China’s rapidly expanding aircraft carrier fleet may be vulnerable to attack from submarines – an area where its defensive capacity lags behind that of the United States – according to a new report.
This gap is drawing increasing attention as Beijing builds more sophisticated carriers and sends them deeper into the western Pacific, where the People’s Liberation Army Navy (PLAN)’s knowledge of the undersea environment continues to lag behind that of the US Navy.
A recent report from the Washington-based Centre for Strategic and International Studies outlined a “cost-imposition” strategy that could help the US and its allies threaten China’s carriers.
It included the use of land-based strike networks, long-range air strikes supported by satellites, cyber and electromagnetic attacks, and drone swarms.
However, the fifth element of this strategy – submarine ambushes – is where many analysts believe the Chinese navy is most vulnerable.
Specifically, the report identified US attack submarines operating in the western Pacific as one of the most potent threats to Chinese carrier groups, arguing that gaps in the navy’s undersea detection and tracking capabilities could leave the high-value ships exposed.
Geography reinforces that vulnerability. Implementing the strategy would require US and allied forces to guard a limited number of maritime chokepoints along the first island chain – a network of archipelagos stretching from Japan down to Borneo – that stands between the Chinese fleet and the wider Pacific.
But according to the strategy outlined in the paper, submarines and other forces could be used to threaten carrier groups as they pass through these strategic waterways.
Further out to sea, carrier-based planes could carry out long-range air strikes on carriers, using satellites for surveillance and targeting, while attacks on sensors and communications could disrupt PLA operations.
Underlining this dynamic, Christopher Sharman, director of the China Maritime Studies Institute at the US Naval War College, speaking in his personal capacity, said the undersea vulnerability identified by the report “remains significant today”, although it was “not a static weakness”.
“In recent years, the PLAN has invested heavily in capabilities intended to improve its awareness and ability to predict the undersea operating environment,” he said.
However, Sharman added that important gaps remained, saying: “PLAN-affiliated authors acknowledge that China’s meteorological and oceanographic capabilities still lag those of the US Navy.
“This comparative lack of knowledge about the undersea ocean battlespace remains an impediment to PLAN submarine and anti-submarine warfare operations, particularly beyond the first island chain.”
Beijing has been working to close that gap. For example, the Transparent Ocean programme, first proposed more than a decade ago, sets out plans to establish a network of satellites, research vessels, buoys, underwater gliders and seabed sensors to collect oceanographic information across strategically important waters such as the western Pacific, South China Sea and Indian Ocean.
Chinese sources have explicitly linked the programme to national security, while Ocean University of China, which first outlined the plan, said it had set up hundreds of deep-sea observation systems and expanded monitoring networks from the South China Sea into the western Pacific.
China has also been working to boost its anti-submarine warfare capacity.
The maritime studies institute has documented its growing fleet of fixed-wing maritime patrol aircraft and Type 927 ocean-surveillance ships equipped with towed-array sonar. Other improvements include upgrading the sensors fitted to the aircraft and helicopters used to hunt submarines.
But naval strategy analysts believe the PLA faces a broader challenge than just protecting its carriers.
“Undersea warfare is a core component of PRC [People’s Republic of China] naval strategy,” Sharman said.
“Within the first island chain, it is critical to achieving the PLAN’s objective of sea control in wartime.
“Beyond the first island chain and into the Indian Ocean, PLA strategists view effective undersea operations as necessary to counter US naval superiority and complicate third-party intervention in a conflict involving Taiwan.”
Beijing regards Taiwan as part of China and has never renounced the use of force to reunite it with the mainland.
Most countries, including the United States, do not recognise the island as independent, but Washington opposes any attempt to take Taiwan by force and is legally bound to provide it with arms to defend itself.
Chinese military-affiliated authors have sometimes warned that the depths of the seas near its coast are a “wide-open door” because the country cannot monitor and control them sufficiently to keep out potential adversaries.
Timothy Heath, head of defence research firm Perceptum, said anti-submarine warfare remained a challenge for China, particularly because US subs were among the quietest in the world.
He also said Japanese intervention in any conflict over Taiwan would raise the stakes, because it could try to target and destroy Chinese warships operating near its coast.
In this scenario, carriers may be better deployed in the western Pacific, where they could provide air cover for naval forces seeking to delay or prevent third-party intervention in any conflict over Taiwan.
But Heath warned “it would be foolish for China to deploy the carriers that far out, anyway” given the multiple ways the US could target them.
“China’s land-based IRBMs [land-based intermediate-range ballistic missiles] are still the best option for threatening US ships out to the second island chain. The carrier is too valuable and costly to deploy in so vulnerable a way,” he said.
The report’s authors argued that the challenges China faced in protecting its carriers as they operate farther from its shores should shape US procurement choices, and called for greater investment in torpedoes, undersea drones and missile production with allies including Japan and Australia.
For Beijing, the challenge is increasingly not just how many carriers it can build, but whether its undersea capabilities can keep pace with its ambitions to operate them farther from China’s shores. -- SOUTH CHINA MORNING POST
