AOSIS stands for Alliance of Small Island States. It is an intergovernmental organization of low-lying coastal and small island countries that are particularly vulnerable to the adverse effects of climate change, especially sea-level rise. Established in 1990, AOSIS serves as a coalition to represent these nations' interests in international climate negotiations, including the UN Framework Convention on Climate Change (UNFCCC) process. The group advocates for ambitious climate action to protect island nations from existential threats posed by global warming.