Sea level change Flashcards
How do we know sea levels have changed in the past?
Submerged cities, terrestrial fossils below sea levels, marine fossils on land, raised beaches.
How long has the Quaternary Ice Age (now) been around for?
Past 2.7 million years.
How can we measure modern sea level change?
Tidal gauges in some locations, satellites.
What provides the most accurate measurements of sea level changes and why?
Satellites because tidal gauges are not located all over the world.
Is sea level rise the same everywhere?
No.
What is the average global increase in sea level?
3mm per year.
How significantly does sea sea ice/ice burgs contribute to sea level rise?
Very little because most sea ice/ice burgs are already underwater (only see top of them on water surface).
What does the Analogue Approach involve?
Looking back at past sea levels and global temperatures to predict rising sea levels. This is useful for predicting long-term changes e.g. over centuries.
What do temperature rises lag behind?
CO2 rises - when CO2 emissions in atmosphere increase it does not cause warming immediately.
What do sea level changes lag behind?
Temperature changes - it e.g. takes time to melt ice.
What can cause glaciers to move towards oceans faster?
Increased melting of top of glacier causes water to move through the cracks which increases lubrication and makes the glacier move faster.
What does the extrapolation approach involve?
Looking at how sea level rise has changed historically.
Name some likely impacts of rising sea levels.
Loss of countries e.g. Tuvalu (population being taken by New Zealand), cities e.g. London threatened by more powerful and frequent storm surges.
