Abstract: Floods resulting from extreme sea levels are among the costliest natural hazards, causing tens of billions of dollars in economic losses globally each year. Without adaption, such losses are certain to worsen in the decades ahead as sea level rises. Adaptation plans are key to reducing this vulnerability while also avoiding costly overprotection measures. However, their success relies on knowledge of how changes in mean climate affect the likelihood of extreme sea-level events. This effect can occur through both changes in storminess and changes in mean sea level (e.g., sea-level rise). While the effects of sea-level rise on extremes are easy to quantify, the role of changes in storminess is challenging to determine owing to low signal-to-noise ratios. Here, I will demonstrate that spatial coherence in sea-level extremes can be leveraged using Bayesian methods to drastically improve signal-to-noise ratios, allowing confident detection and attribution of changes in event probabilities. I will show that, contrary to the prevailing view, trends in surge extremes and sea-level rise both made comparable contributions to the overall change in extreme sea levels in Europe since 1960. The trend pattern of storm surge extremes reflects a combination of a north–south dipole associated with internal climate variability and a single-sign positive pattern related to anthropogenic forcing. These changes are consistent with a strengthening and eastward extension of the North Atlantic storm track, leading to increased storminess over Northwestern and Central Europe.

Francisco M. Calafat is a senior scientist at the National Oceanography Centre (NOC) in the UK and a former Marie Curie Postdoctoral Fellow (2011-2014). He obtained his PhD in Physics from the University of the Balearic Islands in 2010. Francisco is interested in the physics of sea-level changes, the influence of climate change on extreme weather and, increasingly, the transport of heat by ocean circulation. He is currently the NOC PI on the Sea-level CCI+ project focusing on understanding regional influences on global mean sea level, NOC PI on the 4DAtlantic project to quantify ocean heat transport using satellite data, and Co-I on the EPOC project to explain and predict the Atlantic meridional overturning circulation.

Doctoral thesis defense: "Diagnosing 3D ocean fine-scale dynamics: towards the integration of models, remote-sensing and in-situ observations through deep-learning and variational approaches"  by Eugenio Cutolo.

July 14, 2023

11 a.m.

IMEDEA's Seminar Room (first floor) 

Mediterranean Institute for Advanced Studies, Esporles

The court will be composed of: 

Bruno Buongiorno Nardelli, CNR, President.

Aida Alvera Azcárate, U. Liege, Secretary. 

Vincent Combes, IMEDEA(CSIC-UIB), Vocal.