Topic 4, EQ3 Part 2 Flashcards
Why is sea level rising?
The Greenhouse Effect- The release of noxious gases, including carbon dioxide and methane, from the burning of fossil fuels increase the depth of the greenhouse layer in our atmosphere, the Sun’s heat works by radiating through the atmosphere with the majority of it reflecting back out to space, with an increased O-Zone layer less heat escapes and the planet warms up, this can lead to
Thermal Expansion- As the temperature increases water molecules expand in size and increase the volume they exist within, this will increase the global sea level.
Ice Sheets and Glaciers: Ice that melts on land will flow into the sea and exert pressure on the sea and increase the global sea level.
How bad will sea level rise get and will it affect other areas around the globe?
If all the ice in the Antarctic Ice Sheet were to melt, 90% of the world’s freshwater, the sea level would rise globally by 61.1 metres. This (a rise of 2 metres) would put 419,373 properties in the UK at risk, with large areas being in the South East and Norfolk and near the Humber region. It would also threaten to submerge 16% of Bangladesh and displace over 15% of the population (17,000,000). The Maldives many islands could be totally submerged, including the international airport. Lastly, large regions of the Netherlands and Belgium would be at risk of a sea level rise.
How will climate change affect erosion/ deposition?
An increase in the sea level will mean that beaches are flooded and, therefore, waves will erode directly onto sea walls and pre-existing defences and the foundations of buildings, leading to greater erosion. Deposition will increase, groynes could be flooded or destroyed leading to deposition increasing along the coastlines.
How will climate change affect storm frequency, intensity, and storm surge?
If there are more high tides throughout the month there will be a greater chance of this coinciding with low pressure and creating a powerful storm surge. With sea levels higher, if there was to be a drop in pressure to a low pressure the sea level will rise and lead to the storms becoming much more intense and dangerous.
How will storm surges affect people and the environment?
A storm surge will be damaging to coastal defences, thus, leading to a greater spending in defences and damaging the economy. Storm surges will also be dangerous to people, the increased chance of flooding and cliff collapse will increase insurance costing and damage people’s possessions and possibly threaten or inhibit their safety. The environment will suffer too, an increase of storm surges will lead to an increase in destructive waves and damage the coastline and lead to greater coastal erosion, flooding of land could also lead to the destruction of wildlife and plant.
Explain how Groynes and Sea Walls work.
- Groynes will trap sediment from Longshore Drift in wooden barriers built perpendicular to the coastline. This sediment will, over time, increase and form a beach. This beach (compiled sediment) will dissipate the wave energy as the waves hit the shoreline.
- Sea Walls, are curved and will reflect the wave energy back out into the sea, the impenetrable wall can survive from coastal erosion for extended periods of time.
Explain how Beach Replenishment and Slope Stabilisation works.
Beach Replenishment- Sediment and material is either dredged or imported to a beach or unprotected area of coastline, here it is added to pre-existing material and will absorb and dissipate wave energy. It is a form of soft engineering.
Slope Stabilisation- Plants are planted by layering geo-marshes, the roots will bind the sand and sediment together and stabilise the slope. A water/drainage pipe is installed to prevent saturation, thus, preventing mass movement or slope saturation.
What are the advantages and disadvantages for each management type?
Groynes- Groynes are £2000 per metre and will attract tourists through the creation of a sandy or shingle beach. The wood will rot and need maintenance and can appear unattractive.
Sea-Wall- £5000 per metre and can greatly restrict access to beach, they are very effective.
Beach Replenishment- £1/2 to £1 million per kilometre, the process looks relatively natural and cheap but the process must occur multiple times a year, especially after large and destructive storms.
Slope Stabilisation- £1 million per kilometre, very difficult to install but looks natural.
What is the difference between hard and soft engineering? Which is the best option?
Soft engineering- This process looks natural and will not affect tourism, it usually involves small structures which are cost effective and do not inhibit the natural environment, it is usually considered the best option because it looks natural and doesn’t impact the local environment.
Hard engineering- This process involves the use of large structures, usually involving wood or concrete, to stop waves and erosion, it is very costly and can appear ugly and inhibit the natural area and environment. It is effective but the cost can be too much for councils sometimes.
What is Strategic Realignment and which areas might be left to erode?
Strategic realignment is the coastal technique in which areas of low value are left unprotected to erode in order to create better coastal defences for areas of much greater value. Areas which may be left unprotected include agricultural land, very little value, and small villages with little populations, although this can be costly when councils have to pay out on compensation.
Explain why ICZM schemes are a sustainable form of coastal management.
Integrated Coastal Zone Management (ICZM) schemes are sustainable because they allow only the areas of coastline which are important to remain safe and protected, the schemes will also analyse effects of the defences and their cost ensuring a cost effective solution is found which benefits businesses and people along the coast.
