 This removes material, resulting in undercutting and possible collapse of unsupported overhanging cliffs.This erosion can threaten structure or infrastructure on coastlines, and the impact will very likely increase as global warming increases sea level rise.Seawalls are sometimes built-in defense, but in many locations, conventional coastal engineering solutions such as sea walls are increasingly challenged and their maintenance may become unsustainable due to changes in climate conditions, sea-level rise, land subsidence, and sediment supply.