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Mean sea level projection for Hong Kong

Mean sea level projection for Hong Kong
Rainfall

Mean sea level

 Temperature

Under the intermediate (SSP2-4.5) and very high (SSP5-8.5) greenhouse gas emissions scenarios, the annual mean sea level in Hong Kong in 2100 is likely to rise by 0.37 - 0.82 m and 0.57 - 1.08 m respectively relative to the average of 1995-2014 (1.45 m above Hong Kong Chart Datum [Note]). To indicate the potential impact of deeply uncertain ice sheet processes, low confidence scenarios under SSP1-2.6 and SSP5-8.5 are also considered by IPCC. In the longer term, sea level is committed to rise for centuries to millennia due to continuing deep ocean warming and ice sheet melt.

Projected changes in the mean sea level in Hong Kong and its adjacent waters

Projected changes in annual mean sea level in Hong Kong relative to the average of 1995-2014. Coloured solid curves and the grey broken curve show median projections under the 5 emissions scenarios and the SSP5-8.5 Low Confidence scenario respectively. Black horizontal lines indicate median projections in 2100. Coloured bars indicate likely ranges in 2100 under the 5 emissions scenarios. The probability for the likely range to cover the outcome is at least 66%. The grey bar indicates the 17th-83rd percentile range of projection in 2100 under the SSP5-8.5 Low Confidence scenario. (Data source: IPCC AR6)


With rising sea level, the threat of storm surges brought by tropical cyclones will correspondingly increase (see diagrams below). Rare extreme sea level events nowadays will become more frequent. The situation could be even worse as the global mean tropical cyclone intensity is likely to increase.

storm surges

 

» Mean sea level projection data

» Observed change in mean sea level


Note: Reference location: Quarry Bay

 

Data source:

  1. Fox-Kemper, B., H. T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S. S. Drijfhout, T. L. Edwards, N. R. Golledge, M. Hemer, R. E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I. S. Nurhati, L. Ruiz, J-B. Sallée, A. B. A. Slangen, Y. Yu, 2021, Ocean, Cryosphere and Sea Level Change. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In press.
  2. Garner, G. G., R. E. Kopp, T. Hermans, A. B. A. Slangen, G. Koubbe, M. Turilli, S. Jha, T. L. Edwards, A. Levermann, S. Nowikci, M. D. Palmer, C. Smith, in prep. Framework for Assessing Changes To Sea-level (FACTS). Geoscientific Model Development.
  3. Garner, G. G., T. Hermans, R. E. Kopp, A. B. A. Slangen, T. L. Edwards, A. Levermann, S. Nowikci, M. D. Palmer, C. Smith, B. Fox-Kemper, H. T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S. S. Drijfhout, T. L. Edwards, N. R. Golledge, M. Hemer, R. E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I. S. Nurhati, L. Ruiz, J-B. Sallée, Y. Yu, L. Hua, T. Palmer, B. Pearson, 2021. IPCC AR6 Sea-Level Rise Projections. Version 20210809. PO.DAAC, CA, USA. Dataset accessed [2021-08-24] at https://podaac.jpl.nasa.gov/announcements/2021-08-09-Sea-level-projections-from-the-IPCC-6th-Assessment-Report.
  4. We thank the projection authors for developing and making the sea-level rise projections available, multiple funding agencies for supporting the development of the projections, and the NASA Sea-Level Change Team for developing and hosting the IPCC AR6 Sea-Level Projection Tool.