Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region
In: Natural hazards and earth system sciences: NHESS, Volume 23, Issue 7, p. 2475-2504
ISSN: 1684-9981
Abstract. Coastal floods, driven by extreme sea levels, are one of the most dangerous
natural hazards. The people at highest risk are those living in low-lying
coastal areas exposed to tropical-cyclone-forced storm surges. Here we
apply a novel modelling framework to estimate past and/or present and future storm-surge-level and extreme-sea-level probabilities along the coastlines of southern
China, Vietnam, Cambodia, Thailand, and Malaysia. A regional hydrodynamic
model is configured to simulate 10 000 years of synthetic tropical cyclone
activity, representative of a past/present (1980–2017) and high-emission-scenario future (2015–2050) period. Results show that extreme storm surges, and therefore total water levels, will increase substantially in the coming decades, driven by an increase in the frequency of intense tropical
cyclones. Storm surges along the southern Chinese and northern and southern Vietnamese
coastlines increase by up to 1 m, significantly larger than expected changes in mean sea-level rise over the same period. The length of coastline that is presently exposed to storm surge levels of 2.5 m or greater will more than double by 2050. Sections of Cambodian, Thai, and Malaysian coastlines are projected to experience storm surges (at higher return periods) in the
future, not previously seen, due to a southward shift in tropical cyclone
tracks. Given these findings, coastal flood management and adaptation in
these areas should be reviewed for their resilience against future extreme
sea levels.