Europe’s Seabed Is Its Soft Underbelly

Explosions along the Nord Stream pipelines have exposed the vulnerability of energy and communications networks in the continent’s northern seas.

By , a national security and intelligence reporter at Foreign Policy, and , a reporter at Foreign Policy.
A Norwegian Home Guard soldier stands guard, assisting the police with increased security at the Karsto gas processing plant.
A Norwegian Home Guard soldier stands guard, assisting the police with increased security at the Karsto gas processing plant.
A Norwegian Home Guard soldier stands guard, assisting the police with increased security at the Karsto gas processing plant in Rogaland county, Norway, on Oct. 3. Carina Johansen/NTB/AFP via Getty Images)

Explosions along the Nord Stream gas pipelines in the Baltic Sea in September have underscored the vulnerability of Europe’s critical energy and communications infrastructure in its northern seas, as tensions with Russia spiral over Moscow’s invasion of Ukraine. 

Swedish and Danish investigators believe “several hundred kilograms” of explosives were used to blast vast holes in the undersea pipelines, which run from Russia to Germany under the Baltic Sea. While suspicion immediately fell on Moscow, which has sought to exploit its energy dominance over the continent—and particularly wants to starve Europe of energy this winter—ongoing investigations conducted by Sweden, Denmark, and Germany have yet to pinpoint who was behind the attack. Moscow has denied any involvement. 

The explosions had little immediate impact on European energy security. Moscow suspended gas transit through the original pipeline, Nord Stream 1, in July for 10 days, citing technical difficulties, while certification of Nord Stream 2 was suspended by Germany days before the Russian invasion. But the fact that an apparent act of sabotage was able to take place in the busy Baltic Sea, which is surrounded by members of NATO as well as aspiring members Finland and Sweden, has underscored the difficulty of policing Europe’s vast northern waterways, which are home to critical energy facilities and communications networks. 

Explosions along the Nord Stream gas pipelines in the Baltic Sea in September have underscored the vulnerability of Europe’s critical energy and communications infrastructure in its northern seas, as tensions with Russia spiral over Moscow’s invasion of Ukraine. 

Swedish and Danish investigators believe “several hundred kilograms” of explosives were used to blast vast holes in the undersea pipelines, which run from Russia to Germany under the Baltic Sea. While suspicion immediately fell on Moscow, which has sought to exploit its energy dominance over the continent—and particularly wants to starve Europe of energy this winter—ongoing investigations conducted by Sweden, Denmark, and Germany have yet to pinpoint who was behind the attack. Moscow has denied any involvement. 

The explosions had little immediate impact on European energy security. Moscow suspended gas transit through the original pipeline, Nord Stream 1, in July for 10 days, citing technical difficulties, while certification of Nord Stream 2 was suspended by Germany days before the Russian invasion. But the fact that an apparent act of sabotage was able to take place in the busy Baltic Sea, which is surrounded by members of NATO as well as aspiring members Finland and Sweden, has underscored the difficulty of policing Europe’s vast northern waterways, which are home to critical energy facilities and communications networks. 

“Seventy percent of all energy in the world is either found at sea or moves by sea, and 93 percent of all data in the world moves by undersea cables,” said Bruce Jones, a senior fellow with the Brookings Institution. “We have very limited protections for either of those things.”

Norway—which is now the largest natural gas supplier to the European Union as Brussels seeks to wean itself off of its dependency on Russian energy—increased its military alert level on Tuesday after receiving a flurry of reports about unidentified drones flying near offshore energy facilities. Authorities also arrested seven Russians for controlling the drones and photographing sensitive areas, while the Norwegian Embassy in Washington, D.C., said that security and surveillance around energy and petroleum facilities have been stepped up.

“This is the most severe security situation in several decades,” Norwegian Prime Minister Jonas Gahr Store said on Monday. “There are no indications that Russia is expanding its warfare to other countries, but the increased tensions make us more exposed to threats, intelligence operations, and influence campaigns.”

NATO has also increased its air and naval presence in the Baltic and Northern seas in the wake of the attacks, while Germany, France, and the United Kingdom have offered to assist Oslo with monitoring energy infrastructure in the North Sea. In early October, European Commission President Ursula von der Leyen vowed to “stress test” energy and communications infrastructure for security vulnerabilities, noting that the explosions along the Nord Stream pipelines, whose parent company is majority-owned by the Russian state energy behemoth Gazprom, have “shown how vulnerable our energy infrastructure is.” 

Naval experts were unsurprised that the pipelines could be subject to a deliberate attack in the Baltic Sea, though the waters had recently been dubbed a “NATO lake.” Even in a comparatively small area, experts said it is nearly impossible to maintain a constant picture of what’s going on above and below the surface. “Even a relatively small sea is awfully big,” Jones said. 

NATO militaries and navies have warned that Europe’s seabed is its soft underbelly, said Julian Pawlak, a research associate at the University of the Federal Armed Forces in Hamburg, Germany. 

Russia’s annexation of the Crimean Peninsula in Ukraine in 2014 was followed by a dramatic uptick in Russian submarine activity near undersea cables in the North Atlantic. At a 2020 meeting of NATO defense ministers, Russia’s activity was discussed amid growing concern that undersea cable networks in the region could be cut or tapped by Moscow. A report requested by the European Parliament’s subcommittee on security and defense published in June found that while undersea cables provide the “backbone of the global economy,” accounting for the vast majority of global communications including $10 trillion in financial transactions daily, “European governance of cable protection and resilience still lags behind and needs improvement.” 

While the Russian military has struggled to make headway in a conventional land war in Ukraine, despite its relative size advantage, Moscow has long relied on a broad spectrum of intelligence activities including disinformation, political interference, and assassination to disrupt and divide Europe. 

“Major sabotage in the middle of the Baltic Sea, and all the other stuff going on, is a reminder that we are in a very different world compared to January,” said a European official, speaking on background on condition of anonymity. 

As Russia’s ability to leverage its energy chokehold over Europe has waned as the continent scrambles to diversify its fuel supplies, experts said Moscow may increasingly turn to other asymmetric warfare tactics to exert pressure. “Gazprom and Russia don’t have the leverage anymore to inflict economic pain on the gas side,” said Henning Gloystein, an energy expert at the Eurasia Group. “They have to move onward if they want to continue inflicting pain and causing, sort of, insecurity in Europe.”

Moscow has the most sophisticated submarine program in the world after the United States, Jones said, and the undersea fleet has been left largely unscathed by the war in Ukraine, which has bogged down the country’s army. “They have the relevant capabilities for tapping or snapping undersea data cables. Obviously, they have the capability for undersea sabotage of energy pipelines and the like,” he said. 

While Russia has not proved shy about saber-rattling in Europe’s northern seas, Gloystein noted that the explosions along the Nord Stream pipelines were on Russian-owned infrastructure. He questioned whether Moscow would risk the forceful response that could result from sabotaging the pipelines of a European or NATO member state. In January, the head of the U.K.’s armed forces, Admiral Tony Radakin, warned that any attempts to disrupt undersea cables would be viewed as an “act of war.” 

Such an attack on European pipelines has “implications of triggering Article 5; it’s a direct attack on the EU, or maybe on a NATO member in the case of Norway,” said Gloystein. “We still see [that] as unlikely.”

Amy Mackinnon is a national security and intelligence reporter at Foreign Policy. Twitter: @ak_mack

Christina Lu is a reporter at Foreign Policy. Twitter: @christinafei

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