In a fifth utility, an ADIZ is a signaling device. Declaring an ADIZ in the face of foreign opposition or in violation of international law may signal resolve, even strength. It may also signal anger when responding to a preceding event that hurts the ADIZ-declaring state. All this can signal formidability, while the effective enforcement of an ADIZ signals capability.
Some suggest that an ADIZ can be employed to reassure others of the declaring state’s cooperative intention. One observer argues that China tried to use its East China Sea ADIZ as an “instrument of engagement, not aggression.” However, the international opposition to China’s ADIZ is proof that only a fool would use it to signal cooperation.
The sixth function of ADIZ is that of a deterrent. By signaling formidability and capability, one can deter others. But even when an ADIZ is still unborn, a hypothetical ADIZ can also serve as a threat to deter others. China has developed a consistent narrative on the South China Sea ADIZ, saying whether it will declare an ADIZ in the South China Sea depends on the threat level it faces. In this sense, China’s South China Sea ADIZ has already been employed.
When Will China Impose an ADIZ in the South China Sea?
If China wants to use a South China Sea ADIZ for military purposes (early warning and anti-access/area denial), then effective enforcement is a key requirement. With several large artificial islands equipped with four long airstrips and many support facilities in the middle of the sea, China already has sufficient infrastructure needed for this job. Each of the four airbases on these man-made islands has enough hangars to accommodate twenty-four combat aircraft and four to five larger planes such as reconnaissance, transport, refueling, and bomber aircraft. Adding to these well-located air bases, China has since December last year homeported its second aircraft carrier, the Shandong, at Sanya on Hainan Island. While the airfields on the man-made islands at the middle of the South China Sea can accommodate up to ninety-six air-superiority aircraft, the Shandong can add thirty-six more to the number of frontline fighters China can operate at one time in the South China Sea.
Note that of the countries with comparable coastline along the South China Sea, Vietnam has a total of fifty frontline aircraft for its entire territory, Malaysia has thirty-eight, and the Philippines has zero. When a Nimitz-class aircraft carrier of the United States enters the South China Sea, it can add ninety aircraft, including typically sixty-four air-superiority fighters, to the challenges a Chinese ADIZ has to face. Still, supported by the airfields on China’s mainland, Hainan Island, Woody Island, Subi Reef, Fiery Cross Reef, Mischief Reef, and the Shandong, aircraft under China’s Southern Theater Command, including about 198 air-superiority fighters, can more than match the combined air forces of all the major Southeast Asian claimants plus one U.S. aircraft carrier.
Three years after the completion of the major artificial island-building in the South China Sea, China already has the capability to effectively enforce an ADIZ as large as its territorial and maritime claims in the region—the illegal “nine-dash line.” The question for China in the South China Sea is not whether it has the capability to enforce an ADIZ, but what utility it wants to get from an ADIZ and, if it needs to declare an ADIZ, when is the best time to do so.
If China employs its ADIZ as a sovereignty marker (to register sovereignty over the South China Sea territories and get international recognition or acquiescence), then a bargaining chip, or a signaling device, a declaration is more important than de facto enforcement. China does not need an ADIZ to signal its strength and resolve in the South China Sea; its coast guard, militia, and survey ships alone are able to perform the job, as demonstrated repeatedly in its ability to halt Vietnam’s drilling of new oil and gas wells within Vietnam’s EEZ since 2017 and its ability to unilaterally conduct a survey in large areas within the EEZ of Vietnam and Malaysia since 2019, activities that are illegal based on the 2016 rulings of the Permanent Court of Arbitration. An ADIZ can add more to this signaling but its risks appear to outweigh its value-added.
As a sovereignty marker, an ADIZ can be better than the nine-dash line since the latter was invalidated by the international arbitration court in 2016. An ADIZ can also be a weighty bargaining chip in China’s negotiation of the Code of Conduct in the South China Sea (COC) with the ASEAN members. China’s endgame in the South China Sea is a new normal where it is in charge, and the job of the COC, from Beijing’s perspective, is to freeze that new normal. Since China has told the ASEAN members that it wanted to conclude the negotiations of the COC by 2021, Beijing needs to race against this deadline to create new facts on the ground and solidify the new normal. This accelerated aggression in turn will put pressure on many members of ASEAN to finish the negotiation. It is in this context that China has stepped up aggression in the South China Sea in the last years, including the survey activities by the Haiyang Dizhi 8 within the EEZ of Vietnam and Malaysia since last summer. Although Beijing can save an ADIZ to use in the future, its value as a bargaining chip may be highest in the COC negotiations.
If ADIZ is used as a deterrent, then it will lose its value the moment it is declared. With its growing capability, China can impose its early warning systems and exclusion zones under names other than ADIZ, or it can enforce them undeclared on a de facto basis.
Size and Scope
China can manipulate the risks—and with them, the benefits—of its ADIZ by selecting different scopes and sizes for its coverage. Generally, a larger scope will affect more neighbors directly and thus provoke more opposition. The benefits of an ADIZ, however, do not always grow in line with the size. An ADIZ would bring the most benefits for China if it hugs the nine-dash line, China’s invalid claim in the South China Sea. A larger scope will cause much additional opposition while bringing little additional utility.
There are four groups of islands within the nine-dash line—all are disputed. They give China five major options in terms of the scope of a South China Sea ADIZ. The cost-benefit ratio of an ADIZ varies with its scope, depending on the number and opposition of the states that lay sovereignty claims on the territory it covers.
Option 1 would cover the Paracel Islands, which lie between China’s Hainan Islands and Vietnam’s central coast and are disputed by China and Vietnam. The island group has been occupied by China since 1974 but it was administered by successive states from Vietnam, including France as the protector of Vietnam, at least from the eighteenth century until then.
Option 2 would encompass the Pratas Islands, which lie 180 nautical miles southeast of Hong Kong and are currently under Taiwanese administration.
Option 3 would be the sum of option 1 and option 2, hugging China’s South China Sea coast and covering both the Paracel Islands and the Pratas Islands.
Option 4 would stretch out from China’s southern coast and involve the Pratas, the Paracels, and Scarborough Shoal. The latter lies within the Philippine EEZ about one hundred nautical miles off the coast and had been administered by the Philippines at least since the eighteenth century until China seized it during the 2012 Scarborough Shoal standoff.
Option 5 would hug the nine-dash line and contains roughly all the area China claims in the South China Sea, including the Pratas, the Paracels, Scarborough Shoal, the Spratly Islands, including the waters between and surrounding them. The Spratly Islands are claimed entirely by China, Taiwan, and Vietnam, and partly by the Philippines and Malaysia. Brunei claims Louisa Reef to the south of the archipelago. This option will have the largest number of opponents but also the largest benefits among the different versions of a South China Sea ADIZ.
All Things Considered
China’s decision to set up an ADIZ will most likely be the result of its cost-benefit calculation. If China has plans to declare an ADIZ in the South China Sea, then it will likely make the announcement when the anticipated benefits exceed the anticipated costs. The benefits derive mainly from the utility of an ADIZ; the costs depend largely on foreign reaction.
The coronavirus pandemic and the last stage of the COC negotiation, which are incidentally concurrent, offer an opportunity for China to announce its South China Sea ADIZ. The low number of flights over the South China Sea caused by the travel bans to restrict the spread of the virus and the focus of everyone on the coronavirus outbreak would greatly reduce foreign reaction. Except for Vietnam, the hands of Malaysia and the Philippines are additionally tied by China’s aids to help them fight the virus, which ironically originated from China. At the same time, the deadline of the Code of Conduct urges China to maximize its advantage in a new status quo that would be frozen for a while after the Code of Conduct is signed.