Journal of the Korean Society of Marine Environment & Safety (해양환경안전학회지)

The Korean Society of Marine Environment and safety (해양환경안전학회)
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Review on Coastline Change and Its Response Along the Cotonou Coast, Benin in the Gulf of Guinea, West Africa

서아프리카 기니만에 있는 베냉 코토누의 해안선 변화와 대응에 대한 고찰

  • Yang, Chan-Su (Marine Security & Safety Research Center, Korea Institute of Ocean Science & Technology) ;
  • Hong, Hyeyeon (Marine Security & Safety Research Center, Korea Institute of Ocean Science & Technology) ;
  • Shin, Dae-Woon (Department of Convergence Study on the Ocean Science and Technology, Ocean Science and Technology School)
  • 양찬수 (한국해양과학기술원 해양방위안전연구센터) ;
  • 홍혜연 (한국해양과학기술원 해양방위안전연구센터) ;
  • 신대운 (한국해양대학교 해양과학기술대학원 해양과학기술융합학과)
  • Received : 2021.07.14
  • Accepted : 2021.08.27
  • Published : 2021.08.31
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Abstract

The global surface temperature has risen critically over the past century and according to the IPCC Fifth Assessment Report 2014, existing risks in natural and human systems will worsen. Coastal erosion is mostly caused by climate change and among all the coastal areas at risk, Benin, which is part of the Gulf of Guinea, has been ranked very highly as a vulnerable region. Therefore, in this review, we focus on the evolution of coastline change in Cotonou of Benin, summarizing its resultant impacts and applied measures around the coast area by reviewing previous studies. Signs of coastal erosion in Cotonou appeared in 1963. After 39 years, the east shoreline of Cotonou has retreated by 885 m, resulting in the disappearance of more than 800 houses. To solve this problem, Benin authorities built seven groynes in 2013, and have increased the number of the structure as a way to interrupt water flow and limit the movement of sediment. Over the region, shorelines appeared preserved accordingly. In contrast, areas located further east, where groynes were not installed, have suf ered from intensive erosion at a rate of 49 m/yr. In the future, as a next step, the effectiveness of groynes should be studied with local and broader perspectives.

지난 한 세기 동안, 지구 표면 온도는 급격히 상승했다. 급격한 기온 상승은 심각한 지구 기후 변화를 초래한다. 2014년 IPCC 5차 평가보고서에 따르면 현재 추세대로 기온이 계속 상승하면 해수면 상승 현상처럼 자연 및 인간 체계에 위험이 가해지는 것으로 조사되었다. 해안 침식의 위험이 있는 모든 해안 지역들 중에서 기니만에 위치한 베냉은 매우 높은 취약 지역으로 나타났다. 이 보고서에서는 선행 연구들을 참고하여 코토누의 해안선 변화의 진행과정에 초점을 맞추어 이와 같은 변화의 영향을 조사하고, 연안 침식 방지 조치들의 적용 결과를 요약하였다. 베냉의 코토누에 있는 해안 침식의 징후는 1963년에 나타나기 시작했다. 코토누 동쪽의 해안선은 39년간 약 885 m 후퇴했고, 토지 손실과 함께 800여 채의 가옥이 없어졌다. 이 문제를 해결하기 위해 베냉 당국은 2013년에 7개의 돌제를 건설했고, 이후 추가 설치를 진행하였다. 설치 지역의 해안선은 해변 보호가 되고 있었다. 반면 돌제가 설치되지 않은 돌제 동쪽 지역은 연간 49 m의 집중 침식을 겪고 있다. 따라서 다음 단계로 돌제의 효과는 국지적 관점뿐만 아니라 더 넓은 관점에서 연구되어야 한다.

Keywords

Acknowledgement

This research is a part of the projects entitled "Exploring the potential for the development of the Gulf of Guinea's blue economy and Policy research service on the use of diplomacy", funded by the Ministry of Foreign Affairs in Republic of Korea and "NOAA-MOF Joint Project (Temporal Variations of Beaches and Coastal Dunes on the East Coast of Korea)".

References

  1. Boer, W. de, Y. Mao, G. Hagenaars, S. de Vries, J. Slinger, and T. Vellinga(2019), Mapping the sandy beach evolution around seaports at the scale of the African continent. Journal of Marine Science and Engineering, Vol. 7, No. 5, p. 151. https://doi.org/10.3390/jmse7050151
  2. Bokonon-Ganta, E.(1999), Vulnerabilite et adaptation du secteur sante - etablissements humains - littoral au changement climatique, Universite Nationale du Benin / Faculte des Lettres, Arts et Siences Humaines, 54.
  3. Britannica(2021), https://www.britannica.com/place/Gulf-of-Guinea (Accessed Apr-2021).
  4. Choi, K. H., J. S. Kim, and J. C. Lee(2016), Migration of coastal erosional hotspots due to coastal protection structures. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D. M. and McCarroll, R. J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Vol. 1, No. 75, pp. 1062-1066. https://doi.org/10.2112/SI75-213.1
  5. Codjia, C. L., J-M Dubois, J-P Donnay, A. Ozer, F. Boivin, and A. Lavoie(1997), Application de la teledetection a l'etude des changements urbains et des transformations du littoral a Cotonou (Benin). Teledetection des milieux urbains et periurbains, AUPELF-UREF 6, Liege, pp. 299-306.
  6. Colleuil, B.(1984), Un modele d'environnement lagunaire soumis aux conditions des climats equatoriaux temperes: le lac Nokoue, Universite de Bordeaux, 135.
  7. Dossou, K. M. R. and B. Glehouenou-Dossou(2007), The vulnerability to climate change of Cotonou (Benin): the rise in sea level. Environment and Urbanization, Vol. 19, No. 1, pp. 65-79. https://doi.org/10.1177/0956247807077149
  8. Gomez, M. L. A., O. J. Adelegan, J. Ntajal, and D. Trawally (2020), Vulnerability to coastal erosion in the Gambia: empirical experience from Gunjur. International Journal of Disaster Risk Reduction, Vol. 45, No. 101439.
  9. IPCC(2007), International Panel on Climate Change, AR5 Synthesis Report: Climate Change 2007.
  10. IPCC(2014), International Panel on Climate Change, AR5 Synthesis Report: Climate Change 2014.
  11. Kang, Y. K. and C. B. Hong(2016), Development of new coastal erosion management method using wave direction control system (1); new CeM: tendency of coastal erosion and measures, and suggestion of new CeM. Korean Society of Coastal Disaster Prevention, Vol. 3, No. 1, pp. 14-35. https://doi.org/10.20481/kscdp.2016.3.14
  12. KNMI(2021), Royal Netherlands Meteorological Institute, https://climexp.knmi.nl/plot_atlas_form.py (Accessed Jun-2021).
  13. Longueville, F. D., Y. C. Hountondji, L. Assogba, S. Henry, and P. Ozer(2020), Perceptions of and responses to coastal erosion risks: The case of Cotonou in Benin, International Journal of Disaster Risk Reduction, Vol. 51, No. 101882.
  14. MEHU(2003), Ministere de l'Environnement, de l'Habitat et de l'Urbanisme. Strategie nationale de mise en oeuvre au Benin de la convention cadre des Nations Unies sur les changements climatiques, UNDP and UNITAR, p. 80.
  15. Melet, A., R. Almar, and B. Meyssignac(2016), What dominates sea level at the coast: a case study for the Gulf of Guinea. Ocean Dynamics, Vol. 66, pp. 623-636. https://doi.org/10.1007/s10236-016-0942-2
  16. Mensah, C., A. T. Kabo-bah, and E. Mortey(2017), Assessing the effects of climate change on sea level rise along the Gulf Of Guinea. Journal of Energy and Natural Resource Management, Vol. 4, No. 1.
  17. NASA(2019), NASA GISS: NASA News and Feature Releases: New Studies Increase Confidence in NASA's Measure of Earth's Temperature, 2019, May 23, https://www.giss.nasa.gov/research/news/20190523/ (Accessed Jun-2021).
  18. Ndour, A., R. A. Laibi, M. Sadio, C. G. E. Degbe, A. T. Diaw, L. M. Oyede, E. J. Anthony, P. Dussouillez, H. Sambou, and E. B. Dieyei(2018). Management strategies for coastal erosion problems in West Africa: analysis, issues, and constraints drawn from the examples of Senegal and Benin, Ocean Coast Management, Vol. 156, pp. 92-106. https://doi.org/10.1016/j.ocecoaman.2017.09.001
  19. WMO(2021), World Meteorological Organization, https://worldweather.wmo.int/en/city.html?cityId=259 (Accesed Jun-2021).
  20. Worldometer(2021), https://www.worldometers.info (Accessed May-2021).