4.1.3. Resistant layer and sea-level rise
Climate change is accelerating rates of sea-level rise through thermal
expansion of the oceans and melting of land-based ice. Tide gauge records
indicate that global sea-level has risen at a mean rate of 1.7 (1.5
to 1.9) mm/yr between 1900 and 2010 and 3.2 (2.8 to 3.6) mm/yr between
1993 and 2010 (IPPC, 2013). Understanding and quantifying
shore profile response to such changes is a key challenge facing coastal
geomorphologists (Dubois, 2002). Walkden and Dickson (2008) applied
the 2D SCAPE model to assess the response of soft rock shores
fronted by low volume beaches to different rates of sea-level rise.
They demonstrated how profiles steepen with accelerated rates of rise
and presented an expression to predict future rates of cliff recession
based on historic recession and historic and future sea-level rise. To investigate
how vertical variations in resistance interact with sea-level
rise, simulation 1.4 studied the effect of a 3m thick resistant layer (baseline
at 2 m below MSL) subjected to different rates of sea-level rise.