Storm surges, sea-level rise and adaptation responses of the German Baltic coast

 

Reserachers:

Leigh MacPherson

Jan Merkens

 

Background:

Extreme seal levels are a major threat to coastal communities and they are expected to become more severe in warming climate either due to rising mean seal levels or due to potential changes in storminess. Hence, it is utmost importance to adapt coastal zones to increasing sea levels in a changing climate. This is particularly true for the densely populated and micro-tidal environments such as the German Baltic Sea coast, which is very sensitive to changes in sea levels. Despite this, the dynamics of extreme sea levels, their socioeconomic impacts and adaptation responses are poorly understood in this region. Furthermore, many communities are not protected against coastal flooding and there is concern that these could be severely affected in the case of extreme storm surges, with climate change-induced sea-level rise adding to this challenge. Addressing the challenge of adapting to sea-level rise in general and for the Baltic coast in particular requires a close collaboration of a range of natural and social science disciplines and fields. In particular, geophysical science is needed for understanding regional and local processes, which generate extreme sea-level events, geographical science is needed for understanding vulnerabilities, exposure, flood damages, adaptation options and economic and decision sciences are needed for developing effective and robust adaptation pathways.

 

Research Objectives:

Three major research objectives are addressed:

 

  1. To improve the understanding of the occurence of current and future extreme water levels in the German Baltic Sea by developing the local coastal extreme water level statistics and high-end extreme water level scenarios
  2. To improve methods for socio-economic assessment of coastal flood risks by combining hydrodynamic inundation modeling with protection, accomodation and retreat adaptation options
  3. To improve stylized models for regional-scale flood impact assessment and decision-analytical methods for adaptation to sea-level rise under deep uncertainty considering protection, accomodation and retreat options; and to apply thes methods to develop adaptation pathways for the German Baltic Sea coast

 

Methodology:

  • Application of advanced multivariate extreme value statistics to a combination of tide gauge records and the outputs from a high resolution 2D hydrodaynamic-numerical tide+surge model
  • Consideration of high end mean sea level projections in combination with sensitivity analyses of possible changes in storminess (target year: 2100)
  • Detailed segmentation of the German Baltic coastline as basis for the stylized model
  • Assessment of socio-economic impacts, flood characteristics, impacts of extreme events and the effectiveness of different adaptation measures through model simulations
  • Development of a stylized flood impact assessment model combined with a range of suitable decision making frameworks

 

Funding:

German research Foundation (DFG): Priority Program - Regional Seal Level Change and Society

Project Partner: Univerity of Siegen: https://www.bau.uni-siegen.de/fwu/wb/index.html.en?lang=en Global Climate Forum: https://globalclimateforum.org/ Schwerpunktprogramm SSP: https://www.spp-sealevel.de/index.php?id=3130