages. Importantly, the new research, led by archaeologist Ehud Galili from the University of Haifa, shows that humanity's battle against rising sea levels dates back for thousands of years.

Edited from The Times of Israel (18 December 2019), Gizmodo (20 December 2019)