Rising sea levels are causing Tunisia’s beaches to gradually disappear.
This is making life hard for the country’s tourism and fishing industries.
The Maghreb - made up of Morocco, Tunisia, Algeria and Libya - is more affected by coastal erosion than any region outside South Asia, the World Bank found in a 2021 study.
Among these countries, Tunisia has had the highest erosion rates in the last three decades, averaging almost 70cm a year, it found.
At least 85 per cent of Tunisia's population of more than 12 million lives by the coast. This is more than double the global average of about 40 per cent, according to the World Bank.
As a result, the country is disproportionately affected by coastal erosion. So, why is it happening and what impact is it having on local communities?
Rising sea levels are damaging Tunisia’s fishing communities
Rising sea levels, primarily caused by global warming-induced ice melt and rising water temperatures, are one of the main culprits for coastal erosion.
As Tunisian beaches are eroded, fishermen in the coastal town of Ghannouch say their boats and nets are increasingly getting damaged by rocks as they go out to sea.
"The beach sand is significantly reduced and rocks are appearing there instead," says Mohamed Ali, 39, a fisherman in the town, located about 400 km south of Tunis.
"I had my boat damaged several times. It is becoming difficult to go to the sea and fish," the father-of-four adds.
Ali says he makes about $300 (€283) per month fishing, but his income is 20 per cent lower than in previous years before coastal erosion became a major factor. He is one of about 600 fishermen in Ghannouch.
Sassi Alaya, the head of the fisheries guild in the town's southern port, says that half of the local fishermen have been affected along the most eroded areas of the coastline.
Nearly half of Tunisia's 670 km of beaches were acutely threatened by coastal erosion as of 2020 - a figure that has more than tripled since 1995 - according to the Tunisian State Agency for Coastal Protection and Planning (APAL).
On the island of Djerba - about 110 km south of Ghannouch - 52-year-old fisherman Al-Akhdar Ahmed says his income has halved over the last decade due to the shrinking beaches. He now earns just $250 (€236) a month from fishing.
"Rocks are now surrounding about 18 kilometres of the coast of the island, destroying the livelihoods of hundreds of fishermen there," he says.
But rising seas aren’t the only cause.
What else is causing Tunisia’s beaches to disappear?
Overdevelopment on beaches and the destruction of natural defences like dunes are doubling down on the effect of rising sea levels.
Coastal erosion "is getting worse and worse because of human interference," says Oula Amrouni, a researcher for the National Institute of Marine Sciences and Technology (INSTM).
"People and buildings have increasingly been crowding coasts, replacing natural protections against erosion like sand dunes and wetlands," she adds.
Accelerating climate change has also brought soaring temperatures, worsening drought in Tunisia.
Together with rising sea levels, this is harming not only the country's fishing sector but its agriculture and tourism too, experts say.
How is drought contributing to coastal erosion in Tunisia?
INSTM says the government has responded to growing water security concerns by building more dams to save fresh water.
However, dams often trap sand and sediment that would otherwise flow to the sea, thereby fuelling coastal erosion, researchers say.
80 per cent of the coastal sand in Tunisia comes from inland, according to Gil Mahé, research director for the hydrosciences laboratory at France's Montpellier University, who is currently working at INSTM in Tunisia.
"Dams... [are] the major impact increasing the vulnerability of sandy coasts to erosion," he says.
Three years of drought have left many of the country's 37 dams depleted or empty, and driven the government to increase tap water prices for households and companies.
The country is investing in building additional dams to try to store as much fresh water as possible.
Which other industries are impacted by Tunisia’s coastal erosion?
Along the most eroded areas of Ghannouch’s coastline, about 80 per cent of businesses - including restaurants and coffee shops - have also been impacted.
"The rising sea levels and the disappearing sand have severely harmed businesses on the beach," says Alaya, with tourism experiencing a big decline over the last decade.
It is also a "major blow to agriculture", according to Mahé.
As coastal erosion worsens along Tunisia’s coastlines, saltwater moves inland, ruining arable areas.
"And what about all the infrastructure built along the coast? Ports? Nuclear power plants?" Mahé adds.
The estimated annual cost of coastal erosion in terms of damage to land and near-shore buildings amounts to the equivalent of 2.8 per cent of GDP in Tunisia. This is significantly higher than in neighbouring Libya (0.7 per cent), Morocco (0.4 per cent) and Algeria (0.2 per cent), the World Bank study found.
Yet it said the real cost to Tunisia was likely to be higher as the study did not incorporate other factors such as lost tourism revenues.
The erosion of beaches represents "a real socioeconomic bomb", Mahé wrote in a 2021 article for Montpellier University.
What is being done to prevent coastal erosion in Tunisia?
Researchers Mahé and Amrouni say they are working on projects in partnerships with international institutions such as the World Bank and the United Nations' Development Programme (UNDP) to reduce erosion through nature-based solutions.
One initiative - implemented by UNDP together with APAL - has installed 0.9 km of sand trapping fences and 1.1 km of palm fronds pegged to the ground to reduce the impact of huge waves on a beach on Djerba, where coastal erosion has caused heavy flooding of wetland areas.
"We want the beaches to heal by themselves through building dikes, dune fences and wave breakers using natural materials from the ecosystem," says Amrouni.
"Only in this way, can we have better beach conditions in the long run," she adds.
APAL has also built walls to guard the coastline against waves and sourced sand from a nearby sand quarry to rebuild beaches. In 2020 - the latest available data - it had better protected 32 km of coast.