1. The relationship between average annual surface temperature, accumulation and ablation rates, and glacial mass balance

2. Milankovitch Theory:
When 65N summer insolation low, ice accumulates and have glaciation
When 65N summer insolation high, ice ablates and have interglaciation
Note: orbital configuration of maximum and minimum

5. Model Assumptions
Temperatures get colder and accumulation/ablation ratio increases with increasing altitude and latitude
Equilibrium line is at higher elevation towards the south, meets Earth’s surface (sea level) at climate point
Climate point moves N or S in direct proportion to summer insolation
Moves >10 degrees latitude over several 10’s of thousands of years
When it is N of continental edge, continents are ice free
When it dips onto continent, ice accumulates
Elevation of ice adds to accumulation area

11. Timing of insolation forcing and ice sheet response
Rate responds to forcing
Minimum insolation – maximum rate of ice accumulation
Maximum ice volume occurs during period of rising insolation as much of ice sheet is still in accumulation area
Lag between minimum insolation and maximum ice volume is ~¼ of one cycle

14. Activity:
Write out the ice-elevation feedback
Note this feedback is reduced once the ice is so high that little moisture makes it to the interior of the ice sheet

21. Benthic foraminiferal d18O record for last full glacial-interglacial cycle

22. Spectral analysis of:
Summer insolation (65N)
Benthic foram record Ma
Benthic foram record 0.9 – 0 Ma

24. Corals as record of past glacial/interglacial cycles:
Reefs created on uplifting coastlines are good records of past sea level
Uplift separates reefs formed during different sea level events, even if absolute sea level was similar (escalator effect)
Correcting for uplift makes it possible to calculate initial sea level