EQ3 Flashcards
what are the three reasons why sea levels are rising?
Global warming- ice caps and glaciers are melting
thermal expansion- as seas heats up it expands and takes upp more space
tectonics
- thermal expansion (as the sea heats up it expands and takes up more space)
what is eustatic change
when the sea level itself rises and falls. The change is global. In cold glacial periods precipitation falls as snow and forms ice sheets which store the water. At the end of a glacial periods as climate warms, the ice melts and sea levels rise.
whats isostatic change
when the land rises or falls relative to the sea. The change is local. In cold glacial periods the enormous weight of the ice sheets makes the land sink (isostatic subsidence). At the end of the glacial period as the climate warms, the ice melts and the land rises as the weight of the ice sheets reduce (isostatic recovery/ rebound)
what category does thermal expansion come under
eustatic
what category does ice caps and glaciers melting come under
eustatic
what category does terrestrial water storage, extraction of groundwater, building of reservoirs, changes in runoff, and seepage into aquifers come under
eustatic
what category does subsidence in river delta region, land movements and tectonic displacements come under
isostatic
what category does surface and deep ocean circulation changes, storm surges come under
eustatic
Kiribati case study- what is next and why are sea levels rising
- only 1 meter above sea level
- made up of 33 islands
- sea levels are rising due to global warming
- rising sea levels are contaminating groundwater
- people will have to move to Fiji
- population will become environmental refugees
what are submergent coastlines a result of?
sea level rise or isostatic sinking
what are the 4 submergent coastlines?
a ria, a fjord, a fjard, dalmation coats
submergent coastline: whats a ria
Narrow wonding inlet which is deepest at the mouth
- - associated with a rise in sea level
- occur when a valley is flooded
- they are sheltered winding inlets with irregular shorelines
- common in south west England
submergent coastline: whats a fjord
Flooded glaciated u shaped valley with very deep water and steep sides
- - formed when deep glacial troughs are flooded by a rise in sea level.
- the shallower entrance marks where the glacier left the valley
- can be seen in Norway
submergent coastline: whats a fjard
a flooded inlet with low rocky banks on either side
- formed by post glacial drowning of glaciated low and rocky terrain .
- can be seen in the gulf of finland
submergent coastline: whats a dalmatian coast
- rivers flow parallel to the coast
ridges run paralle to the coast
- can be seen in croatia
what are emergent coastlines caused by
a result of isostatic rebound
rise in land
whats an emergent coastline (example)
raised beaches/ fossil cliffs
emergent coastline: how does a raised beach/ fossil cliffs/relic cliffs occur, what is it
as the land rose as a result of isostatic recovery, former shoreline platforms and their beaches were raised above the present sea level.
often the remains of relic cliffs (eroded cliff lines) can be found behind the raised beach, with wave cut notches and caves as evidence of past erosion.
- can be seen on the west coast of scotland
why does past tectonic activity have a direct impact on some coasts across the world, as well as sea levels?
due to the fact that they cause:
they may have a direct effect on the shape of a coast and coastla processes
- uplift of mountain ranges at costal land at destructive and collision plate margins
- local tilting of land, for example, some ancient Mediterranean ports have been submerged and others have been stranded above the current sea level
risk o tsunamis
what are physical factors contributing to costal recession
GEOLOGY(rock type, resistant or not)
MARINE PROCESSES(cpnstructive or destructive)
SUBARIEAL - PROCESSES(weathering, mass movement)
what are human factors contributing to costal recession
- offshore dredging
- costal development
- costal defences/ costal management
- make case study Holderness mind map
located in east yorkshire
-consists of lsd, geogoly, fetch and subariel
geology=unconsilated material-easily eroded- 2m a year
fetch- fetch isnt large norht sea- north sea is relatively depp doesnt experience and friction- hits land at a greater force- more erosion occures.
subariel processes
lsd-casues tgs- groynes paced at hornsea- starved mappleton- causing unequal distribution of sedimemt along the coast
social by 2100 200 homes will be lost
loss of recertional space and amenity value
econ
local tourism loses money, 1.2mil spent on repairs
env
loss of coatsl habists
up to 4m los in some spaces
what is dredging
the removal of material from the seabed- used to make ports, beach nourishment
what are the negatives of dredging
- difficult for kids to do activities (e.g snorkelling)
- removing seafloor species and damaging coral
- increased swell as result of deepening the bay- resulting in erosion and need for costal defences
- sediments converting marine communities