A large proportion of the UK coast is currently suffering from erosion (17% in the UK; 30% in England; 23% in Wales; 20% in Northern Ireland; 12% in Scotland). Almost two-thirds of the intertidal profiles in England and Wales have steepened over the past hundred years, a process which is particularly prevalent on coasts protected by hard engineering structures (this represents 46% of England's coastline; 28% of Wales; 20% of Northern Ireland and 7% Scotland). Both coastal erosion and steepening of intertidal profiles effects are expected to increase in the future due to the effects of climate change, especially sea-level rise and changes to the wave conditions.
The natural response of coastal systems to sea-level rise is to migrate landward according to the roll-over model, through erosion of the lower part of the nearshore profile and deposition on the upper part. This process is accompanied by the onshore transport of sediment. The roll-over model is applicable to estuaries, barriers and tidal flats, and the rate of coastal recession is likely to increase with the rate of sea-level rise. Rocky coasts (hard and soft) are erosional coasts and retreat even under stable sea-level conditions. Their retreat rates are expected to increase as a result of sea-level rise and increased storminess, but along soft-rock coasts, the introduction of cliff material into the nearshore zone may slow down local erosion rates through the formation of beaches. Human activities, such as land reclamation, the building of hard coastal defences and the construction of jetties and marinas significantly impair the ability of coastal systems to respond naturally to changes in the forcing by restricting the free movement of coastal sediments.
It is very important to consider, however, that the coastal response to sea-level rise is very much determined by site-specific factors. These include relative sea-level history, Isostasy is the Equilibrium in the earth's crust such that the forces tending to elevate landmasses balance the forces tending to depress landmasses.isostatic land-level change, solid and drift geology, wave/tide conditions, longshore sediment transport, human impacts and the interactions between different coastal systems. More often than not, it is these site-specific factors that determine the coastal response, rather than a global change in sea level or a regional change in wave climate. Therefore any predictions of coastal response due to climate change will have a low confidence, unless a detailed study is conducted and long-term coastal change data are available.