sea level change Flashcards
what is eustatic sea level change
the rise or lowering of sea levels due to a change in the volume of water in the oceans
what is isostatic sea level change
the rise or lowering of sea levels due to a regional uplift or subsidence of the land, land moves relative to sea
how will land moving vertically down affect sea levels
sea levels will significantly decrease
what are the types of eustatic sea level change
-thermal expansion of water
-glacio eustatic sea level rise
what is thermal expansion of water
as global temps rise, the oceans get hotter. water will expand by 4%
what is glacio eustatic sea level rise
as world temps get hotter, big ice sheets start to melt, releasing huge amounts of trapped water into the oceans causing a rise in the sea level
what is an example of glacio eustatic sea level rise
Antarctica is losing ice mass (melting) at an average rate of about 150 billion tons per year,
what are the types of isostatic sea level change
-isostatic adjustment/rebound
-subsidence
-orogeny
what is isostatic rebound
as ice sheets melt over thousands of years time, it releases pressure on the land and over a very long time the land slowly starts to move back up.
what is subsidence
when land becomes water logged, it collapses. this causes a decrease in the relief of land
how can volcanoes affect the relief of land
repeating lava flows can build up land as they cool down
what is orogeny
new mountains forming through the collision of two plates. such as the oceanic and continental plates moving together
how has sea level changed in the past 10,000 years
during the last ice age 110,000-12,000 years ago,sea level was 130m lower than present. in the last 10,000 years ice sheets have started to melt. global sea level is currently rising at about 2mm a year due to thermal expansion of water, global temps have risen by 1.08 degrees between 1900 and 2016.
how has sea level changed in the past 10,000 years
during the last ice age 110,000-12,000 years ago,sea level was 130m lower than present. in the last 10,000 years ice sheets have started to melt. global sea level is currently rising at about 2mm a year due to thermal expansion of water, global temps have risen by 1.08 degrees between 1900 and 2016.
how many mm a year is sea level rise expected to be by 2100
8-15mm a year