Tonga is an archipelago in the South Pacific consisting of 171 islands (45 of which are inhabited) in Polynesia. Many of the islands that make up Tonga originate from coral line, but some are volcanic, and several volcanos still exist along the western ridge of the country. Tonga’s climate is tropical and is markedly seasonal, with a dry season from May to October and a wet season from November to April. Tonga is vulnerable to climate change-driven extreme weather events, sea level rise, increases in temperature and precipitation, drought, flood, and coral bleaching.  

The temperature in Tonga is projected to increase by the end of the century, however the future temperature rise in Tonga may be below the global average due to the proximity of the ocean (World Bank Group, 2021). As the World Bank Group (2021) notes, ocean cover can distort model simulations, and a higher level of spatial accuracy is needed to more reliably predict climate processes over small island states. Nonetheless, temperature on extremely hot days is projected to increase as well as the frequency of these days. Between 1979 and 2006 Tonga experienced an increase in mean precipitation however estimates for future scenarios are uncertain in precipitation, drought, heatwaves, floods, cyclones, and storm surge (ibid.), although Tonga already faces high risk from cyclones and storm surges. Tonga is almost entirely reliant on rainfall for its water supply, so it is vulnerable to changes in rainfall due to climate change (ibid.). Agriculture – which employs 1/3 of Tonga’s labor force and accounts for 50% of its exports – is also highly vulnerable to changes in rainfall (ibid.). It is likely that sea level rise in Tonga is going to continue to rise even more than historical data-based projections suggest (ibid.). 

In Tonga’s Second NDC (2022) they outline their adaptation priorities as adapting to increases in temperature and sea level. Among other goals, Tonga has a goal of having 30% of land in Tonga used by agro-forestry or forestry by 2025, maintain existing socks of fish and other marine species, and prevent any permanent loss of land to rising sea levels on its four main islands.