Global warming leads to sea level rise, and its potential impact has attracted wide attention from scientists, social groups and governments all over the world. China's coastline is very long, which will undoubtedly be affected by future sea level rise, especially in the low-lying estuary delta, which is densely populated and economically developed, and is more vulnerable to sea level rise.

The coastline of Chinese mainland is10.8 million kilometers, and the coastal estuary delta and coastal plain are vast. The coastal area below 5 meters above sea level is143,900 square kilometers, accounting for about 1.5% of the national land area. It is a vulnerable area affected by sea level rise, among which the Pearl River Delta, the Yangtze River Delta and the coastal areas of northern Jiangsu, the Yellow River Delta and Penglai Bay are the key vulnerable areas. Under the existing moistureproof facilities, if the sea level rises by 30cm at the historical highest tide level in the future, the possible inundation areas of the three key areas are1153,898 and 21kloc-0/0 square kilometers respectively, and the corresponding inundation losses are13.6 billion and/kloc-0 respectively. The cost of heightening and strengthening the corresponding protective seawall is 65.438+76 billion yuan, 320 million yuan and 560 million yuan respectively. If the sea level rises by 65 cm in the future, the areas that may be submerged in the above three areas are 13453, 2724 1 and 23 100 square kilometers respectively, and the corresponding inundation losses are 41600 million, 41700 million and 6/kloc-respectively. The cost of heightening and strengthening the corresponding protective seawall is 29.1000 billion yuan, 65.438+0.654 yuan and 38+0.000 million yuan, respectively, accounting for 0.009%, 0.006% and 0.003% of the annual average GNP of each region, which is higher than that of developed countries.

When all the glaciers in the North and South poles melt, the sea level of the earth will rise by about 60 meters, and the land on the earth will be reduced by about one fifth. Many metropolises such as Shanghai, Hongkong, Dalian, Macau, Ningbo, Shantou and Qingdao will disappear, Hainan Island will be reduced by two thirds, and Taiwan Province Island will be reduced by three fifths. At least twenty countries in the world have disappeared, including various island countries such as Singapore, Tonga and Tuvalu, and Hawaiian, San Francisco and new york in the United States have all disappeared.