The impact of climate changes on coastal flooding hazard

in South and East China Seas

Extreme coastal flooding events caused by heavy rainfall and/or typhoon-induced storm surge are among the most deadly and destructive natural hazards in the coastal regions along South and East China Seas. Because of their dense populations, rapid-developing economy, low elevations, appreciable rates of land subsidence, and/or inadequate adaptive capacity, coastal cities in these regions are most vulnerable to coastal flooding. Such extreme weather events will likely become more frequent or more devastating in future climate due to sea level rise and changing storm climatology. Yet this region is one of the least studied areas in terms of the potential impact of climate changes (IPCC, AR5).

Figure 1: Coastlines along South, East China Seas are one of the most vulnerable regions to coastal flooding caused by future relative or climate-induced sea-level rise. Figure cited from [Nicholls and Cazenave, 2010]

To better understand how climate changes affect coastal flooding hazard along the heavily populated coasts of South and East China Seas and prepare coastal communities for such flooding hazard, we take this NUS-TSU cooperation opportunity and propose an interdisciplinary research project, bringing climate scientists, hydrologists and hydrodynamic experts in this region together and building a strong inter-academic institutional collaboration.

Figure 2: Typhoon tracks in the Northwest Pacific during 1884-2015. The track files are downloaded from International Best Track Archive for Climate Stewardship (IBTrACS) through ftp://eclipse.ncdc.noaa.gov/pub/ibtracs/v03r08/all/shp/basin. The tracks are plotted against GEBCO_2014 Grid data with 30 arc-second interval (http://www.gebco.net/data_and_products/gridded_bathymetry_data/). SCS represents South China Sea and ECS represents East China Sea.

This project has four objectives:

  1. Build a regional coastal hazard database that will collectively synthesise historical typhoon and storm surge events, based on instrumental records, written documents and geological evidences in South and East China Seas
  2. Develop a system of deterministic numerical models coupling atmospheric (wind and pressure), hydrodynamic (ocean wave, tide, and surge), and hydrological (precipitation and flooding) processes. This system of models will be calibrated and validated by historical events and can be used to estimate the potential impact of a future event
  3. Investigate the effects of climate-induced changes and other environmental changes: e.g., sea level rise, storm climatology and land subsidence, etc. The contribution of each affecting factor will be studied by simulating numerous extreme weather events under present climate conditions and future climate conditions
  4. Develop deterministic coastal flooding hazard maps (worst case scenario) and probabilistic coastal flooding maps under present and future climate conditions in selected coastal cities (e.g., Shanghai, Ningbo, Macau, Kaohsiung, Zhuhai, Singapore, Hong Kong, Taiwan, Vietnam, etc.)

The significance of this project lies not only in establishing a knowledge based platform for studying the dynamics of typhoon/surge in the region, but also in developing tool kits and information to prepare coastal communities in the region for such flooding hazard. Most importantly, the project will be a forum for researchers and scholars in the region to discuss how we should adjust our behaviour regionally and globally to reduce the impact of climate change process in the face of further anthropogenic climate warming.

Project supported by the NUS-Tsinghua funds, sponsored by the Ng Teng Fong Charitable Foundation (Hong Kong)