Sea Level Rise in Hong Kong Expected to Accelerate Towards End of the Century

Sea Level Rise in Hong Kong Expected to Accelerate Towards End of the Century

Tong Hang-wai

Mean sea level rise projections for Hong Kong and its adjacent waters under high and medium-low greenhouse gas concentration scenarios

The Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), published in September 2019 by the Intergovernmental Panel on Climate Change, has revised upward the global mean sea level rise projection. Based on the latest data provided by SROCC, the Observatory has also revised the mean sea level rise projections for Hong Kong and its adjacent waters. In the high greenhouse gas concentration scenario, the annual mean sea level in Hong Kong and its adjacent waters in 2091-2100 (incorporating the effect of local vertical land displacement) is expected to be 0.73 – 1.28 m higher than the average of 1986-2005; the sea level rise in 2100 is about 10% higher than the previous projection.

The threat of storm surge caused by tropical cyclones will increase in tandem with the sea level rise. Extreme high sea level events that are now rare will become more frequent, and the situation may be even worse as the average intensity of tropical cyclones may increase worldwide.