Wired Planet: The internet runs on 900,000 miles of fragile undersea cables. Samanth Subramanian captures the wonder

THE UBIQUITY of the internet and the dependence of our lives on it blind us to those very facts— what Samanth Subramanian calls “one of the strange involutions of the modern age” in which “we go onto the internet to see what’s the matter with the internet.” It follows that the “ability to use the internet wirelessly permits us to forget not only its materiality… but also its centrality to our lives.” So, what does the internet run on and what happens when it doesn’t, or ‘disappears’?

The world of communications runs on fibre-optic cables on the seabed that carry terabytes of data per second by splitting light into various wavelengths. Humans have laid about 870,000 miles of these cables which conduct 95 per cent of all the world’s internet traffic. Doubtless, this infrastructure is vulnerable. In shallow waters and where cables come ashore, they are armoured and concealed. But in the deepest places, they just lie on the ocean floor, no thicker than a “garden hose” because armouring them would make the cables too heavy to pick up. But a “century and three-quarters after the first telegraph line was laid across the Atlantic, there’s still nothing to beat the cable.” The planet is wired. Satellites come nowhere near such bandwidth.

What happens then when a cable breaks? In 2022, an underwater volcanic eruption caused a seabed landslide that snapped Tonga’s single-cable connection and plunged the country “into the kind of isolation it hadn’t seen in more than a century.” ATMs shut because banks couldn’t check balances, trade stopped because goods couldn’t be exported, schoolchildren couldn’t have their pandemic-time online classes; Tongans couldn’t even tell how badly affected their islands were but Australian pilots on a visual recce could. A remittance economy collapsed also because relatives abroad couldn’t transfer money. A near-similar thing happened in Taiwan in 2023 when Chinese ships, allegedly, cut off the island of Nangan by cutting its cable. Doctors copied medical records on CDs for the evacuation of emergency patients.

Saboteurs can easily find the cables because their routes are openly mapped for regular shipping operations to steer clear of them. There’s no alternative. And the cables have stuck largely to old routes because those are known and safer.

The Web Beneath the Waves is a fascinating offering from the author of The Divided Island: Stories from the Sri Lankan War (2015), structured basically as a travelogue that brings history, science, Big Tech, and geopolitics together to paint a picture of a precarious present pointing at a fragile future. That future “will entail the weaponization of its submarine cable systems,” warns Subramanian, referring to the frequent incidents of Russian shadow fleets allegedly damaging cables in the Baltic and North Seas, or that China, earlier this year, unveiled a submersible to cut cables at 13,000 feet. It’s a long time since the US tapped Soviet undersea cables but geopolitical rivalry has meant wastage of resources too: the US doesn’t allow Chinese cables to land directly on its shores; those are routed via interconnections in third countries like the Philippines. The world, in fact, is on the verge of splintering into two internets: an American one and a Chinese one.

Private players, or OTTs, laying their own cables was a gamechanger, beginning in the mid-1990s before the dotcom bubble burst. Today, rivalry among Big Tech companies is speeding up the break-up of the internet, with Google, Meta, et al undertaking multibillion-dollar proprietary cable-laying. The internet is already no longer open and neutral.

While the seabed grows thicker with cables, their provenance goes back to empire. At Porthcurno in Cornwall, a pilgrimage spot for the “cable-inclined” with a Vodafone base station where the Empire’s cables once landed, physicist Gareth Parry tells his visitors their “mobile phone signals first go to a base station like this one… and then eventually to a cable. It’s a lightbulb moment for them. They think it’s all done by satellite.”