Coastal hazards pose a significant risk to people, property, and infrastructure in the UK and worldwide. Extreme events already have very significant detrimental impacts to coastal ecosystem and lead to large economic impacts. Coastal hazards will be increasing over the next century driven by unavoidable sea level rise and other aspects of climate change. 

Challenges 

Challenge 1: Current modelling tools cannot determine the effects of multi-hazards driven by extreme weather on the coast

Coastal flooding and erosion mainly happen in response to extreme weather events like storms. Individual aspects of these events can be hazardous (e.g. wind, rain, waves, surges, etc) but it is the collective impact from multi-hazards that commonly matters. By multi-hazard, we mean specific contexts where hazardous events (e.g. wind, rain, surge, waves, etc in our case) may occur simultaneously, cascadingly or cumulatively over time, and taking into account the potential interrelated effects.

Multi-hazards often lead to impacts that are far greater than the sum of the parts. Not being able to understand the effects of multi-hazards means that we cannot predict the consequences of the ‘’perfect storm’’ and we cannot develop effective and sustainable solutions.

Large-scale (e.g. UK scale) coastal hazard modelling systems have not yet been brought together and fully integrated across terrestrial and marine sectors and so cannot fully assess the role of multi-hazards in controlling extreme hydrodynamics, and thus coastal flooding and erosion. 

Challenge 2: The role of realistic complexes of co-located coastal habitats is poorly understood

Both coastal flooding and erosion are significantly controlled by local biogenic and abiogenic habitats. The protective services provided by individual habitats such as saltmarsh and to a lesser extent seagrass and kelp stands, have been documented. However, the cumulative and emergent protective services generated by realistic complexes of co-located coastal habitats in temperate settings are rarely (i) considered beyond simplistic groupings of common habitats and (ii) expanded to regional and national scales. 

Habitats at the land-ocean interface are also at risk themselves, and the long-term vulnerability of these habitats to climate change needs to be considered, at the national scale, to understand the longevity of these services for situations where nature-based solutions may be relied upon long-term. 

Challenge 3: We have very limited understanding of how nature-based solutions function across generic coastal systems

Approaches that work with natural processes are now championed around the world to help protect the coast. This means that a wider range of management options has become available, which in turn increases the complexity of decision making. Existing schemes have typically been developed at local scales and feasibility studies often rely on detailed case-specific high-complexity numerical modelling. Yet, much can be learned about the response of the coast from simplified analyses for generic coastal systems.