Historical storm tracks facing climate change in coastal socio-ecological systems – HiStoTracks

In the current context of climate change, coastal extreme events are becoming a major environmental issue. However, many uncertainties remain regarding the evolution of extratropical low-pressure systems at the origin of these storms. In view of the recent occurrences of some major events that have caused dramatic marine submersions (as during the Xynthia event in 2010), or significant damage inland (as during the Lothar and Martin storms during the winter 1999), this hiatus is a major scientific obstacle today. To tackle these scientific challenges, the HiStoTracks project aims to understand the historical evolution of storm tracks along the French Atlantic coast by offering an unprecedented temporal depth, to assess the evolution of these physical processes before the use of meteorological data. The integration of new knowledge will have a direct impact on society, by integrating these issues into coastal planning and post-disaster management, as well as contributing to the development of a risk culture in the societies affected.
The general hypothesis of this project is based on the principle that intense storm tracks can evolve latitudinally over decades, as demonstrated in recent times by the impact of North Atlantic Oscillation (NOA) and Jet Stream cycles on European stormy winters, coupled with a possible poleward shift of low-pressure systems over longer time scales. The aim of this project is therefore to understand whether this type of dynamic is reflected in ancient history, particularly over the last millennium. The project aims to structure a database of stormy impacts identified during the last millennium from multidisciplinary sources (historical and geophysical), to then model the trajectories of the most impactful extreme events identified in France.
Firstly, the delving of historical archives in municipal and departmental archive centers will enrich current data. A mass of spatialized data covering the historical and environmental impacts of the most significant events of the last millennium will thus become available, structured and mappable. A model of the ancient evolution of trajectories will be deployed, firstly with an initial assessment of their variation during the recent past, which will serve as a basis, notably thanks to recent meteorological data. This base will then be extrapolated over the last millennium with the help of ancient qualitative information extracted from archives, which will calibrate the model. The latitudinal evolution of historical trajectories will then be crossed with the main oceanological and climatological indices guiding European stormy activity. By understanding the mechanisms likely to influence this hazard in the past, new knowledge will be brought to identify future trends. A WebSig will be developed as part of this project highlighting the spatialized database and the main storm spatial extent estimated, as well as demonstrators illustrating the results of the historical trajectories modeling. These digital tools will be co-constructed throughout the project with stakeholders subject to these hazards (inter-municipalities, emergency services, scientific mediation players).
This project is therefore at the interface between spatial analysis and the environment. Centered on the digital humanities, it relies on experts in modeling, climatology and geography, national research groups and the support of local authorities and associations to disseminate and popularize this information to coastal area planners, schoolchildren and the general public.