Mr Christopher Sharples1
1University of Tasmania, Hobart, Australia
The approximately 21 centimetres of global mean sea-level rise that has occurred over the last century could in principle have caused some soft shorelines to erode and recede by distances in the order of 10 to 20 metres. However it appears to be widely assumed that whilst this will ultimately occur, it is likely to be some decades before clear physical shoreline responses to sea-level rise will be distinguishable from the “noise” of the many other coastal processes that also drive soft shoreline behaviour. Historical studies of the behaviour of soft Tasmanian shorelines over the 70 year period for which repeated air photo imagery is now available demonstrates that while many soft sandy shores are not showing any significant long-term (multi-decadal) departures from cyclic erosion and recovery behaviour as yet, a smaller number have undergone significant long-term changes (to progressive and accelerating recessional behaviour) that are consistent with expected responses to sea-level rise and climate change (including increasing local wind-wave generation), and which are not readily accounted for in other ways. Work in progress is endeavouring to test the hypothesis that certain types of coastal process environments may allow early morpho-dynamic responses to sea-level rise whilst other ‘late responder’ environments will only show clear physical responses to sea-level rise over longer time frames. Improved capacity to identify early and late responding coastal environments will be of great value in planning for coastal sea-level rise adaptation.
Chris Sharples is a a consulting geologist who has specialised in geomorphology for nearly thirty years and has had a focus on coastal geomorphology for nearly twenty of those. He is currently endeavouring to use a full-time PhD candidature as an opportunity to focus on the identification of sea-level rise impacts on coastal landforms.