The Consequences of Severed Subsea Communications Cables

A 1,200km subsea cable connecting Finland and Germany was severed earlier in November 2024 near Oland Island in Sweden. This happened within the same time frame as the cutting of a second cable that was only 10 miles away from the first.

Authorities from Finland and Germany suggest the damage could have been caused by external impact from a ship anchor or seabed trawling, but also say that sabotage could not be ruled out.

“The fact that such an incident immediately raises suspicions of intentional damage speaks volumes about the volatility of our times. A thorough investigation is underway,” said the Foreign Ministers of both nations in a joint statement.

They added that security is “not only under threat from Russia’s war of aggression against Ukraine, but also from hybrid warfare by malicious actors”. They have called for the safeguarding of shared critical infrastructure, stating it is vital to the security and resilience of wider society. 

Threats to global digital infrastructure

Subsea cables refer to underwater cables that are laid on the seabed between land-based stations to carry telecommunication signals across stretches of ocean and sea. As demand for connectivity has increased over the years, these cables have evolved to transport vast amounts of data across open waters in seconds.

Now, submarine cables carry roughly 95% of intercontinental internet traffic. Such an event in the Baltic Sea highlights how quickly subsea communication networks can become vulnerable, particularly if they are damaged or sabotaged. 

The US has been continually warning of increased activity from Russia near cables that carry the vast majority of intercontinental internet traffic. The damage to both cables happened to coincide with Ukraine’s use of long-range missiles inside Russia for the first time.

In May 2024, leading experts from across NATO met for the first meeting of NATO’s new Critical Undersea Infrastructure Network. This was designed in response to rising challenges to undersea infrastructure, with the Alliance putting in place new tools to enhance the security of undersea cables and pipelines - whilst also monitoring possible threats.

Secretary General Jens Stoltenberg, who opened the conference, said Allies must continue to do more.

“The increasing dependency of our societies on undersea infrastructure means we need to do more to enhance their security,” he explained at the time. “NATO is well-placed to take on a greater role given our Allies’ unique military capabilities, vast intelligence network, and operational expertise.”

How this impacts the data centre sector

The financial implications of cable disruptions can be severe. In areas served by multiple subsea cables, data traffic is typically rerouted very quickly, as was the case with the two incidents above. However, cable damage has the potential to leave an entire nation cut off from global data, leaving them solely reliant on satellites to communicate. 

Attacks on underwater cable networks in recent months, such as in the Red Sea, have highlighted the importance of managing geopolitical threats as a way of protecting cables.

This level of repair operations present their own challenges, with average repair time for a subsea cable sitting around two weeks, as reported by the BBC. However, this can be extended significantly in more geopolitically sensitive areas or extreme weather conditions. 

For data centre operators, redundancy planning has also become increasingly complex, with many now requiring connectivity through at least three geographically diverse cable systems.

As digital dependency grows, the resilience of subsea communications infrastructure becomes increasingly critical. Those across the sector have had to respond by developing more sophisticated traffic management systems.

The data centre industry could stand to mitigate risk by taking natural disasters and malicious attacks into consideration. 

Explore the latest edition of Data Centre Magazine  and be part of the conversation at our global conference series, Tech & AI LIVE and Data Centre LIVE. 

Discover all our upcoming events and secure your tickets today. 

Data Centre Magazine is a BizClik brand