Statistical Methods for Assessing Flood Risk and the Climate Change Challenge*

Actual and potential effects of climate change and climate variability will increasingly challenge hydrologists, civil engineers and planners concerned with flood risk. In general, it is difficult to understand flood risk in particular areas as available records tend to be limited. Our flood quantile estimators are more uncertain than people realize. If we recognize historical climate variability and climate change in our analyses, we will learn that we know even less. In many cases, it is not even clear whether global warming will increase or decrease flood risk. So the challenge is to use all the information available on past floods and future climate, along with a deep understanding of hydrologic processes, to forecast flood risk in the future.