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The University of Southampton
Engineering

Understanding extreme sea levels for coastal risk and adaptation analysis Seminar

Time:
16:00
Date:
15 November 2016
Venue:
Building 06/1081 L/R B

For more information regarding this seminar, please email Dr Abiy Kebede at A.S.Kebede@soton.ac.uk .

Event details

Impacts of sea-level rise on human settlements and infrastructure primarily occur via extreme sea levels (ESL), which are modulated by mean sea-level rise (MSLR), rather than as a direct consequence of changes in mean sea-level alone. Hence, robust information on both MSLR and ESL is necessary for assessing impacts of and adaptation to MSLR. While substantial research efforts are directed towards quantifying projections and uncertainties of future global MSLR, corresponding uncertainties in ESL have not been assessed and projections are limited. This is exemplified by a very short and rather incomplete chapter on the topic in the 5th Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), compared to an extensive mean sea-level chapter. In my presentation I will discuss, at global scale, the main uncertainties inherent to present-day ESL estimates, which have by default been ignored in broad-scale sea-level rise impact assessments to date. These uncertainties stem from hydrodynamic or empirical models used to simulate storm surges and from statistical methods used to parameterize extreme events. Combined, these uncertainties exceed those from global MSLR projections and, assuming that we meet the Paris agreement, the projected MSLR itself by the end of the century. It will be shown that it is crucial for risk and adaptation analysis to: (1) carefully assess present-day ESL with appropriate extreme value analysis methods, (2) make use of the improved computational capabilities and global reanalysis, and apply advanced dynamical models to simulate coastal sea levels; (3) extend model hindcasts and continue data archeology to obtain long enough time series for robust conclusions; and (4) exploit the rich and constantly growing (in time and space) observational data base to remove model bias wherever possible. The important recent and ongoing improvements in narrowing the uncertainties and providing more robust future MSLR projections are otherwise in danger of being of no benefit due to the uncertainties in ESL.

Speaker information

Dr. Thomas Wahl,is a coastal engineer, who obtained a Diploma and PhD in Civil Engineering at the University of Siegen in Germany. Before joining Engineering and the Environment at the University of Southampton as a Marie Sklodowska Curie fellow he held a postdoc position at the College of Marine Science at the University of South Florida. Through his research Thomas connects engineering and various science disciplines to better understand the vulnerability of coastal societies, built infrastructure, and fragile ecosystems under climate change conditions. He studies changes in coastal sea levels (mean and extreme), ocean waves, and freshwater flows and the associated impacts to support the development of sustainable adaptation strategies. Recently, Thomas has been appointed as Assistant Professor in Civil Engineering and core faculty member of the Sustainable Coastal Systems cluster at the University of Central Florida where he will continue his work in 2017.

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