In January, the Philippines instituted arbitration proceedings against China under the United Nations Convention on the Law of the Sea (UNCLOS) with regard to disputes between the two countries in the South China Sea.

China has chosen not to take part in these proceedings, claiming that the compulsory dispute settlement procedures under UNCLOS do not apply. Does China's rejection of the arbitration request have a basis in international law?

The international legal system is based on the sovereign equality of states. One of the consequences of this fundamental principle is that international courts and tribunals can exercise jurisdiction over states only with their consent.

In case of doubt, such consent must be interpreted restrictively. Both the Philippines and China have given general consent to the jurisdiction of an arbitral tribunal under UNCLOS when they became parties to the Convention. However, the scope of that jurisdiction is limited to disputes "concerning the interpretation or application of this Convention."

Disputes which are related to the sea but which are not governed by the Convention are thus removed from the jurisdiction of the tribunal. The jurisdiction established by the Convention is also subject to far-reaching exceptions.

The Convention itself excludes, for example, disputes concerning the exercise by a coastal state of its sovereign rights over the natural resources in the exclusive economic zone and the continental shelf.

The crucial question is thus whether the case brought by the Philippines against China falls within the limited jurisdiction conferred upon the arbitral tribunal by the parties.

The object of the dispute is defined by the relief sought by the Philippines as set out in its "Notification and Statement of Claim." The Philippines requests the tribunal to adjudicate on 13 points.

Two of the matters can be disposed of right away. The Philippines asks the tribunal to declare that the parties' rights in the South China Sea are those established by UNCLOS. This is basically stating the obvious and is not disputed by China. The same is true for the declaration that the Philippines is entitled under UNCLOS to a 12-nautical mile territorial sea, a 200-nautical mile exclusive economic zone and a continental shelf.

The other issues raised by the Philippines cannot be decided without deciding on matters outside the jurisdiction of the tribunal.

For example, the claim that China's maritime claims in the South China Sea based on the so-called nine-dash line are invalid, the claim that China has unlawfully claimed maritime entitlements beyond 12 nautical miles around certain insular features and has prevented Philippine vessels from fishing in the waters adjacent to those features, and the claim that China has unlawfully interfered with the exercise by the Philippines of its right to navigation and other rights cannot be decided without touching upon China's claim to historic title and rights within the area of the nine-dash line.

In addition, any measures taken by China against the Philippine vessels may also be subject to the "law enforcement activities" exception with regard to fisheries matters or may be excluded as an exercise of China's sovereign rights and jurisdiction provided by UNCLOS.

The claim that China unlawfully occupies certain low-tide elevations in the South China Sea cannot be addressed without dealing with the question of sovereignty or other rights over these insular land territories.

Finally, declarations that certain submerged features form part of the continental shelf of the Philippines, that China has unlawfully exploited the living and non-living resources in the Philippines' exclusive economic zone and continental shelf, and that China has interfered with the Philippines' right to navigation and other rights in areas within and beyond 200 nautical miles of the Philippines cannot be made without engaging in sea boundary delimitations.

In conclusion, none of the 13 points addressed either gives rise to a dispute or can be addressed without considering matters outside the jurisdiction of the tribunal. There is thus no case to answer for China. The tribunal would be well advised to decline jurisdiction in the present case.

The author is director of the Institute of Public International Law at the University of Bonn and a Supernumerary Fellow of St Anne's College, Oxford. opinion@globaltimes.com.cn