If sea level rose one meter, inundation or more frequent flooding would cover 125,000 square kilometers, home to 73 million people on China's long coastline. Protective dikes are already overtopped during typhoons, coasts are eroding and saltwater intrudes along the four large coastal plains.
Natural subsidence is exacerbated by excessive drawing of groundwater.
But protection of these coasts would be both affordable and economically effective, according to the authors. China began constructing dikes 1,000 years ago, and the rate of protection has been increasing. All of the low-lying areas are now protected to varying degrees. But typhoons may be intensified by global warming. The typhoons have been taking more northerly paths since the 1970s, possibly as a result of global warming, but research is needed to confirm this.