espionage, sabotage… diplomatic tensions are also expressed under the sea

Project engineer, François Douillard leaves for several months a year, aboard a huge boat. In the waters of the Persian Gulf, in the Middle East, the ship has the perilous task of installing cables in the seabed, without ever deviating from its long-prepared trajectory. “If the route of the cable crosses that of a gas pipeline, there could be a risk of explosion,” he explains. The boat follows a precise path to unwind the cable and bury it over hundreds of kilometers, using day and night teams. »

No bigger than garden hoses under their anti-erosion sheathing, more than 500 submarine cables are buried beneath the seas and oceans. They contain countless thin optical wires that transmit our electricity and communications networks around the world. Thanks to them we can make a call between the United States and France, use Facebook, WhatsApp or Google. Vast tentacles, less expensive and more efficient than satellites, which carry 99% of our digital data over more than 1.3 million kilometers. A little more than three times the distance between Earth and the Moon.

This impressive network is, however, fragile. At sea, seismic tremors and fishing nets from trawlers constantly threaten to damage it. Western navies also fear malicious acts. On December 27, 2024, NATO announced that it would strengthen its military presence in the Baltic Sea. Objective: to monitor Russia and its ships, suspected of espionage operations and cable sabotage.

On Christmas Day, an electricity cable – the Estlink 2 – was damaged in the waters between Finland and Estonia. Just a few weeks after two cables broke near Sweden. Finnish police suspect the ship Eagle S and Putin’s Russia, which is increasing its hostile gestures against NATO. “It is difficult to prove that Russian ships are the perpetrators,” warns Cyrille Bret, associate researcher at the Jacques-Delors Institute. But Russia may attempt sabotage to paralyze some of the businesses and public authorities in this area of ​​northern Europe. »

State dependence

Because submarine cables are a real financial windfall, invisible to our eyes as earthlings: nearly 10,000 billion dollars pass through this network every day. Stock market operations, but also access to the Internet are at stake. In 2017, Somalia lost its access to the Web for three weeks, after a container ship cut the country’s only communications cable.

In France, there is little risk of such a scenario occurring. Because France has secured its network by connecting to the rest of the world by more than twenty cables, towards the Atlantic, the Mediterranean and even the Suez Canal. A few very rare incidents, however, can have a resounding effect. In October 2022, a terrestrial fiber cable cut near Aix-en-Provence affected the submarine network in the Mediterranean and the Atlantic, thus slowing down the Internet of millions of users around the world.