OA lecture 5 - Jasmine Flashcards
define mean sealevel (MSL)
Mean sea level: is the average height of the sea over longer periods of time (usually a month or year)
what is filtered out in sea level change
Short-term variations in waves, tides & storm surges are filtered out
how much higher was the last interglacial
Last interglacial (125,000 years ago) sea level 5 m above that of today
when the sea level fells, where was water trapped? how far did the sea level fall?
The sea level fell to >100 m below today; water was trapped in ice sheets during the last ice age.
has the sea level changed much in the past 2000 years?
no- very little
recent changes in MSL how much- during late 19th and early 20th centuries
1.7mm/yr-1
recent changes in MSL how much- 20th century
1.7mm/yr-1
recent changes in MSL how much- 1993-2021
3.3mm/yr-1
identify vulnerable regions to mean sea level rise
Highest risk to changes in MSL are coastal zones with
dense populations
low elevations
appreciable rates of subsidence
and/or inadequate adaptive capacity
Rate of rise is not….
uniform
natural variability in SLR due to…
ENSO
ocean current
3 major contributors to MSL
Thermal expansion;
Glaciers;
Ice sheets (Greenland and Antarctica).
what is the natural process of Melting of glaciers and polar ice caps
Summer: Naturally melt back
Winter: Snow balances out the melting
what have rising temperature caused to the melting of glaciers and polar ice caps
Rising temperatures caused:
greater than average summer melting
reduced snowfall
what has been lost from Greenland + West Antarctica
Melting of small glaciers & polar ice caps projected MSLR ~ 0.5m
Melting of Greenland ice sheet projected MSLR ~ 7.2m
Melting of Antarctic ice sheet projected MSLR ~ 61m