By Elizabeth Barrett

China’s success in establishing an Air Defense Identification Zone (ADIZ) in the East China Sea has sparked speculation about the possibility of a Chinese ADIZ in the South China Sea. Further increasing this speculation, last November, when the East China Sea ADIZ was announced, China’s Ministry of Defense spokesman stated: “China will establish other Air Defense Identification Zones at the right moment after necessary preparations are completed.” Many are now wondering what the circumstances are under which China establish a South China Sea ADIZ.  Several factors will contribute such a decision, and only the right combination of those factors will result in a new Chinese ADIZ.

• When China has increased military capabilities in the region

China currently lacks the capabilities to adequately monitor and enforce such a zone in the South China Sea. The PLA Air Force’s (PLAAF) limited aerial refueling capabilities constrain its ability to project airpower. While the PLAAF does have radar capabilities, including passive electronically-scanned array radars for fighters and an over the horizon radar system, it cannot cover the entire South China Sea. The PLA Navy’s aircraft carrier Liaoning, which recently conducted an exercise there, could help monitor the airspace, but it will not be fully operational for a few years.

China is increasing its capabilities and presence within its claimed nine-dashed line, however. The South Sea Fleet conducted a combat drill last October and in January three Chinese ships patrolled James Shoal, an island 50 miles from Malaysia that marks the southernmost part of China’s territorial claim. Beijing plans to base a 5,000 ton civilian patrol ship in Sansha City, on the Paracel Islands, from which it will “establish a regular patrol system” to safeguard the nation’s maritime interest. Once China develops sufficient capabilities to effectively monitor the sea and airspace in the region, the establishment of an ADIZ in the South China Sea is more likely.

• When China has convinced its neighbors of its non-aggressive intentions

China has yet to ease its neighbors’ fears of Chinese aggression in the South China Sea. Hua Chunying, from the Ministry of Foreign Affairs, emphasized China’s commitment to regional peace during a January press conference. Such statements ring hollow, however, given that China is seen throughout the region as challenging freedom of navigation, undermining the rule of law, and prioritizing its interests over those of its neighbors.

While Beijing insists that it has non-aggressive intentions regarding the South China Sea, its rhetoric is unlikely to allay the worries of its neighbors any time soon. As Robert Sutter argues, China is risk-averse, and any preemptive coercive action in the South China Sea, such as setting up an ADIZ, may bring unwelcome consequences, including the involvement of the United States. Beijing may therefore seek to garner the support of ASEAN nations through economic cooperation and joint development schemes prior to announcing a South China Sea ADIZ.

• When China feels provoked by neighbors

It is easy to think of China as the provocateur, but it can also feel threatened by neighbors. The U.S. rebalance to Asia has made China uneasy and fearful of a potential anti-China coalition on its periphery. These fears will undoubtedly be reinforced by the U.S.-Philippines Agreement on Enhanced Defense Cooperation, which reportedly will grant the United States an increased military presence in the country.

Moreover, the Philippines, Malaysia, and Vietnam, all of whom are claimants in the South China Sea, met in February 2014 to discuss possible cooperation in the disputed areas and will hold another meeting in late March. If these three countries were to coordinate their diplomatic positions and responses, this could increase pressure in China to take additional measures in the South China Sea to defend Chinese sovereignty. Along with the Philippines’ case against China filed in January 2013 with the International Tribunal for the Law of the Sea, these external factors may trigger a Chinese decision to establish a second ADIZ.

At present China lacks sufficient military capabilities to enforce such a zone, has yet to successfully persuade its neighbors of China’s benign intentions, and does not see regional nations as posing an imminent threat to Chinese interests. Therefore, Beijing is unlikely to establish an ADIZ for the time being. It is only a matter of time, however, before China attains the necessary military capabilities to maintain an ADIZ in the South China Sea. Once China has that military capacity, either of the other two factors above could trigger a new ADIZ. If China is both strong enough and can either successfully convince its neighbors in the South China Sea of its benign intentions, or if Beijing feels sufficiently threatened by those same neighbors, China will then be highly likely to set up an ADIZ in the area.

Ms. Elizabeth Barrett is a researcher with the Freeman Chair in China Studies at CSIS.