GEOL 5700-8

Super-Problems in Quaternary Climate:
Glacial-Interglacial CO2

Spring 2014

800 kyr of Antarctic temperature and atmospheric CO2

Archived past offerings:
Glacial Ocean Circulation (Spring 2010)
Glacial-Interglacial CO2 (Fall 2008)

Course description: Investigates major problems in the study and understanding of Quaternary climate variation, in seminar format. Each year one major topic will be addressed, such as: the physics and chemistry of the ice age ocean circulation; the theory and mechanics of glacial/interglacial atmospheric CO2 change; or the origins of the 20, 40, and 100 kyr orbital (Milankovitch) climate cycles.

In Spring '14, we will focus on the theory and mechanics of glacial/interglacial atmospheric CO2 change.

Expectations and grading: Students will be required to make presentations on assigned readings from both the historic and current research literature. There will be one or two discussion leaders per week, but everyone is responsible for reading the papers and participating in the discussion. Presentations should go beyond the papers at hand by providing relevant background material that helps to place the papers in the context of previous studies. We are not looking for an exhaustive summary of the reading, but rather a framework from which the group can discuss and better understand the papers. Grades will be based on the quality of presentations (60%) and on overall participation, which includes attendance (40%).

Readings will be available as online pdfs.

Meets: Mondays 1-3, ARC 248
Instructors: Tom Marchitto, tom.marchitto@colorado.edu; Scott Lehman, scott.lehman@colorado.edu
Office Hours: By appointment
Credits: 2

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Course schedule
Note that many of the links below must be accessed from a campus computer or via VPN

Week 1 (M 1/13): Natural carbon cycle and CO2 in seawater (instructor presentations)
Required Reading: Sundquist, The global carbon dioxide budget, Science, 259: 934-941, 1993. (stop when you reach "Historical and Recent CO2 Budget" (p. 937) which is now outdated)
Supplemental Reading: IPCC4, The Physical Science Basis, Chapter 7 provides a good overview of the Earth's current carbon budget

Week 2 (M 1/20): No Class (Martin Luther King Day)

Week 3 (M 1/27): Ice core CO2 records
Required Reading: Petit et al., Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica, Nature, 399: 429-436, 1999. (Hannah)
Required Reading: Monnin et al., Atmospheric CO2 Concentrations over the Last Glacial Termination, Science, 291: 112-114, 2001. (Natalie)

Week 4 (M 2/3): Terrestrial biosphere and the shelf hypothesis
Required Reading: Broecker, Glacial to interglacial changes in ocean chemistry, Progress in Oceanography, 11: 151-197, 1982. (Chris)
Supplemental Reading: Crowley, Ice age terrestrial carbon changes revisited, Global Biogeochemical Cycles, 9: 377-389, 1995.

Week 5 (M 2/10): Coral reef hypothesis
Required Reading: Berger, Deglacial CO2 buildup: Constraints on the coral-reef model, Palaeogeography, Palaeoclimatology, Palaeoecology, 40: 235-253, 1982. (Sarah)
Required Reading: Opdyke and Walker, Return of the coral reef hypothesis: Basin to shelf partitioning of CaCO3 and its effect on atmospheric CO2, Geology, 20: 733-736, 1992. (Simon)

Week 6 (M 2/17): Rain ratio hypothesis & the lysocline constraint
Required Reading: Archer and Maier-Reimer, Effect of deep-sea sedimentary calcite preservation on atmospheric CO2 concentration, Nature, 367: 260-263, 1994.
Required Reading: Sigman et al., The Calcite Lysocline as a Constraint on Glacial/Interglacial Low-Latitude Production Changes, Global Biogeochemical Cycles, 12: 409-427, 1998.

Week 7 (M 2/24): Polar dominance (Harvardton Bears)
Required Reading: Knox and McElroy, Changes in atmospheric CO2: Influence of the marine biota at high latitude, Journal of Geophysical Research, 89: 4629-4637, 1984. (Hannah)
Required Reading: Siegenthaler and Wenk, Rapid atmospheric CO2 variations and ocean circulation, Nature, 308: 624-626, 1984. (Simon)
Required Reading: Sarmiento and Toggweiler, A new model for the role of the oceans in determining atmospheric pCO2, Nature, 308: 621-624, 1984. (Simon)
Follow-up Reading: Broecker et al., How strong is the Harvardton Bear constraint?, Global Biogeochemical Cycles, 13: 817-820, 1999.

Week 8 (M 3/3): Nutrient deepening and polar alkalinity
Required Reading: Boyle, The role of vertical chemical fractionation in controlling late Quaternary atmospheric carbon dioxide, Journal of Geophysical Research, 93: 15701-15714, 1988.
Required Reading: Broecker and Peng, The Cause of the Glacial to Interglacial Atmospheric CO2 Change: A Polar Alkalinity Hypothesis, Global Biogeochemical Cycles, 3: 215-239, 1989.

Week 9 (M 3/10): Polar nutrient utilization
Required Reading: Martin, Glacial-interglacial CO2 change: The iron hypothesis, Paleoceanography, 5: 1-13, 1990. (Sarah)
Required Reading: Sigman et al., The polar ocean and glacial cycles in atmospheric CO2 concentration, Nature, 466: 47-55, 2010. (Chris)

Week 10 (M 3/17): Deep ocean chemical divide
Required Reading: Toggweiler, Variation of Atmospheric CO2 by Ventilation of the Oceanís Deepest Water, Paleoceanography, 14: 571-588, 1999. (Natalie)

Week 11 (M 3/31): Polar stratification and gas exchange
Required Reading: Stephens and Keeling, The influence of Antarctic sea ice on glacialĖinterglacial CO2 variations, Nature, 404: 171-174, 2000. (Simon)
Required Reading: Gildor and Tziperman, Physical mechanisms behind biogeochemical glacial-interglacial CO2 variations, Geophysical Research Letters, 28: 2421-2424, 2001. (Chris)
Required Reading (no presentation): Keeling and Visbeck, Antarctic stratification and glacial CO2 (comment on Sigman and Boyle, 2000), with reply by Sigman and Boyle, Nature, 412: 605-606, 2001.

Week 12 (M 4/7): Nitrogen fixation and silica leakage
Required Reading: Falkowski, Evolution of the nitrogen cycle and its influence on the biological sequestration of CO2 in the ocean, Nature, 387: 272-275, 1997. (Hannah)
Required Reading: Brzezinski et al., A switch from Si(OH)4 to NO3- depletion in the glacial Southern Ocean, Geophysical Research Letters, 29: 1-4, 2002. (Sarah)

Week 13 (M 4/14): Paleo-atmospheric d13C
Required Reading: Schmitt et al., Carbon Isotope Constraints on the Deglacial CO2 Rise from Ice Cores, Science, 336: 711-714, 2012. (Simon)
Required Reading: Burke & Robinson, The Southern Oceanís Role in Carbon Exchange During the Last Deglaciation, Science, 335: 557-561, 2012. (Natalie)

Week 14 (M 4/21): Silicate weathering thermostat
Required Reading: Walker et al., A negative feedback mechanism for the long-term stabilization of Earth's surface temperature, Journal of Geophysical Research, 86(C10): 9776-9782, 1981. (Sarah)
Required Reading: Zeebe and Caldeira, Close mass balance of long-term carbon fluxes from ice-core CO2 and ocean chemistry records, Nature Geoscience, 1: 312-315, 2008. (Hannah)

Week 15 (M 4/28): Long-term fate of fossil fuel CO2
Required Reading: Sinks for anthropogenic carbon, Physics Today, August 2002, pp. 30-36. (Natalie)
Required Reading: Archer, Fate of fossil fuel CO2 in geologic time, Journal of Geophysical Research, 110: C09S05, doi:10.1029/2004JC002625, 2005. (Chris)
Supplemental Reading: Falkowski et al., The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System, Science, 290: 291-296, 2000.