Modelling the impacts of climate change on an eroding coast over the 21st Century.

TitleModelling the impacts of climate change on an eroding coast over the 21st Century.
Publication TypeTyndall Working Paper
SeriesTyndall Centre Working Papers
Tyndall Consortium Institution


Secondary TitleTyndall Centre Working Paper 103
Keywords21st Century, eroding coast, impacts of climate change, Modelling
AuthorsDickson, M. E., M. Walkden, and J. Hall
Year of Publication2006

A numerical model detailing the functioning and emergent behaviour of an eroding coastal system is described. Model output from a 50-km study region centred on the soft-rock shore of northeast Norfolk, was verified through comparison with cliff recession rates that were extracted from historical maps spanning more than a century. Predictions were then made for the period 2000 to 2100 under combined climatic change and management scenarios. For the scenarios evaluated, the model was relatively insensitive to increases in offshore wave height and moderately sensitive to changes in wave direction, but the most important effects were associated with accelerated sea-level rise (SLR). In contrast to predictions made using a modified version of the Bruun rule, the systems model predicted a complex suite of responses to SLR. For instance, on some sectors of coast, whereas the Bruun rule predicted accelerated recession under SLR, the systems model actually predicted progradation owing to the delivery of sediment from eroding coasts up-drift. By contrast, on coasts where beaches are underlain by shore platforms, both the Bruun-rule and the systems model predicted accelerated recession rates. However, explicit consideration of the interaction between beach and shore platform within the systems model indicates that these coasts have a broader range of responses and lower overall vulnerability to SLR than predicted by the Bruun-rule.

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