China’s growing carrier fleet faces persistent undersea threat, US think tank warns

New Delhi, August 13. China’s rapidly expanding aircraft carrier fleet could face significant vulnerabilities from submarine attacks as the People’s Liberation Army Navy (PLAN) seeks to extend its maritime reach beyond waters close to the Chinese mainland, according to a study by the Washington-based Center for Strategic and International Studies (CSIS).

The report, cited by PTI news agency, outlines a potential US and allied “cost-imposition” strategy aimed at raising the risks and costs for Chinese carrier operations. The proposed approach combines several capabilities, including land-based strike systems, long-range airpower supported by satellites, cyber and electromagnetic warfare, drone swarms and attacks by submarines.

Of these, the report identifies submarine ambushes as one of the most potentially effective ways of exploiting a persistent weakness in China’s naval capabilities – its ability to detect, track and counter underwater threats over extended distances.

US attack submarines operating in the western Pacific could pose a particularly serious challenge to Chinese carrier strike groups, the study suggests. Any gaps in China’s undersea surveillance and anti-submarine warfare capabilities could leave its high-value carriers exposed as they move farther from the protection of China’s coastal military infrastructure.

China currently operates three aircraft carriers. Its first, Liaoning, a refitted Soviet-era vessel, entered service in 2012, followed by the domestically built Shandong in 2019. The third and most advanced carrier, Fujian, was commissioned last November in a ceremony attended by President Xi Jinping.

The Fujian represents a major technological advance for the PLAN. With a full-load displacement exceeding 80,000 tonnes, it is equipped with an electromagnetic aircraft launch system (EMALS), making it only the second operational aircraft carrier in the world to employ electromagnetic catapults after the US Navy’s USS Gerald R Ford.

Chinese defence authorities have said aircraft including the J-15T fighter, J-35 stealth fighter and KJ-600 airborne early-warning aircraft have completed catapult-assisted take-offs and arrested landings aboard the Fujian.

Unlike the US Navy’s nuclear-powered carriers, however, all three Chinese carriers – Liaoning, Shandong and Fujian – are conventionally powered.

China’s carrier expansion reflects Beijing’s ambition to develop a navy capable of operating farther from the mainland and supporting Chinese interests across increasingly distant maritime theatres. Analysts have suggested that future Chinese carrier operations could extend into strategically important routes, including the Indian Ocean.

That ambition, however, creates an increasingly difficult protection problem.

Christopher Sharman, director of the China Maritime Studies Institute at the US Naval War College, said the PLAN’s undersea vulnerability remains significant, although he cautioned that it is not a fixed or unchanging weakness.

China has invested substantially in recent years in improving its ability to understand and monitor the underwater environment, including its anti-submarine warfare and undersea surveillance capabilities. Nevertheless, important gaps remain.

Sharman pointed to shortcomings in China’s meteorological and oceanographic knowledge of the underwater battlespace compared with the United States. These limitations become more consequential when Chinese naval forces operate beyond the first island chain, where China’s coastal surveillance and military infrastructure provide less support.

The ability of US attack submarines to operate quietly and remain difficult to detect could further complicate the PLAN’s efforts to protect its carriers. Timothy Heath, head of defence research at Perceptum, said anti-submarine warfare remains a major challenge for China, particularly given the acoustic advantages of US submarines.

The Taiwan contingency could make the problem even more complex. Japanese involvement in a conflict could expose Chinese naval forces to additional threats, particularly if Japanese forces attempted to engage Chinese warships operating close to Japanese territory.

Chinese carriers could potentially be deployed in the western Pacific to provide air cover and support naval operations intended to deter or delay intervention by third parties. But operating the carriers farther from China’s mainland would also expose them to a wider range of US and allied capabilities.

Heath argued that Beijing would have to weigh carefully the risks of committing its most valuable naval assets deep into contested waters. China’s land-based intermediate-range ballistic missiles remain a major means of threatening US naval forces as far as the second island chain, potentially making them a more cost-effective option than exposing a carrier to enemy submarines and other long-range strike systems.

The CSIS study consequently argues that the vulnerability of Chinese carriers should influence US and allied defence procurement decisions. It calls for increased investment in torpedoes, unmanned underwater systems and missile production, including through greater cooperation with allies such as Japan and Australia.

The broader issue for China is therefore no longer simply how quickly it can expand its aircraft carrier fleet. As the PLAN seeks to transform its carriers into instruments of power projection farther from China’s shores, Beijing will also need to develop a much more sophisticated anti-submarine warfare and undersea surveillance architecture to protect them.

The challenge is particularly acute because aircraft carriers are among the most valuable and visible assets in a naval force. A larger carrier fleet may enhance China’s global naval presence, but unless the PLAN can build an effective protective shield against submarines and other long-range strike capabilities, operating those carriers in contested waters could carry substantial risks.

For the US and its allies, the report suggests that China’s carrier expansion may therefore create an opportunity as much as a challenge: rather than attempting to match Beijing ship-for-ship, they could exploit the vulnerabilities of China’s most expensive naval assets through a combination of submarines, long-range missiles, unmanned systems, airpower, cyber and electronic warfare.