Climate And Sea Level Change Flashcards
What is the Quaternary period?
The period where humans evolved.
Why do we have a lot of evidence about what’s happened in the quaternary period?
Because it’s recent so less information is lost.
How do we find out what’s happened in the past?
We use palaeoecological material to see the past
How many cycles are in between glacial and interglacial periods?
103
How do we know if a certain era was interglacial or glacial?
Oxygen isotopes
What journal links to oxygen isotopes and orbital forcing?
Haysetal Science 1976
What proxies do we measure in ice cores?
Oxygen isotopes-temp Deuterium excess-humid activity Conductivity (SO4)- volcanic activity CO2, CH4, N2O- Atmosphere Dust- moisture
What causes glacial and interglacial changes?
Orbital forcing
What do ice sheets respond to?
Summer isolation via temp
What does orbital forcing do?
It changes the temp
What are the 3 types of sea level change?
Isostatic
Eustatic
Steric
What are the two types of isostatic sea level change?
Hydro-isostacy (refers to the earth’s response to changes in surface ice and water loading during glacial cycles)
Glacial-isostacy (the process of depression beneath the weight of an ice sheet from the crust and upper mantle and subsequent rebound when the ice mass is reduced or removed)
Which type of sea level change measures a change in volume?
Eustatic
What does steric sea level change measure?
Salinity and the density of water as well as temperature
How can Eustatic sea level change come about?
Melting ice
Freshwater flooding
This has a massive impact!
What are the 5 natural causes of climate and sea level change?
Vegetation Atmosphere Ice Land surface Ocean
What are the 5 human impacts of climate and sea level change?
Increased sea level Increased rear line air temp Increased surface temp Increased surface air temp Decrease in summer arctic sea-ice extent
What do we do when we record ice cores?
We record annual layers of ice and trapped bubbles. The centre of the ice sheet is the best because there’s less deformation of the annual layers.
What was the green Sahara?
An example of how climate has changed dramatically. The Sahara used to house animals like elephants so it wasn’t just a desert. These changes are due to the monsoon.
How does a monsoon come about?
It is driven by the temperature difference between the land and sea.
