Dr. Thomas Wahl (Assistant Professor, UCF CECE)

Title: Sea-level rise and storm surges, relationship status: complicated!

Abstract

Increasing coastal flood risk is one of the major consequences of mean sea level rise (SLR) and will make a costly adaptation, and in extreme cases migration to higher ground, inevitable. Extensive research has been directed toward reconstructing past SLR and developing global and regional SLR projections, which are used in impact and adaptation studies to facilitate risk-informed decision making. These projections do not account for the significant temporal variability that is evident in most sea-level records at seasonal to multi-decadal time scales. Furthermore, in order to understand coastal impacts under current and future climate and socio-economic conditions, not only robust SLR projections are required but also a profound knowledge of the drivers and occurrence of present-day and future extreme sea levels (ESL), as ESL drive the impacts. Finally, recent events like hurricanes Harvey or Irma have highlighted the vulnerability of coastal cities to combined storm surge and precipitation/discharge events, which can lead to compound flooding. While the relationship between the two flood drivers in coastal areas is well-known, current risk assessment techniques are mainly univariate (i.e., consider one driver at the time) and ignore the dependence between them leading to underestimation or overestimation of the underlying risk. In my presentation, I will discuss some of the abovementioned drivers in changes of coastal flood risk (with a focus on the U.S. Gulf and east coast) which have been widely ignored in previous assessments but are important to be accounted for to fully understand the potential impacts and adaptation needs.