1. Glacial-Interglacial Variability Records of the Pleistocene Ice Ages
Antarctic and Greenland Ice Cores
Glacial-Interglacial Variability Records of the Pleistocene Ice Ages
740 kyr - Present
Vostok
European Project for Ice Coring in Antarctica (EPICA)

2. Ice Coring

3. Temperature and Greenhouse Gases from Ice Core Records
Greenhouse Gases trapped in air bubbles:
Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O)
Oxygen isotopes from benthic forams are a proxy for ice volume
Variations of Deuterium (heavy isotope of Hydrogen) used as a proxy for temperature change

4. Glacial-Interglacial cycles during past ~450 kyr are of large amplitude and last approximately 100 kyr
Interglacial warm periods constitute only about 20% of the time and were similar in length to the Holocene
Earlier interglacials were generally colder on average
Compare to
modern levels:
CO2 (370 ppm) CH4 (1750 ppb)
N2O (315 ppb)

5. How do the Glacial-Interglacial variations in greenhouse gases (GHGs) compare with the Industrial Era GHG increase?

6. Gray bars
show range
of natural
variability
N2O
CO2
CH4

7. Probably about 3 pages single-spaced Use images and references
Homework #9
Introduction (justification, background?)
Description of Experiments
Description of GCM you are using
Attach print outs of Simulation Summary and Rundeck for all runs you set up
Probably about 3 pages single-spaced
Use images and references

8. Glacial/Interglacial Cycles Orbital Variations and the Ice Ages
(Sea Level Change)

9. Solar Irradiance Across Latitude and Time
DJF
Ann.
JJA

10. Orbital Variations Eccentricity Obliquity Precession of the Equinoxes
(OmegaT in EdGCM)
Milankovitch Cycles

11. No Can GCMs simulate the onset of Ice Ages? Sort of
Gallimore and Kutzbach (1996) suggested that tundra increase and boreal forest decrease may have helped trigger ice ages.
But, not really
Other models don’t get this result and the distribution of snow accumulation was not correct in G&K
115,000 solar insolation based on orbital parameter changes.
+ reduced CO2
+ ground albedo increase (tundra expansion)
+ more albedo increase
(boreal forest reduction)
Gallimore and Kutzbach, Nature, 1996

12. Sea Level Rise: Last Glacial Maximum to Present

13. Sea Level Rise:
Sea Level Rise

14. Onset of melting during last interglacial period
Last interglacial melting begins (135kyr BP)
Max N.H. summer insolation last interglacial (135kyr BP)
Most recent interglacial melting begins (15kyr BP)
Max N.H. summer insolation current interglacial
(15kyr BP)
Overpeck et al., Science, 2006

15. Source of sea level rise during last interglacial
Evidence that West Antarctic Ice Sheet (WAIS) contributed to sea level rise during last interglacial includes ice core temperature data showing a substantial warming over East Antarctica despite the lack of a significant insolation signal at that latitude. A

16. GCM Simulations of Climate Change in Greenland and Antarctica:
Last Interglacial & Future Global Warmings
AD2130
Anomaly
(~4xCO2)
Last Interglacial
Anomaly
AD2100
Anomaly
Modern

17. GCM Simulations of Climate Change in Greenland:
Current Global Warming (EdGCM, GISS Model II)
∆ minus

18. GCM Simulations of Climate Change in Greenland:
Current Global Warming (EdGCM, GISS Model II)
∆ minus

19. GCM Simulations of Climate Change in Greenland:
Current Global Warming (Observations)