Journal of Coastal Conservation

, Volume 21, Issue 6, pp 719–730 | Cite as

Identifying and assessing evidence for recent shoreline change attributable to uncommonly rapid sea-level rise in Pohnpei, Federated States of Micronesia, Northwest Pacific Ocean

  • Patrick D. NunnEmail author
  • Augustine Kohler
  • Roselyn Kumar


Those parts of the northwest Pacific Ocean where sea level has been rising fastest over the past few decades include islands in the Federated States of Micronesia. To understand the possible effects of rapid sea-level rise, coastal surveys were undertaken within Pohnpei State in October 2014. The high volcanic island of Pohnpei was targeted along with 10 reef-edge island groups on its surrounding barrier reef as well as islands on Ant Atoll, 15 km southwest. Evidence of shoreline erosion attributable to sea-level rise is found only in a few places along the main island’s northeast (windward) coast. High rainfall has led to the accumulation of terrestrial sediment along the coast that is covered with mangrove forest 2–3 km broad in places shielding the island’s coast from wave erosion. A different picture is found on reef-edge islands around which erosion over the last few decades can mostly be explained by recent sea-level rise. Islands have disappeared within living memory, others drastically reduced in size in the past decade, while others – their sand cover washed away – are being reduced to a skeletal (boulders anchored by mangrove) state. The coasts of Ant Atoll appear little affected by erosion ascribable to sea-level rise. In summary, fewer effects than might be expected from recent sea-level rise were seen in Pohnpei, largely for reasons of natural coastal resilience or a lack of record, especially for reef-edge islands. The importance of mangrove conservation and an understanding of sediment dynamics on the broad reef-lagoon shelf surrounding the main island is manifest.


Islands Erosion Mangroves Coral reef Reef islands Climate change 



The Government of the Federated States of Micronesia endorsed the research on which this study is based. PN and RK were funded by the Faculty of Arts and Business at the University of the Sunshine Coast. Kalahngan to our many friends on Pohnpei especially Jerry Martin, Allois Malfitani (Pohnpei Surf Club), and Ertin Poll (Kehpara Island). Petra Nunn helped in numerous ways.


  1. Athens JS (1983) The megalithic ruins of Nan Madol. Nat Hist 92:50–61Google Scholar
  2. Becker M, Meyssignac B, Letetrel C, Llovel W, Cazenave A, Delcroix T (2012) Sea level variations at tropical Pacific islands since 1950. Glob Planet Change 80–81:85–98. doi: 10.1016/j.gloplacha.2011.09.004 CrossRefGoogle Scholar
  3. Bloom AL (1970) Holocene submergence in Micronesia as the standard for eustatic sea-level changes. Quaternaria 12:145–154Google Scholar
  4. BOM (2011) Climate Change in the Pacific: Scientific Assessment and New Research. Bureau of Meteorology (BOM)/CSIRO, Melbourne, pp 273Google Scholar
  5. Chang YT, Du L, Zhang SW, Huang PF (2013) Sea level variations in the tropical Pacific Ocean during two types of recent El Nino events. Glob Planet Change 108:119–127. doi: 10.1016/j.gloplacha.2013.06.001
  6. Church JA, Clark PU, Cazenave A, Gregory JM, Jevrejeva S, Levermann A, Merrifield MA, Milne GA, Nerem RS, Nunn PD, Payne AJ, Pfeffer WT, Stammer D, Unnikrishnan AS (2013) Sea level change. In: Stocker TF et al (eds) Climate Change 2013: The Physical Science Basis. Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, pp 1137–1308Google Scholar
  7. Di Nitto D, Neukermans G, Koedam N, Defever H, Pattyn F, Kairo JG, Dahdouh-Guebas F (2014) Mangroves facing climate change: landward migration potential in response to projected scenarios of sea level rise. Biogeosciences 11:857–871. doi: 10.5194/bg-11-857-2014 CrossRefGoogle Scholar
  8. Dickinson WR (2000) Hydro-isostatic and tectonic influences on emergent Holocene paleoshorelines in the Mariana Islands, western Pacific Ocean. J Coast Res 16:735–746Google Scholar
  9. Dickinson WR (2001) Paleoshoreline record of relative Holocene sea levels on Pacific islands. Earth Sci Rev 55:191–234. doi: 10.1016/s0012-8252(01)00063-0 CrossRefGoogle Scholar
  10. Dixon TH, Batiza R, Futa K, Martin D (1984) Petrochemistry, age and isotopic composition of alkali basalts from Ponape Island, western Pacific. Chem Geol 43:1–28CrossRefGoogle Scholar
  11. Drexler JZ, Ewel KC (2001) Effect of the 1997-1998 ENSO-related drought on hydrology and salinity in a Micronesian wetland complex. Estuaries 24:347–356. doi: 10.2307/1353237 CrossRefGoogle Scholar
  12. FAO (2008) Climate change and food security in Pacific Island countries. Food and Agriculture Organisation of the United Nations, RomeGoogle Scholar
  13. Fletcher C, Richmond B (2010) Climate change in the Federated States of Micronesia: food and water security, climate risk management, and adaptive strategies. Center for Island Climate Adaptation and Policy (ICAP). University of Hawai'i Sea Grant College Program, Honolulu, p 68Google Scholar
  14. Ford M (2011) Shoreline changes on an urban atoll in the Central Pacific Ocean: Majuro atoll. Marshall Islands. Journal of Coastal Research:11–22. doi: 10.2112/jcoastres-d-11-00008.1
  15. Fujimoto K, Tabuchi R, Mori T, Murofushi T (1995) Site environments and stand structure of the mangrove forests on Pohnpei Island, Micronesia. Jarq-Japan Agricultural Research Quarterly 29:275–284Google Scholar
  16. Golbuu YM, Fabricius K, Victor S, Richmond RH (2008) Gradients in coral reef communities exposed to muddy river discharge in Pohnpei, Micronesia. Estuar Coast Shelf Sci 76:14–20. doi: 10.1016/j.ecss.2007.06.005 CrossRefGoogle Scholar
  17. Hanlon D (1988) Upon A Stone Altar: A History of the Island of Pohnpei to 1890. University of Hawaii Press, HonoluluGoogle Scholar
  18. Hoeke RK, McInnes KL, Kruger JC, McNaught RJ, Hunter JR, Smithers SG (2013) Widespread inundation of Pacific islands triggered by distant-source wind-waves. Glob Planet Change 108:128–138. doi: 10.1016/j.gloplacha.2013.06.006 CrossRefGoogle Scholar
  19. Houser C, D'Ambrosio T, Bouchard C, Heyman W, Darbonne K, Kuykendall S (2014) Erosion and reorientation of the Sapodilla cays, Mesoamerican reef Belize from 1960 to 2012. Phys Geogr 35:335–354. doi: 10.1080/02723646.2014.913932
  20. Keim ME (2010) Sea-level-rise disaster in Micronesia: sentinel event for climate change? Disaster Medicine and Public Health Preparedness 4:81–87CrossRefGoogle Scholar
  21. Krauss KW, Cahoon DR, Allen JA, Ewel KC, Lynch JC, Cormier N (2010) Surface elevation change and susceptibility of different mangrove zones to sea-level rise on Pacific high islands of Micronesia. Ecosystems 13:129–143. doi: 10.1007/s10021-009-9307-8 CrossRefGoogle Scholar
  22. Krauss KW, McKee KL, Lovelock CE, Cahoon DR, Saintilan N, Reef R, Chen LZ (2014) How mangrove forests adjust to rising sea level. New Phytol 202:19–34. doi: 10.1111/nph.12605 CrossRefGoogle Scholar
  23. Lebel L (2013) Local knowledge and adaptation to climate change in natural resource-based societies of the Asia-Pacific. Mitig Adapt Strateg Glob Chang 18:1057–1076. doi: 10.1007/s11027-012-9407-1 CrossRefGoogle Scholar
  24. McMillen HL, Ticktin T, Friedlander A, Jupiter SD, Thaman R, Campbell J, Veitayaki J, Giambelluca T, Nihmei S, Rupeni E, Apis-Overhoff L, Aalbersberg W and Orcherton DF (2014) Small islands, valuable insights: systems of customary resource use and resilience to climate change in the Pacific. Ecology and Society 19:article 44. doi: 10.5751/ES-06937-190444
  25. McNamara KE (2013) Taking stock of community-based climate-change adaptation projects in the Pacific. Asia Pacific Viewpoint 54:398–405. doi: 10.1111/apv.12033 CrossRefGoogle Scholar
  26. McNaught R, Warrick O, Cooper A (2014) Communicating climate change for adaptation in rural communities: a Pacific study. Reg Environ Chang 14:1491–1503. doi: 10.1007/s10113-014-0592-1 CrossRefGoogle Scholar
  27. Namakin B (2007) Climate change is real. Micronesian Counselor. Micronesian Seminar, Pohnpei, pp 1–19Google Scholar
  28. Nunn P (2000) Coastal changes over the past 200 years around Ovalau and Moturiki Islands, Fiji: implications for coastal zone management. Aust Geogr 31:21–39. doi: 10.1080/00049180093510 CrossRefGoogle Scholar
  29. Nunn PD (2007) Climate, Environment and Society in the Pacific during the Last Millennium. Elsevier, AmsterdamGoogle Scholar
  30. Nunn PD (2009) Responding to the challenges of climate change in the Pacific Islands: management and technological imperatives. Clim Res 40:211–231. doi: 10.3354/cr00806 CrossRefGoogle Scholar
  31. Nunn PD, Aalbersberg W, Lata S, Gwilliam M (2014) Beyond the core: community governance for climate-change adaptation in peripheral parts of Pacific Island countries. Reg Environ Chang 14:221–235. doi: 10.1007/s10113-013-0486-7 CrossRefGoogle Scholar
  32. Nunn PD, Kumar L, Eliot I, McLean RF (2016) Classifying Pacific islands. Geosci Lett 3:1–19. doi: 10.1186/s40562-016-0041-8
  33. Nunn PD, Runman J, Falanruw M and Kumar R (2017) Culturally-grounded responses to coastal change in the Federated States of Micronesia, northwest Pacific Ocean. Reg Environ Chang 14:221-235Google Scholar
  34. Palanisamy H, Cazenave A, Delcroix T, Meyssignac B (2015) Spatial trend patterns in the Pacific Ocean sea level during the altimetry era: the contribution of thermocline depth change and internal climate variability. Ocean Dyn. 65:341-356. doi: 10.1007/s10236-014-0805-7
  35. Pam C, Henry R (2012) Risky places: climate change discourse and the transformation of place on Moch (Federated States of Micronesia). Shima: The International Journal of Research into Island Cultures 6:30–47Google Scholar
  36. Parsonson GS (1966) Artificial Islands in Melanesia: the role of malaria in the settlement of the Southwest Pacific. N Z Geogr 22:1–21. doi: 10.1111/j.1745-7939.1966.tb00001.x CrossRefGoogle Scholar
  37. Preston B, Suppiah R, Macadam I, Bathols J (2006) Climate Change in the Asia/Pacific region. CSIRO Marine and Atmospheric Research, Aspendale, p 92Google Scholar
  38. Rehman HU, Nakaya H, Kawai K (2013) Geological origin of the volcanic islands of the Caroline Group in the Federated States of Micronesia, western Pacific. South Pacific Studies 33:101–118Google Scholar
  39. Rooney JJB, Fletcher CH (2005) Shoreline change and Pacific climatic oscillations in Kihei, Maui, Hawaii. J Coast Res 21:535–547. doi: 10.2112/03-0077
  40. Spengler SR (1990) Geology and Hydrogeology of the island of Pohnpei. University of Hawaii, Federated States of MicronesiaGoogle Scholar
  41. Staudigel H, Clague DA (2010) The geological history of deep-sea volcanoes: biosphere, hydrosphere and lithosphere interactions. Oceanography 23:58–71CrossRefGoogle Scholar
  42. Terry JP (2007) Tropical Cyclones: Climatology and Impacts in the South Pacific. Springer, BerlinGoogle Scholar
  43. Victor S, Neth L, Golbuu Y, Wolanski E, Richmond RH (2006) Sedimentation in mangroves and coral reefs in a wet tropical island, Pohnpei, Micronesia. Estuar Coast Shelf Sci 66:409–416. doi: 10.1016/j.ecss.2005.07.025 CrossRefGoogle Scholar
  44. Webb AP, Kench PS (2010) The dynamic response of reef islands to sea-level rise: evidence from multi-decadal analysis of island change in the Central Pacific. Glob Planet Change 72:234–246. doi: 10.1016/j.gloplacha.2010.05.003 CrossRefGoogle Scholar
  45. Woodroffe CD (2008) Reef-island topography and the vulnerability of atolls to sea-level rise. Glob Planet Change 62:77–96. doi: 10.1016/j.gloplacha.2007.11.001 CrossRefGoogle Scholar
  46. Zhang XB and Church JA (2012) Sea level trends, interannual and decadal variability in the Pacific Ocean. Geophys Res Lett 39:Article L21701. doi: 10.1029/2012gl053240

Copyright information

© Springer Science+Business Media B.V. 2017

Authors and Affiliations

  • Patrick D. Nunn
    • 1
    Email author
  • Augustine Kohler
    • 2
  • Roselyn Kumar
    • 1
    • 3
  1. 1.Sustainability Research CentreUniversity of the Sunshine CoastMaroochydoreAustralia
  2. 2.Department of National Archives, Culture and Historic PreservationGovernment of the Federated States of MicronesiaPalikirFederated States of Micronesia
  3. 3.Pacific Studies Programme (OCACPS)University of the South PacificSuvaFiji Islands

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