Vital Yet Vulnerable: Undersea Infrastructure Needs Better Protection


Mar 11, 2024

Undated photo of a damaged Balticconnector gas pipeline that connects Finland and Estonia, in the Baltic Sea, photo by Finnish Border Guard/Reuters

Undated photo of a damaged Balticconnector gas pipeline that connects Finland and Estonia, in the Baltic Sea

Photo by Finnish Border Guard/Reuters

On Monday, March 4, the Seacom, TGN-Gulf, Asia-Africa-Europe 1, and Europe India Gateway submarine cables in the Red Sea were cut, affecting 25 percent of data traffic flowing between Asia and Europe. The incident is currently under investigation, as officials try to determine if it was deliberate or accidental. While it is plausible that the incident is an extension of the attacks by Houthi rebels on international shipping, they have so far denied any involvement. This disruption highlights the vulnerability of critical subsea infrastructure, which are some of the most important assets to modern economies.

The seabed hosts a large number of subsea cables and pipelines that provide several different services to modern digital society. For example, while satellites get all the fame for helping modern humans talk to one another, more than 97 percent of the world's telecommunications are transmitted through cables beneath the sea that are thousands of kilometres long. These cables also play a vital role in supporting financial services, as they carry almost £8 trillion in financial transactions every day.

The seabed also supports the energy needs of our economies: amidst efforts to reduce European reliance on Russian exports, for example, the North and Mediterranean Seas' oil and gas pipelines play a particularly important role in safeguarding access to energy. European countries are also connected through subsea electricity cables. For example, as an island nation the United Kingdom already has electricity interconnectors to France, the Netherlands, Belgium, Ireland, and Norway, with planned connections to Denmark, Germany, and even Morocco. These interconnections make it possible to transfer electricity between countries, which makes it easier to match the supply and demand of electricity.

More than 97 percent of the world's telecommunications are transmitted through cables beneath the sea that are thousands of kilometres long.

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While the earliest subsea cables and pipelines date back to the 19th century, they are nowhere near obsolete. In fact, critical undersea infrastructure is growing in size, complexity, and importance. As internet traffic grows, we will need more subsea telecommunications cables. While the urgency of climate change, coupled with the depletion of North Sea oil and gas fields, will lead to a reduction in the number of offshore pipelines in Western Europe, some undersea oil and gas infrastructure may be repurposed to transport hydrogen or for carbon capture utilisation and storage. Net-zero policies also mean that we will need a lot more renewable energy. With the planned rollout of large amounts of offshore wind power, more seabed electricity cables will be needed to link these offshore wind farms up to the electricity grid.

However, this critical undersea infrastructure is vulnerable, as the explosions of the Nord Stream gas pipelines in September 2022 and the disruption of the Balticconnector gas pipeline in October 2023 have shown. Most of the assets described above have no specific defence mechanisms. We rely on the relative remoteness of their location on the sea floor to protect them. However, as technology advances and geopolitics become more tense, this is no longer enough. Advances in robotics have increased the risks of unmanned underwater vehicles being used to attack remote undersea targets and as cables and pipelines increasingly become digitally monitored and controlled, they will be more vulnerable to cyberattacks. Previously, only the most powerful nation states had the capacity to interfere with undersea infrastructure, but new technology means this capacity is now extending not only to other states, but also in time to terrorist organisations and criminals.

We should stress that disruptions to undersea infrastructure are already common. These disruptions are mostly caused by accidents or natural events, and hostile action remains comparatively rare. Because of this, most undersea infrastructure is designed with some resilience and the probability of damage in mind. Telecommunications cables, for example, can be repaired relatively quickly and they have a high level of redundancy, because there are many of them. There are fewer undersea electricity cables, which means they have less redundancy, but overall, the power system as a whole is designed with the likely breakage of individual components in mind, which could limit the impact of disruptions. Oil and gas pipelines are more easily affected, as the disruption of a pipeline connecting an oil or gas field to the mainland could result in the entire field going offline. However, these pipelines are typically made of thick steel and occasionally encased in concrete, which increases their physical protection and resilience.

All this means that an attack on any single connection in the networks that brings fuel, power, and data to our shores would likely have a relatively limited impact. However, a coordinated disruption to critical nodes and hubs could lead to cascading impacts which could affect entire systems and lead to spiralling costs of disruption, with knock-on effects across the wider economy as well as government functions, hospitals, and services. This could be a prelude to wider military action, or a hostile attempt to coerce a target state short of war.

There are so many subsea cables and pipelines that it is impossible to permanently monitor and defend all subsea infrastructure. This is also acknowledged in European policymaking. The recently released European Commission white Paper “How to master Europe's digital infrastructure needs?” highlights the absence of an accurate mapping of existing cable infrastructures and the resulting lack of a consolidated EU-wide assessment of risks, vulnerabilities, and dependencies.

Meanwhile, the imminent North Sea agreement between Belgium, Denmark, Germany, the Netherlands, Norway, and the United Kingdom is expected to focus on information-sharing across Europe, through the creation of a platform for registering and sharing data about suspicious movements at sea. As part of mounting sufficient defence, governments must understand which parts of the systems are critical and focus their attention and resources on protecting these elements. This is not an easy job but partnering with private companies to identify the critical points—and share the burden of protecting them—might help. Technology can make it easier to defend assets but also increase the range of threats, and governments would be wise to look at ways to enable early warning systems for disruption. Unmanned underwater vehicles could be a relatively affordable way to patrol key assets or carry out emergency repairs.

As part of mounting sufficient defence, governments must understand which parts of the systems are critical and focus their attention and resources on protecting these elements.

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Other key actions focus on coordination. Within governments, decisions need to be made on who will have a seat at the table. Discussions should involve people in energy security, critical infrastructure, media and technology, transportation, and intelligence. Between governments, there needs to be coordination between the various initiatives on subsea infrastructure protection. For example, the new EU Critical Entities Directive mandates member states to protect critical infrastructure. Meanwhile, the EU-NATO Task Force on the resilience of critical infrastructure recommended EU and NATO staffs to collaborate further on the monitoring and protection of critical maritime assets. Staff exchange have increased through the establishment of the Brussels-based NATO Critical Undersea Infrastructure Coordination Cell and a London-based Maritime Centre for the Security of Critical Infrastructure. RAND researchers and others have encouraged NATO to establish an international undersea infrastructure protection corps, combining both government and private-sector defence approaches to protect and maintain subsea assets. Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, the Netherlands, Norway, the United Kingdom, and Sweden are members of the Joint Expeditionary Force, which has taken an active role in countering threats against subsea infrastructure protection, including the recent launch of joint naval patrols. Governments need to make sure that these initiatives work efficiently together, without duplication.

Taking these actions will not guarantee a stop to hostile disruptions of undersea infrastructure. However, there are important steps that should be taken—and soon—to decrease the impact of attacks on European critical infrastructure systems that have been taken for granted for too long.

Henri van Soest is a senior analyst and Harper Fine is a junior analyst at RAND Europe.