Developing a model for coastal cliff erosion

Risk of coastal cliff erosion in the next century is mostly driven by feedbacks between different components of the coastal system – the atmosphere, land and ocean – rather than from the threat from climate change and sea-level rise, according to a new study.

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The research, led by Dr Andres Payo and colleagues at the Environmental Change Institute presents a new methodology for modelling and assessing the role of different feedbacks and processes that affect coastal change.

Coastal managers have significant experience in planning and managing the ever-changing cliff shoreline. However, the need for more resilient coastal systems means that it is necessary to anticipate and plan for future change at timescales as large as 50 to 100 years, posing new challenges for coastal managers and modellers.

To help coastal system modellers address this challenge, this study develops a framework of how different processes interact with each other and the role of a given feedback in the overall cliff system.

A feedback is a change to a component of the coastal system that causes a knock-on effect which further alters the original change. A positive feedback increases the rate of cliff erosion. For example as waves erode the cliff, abrasive material such as sand and gravel will become loose, and the incoming waves will carry these materials, resulting in even more cliff erosion. Negative feedbacks have the opposite effect and decrease the rate of cliff erosion.

The study contributes to the ongoing effort of scientists to identify potential feedbacks, determine their direction of influence, and assess their relative importance. By understanding how the individual and overall feedback strengths are influenced by different future environmental and human intervention scenarios, it will be possible to provide better assessment at the time scales needed for coastal management.

This research was funded by UK Natural Environmental Research Council with support from the Environment Agency as part of the project: iCOASST Integrating Coastal Sediment Systems.

Reference

Payo, A., Hall, J.W., Dickson, M.E. and Walkden, M.J.A. (2014) Feedback structure of cliff and shore platform morphodynamics. Journal of Coastal Conservation. DOI 10.1007/s11852-014-0342-z

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