What AOSIS is and how it works

An alliance with no founding convention

The United Nations Office of the High Representative for the Least Developed Countries, Landlocked Developing Countries and Small Island Developing States records the alliance as an intergovernmental organisation established in 1990, during the Second World Climate Conference in Geneva. The Permanent Mission of the Maldives, which counts itself among the founders alongside Trinidad and Tobago and Vanuatu, describes it as an ad hoc lobby and negotiating voice for small island developing states within the United Nations system. Its bureau is a list of permanent representatives at their missions in New York, and the chair moves between the three groupings the alliance sorts its own members into: the Caribbean, the Pacific, and Africa, the Indian Ocean and the South China Sea. Belize held the chair, then Antigua and Barbuda, which handed it to Samoa at a plenary on 30 January 2023.

The members that are not islands

Belize, Guyana and Suriname sit on the alliance's Caribbean list and Guinea-Bissau on its African, Indian Ocean and South China Sea list. None of the four is an island. This catalogue files Belize in Central America, Guyana and Suriname in South America and Guinea-Bissau in West Africa, and what admits them is the second half of the alliance's own description of its membership, which reads small island and low-lying coastal developing states.

The high points on the member records start at 5 metres. The Maldives records Villingili at 5 metres and Tuvalu records Niulakita at 5; the Marshall Islands records Likiep Atoll at 10, the Bahamas records Mount Alvernia at 63 and Nauru records Command Ridge at 70. Papua New Guinea records Mount Wilhelm at 4,509 metres, Timor-Leste records Tatamailau at 2,963 and Cape Verde records Pico do Fogo at 2,829.

What the bloc has asked for

The alliance's leaders' declaration of 2024 traces the collective case back to the Male Declaration on Global Warming and Sea Level Rise, adopted in the Maldives in November 1989, a year before the alliance itself. Small island developing states were recognised as a special case for both their environment and their development at the United Nations Conference on Environment and Development, held in Rio de Janeiro in 1992.

The first drafted proposal followed in 1994. On 20 September the Permanent Representative of Trinidad and Tobago transmitted a draft protocol prepared by the alliance to the interim secretariat of the climate convention, and it was circulated on 27 September as A/AC.237/L.23, for the eleventh session of the Intergovernmental Negotiating Committee in New York. Article 3 required each Annex I party to reduce its 1990 level of anthropogenic carbon dioxide emissions by at least 20% by the year 2005.

The development track kept its own rhythm: the Barbados Programme of Action in 1994, the Mauritius Strategy in 2005, the SAMOA Pathway in 2014, and the Antigua and Barbuda Agenda for SIDS, adopted after the fourth international conference on small island developing states, held from 27 to 30 May 2024.

Statehood, and the zones drawn from a coastline

At New York on 23 September 2024 the heads of state and government of the alliance agreed a declaration on sea level rise and statehood. It declares that maritime zones established and notified to the Secretary-General of the United Nations under the Law of the Sea convention, and the rights that flow from them, continue to apply without reduction notwithstanding physical changes connected to sea level rise; that statehood cannot be challenged under any circumstance of such change; and that membership of the United Nations, its specialised agencies and other intergovernmental organisations continues.

Two members had already put the argument to a tribunal. Antigua and Barbuda and Tuvalu signed the agreement establishing the Commission of Small Island States on Climate Change and International Law at Edinburgh on 31 October 2021, and it entered into force on signature that day; Niue, Palau, Saint Lucia, Vanuatu, Saint Vincent and the Grenadines, Saint Kitts and Nevis and the Bahamas acceded afterwards. The commission requested an advisory opinion from the International Tribunal for the Law of the Sea on 12 December 2022, and the tribunal delivered it on 21 May 2024. The International Court of Justice delivered a separate advisory opinion, on the obligations of states in respect of climate change, on 23 July 2025.

Where the edges are argued

Two members hold no seat at the United Nations. The Cook Islands and Niue appear on the alliance's Pacific list and on the United Nations list of small island developing states, and this catalogue files both as dependencies in free association with New Zealand, self-governing since 4 August 1965 and 1 January 1974. Both readings are on the record and neither is settled here.

The alliance's roster and that United Nations list carry the same 39 names, which is not true of the wider category. The list is published beside 18 associate members of the United Nations regional commissions, from American Samoa to the United States Virgin Islands, which are counted as small island developing states and do not sit in the alliance.

Income is not part of the test. Singapore's record carries a gross domestic product per capita of 98,814 US dollars for 2025 and a Human Development Index of 0.939 for 2021, while Kiribati's carries 2,559 US dollars for 2025 and 0.624 for 2021. The same United Nations list marks Comoros, Guinea-Bissau, Haiti, Kiribati, Solomon Islands, Timor-Leste and Tuvalu as least developed countries as well.

The alliance also sits on top of the regional bodies its members already belong to rather than in place of them. Singapore's record files it in ASEAN and in the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, Cape Verde's in the African Union and ECOWAS, Cuba's in CELAC, fourteen of the members in the Pacific Islands Forum and fourteen in the Caribbean Community.