Coasts (Sea Level Change) Flashcards
Outline the global sea level change and predictions
Rising almost 2mm every year - forecasted to increase to 4 or 5 mm a year
Define Eustatic sea level change
Sea level change caused by the change in volume of H2O in the sea/shape of ocean basins
Outline the tectonic cause of Eustatic sea level change
Tectonic movement of the Earth’s crust that change the shape of ocean basins
e.g: Sea floor spreading increases volume of basin - decrease sea level
Outline the 2 causes Eustatic sea level change through climate change
- Increase in temp - melting ice sheet & expands H2O to expand - increase sea level
- Decrease in temp - snowfall, increases volume stored in glaciers - decreases sea level
What are the impacts of Eustatic sea level change
Global
Define Isostatic sea level change
Vertical movement of land relative to sea
e.g
Downward movement of land - sea level rise
Upward land movement - sea level fall
Outline the effects of Isostatic sea level change
Local
Outline the causes of Isostatic sea level change
- Tectonic = uplift or depression occurs mostly at plate boundaries
- Compression/decompression - ice sheet accumulation/melting
- Subsidence of land due to shrinkage after abstraction of groundwater
Outline the impact on flooding due to sea level change
More frequent & more severe flooding
More rises = more flooding
E.g 20th century St Mark’s Square in Venice flooded <10 times/yr
1996 - flooded almost 100 times
Outline the impact on submergence of low-lying islands due to sea level change
Disappeared as sea level risen - risk
e.g
If sea level rises by 0.5m from current level - most of Maldives submerged
Outline the impact on coastline changes due to sea level change
Islands created & area of land decreases
e.g
Over 10,000 years sea level rise Britain separated from mainland Europe.
If 0.3m rise from current level 8000km^2 of Bangladesh lost
Outline the formation of RIAS landforms
River valleys - partially submerged
Gentle cross/long profile
Wide & deep at mouth
Become narrower & shallower further inland
Outline the formation of FJORD landfroms
Like rias
Drowned glacial valleys
Straight, narrow, steep sides, shallow mouth caused by raised bit of ground.
Deep further inland
Outline the formation of a Dalmatian Coastline
Valleys lie parallel to the coast - increase in sea level causes flooding - islands parallel to coastline
Outline the formation of a coastline of emergence
Sea level falls - new coastline emerges
Different landforms
Outline the 2 landforms made on coastlines of emergence
- Raised beaches - sea level exposes wave-cut platforms & their beaches
Beach sediment vegetated - develops into soil - Relict cliffs - ciffs above raised beaches no longer eroded by sea, slowly covered by vegetation
Degrade over time forming caves, arches, etc
Outline the case study of Kiribati
Consists of 33 islands in Pacific Ocean - USA length stretch
Low-lying sand islands (1m or less above sea level)
Outline the predictions of the sea-level change’s impact on Kiribati
Many islands could disappear in the next 50 years - sea level rising by 1.2cm a year
What did the president of Kiribati do in 2014?
Purchased 20km^2 of land from Fiji
Outline the impact of rising sea levels on Kiribati what is being done to solve this?
Groundwater contaminated by seawater - impacts crop growth short term
Threatens food security long term
Fiji used as a resource for agriculture & fish farming
Outline Kiribati’s ‘migration with dignity’ policy
Allowed ppl to apply for jobs in neighbouring countries like New Zealand.
If submerged Kiribati residents will become environmental refugees
