Make or break: Houthi underwater cables carry more than just megabits

Due to their specific locations, the cables are of immense strategic importance. Their disablement could cause massive shutdowns.

From casual chats to commercial trades and confidential information, the transport and targeting of data under the Red Sea is a major issue. Can the Houthis cripple the world's communications?
Dave Murray
From casual chats to commercial trades and confidential information, the transport and targeting of data under the Red Sea is a major issue. Can the Houthis cripple the world's communications?

Make or break: Houthi underwater cables carry more than just megabits

In recent years, intricate webs of pipes and cables have been laid not just on land but along the beds of seas and oceans.

While underwater (or submarine) pipes tend to transfer oil and gas, submarine cables tend to transfer data. Both are valuable, but one far more so than the other.

Pipelines carry tens of millions of dollars worth of oil or gas a day. Data cables carry daily transactions of up to $10tn. One keeps the lights on; the other keeps the economy on.

Submarine cables play a pivotal role in the global digital infrastructure. By and large, they are how we get our internet, our messages, our anything-digital.

As veins and arteries move blood around the body, these cables move information, data, and money in the form of transactions.

Spinning a web

Optical fibre cables now form such an extensive network that they span the globe like a web. They extend for hundreds of thousands of miles beneath the ocean surface, connecting continents and serving as conduits for the essential global resource that is data.

Therefore, the potential disruption of sea or air freight traffic, whether for logistical or security reasons, raises concerns about market upheavals, production challenges, and supply shortages, all with far-reaching consequences.

These cables have always been vulnerable to unintentional damage caused by cargo ships, encounters with large marine animals like whales, or deliberate acts of destruction by anyone capable of reaching the required depth.

Dave Murray
Submarine cables carry most of the world's communications. Those under the Red Sea carry data between Europe and Asia.

The ramifications of any resulting disruption extend beyond the mere physical damage to the cables; they pose a significant threat to world connectivity, potentially paralysing companies, banks, financial markets, and navigation systems.

In an era where lives are intricately intertwined with communication, data exchange, and reliance on computers and mobile phones, the cutting of a global submarine cable network could have profound effects on all.

Mapped significance

Approximately 95% of the world's internet traffic traverses these cables, covering an expansive distance in a market valued at $14bn. Maps show where they are.

The significance of each varies based on its location and whether there are backup cables.

Assessing risk, telecoms and data companies have established alternative routes to mitigate the potential damage caused by damage.

Yet for various reasons, including geographical, some cable routes are simply without a viable substitute.

As such, they hold immense strategic importance due to their specific locations. Their disablement could cause massive shutdowns until they were fixed.

The common misconception is that wireless internet service (or Wi-Fi) is delivered through satellites or cloud computing. Ironically, the backbone of internet services is reliant on submarine cables.

Due to their specific locations, the cables are of immense strategic importance. Their disablement could cause massive shutdowns.

Big telecom firms and tech giants like Amazon and Google have strategically invested in laying their own submarine cables, giving uninterrupted service to their customers.

It shows that safeguarding the Internet's vital plumbing has become paramount with our growing dependence on Internet services in our daily lives.

Houthi attacks

In February 2024, Yemen's internationally backed government claimed that the country's Houthi rebels intended to cut Red Sea cables running through Yemeni maritime jurisdictions as part of its war with the West over Israel's war in Gaza.

This week, it was reported that three Red Sea internet and telecom cables had been cut in Yemeni waters.

Global communications consultancy HGC said the cuts affected 25% of data traffic between Asia and Europe, adding that work was already underway to reroute them.

The Houthis, who had earlier shared a map showing that they knew the location of these nearby cables, now say they were not behind this week's damage.

Analysts have questioned whether they have the submersible capability to do so. Others say the shallow depth of the cables would suggest that this was more than possible.

Whoever is behind the attack, it highlights the importance of the Red Sea for data flows, not just for shipping, it being a key route for about 12% of global maritime trade.

Cable industry

Seabed cables are nothing new. The first submarine communication cables were laid in 1850 by a British company connecting the UK and France.

Despite its brief operational life, this laid the foundation for the concept that eventually facilitated the global transmission of data and the interconnectedness of continents.

The vision to extend this cable technology across the Atlantic Ocean was conceived in 1958. Today, they are placed by cable layer ships, which carry thousands of miles of cables on their deck, enabling high-speed data transmission.

They are placed along secure routes, avoiding areas of deep-sea fishing, potential anchorage sites, or any other hazards. Technicians then dive into the sea at cable deployment points to ensure precise positioning.

The current expanse of the submarine cable network covers more than 800,000 nautical miles, more than three times the distance between the Earth and the Moon.

Cable science

They comprise several dense layers of iron, plastic, and silicon that protect and isolate an inner layer of thin optical fibres that transmit billions of units of data per second.

Diana Estefanía Rubio

Moreover, they are designed to do so over incredibly large distances. These cables apply the theory of light beam reflection, known as total internal reflection, to enhance the speed of data transmission.

As the name suggests, this involves the reflection of laser beams carrying data at the speed of light along the inside of cables.

Tech giants increasingly want to develop their own custom cables rather than rely on those of others. Given the rising demand and bumper profits available, the cable sector has become a lucrative investment opportunity.

Ownership of these cables helps ensure data security for customers, so the likes of Google, Amazon, Facebook, and Microsoft have publicly disclosed plans to establish private cable networks, rather than rent them from third parties.

The importance of these data cables only deepened with the arrival and widespread uptake of cloud computing.

This lets users store their data 'online' at a nominal cost without the user needing their own extensive equipment or advanced technology.

Satellite alternatives

Do we need these submarine cables that will always be vulnerable to sabotage, or can we instead just use satellites that are far less susceptible to attack?

Global and universal internet connectivity through satellites is a promising idea with numerous advantages, particularly in providing internet access to remote areas. Companies like Elon Musk's SpaceX have embraced it.

They sell devices that receive internet signals from the company's satellites that follow specific orbits, enabling them to offer services to users in regions where traditional internet access is challenging due to the absence of wireless towers.

Yet, despite its promise, there are problems with the satellite-based approach to replacing submarine cables.

One is the cost of manufacturing, launching and maintaining a fleet of satellites. This is significantly higher than using a boat to lay cables at sea, despite the cost having come down in recent years.

There are problems with the satellite-based approach to replacing submarine cables. One is the cost of manufacturing, launching and maintaining a fleet of satellites.

Another issue is efficiency. For truly global coverage, you need a lot of satellites. This leads to congestion in low orbit, data interference, and an increased risk of collisions, none of which adds to their reliability or security.

Furthermore, satellites must be precisely positioned to provide internet service. Any deviation from their designated orbit means intricate adjustments to the constellation. This technical complexity is unlikely to be resolved soon.

The deployment of satellites involves navigating complex international laws and treaties governing outer space, whereas clear and explicit agreements guide the laying and maintenance of submarine cables.

Information security is also a critical factor. Data transmitted through the air is more susceptible to data breaches than data transmitted through a multi-layered cable lying under the seabed, under hundreds of metres of water.  

Size matters

Like oil and gas pipelines, submarine cables play a critical role in global connectivity, so their potential disruption could affect numerous countries. To understand how, the scale, dimensions, and locations of these cables is crucial.

The telecoms consulting company TeleGeography has crafted an interactive map showcasing 420 cables worldwide. The longest, at 39,000km, is SEA-ME-WE 3, which links Southeast Asia with Western Europe via the Red Sea.

Africa 2, a submarine cable under construction, is set to be even longer. Spanning 45,000km, it will connect 33 countries across Asia, Africa, and Europe.

Notably, the Atlantic Ocean hosts the largest concentration of cables, connecting Europe with North America, while cables across the Indian Ocean link America to Asia and Australia.

Diana Estefanía Rubio

The data science concept of a "single point of failure" is significant, implying that data flows through specific cables concentrated where many others converge. Attacking such a cable can have a cascading impact.

Positioning of cables

Until the Houthi attacks of recent months, the Suez Canal was a major transit route for commercial ships between Asia and Europe.

Below the surface, it is also a major transit route for 16 crucial cables facilitating about 17% of the world's internet volume.

Geography and politics often mean that companies need to route their cables across the sea for 100 miles or more, exposing them to risks. This is especially so in the absence of alternative routes to the Mediterranean.

As if to demonstrate the point, an alternative route linking Asia to Europe through Syria was destroyed at the onset of the Syrian war. This left Egypt and the Suez Canal vulnerable, due to the ease with which cables can be damaged.

In June 2022, a major cable connecting Asia to Africa and Europe (Asia-Africa-Europe-1, or AAE1), was cut off, affecting internet traffic in seven countries.

At 15,500 nautical miles long, it connects Hong Kong to France, via Egypt and the Suez Canal.

An observatory for internet traffic recorded outages in Ethiopia, Somalia, Tanzania, Pakistan, Djibouti, and Saudi Arabia. Ethiopia and Somalia were among the most affected, with service outages of 90% and 80%, respectively.

Below the surface, the Suez Canal is a major transit route for 16 crucial cables facilitating about 17% of the world's internet volume.

Owned and controlled

Although the internet outage was short-lived, it focused attention. The incident had a significant impact on cloud computing service providers such as Google, Amazon, and Microsoft.

Google said it had significant repercussions on the delivery of cloud computing infrastructures such as virtual private cloud technology, as well as on the cloud delivery service. Google also said customers in the Middle East had had data stolen.

Several companies later allocated large sums of money to lay and own private submarine cables. This lets them fully control the service and transfer it from one cable to another in the event of a problem.

The cost of repairing a single damaged internet cable is more than $2mn, borne by the operating company. This is considered direct losses. Every hour that passes during the service outage costs the global economy $1.5mn in losses.

A member of the US Federal Reserve emphasised the significance of submarine cables by saying the global economy would grind to a complete halt without them.

Why we cable

Submarine cables have two key advantages: they can transmit massive amounts of data at once and are cost-effective.

They significantly contribute to global trade, let businesses promote themselves, facilitate transactions, open global markets, and overcome the challenge of distance.

The evolution of cloud computing services allows telecom companies to offer consumer services without the need for expensive, specialised computer equipment.

In the era of AI and the Internet of Things (IoT), the world has grown ever more reliant on these cables.

Diana Estefanía Rubio

Domestically, they let users control their homes or devices within them, issue voice commands, and operate surveillance cameras and smart gadgets.

A modern communications infrastructure is as vital as roads, raw materials, and a skilled workforce to attract foreign investment, leading to job creation and sustained economic stability.

Internet and communication services contribute to the GDP of each country. When these services are interrupted, economic losses escalate.

Different countries have different rates of internet adoption and storage practices. Some, like the United States, store data locally. Others, like Australia and New Zealand, make extensive use of the cloud.

The greater the reliance on the internet and external data storage, the more profound the economic losses if these cables are disrupted.

Tapping the wires

Internet and communication cables can be susceptible to espionage and information gathering when specialised equipment is deployed to access important cable sites on the seabed and ocean floor.

In 2013, National Security Agency whistleblower Edward Snowden revealed TEMPORA, a secret programme run by the British signals intelligence service GCHQ that tapped some of the biggest fibre optic internet cables to extract data.

It showed how the cables could be accessed and their data intercepted for intelligence purposes. This included phone calls, emails, internet searches, and transactions.

Submarine cable have two key advantages: the ability to transmit massive amounts of data at once, and cost effectiveness. 

While encrypted data presents a challenge, decryption technology is available. This enables access to the most sensitive military, economic, and personal data.

In 2015, US sensors detected a submarine operating near undersea cables, raising concerns about potential spying on these critical communication lines.

On the high seas, spying on submarine cables in international waters is not considered a violation of state sovereignty, regardless of whether the cable was laid by states or by private companies.

Contemporary warfare extends as far as orbit and as deep as the seabed.

Data today is a potent weapon. All nations vie to acquire the data of others and to safeguard their own. Guarding and raiding cables have become military priorities.

Information is the oxygen of the international system, whether in economics, finance, politics, diplomacy, defence, or culture.

Information holds immense power. So, therefore, do the cables that carry it.

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