Global warming has accelerated the rise of sea level, and has become or will become a major disaster in the coastal zone. In the past 100 years, the average sea level in the world has increased by about 12 centimeters. By 2100, the sea level will rise by 1 meters. If no protective measures are taken, first of all, large areas of land and many coastal cities should be submerged. Nearly 70% of the coastal zones around the world, especially the flat delta plain, will invade twenty or thirty to fifty or sixty kilometers, or even farther, by Cheng Zeguo. Many of the world's famous cities on it, such as New York, London, Amsterdam, Venice, Sydney, Tokyo, Rio De Janeiro, Tianjin, Shanghai, Guangzhou, will be flooded. Some low-lying islands in the South Pacific and India ocean will be semi submerged. And Maldives will disappear because the island's altitude is 1~2 meters above sea level.