Another session featured CNRS specialists C\u00e9cile Vittori, Laurent Augustin and Christine Oberlin. They explained how coring, microfossils and dating help rebuild the history of the lagoons between the two strips.<\/p>\n\n\n\n
In Goiran’s account, a channel of seawater once wrapped around the two hills of Giens. Coverage shared by the lab places this island stage around 5,000 B.C. River sand then began to build the links.<\/p>\n\n\n\n
Two sand strips, 2.5 miles each<\/h2>\n\n\n\n
A tombolo is a ridge of sand or gravel that joins an island to other land. Giens has two of them, each about 4 kilometers (2.5 miles) long. They run north to south on either side of the Pesquiers lagoon and its old salt pans.<\/p>\n\n\n\n
La Capte forms the eastern strip and Almanarre the western one. A 2022 report by France’s environmental inspectorate says such double tombolos can be counted “on the fingers of one hand” worldwide (translated from French).<\/p>\n\n\n\n The city of Hy\u00e8res<\/a> credits three coastal rivers, the Gapeau, Pansard and Batailler, with supplying the sediment. Shallow shoals anchored it, and seagrass meadows helped hold it in place. The city considers Almanarre the older of the two.<\/p>\n\n\n\n People have reshaped the western strip for two centuries. Between 1809 and 1900, sand was taken from the beach for building projects, including the port of Toulon. In 1822, the Roubaud river was diverted, which ended the natural flow of sediment from land.<\/p>\n\n\n\n Salt pans were laid out in the Pesquiers marsh in 1848 and 1849, eating into the dune. Then, in 1969, a paved road called the Salt Road was built on the dune itself.<\/p>\n\n\n\n By “hardening” the dune, the road left the tombolo weaker against erosion, inspectors wrote (translated from French). Behind it, the Pesquiers saltworks, which the city says made salt until 1994, span about 550 hectares (1,359 acres) of shallow ponds. Protected pied avocets and common shelducks use the area to feed or breed, according to the city.<\/p>\n\n\n\n Vella links his timeline to the most recent climate report. The Intergovernmental Panel on Climate Change covers the region in the Mediterranean chapter of its 2022 assessment<\/a>, which puts 20th-century sea level rise at about 1.4 millimeters a year. Between 1993 and 2012, the rate was closer to 2.4 millimeters a year.<\/p>\n\n\n\n The panel says the sea could climb 1.1 meters (3.6 feet) or more around 2100 with 3\u00b0C of warming. Narrow sandy beaches are the most exposed. They “eventually disappear where sedimentary stocks are small,” the panel writes.<\/p>\n\n\n\n Almanarre has had no river sand since the Roubaud was rerouted in 1822. If it broke, La Capte would still hold Giens to the coast, so a return to island life is not imminent. Goiran, in an interview the lab also lists, spoke of a few centuries.<\/p>\n\n\n\n Sand budgets decide many coastlines. Some atolls keep growing despite rising seas<\/a>, while many U.S. coastal wetlands are falling behind the water<\/a>.<\/p>\n\n\n\n Hy\u00e8res has already proposed a fix for the northern end of Almanarre, where erosion bites hardest. The General Inspectorate for the Environment and Sustainable Development (IGEDD)<\/a> reviewed it in 2022. The plan calls for a submerged dike about 450 meters (1,476 feet) long.<\/p>\n\n\n\n Its crest would be 10 meters (33 feet) wide, about 1 meter (3.3 feet) underwater and 150 meters (490 feet) offshore. Studies by the firm ARTELIA, quoted in the report, say crews repair the dune after every winter. They shovel back sand thrown onto the road, up to about 1,000 cubic meters (35,000 cubic feet) a year.<\/p>\n\n\n\n Inspectors Thierry Boisseaux and Raynald Vall\u00e9e did not rule the dike out. Still, they asked for a baseline scenario and a comparison with other options. They urged study of “a solution that does not try to oppose the force of the sea, but to adapt to it as well as possible” (translated from French).<\/p>\n\n\n\n Traffic adds pressure. At the summer peak, about 1,300 vehicles an hour drive onto the peninsula each morning. Some 31 percent of them head for the Salt Road beaches.<\/p>\n\n\n\n Other countries are testing softer defenses, like the sand-filled tubes India is sinking offshore<\/a>. Meanwhile, sand itself is getting scarce worldwide<\/a>.<\/p>\n\n\n\n The core data have not yet appeared in a peer-reviewed journal. For now, the dates come from the September talks and from interviews with the researchers. Even the meeting program shows open questions: one talk asked whether the Giens tombolo is protohistoric or far older.<\/p>\n\n\n\n The 80-year figure is an expert estimate for one strip, not a modeled date. The inspectorate notes that erosion is acute on the northern part of Almanarre. It is much weaker along the other 90 percent of the strip.<\/p>\n\n\n\n The main official sources are the program of the Hy\u00e8res scientific days, published by the Arch\u00e9orient lab, and IGEDD report No. 014042-01, published July 11, 2022.<\/p>\n\n\n\n Photo: Yyuri1989 \/ Wikimedia Commons, CC BY-SA 3.0<\/p>\n","protected":false},"excerpt":{"rendered":" France’s Giens peninsula, a hilly strip of land south of Hy\u00e8res on the Var coast, was once a true island. … <\/p>\n![\"Side-by-side](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/10\/giens-east-west-tombolos.jpg\")
Sand taken for Toulon’s port<\/h2>\n\n\n\n
Mediterranean levels climbing faster<\/h2>\n\n\n\n
Hy\u00e8res plans a 1,476-foot dike<\/h2>\n\n\n\n
Core results still unpublished<\/h2>\n\n\n\n