sea level change Flashcards
why does sea level fall
- water is stored as ice on land
- land emerging
why does sea level rise
- ice melts due to global warming
- thermal expansion
- subsidence of land
what is eustatic sea level change
- global
- when ice melts, volume of water increase and sea level rise
what is isostatic sea level change
- local
- as a result of the weight of ice
- when ice sheets cover land, causes sea level to rise as land is weighed down
what is tectonic sea level change
- the spreading of the ocean floor through plate divergence.
- creates a eustatic fall in sea level
- changes as a change in size of ocean basin
what is isostatic readjustment
when ice melts, the sea level falls because land rises
what human factors cause sea level change
climate warms
steric effect
extraction of resources
how does climate warms affect sea level change
ice melts meaning the volume of water increases
how does steric effect affect sea level change
warming lowers the density of water, the upper layers of the ocean wamr and expand, increasing total volume
how does extraction of resources affect sea level change
removing groundwater and fossil fuels from low lying areas
what natural factors change sea level
climate cools
tectonic activity
glacial rebound
how does climate cools affect sea level chnage
more water as ice means less in oceans
how does tectonic activity affect sea level change
local tilting leads to submergance
how does glacial rebound affect sea level change
gradual rise of land after an ice sheet that one weighed it down
what are the 2 emergent landforms
marine terraces
raiased beaches
what are marine terraces
-formly submerged land is exposed by uplift or lowering sea levels
what are raised beaches
- areas of former wave cut platoforms and their beaches that are at a higher level than current sea level
- common in Scotland where 3 levels are noticed
what are the 4 emergent landforms
fjord
dalmation coasts
ria
submerged forests
what Is a fjord
- drowned glacial valley
- found in Canada
- steep valley sides are straight and narrow
- formed when sea drowned the lower part of a glacier valley
what are dalmation coasts
- when the shape of the land runs parallel to the coast and floods by sea level rise
- coast of croatia
what are ria’s
- created by rising sea level drowing a river valley
- Devon
what are submerged forests
- climate warms and marsh and forests grew but end up drowned
- only tree stumps remain
- In Borth north wales
why is sea level rising
- increased volume of the ocean = warming due to CC, water as ice melts
- subsidence of the coast
impacts of sea level rise
- coastal flooding
- greater migration away from coasts
- increased cost for flood protection
- underwater ground resources has to be moved
- threat to coastal habitats
