Makati city: The Philippine government must issue a counter-declaration to China's statement denying the existence of high seas in the South China Sea, former Senior Associate Justice Antonio Carpio said on Tuesday. Speaking at the French Embassy-Stratbase Institute forum on advancing ocean governance, Carpio emphasized the urgency for Manila to take diplomatic action within a year or two to avoid implicitly consenting to China's jurisdictional claims in the region.

According to Philippines News Agency, Carpio highlighted a principle in international law known as the doctrine of acquiescence, which suggests that a state's silence or inaction in response to a situation or claim implies consent. "If we do not protest this declaration of China, we are deemed to have impliedly accepted it. So we must protest. Up to today, we have not protested, no state has protested," he stated.

China ratified the landmark Biodiversity Beyond National Jurisdiction (BBNJ) Agreement, also referred to as the High Seas Treaty, in December 2025. In signing the pact, Carpio noted that Beijing asserted the agreement and its implementation "shall under no circumstances" affect its territorial sovereignty, maintaining its claims over the South China Sea and the high seas it encompasses.

Carpio underscored the importance of timely action, advising that the Philippines should lodge a protest within one year, as waiting longer could lead to complications. "In my opinion, we should protest within one year because there are cases where you can protest within two years, but we have to play it safe," he advised. The BBNJ represents the first legally binding international accord focused on the conservation and sustainable use of marine biological diversity in the high seas.