Natalie Parletta
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
By Natalie Parletta
Around 7000 years ago, Neolithic villagers built an extensive seawall to protect themselves against sea-level rise in the Mediterranean.
It is the oldest known coastal defence evidenced by submerged archaeological remains, but the effort proved to be in vain.
According to a study published in the journal PLOS ONE, the Tel Hreiz settlement on the Carmel coast of what is now Israel was flooded and abandoned.
During the Neolithic, Mediterranean populations would have experienced a sea-level rise of four to seven millimetres a year or approximately 12-21 centimetres during a lifetime, according to lead author Ehud Galili, from the University of Haifa in Israel.
This rate of sea-level rise means the frequency of destructive storms damaging the village would have risen significantly, he says, and would have been apparent to people within their generation.
“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.”
Tel Hreiz emerged as an archaeological site in the 1960s but winter storms in 2012 and 2015 exposed remains from the current coastline to four metres below sea level, including those of the 100-metre-long seawall on the seaward side of the settlement.
The researchers extrapolated from the historical context, mode of construction and radiometric dating to show that the unique feature, unlike any other structures from the region, corresponded with the flooded settlement.
The linear structure was built three metres above sea level using boulders sourced from riverbeds one to two kilometres away from the village.{%recommended 6926%}
“Its length, use of large non-local boulders and specific arrangement in the landscape reflect the extensive effort invested by the Neolithic villagers in its conception organisation and construction,” the authors write.
“However, this distinct social action and display of resilience proved a temporary solution and ultimately the village was inundated and abandoned.”
Their efforts are strikingly similar to those by contemporary cities like Jakarta but would have impacted far less people than the millions who call the sinking Indonesian capital home.
“Modern sea-level rise has already caused lowland coastal erosion around the world,” says co-author Jonathan Benjamin, from Australia’s Flinders University.
“Given the size of coastal populations and settlements, the magnitude of predicted future population displacement differs considerably to the impacts on people during the Neolithic period.”
Although the current rate of sea level rise is thought to be lower, recent estimates project that more than 300 million people’s homes could be impacted by coastal flooding from rising sea levels in just thirty years from now.
As Galili warns: “Many of the fundamental human questions and the decision-making relating to human resilience, coastal defence, technological innovation and decisions to ultimately abandon long-standing settlements remain relevant.”
Photographs from the Tel Hreiz settlement: (a-b) exposure of stone-built features in shallow water; (c) wooden posts dug into the seabed; (d) bifacial flintadze; (e) in situ stone bowl made of sandstone; (f) in situ basalt grounding stone (scale = 20cm); (g) burial; (h) suspected stone-built cist grave (scale = 20cm); (i) in situ antler of Mesopotamian fallow deer, Dama dama mesopotamica.
