Impacts of climate change on coastal erosion
Gerd Masselink and Paul Russell
Masselink, G. and Russell, P. (2013) Impacts of climate change on coastal erosion, MCCIP Science Review 2013, 71-86, doi:10.14465/2013.arc09.071-086
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A large proportion of the coastline of the UK and Ireland is currently suffering from erosion (17% in the UK; 20% in Ireland) and of the 3,700 km coastline of England and Wales 28% is experiencing erosion greater than 10 cm per year
The natural response of coastal systems to sea-level rise is to migrate landward, through erosion of the lower part of the nearshore profile and deposition on the upper part. The roll-over model is applicable to estuaries, barriers and tidal flats. Rocky coasts are erosional coasts by their nature and retreat even under stable sea-level conditions. Where the coast is protected by engineering structures, coasts are generally experiencing a steepening of the intertidal profile.
Coastal response to sea-level rise is strongly determined by site-specific factors and usually it is these factors that determine the coastal response, rather than a global change in sea level or a regional change in wave climate. Any predictions of general coastal response due to climate change are therefore rather meaningless and will have a low confidence. However, if a detailed study is conducted and long-term coastal change data are available, then local or regional predictions of coastal response to climate change can have medium confidence.
In the absence of a clear understanding of the coastal-change processes, and therefore a reliable predictive tool, the default position is to assume that present-day coastal change will persist; however, it is very likely that currently eroding stretches of coast will experience increased erosion rates due to sea-level rise.
The coastal management strategy (e.g., hard coastal defences, beach nourishment, managed realignment) is also a key aspect for determining the long-term response of the coast to climate change effects, including sea-level rise. Managed realignment is likely to increase in the future as a key management strategy and although this will result in increased local erosion rates, the enhanced erosion may benefit other sections of coast by reducing erosion or even causing accretion. Adaptation is emerging as the key coastal management paradigm to cope with coastal erosion.