Weeks after Chinese President Xi Jinping issued a disturbing reminder that war remains an option for China to achieve unification with Taiwan, one of the island’s government think tanks is now warning that the cables connecting Taiwan’s internet system to the world are vulnerable to attacks by the People’s Liberation Army.

Virtually all the undersea cables that handle Asian data transmission traffic run in a narrow band through the Taiwan region. What sabotage could bring about was illustrated in 2006, when an earthquake rocked the sea floor 13 kilometers off southern Taiwan, damaging the 18 undersea fiber-optic cables that handle billions of data transmissions across the Pacific Ocean and throughout the region. Communications, including in Taiwan, the Philippines and Hong Kong, were a mess for days, causing billions of dollars in damage as vital financial and other information ceased to flow.

In 2013 Egypt arrested three divers trying to cut through an undersea internet cable. Corresponding disruptions off Egypt that slowed internet connections in Europe, Africa, the Middle East and Asia were obviously associated with the incident.

“The likelihood of the PRC damaging or corrupting submarine cables and related infrastructure that connect Taiwan to the outside world should not be underestimated nor overlooked by the international community, said Tzeng Yi-suo of the Taipei-based Institute for National Defense and Security Research in the think tank’s January newsletter.

“To directly damage submarine cables in the seabed would pose a major challenge for PLAN [People’s Liberation Army Navy]. The PRC is more likely to try and damage the physical fiber cable connections at Taiwan’s four landing stations [Toucheng in the northeast, Tamsui and Bali in the north and Fangshan in the south] or go after the undersea cables laid at depths of less than 300 meters,” Tzeng added.

The US and Russian navies have nosed around cables from time to time ever since the Cold War, mainly – apparently – for eavesdropping purposes.

Internationally, treaties such at the International Convention for the Protection of Submarine Cables and the United Nations Law of the Sea Convention (UNCLOS) impose obligations on nations to safeguard and protect submarine cables and allow naval forces to investigate and take appropriate action against vessels likely to damage submarine cables, either intentionally or by negligence, according to the International Cable Protection Committee.

The conventional way to repair the cables is for surface ships to search for them with grappling hooks on the muddy seabed, then pull them up, but some countries, including the US and Russia, have special forces units have missions and capabilities to damage them. China’s PLA has specialized submarines that could easily locate and cut these cables, according to the US-based RAND think tank.

Experts believe the most likely time for a PLA attack on Taiwan’s cables would be prior to or just after the shooting starts.

“In terms of impact, the result would likely be severe disruption not only to Taiwan’s access to the Internet, but also to the financial markets that Taiwan is connected to,” said Timothy R. Heath, Senior International Defense Research Analyst, RAND.

“In a conflict, cutting the telecommunications cable could create panic on the island, help control information flowing out of the island, and perhaps disrupt efforts by Taiwan’s military to communicate with the United States. However, given that Taiwan’s military would have other means to reach the US, such as satellite communications, the PLA would probably have to attack satellite communications as well if it really sought to impose an information blackout on the island,” he added.

Nevertheless, Heath questioned whether a cut would be a good idea for China. Although relatively easy to do, cutting Taiwan’s submarine cables would almost certainly cause Japan, Australia, South Korea, and many other countries seeing their financial and business interests damaged.

“And, cutting telecommunications access will likely anger the Taiwan people, as their ability to pass information to authorities and communicate with family and friends would grow more difficult,” Heath said. “Third, China would lose a critical means of communicating with Taiwan’s leadership and with the people, which is important because Beijing would probably want some way to negotiate an end to conflict with Taiwan’s leaders,” he added.

Thu it is probably actually better to keep Taiwan connected and use the connectivity for all kinds of cyber attacks.

Other observers point out that China also has a number of cables. In the 2006 earthquake, China Telecom Corp., the mainland’s largest fixed-line carrier, reported that 97 percent of mainland Internet users had difficulty accessing overseas websites, and 57 percent of them said their lives and work had been affected.

“People who live in glass houses should not throw rocks,” said John Pike, Director of U.S.-based think tank GlobalSecurity.org. “Taiwan's ability to cut the Chinese cables is not evident, but they do have offshore ships that do cable work,” he added.

James R. Holmes, a professor at the US’s Naval War College, noted that it’s possible a family of unmanned Taiwanese subsurface and surface vehicles could detect PLA subs making mischief and vector in anti-submarine forces to shoo them away. It’s also possible Taipei could deter Beijing by developing the ability to cut Chinese cables, according to him.

“Call it mutually assured cable destruction. Imaginative thinking is at a premium on the island, in this as so many areas of cross-strait competition,” Holmes said.

Rick Fisher, Senior Fellow, International Assessment and Strategy Center, gets down to the nitty-gritty.

“It would be most advisable for Taiwan to counter threats to undersea cables and satellites with the ability to launch hundreds if not thousands of micro satellites, cubes at to 100kg in size, to reestablish communication links while adding hugely to surveillance capabilities to improve targeting,” Fisher said.