Coastal Zones Flashcards
Sea Level rise case study: East Anglia
What are the causes of Sea Level rise?
Main cause: thermal expansion of seawater- absorbs heat from the atmosphere
Melting glaciers/ ice (from land and sea) will increase the amount of water in the oceans
(but not significantly)
Sea rise case study: East Anglia
What are the social effects of Sea rise in East Angia?
- Loss of homes due to increased erosion 🌊🏡
- Properties devalued as a result
- Loss of jobs- coastal industries shut down due to tourism decrease, damage to work buildings or equipment…
- Migration from the area
Sea rise case study: East Anglia
Géneral effects.
Past 15 years: sea levels have risen on average by 3mm per year (varies from place to place)
The Intergovernmental Panel on Climate Change (IPCC) predicts a rise in global sea levels of between 28 and 43cm by the end of the century. —> dependent on levels of global warming.
In UK, most under threat= South East and East.
—> land is flat and at very low altitudes.
Sea rise case study: East Anglia
Social effects.
Loss of homes
Properties devalued
Loss of jobs:
-coastal industries shut down due to tourism decrease, damage to buildings etc.
Migration from the area
Sea rise case study: East Anglia
Economic effects.
The Thames Barrier will need replacement…
- currently protects buildings worth £80 billion
- will need replacement in the next 30-50 years
- large areas of the lower Thames estuary will be at risk from flooding–> affects housing, industry and farmland.
Flooding of the Norfolk Broads:
- popular tourist destination
- currently bring £5m to the area
- destroys the economy of the area!!
Sea rise case study: East Anglia
Political effects.
Managed retreat will in some places breach sea walls to allow deliberate flooding so that salt marshes can reform—> controversial political decision.
Sea rise case study: East Anglia
Environmental effects.
Many areas are at risk of FLOODING!
-Lower Thames estuary
-The Norfolk Broads
1m sea level change will change will flood London.
Possible storm surges
-East Anglia: in 1953, 300 people were killed by astir surge.
Agricultural land is flooded, eg in THE FENS, Norfolk
Loss of habitats:(
Areas of salt marsh are being squeezed between sea walls and rising sea
-22% of East Anglia’s salt marsh could be lost by 2050.
Cliff collapse case study: Barton-on-sea
What is Barton on sea?
A small settlement affected by Coastal erosion and cliff collapse.
Christchurch Bay is 16km long.
Parts are exposed to waves, with a fetch of 3000km for the Atlantic.
The area is densely populated with a number of towns situation along it. Tourism is important.
Cliff collapse case study: Barton-on-sea
Why are cliffs collapsing?
Marine processes, Sub-aerial processes, Geology, Human activity.
Cliff collapse case study: Barton-on-sea
Explain cliff collapse due to Marine processes.
The base of the cliffs are being attacked by the waves (hydraulic action and abrasion).
The large fetch results in powerful, destructive waves.
Cliff collapse case study: Barton-on-sea
Explain cliff collapse due to Sub-aerial processes.
Weathering is weakening the Rock, they are easily eroded and have little strength to resist collapse.
Slumping and Rock fall is leading to collapse.
Cliff collapse case study: Barton-on-sea
How does the geology of the area worsen cliff collapse?
The rocks are arranged as permeable sands on top of impermeable clay.
This causes water to ‘pond up’ within the cliffs when it rains, so the weight of the cliff increases.
The increase in water pressure within the cliffs encourages cliffs to collapse.
Cliff collapse case study: Barton-on-sea
How does human activity worsen cliff collapse?
Extensive building along the cliff top has resulted in too much weight on the soft cliffs, making them more vulnerable to collapse.
Cliff collapse case study: Barton-on-sea
How do the winds increase cliff collapse?
The Barton-on-sea stretch of coastline faces the direct force of the prevailing south- westerly winds.
The waves have a long fetch as a result so they cause great erosion.
Cliff collapse case study: Barton-on-sea
How do streams increase cliff collapse?
Small streams flow towards the coast, disappearing into the permeable sands before reaching the sea.
This increases water levels in the cliffs… increasing weight…