Tropical-cyclone data and the statistics of tropical-storm casualties and damagesince the 1950s were collected and analyzed. The results show that annual and decadelongvariations are obvious in the annual number of tropical cyclones generated over thewestern North Pacific (including the South China Sea), those making landfall inmainland China, and those that induced disastrous storm surges. It is worthy notingthat these variations are not always in phase. For example, an active year for more cyclonesin the western North Pacific may have fewer landing in China, or vice versa.Also, the tropical cyclones that make landfall do not always cause storm-surge disasters.It sometimes happens that a year with more but weaker tropical cyclones making landfallhas fewer storm-surge events than a year with fewer but more intense storms. In thelong term, the tropical cyclone landfall probability has been gradually increasing sincethe mid 1960s. Over the past twenty years, major storm-surge disasters have occurredmore frequently but there have been fewer overall tropical cyclones. This has beenlinked to El Niño Southern Oscillation (ENSO) phases, in that fewer but more intensetropical cyclones influence China in the El Niño year.The intensity of disastrous storm-surges is obviously site-specific, strongly related tothe intensity and tracks of tropical cyclones reaching land, local tidal ranges and tidalphase, the standard of coastal region infrastructure and public education regarding offlood dangers. Since global warming can be expected to increase tropical cyclone intensityand storm surges, some countermeasures should be strictly carried out, includingperfecting the tropical cyclone and storm-surge warning services, elevating the standardsof coastal infrastructures, and improving public awareness of disaster defense.

长江三角洲人地相互作用经历了三个大的发展阶段，在此过程中人对环境的影响不断增强。早期人类的生活和生产方式主要依附于三角洲的自然环境，人们的生产活动场所也受制于三角洲发育的影响。之后人们逐渐采取适应自然变化的措施，力争能与自然协调发展。随着人口增长，经济发展、技术进步，过度的人类活动已使长江三角洲生态环境不断恶化。主要的问题包括地面沉降、洪涝灾害、污染、盐水入侵和海岸侵蚀等，三角洲已经成为全球变化的主要脆弱区之一。由于影响长江三角洲环境的因素众多，关系复杂，以及人类的主动适应能力，目前难以确定三角洲系统的气候变化阈值，即超过它系统将发生不可逆转的衰退。