Due to climate change, the common assumption of stationarity in extreme value analysis of climate extremes has been gradually challenged. The familiar concepts such as a return period and a return level do not apply in a changing climate. To quantify and communicate risk of climate extremes in a changing climate, nonstationarity should be considered carefully. In this chapter, both the concepts and interpretations of return period, return level, failure risk, and reliability under nonstationary condition were interpreted. It was concluded that the two interpretations of the return period became divergent under nonstationary condition, while the two interpretations of failure risk were consistent irrespective of stationarity. Moreover, two examples of risk communication based on generalized extreme value (GEV) distribution for nonstationary climate extremes were presented. In the first example, climate change and its impacts on global air temperature extremes were detected. In the second example, extreme value analysis was firstly applied to precipitation extremes at two weather stations in China. Then, the fitted GEV distribution on historical records was also extrapolated for future risk communication. With these examples, the concepts those were related to risk measure and communication in a changing climate could be easily understood and applied in practice.
Part of the book: Advances in Environmental Monitoring and Assessment