Current Forecast: Tonga and a Changing Climate

The future of human habitation and subsistence agricultural production in Tonga is threatened by rising sea levels, warming seas, and increasingly extreme rainfalls.

• The country, in brief. The Kingdom of Tonga is an archipelago of 169 islands, 36 of which are continuously inhabited. There are about 103,000 inhabitants. Remittances, foreign aid, and tourism are the main drivers of the Tongan economy. The tourism industry is relatively underdeveloped, but cruise ships stop in the Vava’u group of islands for whale watching, game fishing, surfing, and the beaches. The climate of Tonga is tropical, and the islands can be divided into two types, limestone base from uplifted coral formations, and limestone over a volcanic base.

• Sea-level rise threatens agriculture and settled areas. The sea level has risen by about 6 mm per year, well above the global average. The rise threatens subsistence agricultural production and human habitation. The majority of Tonga’s population is settled on the coasts of the larger islands at sea level. The higher ground in Tonga is mountainous and ill-suited for human habitation. Several communities have already relocated to other Tongan islands as rising seawater overtook their old villages. Local infrastructure at sea level must be rebuilt every year as roads and paths are washed away due to the rising sea level and more frequent storms.

• Warming seas threaten subsistence fishing. The increase in ocean temperature and sea acidification harms the health of coral reef ecosystems and the surrounding ocean. Fish migratory patterns may be affected by the temperature change and acidification. Tongans rely on coral reefs and the open ocean for subsistence fishing. Sport fishing that attracts tourism may be impacted negatively as well.

• Increased extreme rainfall threatens agriculture. Extreme rainfall is expected to occur with greater frequency and intensity. Subsistence agriculture is threatened by severe rain washing away local crops, possibly including the small-scale export of agricultural products such as copra. Human habitation is threatened as well, as a portion of the population lives in traditional villages with poor infrastructure that are susceptible to violent rain and storms.

• For the full country profile, visit the Tonga’s page on the Pacific Climate Change Portal.

The Response

Tonga has undertaken an official climate change policy focused on resilience – the National Strategic Development Framework 2015-2025. The initiative aims to build a resilient Tonga by 2035 by investing in the Joint National Action Plan for Climate Change Adaptation and Disaster Risk Management, including all relevant sector policies and plans in regards to resilience and mitigation. The strategy is focused on the goals of strengthening integrated risk management to enhance climate and disaster resilience; lowering carbon development; and strengthening disaster preparedness, response, and recovery.