Identifying and addressing the components of extreme physical-oceanographical events for improved risk management in coastal systems

Eric 'Pieter Achterberg^1*Fabian Rackelmann²Ananya Ramesh²Jack O'Connor²Ovidio García-Oliva³Saranya Jayachandran¹Viktoria Wichert³Xiangyu Li⁴Kaveh Purkiani⁵David Michael Needham¹Ingeborg Bussmann⁶Philipp Friedrich Fischer⁶Achim Kopf⁷Carsten Lemmen³Jörn Peter Scharsack⁸Christian Siebert⁹Norbert Kamjunke¹⁰Inna Sokolova¹¹Holger Brix³

• ¹GEOMAR Helmholtz Center for Ocean Research Kiel, Helmholtz Association of German Research Centres (HZ), Kiel, Germany
• ²United Nations University Institute for Environment and Human Security, Bonn, Germany
• ³Helmholtz-Zentrum Hereon, Geesthacht, Germany
• ⁴Leibniz-Institut fur Ostseeforschung Warnemunde, Rostock, Germany
• ⁵Bundesamt fur Seeschifffahrt und Hydrographie, Hamburg, Germany
• ⁶Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung, Bremerhaven, Germany
• ⁷Universitat Bremen Zentrum fur Marine Umweltwissenschaften, Bremen, Germany
• ⁸Johann Heinrich von Thunen-Institut Institut fur Fischereiokologie, Bremerhaven, Germany
• ⁹Helmholtz-Zentrum fur Umweltforschung UFZ Department Bodensystemforschung, Halle (Saale), Germany
• ¹⁰Helmholtz-Zentrum fur Umweltforschung UFZ Standort Magdeburg, Magdeburg, Germany
• ¹¹Universitat Rostock, Rostock, Germany

Extreme physical-oceanographic events, such as marine heatwaves, fluvial floods, droughts and storm surges, have major impacts on local communities, economic sectors and ecosystems, and their frequency, intensity and duration increase due to climate change. There is a lack of understanding of the systemic drivers of extreme events as well as of their interconnected impacts on estuarine and coastal ecosystems. This knowledge is essential for assessing future impacts on ecosystem services and the local communities that depend on them, and to inform robust risk assessments and develop comprehensive risk management and adaptation strategies including early warning systems. Considering this, the German Alliance for Marine Research (DAM)-funded programme "ElbeXtreme" focuses on an integrated approach utilising stakeholder engagement, data mining, experimental and field observations to develop novel observational and modelling approaches for assessing and monitoring risks in the Elbe estuary. The programme will deliver new insights into risks and impacts of extreme events in the estuarine system of the Elbe and the adjacent region of the North Sea (German Bight) to build a systemic risk understanding and support adaptation planning for local communities and ecosystems. Here we outline the rationale of the ElbeXtreme project and its planned activities, with the aim of stimulating national and international collaboration in tackling the urgent issue of marine and coastal risks.