7.4.3-eng-氣候變化對香港的影響

The impacts of climate change in Hong Kong

The climatic trends observed in Hong Kong are basically consistent with the global trends. As for the future climate in Hong Kong, the Hong Kong Observatory utilized computer climate model data from the Fifth Assessement Report of IPCC to conduct the projection under different greenhouse gas concentration scenarios. The scenarios considered include low concentration, medium-low concentration, medium-high concentration and high concentration.

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Climate Projections for Hong Kong
https://www.hko.gov.hk/climate_change/future_climate_e.htm

Even under the medium-low concentration scenario, the annual number of hot nights and very hot days in Hong Kong will increase significantly. Under the high concentration scenario, the annual number of very hot days at the end of the century will exceed one hundred. For the rest of the century, the number of extremely dry years will be more or less the same as the historical observation. However, the number of extremely wet years will significantly increase. Regardless of the greenhouse gas concentration scenario, sea level in Hong Kong will continue to rise.

Fig 4.18 Future climate of Hong Kong (Source: HKO)


Fig 4.19 As extreme rainfall increases, the risks of flooding and landslides will increase correspondingly.

As the climate warms, the average intensity of tropical cyclones and the associated rainfall will increase. More intense tropical cyclones will be more damaging. Exacerbated by sea level rise, the threat of storm surge will heighten.


Fig 4.20 Over 60,000 reports of fallen trees due to Super Typhoon Mangkhut in 2018	Fig 4.21 Super Typhoon Hato hit the Pearl River estuary in 2017. The storm surge brought about by Hato raised water level in Hong Kong generally by about one to two metres. Coinciding with the high water of the astronomical tide, the aggregated effect caused inundation of many low-lying areas in Hong Kong by sea water. Super Typhoon Mangkhut came in 2018 with record breaking storm surges. The maxium sea level recorded at Quarry Bay was even higher than that recorded during the passage of Hato, causing serious flooding in many coastal and low-lying areas in Hong Kong.