Tonga is an archipelago in the South Pacific consisting of 171 islands, of which 45 are inhabited, located in the Polynesian region. Many of the islands are formed from coral limestone, while others are volcanic in origin, with several active volcanoes along the country’s western ridge. Tonga has a tropical climate with marked seasonal variation, including a dry season from May to October and a wet season from November to April. The country is highly vulnerable to climate change impacts, including extreme weather events, sea level rise, rising temperatures, changes in precipitation, droughts, floods, and coral bleaching. 

Temperatures in Tonga are projected to increase by the end of the century, although warming may be slightly lower than the global average due to the moderating influence of the surrounding ocean (World Bank Group, 2021).  However, both the intensity and frequency of extremely hot days are expected to rise. Between 1979 and 2006, Tonga experienced an increase in average precipitation, although future projections for rainfall, droughts, heatwaves, floods, cyclones, and storm surges remain uncertain. Despite this uncertainty, Tonga already faces high risks from cyclones and storm surges. The country relies heavily on rainfall for its freshwater supply and is therefore highly vulnerable to changes in precipitation patterns (ibid.). Agriculture — which employs about one third of the labor force and accounts for around 50 percent of exports — is also highly sensitive to rainfall variability. Sea level rise is expected to continue and may exceed projections based on historical trends (ibid.). 

In its Second NDC (2022), Tonga outlines adaptation priorities focused on responding to rising temperatures and sea level rise. The country also aims to expand agroforestry and forestry to cover 30 percent of land by 2025, maintain sustainable stocks of fish and other marine species, and prevent permanent land loss from sea level rise on its four main islands.