'Common but differentiated' motivations? Requests for advisory opinions concerning climate change and the law of the sea

This research analyses the motivations of three key states (Antigua and Barbuda, Tuvalu, and Vanuatu) in seeking advisory opinions on climate change based on the United Nations Convention on the Law of the Sea (UNCLOS). While Vanuatu spearheaded the request from the International Court of Justice (ICJ), Antigua and Barbuda and Tuvalu led the request from the International Tribunal for the Law of the Sea (ITLOS). The literature has seldom discussed the motivations of states to resort to advisory opinions over contentious cases or diplomatic means. Considering this research gap, this research answers the two questions: (1) why did three states opt for advisory opinions, and (2) why did they choose the ICJ or ITLOS instead of other international courts and tribunals? This research draws upon the literature to build an analytical framework classifying states' motivations into legal reasons, strategic reasons, communal or social motivations, and domestic circumstances. This research employs a twofold methodology, by first analysing statements from the governments of the three states and then conducting semi-constructed interviews with legal experts involved in the ICJ and ITLOS proceedings. The findings show that both requests were driven by a combination of legal reasons, strategic reasons, communal or social motivations, and domestic circumstances. The most apparent difference between the two requests was communal or social motivations, with the ICJ request initiated by a bottom-up approach. The findings can be expanded to other transboundary environmental issues that could potentially be raised as another advisory opinion.