coastal risks

• sea level change

  isostatic change

  isostatic change refers to the level of the land

  during an ice age, the weight of the ice forces the land to sink
• eustatic change

  eustatic change is the rising and falling of sea levels influences by ice ages

  water is stored as ice which causes the sea level to fall
• tectonic change

  tectonic change causes land to either rise of sink at the boundaries where tectonic plates meet
• submergent coastlines

  a submergent coastline cause the formation of rias, fjords and Dalmatin coastlines

  • a ria is a flooded river valley formed when rising sea levels flood the valley
  • a fjord is an example of a flooded glaciated valley formed when a glacier erodes vertically, creating a u-shaped valley
  • Dalmatian coastlines are formed because of the arrangement of alternating rock types parallel to the coast
• emergent coastlines

  • cause the formation of raised beaches and fossil cliffs caused by isostatic rebound
  • a raised beach and fossil cliff are formed when the land rebounds such as fife, scotland
• rising sea levels

  higher sea levels could cause higher tides and this would increase the frequency of coastal flooding

  higher tides could remove more material from beaches, leaving cliffs less protected
• global warming

  changes in the worlds temperatures are causing thermal expansion of the oceans, melting of glaciers and ice sheets
• increased frequency of storms

  the strong winds caused by storms create high energy, destructive waves which have erosional power

  the increased energy of the sea will mean more material can be transported and for greater distances

  this could lead some areas more vulnerable to erosion
• dredging involves the removal of sediment for use in construction

  this process has been linked to increased rates of coastal retreat
• subaerial processes combine to increase the rate of coastal recession
• hard engineering can disrupt sediment cells and reduce the amount of sediment that can be stored
• the rate of coastal recession varies and is caused by several factors, these include: short and long-term wind direction, tides, seasons, weather systems and storm occurrence
• weather systems are influences by areas of high pressure, creating anticyclones, and areas of low pressure, creating depressions
• increased belts of high pressure reduce the rate of coastal recession because this leads to calmer weather
• belts of low pressure systems cause unsettled weather conditions
• during the winter season , the rate of coastal erosion tends to be greater than during summer
• winter brings stormy weather linked with higher tides and long wave fetch
• wind direction controls the movement of waves, influencing the rate of coastal erosion
• a dominant wind direction causes powerful destructive waves to attack the coastline
• tides are linked to gravitational pull, when the pull is at its strongest there are high tides, when the pull is at its weakest, there are low tides
• the Maldives

  the removal of mangroves is leading to an increased risk of flooding with increased wave height and less stable cliffs
• mangroves would normally act as a barrier, helping to dissipate the waves energy before it reaches land
• Bangladesh

  in Bangladesh, storm surges threaten the lives of those living near the coast

  the rate of coastal erosion is expected to increase in the future id storm surge events continue
• climate change is changing the frequency and intensity of low-pressure depressions and tropical storms
• rising global temperatures are causing our oceans to warm, triggering these low pressure systems