Abstract
The IPCC 4th Report indicates that the global mean sea level will increase and tropical cyclone may become more intense. The change in water level and waves due to the climate change is one of critical factors in the life extension plan of coastal defense facility. This paper, therefore, reviews the current design storm water level and offshore wave from a view of their return periods. Then, this paper summarizes the current scientific knowledge on the past and future change in mean sea level, storm surges, and waves, and then propose a method to give the future storm water level and offshore wave criteria for the performance evaluation of coastal defense facility at each year during the lifetime. These criteria are determined using the same concept as the current design but considers the climate change effects. Moreover, this paper discusses on a few technical issues, such as the design criteria for new or upgraded facility, the level 2 storm water level, and the continuity of wave and tide monitoring.
