Geomorphic modelling is a key method to understand the soft cliff recession process to predict future rates of
retreat and responses to climate change. A range of process-basedmodels have been used; however the influence
of varied vertical lithology has yet to be quantified. This paper describesmodifications to the 2D SCAPE (Soft Cliff
and Platform Erosion) model, carried out to explore such interactions between vertical changes in cliff resistive
strength and prevailing coastal conditions. As expected, weaker (/more resistant) layers lead to more (/less)
rapid retreat. However, this effect is strongly influenced by the position of such layers relative to mean sea
level, where the erosive potential is greatest. Moreover, model simulations reveal that layers of variable
resistance give an asymmetric response in terms of both rates of retreat and the timeframe for the effect to be
realised. For example, a reduction of material strength of 1/5 (in comparison to the remainder of the cliff)
about mean sea level results in a rapid 130% increase in the rate of retreat in comparison to the introduction of
a five times more resistant layer of the same characteristics. This variation in response can be attributed to the
different magnitudes of feedback governing profile reshaping associated with the change in lithology. For
example, the introduction of a weaker layer amplifies erosion through its greater erosive potential combined
with steepening of the overlying section. The results have important implications for themanagement of coastal
cliffs exhibiting variable stratigraphy, combined with the potential for future interactions with sea-level rise.