The Kingdom of Tonga is located in the Western Pacific ocean and is made up of 171 islands, 36 of which are inhabited (Miura, 1997). The impacts of changing climate conditions are arguable most prevalent in the small island nation states of the South Pacific Ocean. Tonga is no exception, given the nations reliance on coastal agriculture and coral reef ecosystems for survival and economic productivity (Barnett, 2011).

Climate Hazards

Global sea levels have been increasing at an average rate of 3.2 mm (+/- 0.4 mm) (IPCC, 2014). South Pacific islands often face a greater average sea level rise due to their proximity to the equator by cause of thermal expansion (IPCC, 2014). Since these islands are close to the equator, the average ocean temperatures are warmer, which causes the ocean water to expand and further amplify the rise in average annual sea levels (IPCC, 2014). Tonga faces an average annual sea level rise of about 6 mm, almost twice the value of the global average sea level rise (Englart, 2011; Australia, 2011). Projections from current sea level rise onto the future of Tonga show the possibility of a 5 cm-15 cm rise by 2030 and a 20 cm-60 cm rise by 2090 (Englart, 2011).


Sea level rise, in the Pacific Ocean specifically, is subject to direct fluctuation due to El Niño and La Niña oscillation patterns (IPCC, 2014).During La Niña events, the trade winds increase, pushing a large warm water mass across to the Western Pacific (IPCC, 2014). La Niña exposes small islands to thermal expansion from the warm mass of water and sea levels rise (IPCC, 2014). These climate events cause +/- 20 cm-30 cm fluctuations in sea levels putting small islands in the Pacific at much greater risk (IPCC, 2014).

Exposure and Vunerability

Sea Level Rise Threatens Agriculture

Agricultural practice faces the impacts of salt water intrusion especially during weather events with substantial storm surge (Australia, 2011). When sea levels rise and inundate fertile crop land, the crops are often destroyed along with the productivity of the soil (IPCC, 2014). As the soil becomes infertile, crops are planted further inland to find soil that is adequate for productivity (Barnett, 2011). The small islands provide a finite amount of space and resources in terms of finding new suitable cropland (Barnett, 2011; Mimura, 1997). Stresses on agricultural land produce similar impacts on the economy; in order to preserve food security Tonga must increase its imports to accommodate for the loss of agricultural productivity (IPCC, 2014; Mimura, 1997).

Coral bleaching and coastal mangrove erosion deteriorate natural buffers for the island to rising seas and storm surge.

Adaptation and Resiliency (el nino graphic) (citation background)

  1. IPCC, 2014: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 688 pp.
  2. Englart, J. (2011, December 10). Tonga and climate change: Sione Taulo Fulivai "Our people are on the line, our cultures are going to disappear". Retrieved March 07, 2017, from 
  3. Australia. (2011, November). Current and Future Climate of Tonga. Retrieved March 7, 2017, from 
  4. W. (2015, September 14). Parliament's soft closing ceremony marks end 2016/2017 sessions. Retrieved March 07, 2017, from 
  5. Woonton, N. (2015, March 16). Secretariat of the Pacific Regional Environment Programme. Retrieved March 07, 2017, from 
  6. Mimura, N., & Pelesikoti, N. (1997). VULNERABILITY OF TONGA TO FUTURE SEA-LEVEL RISE. Journal of Coastal Research, 117-132. Retrieved from 
  7. Barnett, J., 2011: Dangerous climate change in the Pacific Islands: food production and food security. Regional Environmental Change, 11(1), 229-237. 
  8. Bell, J.D., C. Reid, M.J. Batty, P. Lehodey, L. Rodwell, A.J. Hobday, J.E. Johnson, and A. Demmke, 2013: Effects of climate change on oceanic fisheries in the tropical Pacific: implications for economic development and food security. Climatic Change, 119(1), 199-212. 
  9. Brandt, M.E. and J.W. McManus, 2009: Disease incidence is related to bleaching extent in reef-building corals. Ecology, 90(10), 2859-2867. 
  10. Bennardo , G. (2017). Tonga. Retrieved March 07, 2017, from 
  11. Gilman, E.L., J. Ellison, N.C. Duke, and C. Field, 2008: Threats to mangroves from climate change and adaptation options: a review. Aquatic Botany, 89(2), 237- 250.