Course description: Paleoclimatology is one of the cornerstones of understanding anthropogenic climate change. Are there past analogs for current levels of atmospheric CO2 and its rate of increase, and if so what was Earth’s climate like? Can we measure the Earth’s ‘climate sensitivity’ (equilibrium response to radiative forcing) using past climate states like the Last Glacial Maximum or the Eocene Climatic Optimum? What rates and magnitudes of global sea level rise is the Earth capable of? How unusual is current warmth compared to the pre-industrial era? These questions and more are addressed in the Paleoclimate chapter of the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5). This course will entail a seminar-style critical reading of the Paleoclimate chapter of AR5, and of many of the primary references that are cited in that chapter. Expectations and grading: Students will be required to make brief AGU-style presentations on assigned readings, and to lead discussions of those readings. There will be one or two discussion leaders per session, but everyone is responsible for reading the papers and participating in the discussions. Grades will be based on overall participation (50%) and on the effort put into the presentations (50%).
Readings: Weekly readings will be taken from IPCC AR5 Chapter 5. Additional readings from the primary research literature will be available below as pdfs. Meets: Fridays 2-4:30, RL1 Mort Turner Room _________________________________________________________________________________
Week 1: Past climate forcings
Week 2: Foram Workshop, No Class
Week 3: High-CO2 worlds and temperatures
Week 4: Glacial-interglacial dynamics
Week 5: Last Glacial Maximum and equilibrium climate sensitivity
Week 6: Past Interglacials
Week 7: Temperatures over the past 2000 years
Week 8: Modes of past climate variability
Week 9: Holocene regional temperatures
Week 10: Holocene sea ice and glaciers
Week 11: Holocene preciptitation: monsoons, ITCZ, megadroughts, and floods
Week 12: Mid-Pliocene sea level
Week 13: Last Interglacial sea level
Week 14: Fall Break, No Class
Week 15: Last deglaciation and Holocene sea level
Week 16: Abrupt climate change and irreversibility (and Wrap-up)
Instructor:
Tom Marchitto, tom.marchitto@colorado.edu
Office Hours: By appointment
Credits: 3
D2L pageCourse schedule (updated weekly)
Note that many of the links below must be accessed from a campus computer or via VPN
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AR5 Reading: 5.1, 5.2, FAQ 5.1, Box 5.1
Tom's powerpoint
Literature Reading: none (below are some key references)
10 Ma of insolation: Berger and Loutre (1991), with data
Holocene solar irradiance: Steinhilber et al. (2009)
1500 yr of volcanic forcing: Gao et al. (2008)
800 ka of pCO2 from ice: Luthi et al. (2008)
4 Ma of Southern Ocean dust: Martinez-Garcia et al. (2011)
AR5 Reading: 5.3.1
Literature Reading:
Lunt et al. (2012) A model–data comparison for a multi-model ensemble of early Eocene atmosphere–ocean simulations: EoMIP (discussion: Simon)
Dowsett et al. (2012) Assessing confidence in Pliocene sea surface temperatures to evaluate predictive models (presentation: Isaac)
AR5 Reading: 5.3.2, Box 5.2
Literature Reading:
Ganopolski and Calov (2011) The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles (discussion: Brigitta)
Shakun et al. (2012) Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation (presentation: Garrett)
AR5 Reading: 5.3.3
Literature Reading:
Schmittner et al. (2011) Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum (presentation: Abby)
Hargreaves et al. (2012) Can the Last Glacial Maximum constrain climate sensitivity? (discussion: Sarah)
Additional Background:
MARGO reconstruction
AR5 Reading: 5.3.4
Literature Reading:
Masson-Delmotte et al. (2010) EPICA Dome C record of glacial and interglacial intensities
Turney & Jones (2010) Does the Agulhas Current amplify global temperatures during super-interglacials?
AR5 Reading: 5.3.5
Literature Reading:
Mann et al. (2008) Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia (presentation: Vikki)
Christiansen and Ljungqvist (2012) The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability (discussion: Garrett)
AR5 Reading: 5.4
Literature Reading:
Olsen et al. (2012) Variability of the North Atlantic Oscillation over the past 5,200 years (presentation: Brigitta)
Braganza et al. (2009) A multiproxy index of the El Niño–Southern Oscillation, A.D. 1525–1982 (discussion: Isaac)
AR5 Reading: 5.5.1
Literature Reading:
Marcott et al. (2013) A Reconstruction of Regional and Global Temperature for the Past 11,300 Years (presentation: Simon)
Kobashi et al. (2011) High variability of Greenland surface temperature over the past 4000 years estimated from trapped air in an ice core (discussion: Abby)
Additional Background Opus:
Wanner et al. (2008) Mid- to Late Holocene climate change: an overview
AR5 Reading: 5.5.2, 5.5.3
Literature Reading:
Wiles et al. (2008) Century to millennial-scale temperature variations for the last two thousand years indicated from glacial geologic records of Southern Alaska (presentation: Sarah)
Polyak et al. (2010) History of sea ice in the Arctic (discussion: Vikki)
AR5 Reading: 5.5.4, 5.5.5
Literature Reading:
Cook et al. (2010) Asian Monsoon Failure and Megadrought During the Last Millennium (presentation: Simon)
Cook et al. (2010) Megadroughts in North America: placing IPCC projections of hydroclimatic change in a long-term palaeoclimate context (discussion: Sarah)
Other interesting papers:
Ely et al. (1993) A 5000-Year Record of Extreme Floods and Climate Change in the Southwestern United States
Meko et al. (2007) Medieval drought in the upper Colorado River Basin
Zhang et al. (2008) A Test of Climate, Sun, and Culture Relationships from an 1810-Year Chinese Cave Record
AR5 Reading: 5.6.1
Literature Reading:
Miller et al. (2012) High tide of the warm Pliocene: Implications of global sea level for Antarctic deglaciation (presentation: Garrett)
Naish et al. (2009) Obliquity-paced Pliocene West Antarctic ice sheet oscillations (discussion: Vikki)
Background on isostatic effects:
Raymo et al. (2011) Departures from eustasy in Pliocene sea-level records
AR5 Reading: 5.6.2
Literature Reading:
Kopp et al. (2009) Probabilistic assessment of sea level during the last interglacial stage (presentation: Abby)
Rohling et al. (2008) High rates of sea-level rise during the last interglacial period (discussion: Brigitta)
Short paper covering the methods used by Rohling in the Red Sea:
Siddall et al. (2003) Sea-level fluctuations during the last glacial cycle
AR5 Reading: 5.6.3, FAQ 5.2
Literature Reading:
Deschamps et al. (2012) Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago (presentation: Vikki)
Kemp et al. (2011) Climate related sea-level variations over the past two millennia (discussion: Isaac & Simon)
AR5 Reading: 5.7, 5.8, 5.9
Literature Reading:
Marcott et al. (2011) Ice-shelf collapse from subsurface warming as a trigger for Heinrich events
DeConto and Pollard (2003) Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2