GEOL 5705

Seminar in Paleoclimate: Greenhouse Forcings and Feedbacks

Spring 2023

Cenozoic Paleo-CO2
Cenozoic Palaeocean-CO2

Archived past offerings:
Seminar in Paleoclimate: Past Climate Extremes (Spring 2022)
Seminar in Paleoclimate: Presenter's Choice (Spring 2021)
Rapid Warming, Ocean Acidification, and Anoxia: Lessons from the Past (Spring 2019)
Paleoclimate Landmarks and Heroes (Spring 2017)
Paleoclimate Contributions to the 5th IPCC Report (Fall 2015)
Warm Periods of the Earth's Past (Spring 2007)
Rapid Climate Change: Holocene to Anthropocene (Spring 2005)
Recent Developments in Rapid Climate Change Research (Spring 2003)

Course description: This course will entail a weekly seminar-style critical reading of journal articles in paleoclimate (one paper per week, curated by the instructor). This year, we will focus on the causes of past Greenhouse climates (including 'relative' Greenhouse warmth like the Holocene), and feedbacks within those climate states.

Expectations and grading: During the semester, each student will be required to lead the discussion of two papers. Each presenter will be selected one week ahead of time. Papers may be presented informally and with or without visual aids, according to the presenter's preference. The presenter should touch on the paper's main Problem, Claim, Evidence, and Uncertainties. Presenters should encourage discussion by asking questions of the group. Each week, everyone is responsible for reading the paper and participating in the discussions. Readers should also identify and share one part of the paper that they had trouble understanding. Grades will be based on overall participation (50%) and on the effort put into the presentations and discussion-leading (50%).

Meets: Wednesdays 12:20-1:10 pm, BESC 1B81
We may use this Zoom link as necessary (see class email for password)
Instructor: Tom Marchitto,
Office Hours: By appointment
Credits: 1


Course schedule (updated weekly)
We will only be discussing the papers with names assigned after them; any others are for background
Note that most of the links below must be accessed from a campus computer or via a CU VPN
Refresh your browser if links are missing or dead

January 18: No class (snow day)

January 25: Subduction and volcanism
East et al. (2020) Subduction history reveals Cretaceous slab superflux as a possible cause for the mid-Cretaceous plume pulse and superswell events (Tom)

February 1: Weathering intensity
Caves Rugenstein et al. (2019) Neogene cooling driven by land surface reactivity rather than increased weathering fluxes (Rob)

February 8: No class (Tom traveling)

February 15: Organic carbon burial
Li et al. (2023) Neogene burial of organic carbon in the global ocean (Haley)

February 22: Ocean sequestration of CO2
Rafter et al. (2022) Global reorganization of deep-sea circulation and carbon storage after the last ice age (Hayley)

March 1: Lunch with Jody Wycech, Colloquium speaker from USGS

March 8: Cloud feedbacks
Zhu et al. (2019) Simulation of Eocene extreme warmth and high climate sensitivity through cloud feedbacks (Stephanie)

March 15: Tropical Pacific mean state
White and Ravelo (2020) The Benthic B/Ca Record at Site 806: New Constraints on the Temperature of the West Pacific Warm Pool and the “El Padre” State in the Pliocene (Trish)

March 22: Biotic recovery
Lyson et al. (2019) Exceptional continental record of biotic recovery after the Cretaceous–Paleogene mass extinction (Rob)

March 29: No class (Spring Break)

April 5: Sea level
Clark et al. (2020) Oceanic forcing of penultimate deglacial and last interglacial sea-level rise (Hayley)

April 12: Ocean anoxia
Bryant et al. (2021) Microfossil and geochemical records reveal high-productivity paleoenvironments in the Cretaceous Western Interior Seaway during Oceanic Anoxic Event 2 (Haley)

April 19: Antarctic ice
O'Brien et al. (2020) The enigma of Oligocene climate and global surface temperature evolution (Stephanie)

April 26: Seasonality
Bova et al. (2021) Seasonal origin of the thermal maxima at the Holocene and the last interglacial (Tom)

May 3: Calcite burial
Komar and Zeebe (2021) Reconciling atmospheric CO2, weathering, and calcite compensation depth across the Cenozoic (Trish)

List of possible papers that look interesting (a work in progress). Sorted in rough stratigraphic order according to the time period considered. This lists reflects the bias of Tom's interests, and not all may be appropriate for this year's topic. Students are very welcome to make their own suggestions!
Caesar et al. (2021) Current Atlantic Meridional Overturning Circulation weakest in last millennium
Bramante et al. (2020) Increased typhoon activity in the Pacific deep tropics driven by Little Ice Age circulation changes
Lawman et al. (2020) A Century of Reduced ENSO Variability During the Medieval Climate Anomaly
Evans et al. (2022) Intrinsic Century-Scale Variability in Tropical Pacific Sea Surface Temperatures and Their Influence on Western US Hydroclimate
Mann et al. (2021) Multidecadal climate oscillations during the past millennium driven by volcanic forcing (or, The AMO does not exist)
Degroot et al. (2021) Towards a rigorous understanding of societal responses to climate change
Lapointe et al. (2020) Annually resolved Atlantic sea surface temperature variability over the past 2,900 y
Brierley et al. (2020) Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations
Lawman et al. (2022) Unraveling forced responses of extreme El Niño variability over the Holocene
Schimmenti et al. (2022) Insights into the deglacial variability of phytoplankton community structure in the eastern equatorial Pacific Ocean using [231Pa/230Th]xs and opal-carbonate fluxes
Barker et al. (2019) Early Interglacial Legacy of Deglacial Climate Instability
Li et al. (2020) Rapid shifts in circulation and biogeochemistry of the Southern Ocean during deglacial carbon cycle events
Gottschalk et al. (2020) Glacial heterogeneity in Southern Ocean carbon storage abated by fast South Indian deglacial carbon release
Shuttleworth et al. (2021) Early deglacial CO2 release from the Sub-Antarctic Atlantic and Pacific oceans
Nehrbass-Ahles et al. (2020) Abrupt CO2 release to the atmosphere under glacial and early interglacial climate conditions
Lora et al. (2017) North Pacific Atmospheric Rivers and Their Influence on Western North America at the Last Glacial Maximum
Seltzer et al. (2021) Widespread six degrees Celsius cooling on land during the Last Glacial Maximum
Zhu et al. (2021) Assessment of equilibrium climate sensitivity of the Community Earth System Model version 2 through simulation of the Last Glacial Maximum
Repschlaeger et al. (2021) Active North Atlantic deepwater formation during Heinrich Stadial 1
Rae et al. (2020) Overturning circulation, nutrient limitation, and warming in the Glacial North Pacific
Klockmann et al. (2020) Coupling of the Subpolar Gyre and the Overturning Circulation During Abrupt Glacial Climate Transitions
Farmer et al. (2022) The Bering Strait was flooded 10,000 years before the Last Glacial Maximum
Walczak et al. (2020) Phasing of millennial-scale climate variability in the Pacific and Atlantic Oceans
Orihuela-Pinto et al. (2022) Interbasin and interhemispheric impacts of a collapsed Atlantic Overturning Circulation
Orihuela-Pinto et al. (2022) Reduced ENSO Variability due to a Collapsed Atlantic Meridional Overturning Circulation
Windler et al. (2020) Unraveling Glacial Hydroclimate in the Indo-Pacific Warm Pool: Perspectives From Water Isotopes
Geibert et al. (2021) Glacial episodes of a freshwater Arctic Ocean covered by a thick ice shelf
Friedrich and Timmermann (2020) Using Late Pleistocene sea surface temperature reconstructions to constrain future greenhouse warming
Shackleton et al. (2020) Global ocean heat content in the Last Interglacial
Galaasen et al. (2020) Interglacial instability of North Atlantic Deep Water ventilation
Glasscock et al. (2020) Changes in Antarctic Bottom Water Formation During Interglacial Periods
Foerster et al. (2022) Pleistocene climate variability in eastern Africa influenced hominin evolution
Farmer et al. (2019) Deep Atlantic Ocean carbon storage and the rise of 100,000-year glacial cycles
Barker et al. (2022) Persistent influence of precession on northern ice sheet variability since the early Pleistocene
de la Vega et al. (2020) Atmospheric CO2 during the Mid-Piacenzian Warm Period and the M2 glaciation
Bhattacharya et al. (2022) Expansion and Intensification of the North American Monsoon During the Pliocene
Ford et al. (2022) Sustained mid-Pliocene warmth led to deep water formation in the North Pacific
Abell et al. (2021) Poleward and weakened westerlies during Pliocene warmth
Tauxe and Feakins (2020) A Reassessment of the Chronostratigraphy of Late Miocene C3–C4 Transitions
Reichgelt et al. (2020) Elevated CO2, increased leaf-level productivity, and water-use efficiency during the early Miocene
Modestou et al. (2020) Warm Middle Miocene Indian Ocean Bottom Water Temperatures: Comparison of Clumped Isotope and Mg/Ca-Based Estimates
Steinthorsdottir et al. (2021) The Miocene: the Future of the Past
Paytan et al. (2021) A 35-million-year record of seawater stable Sr isotopes reveals a fluctuating global carbon cycle
Rohling et al. (2022) Comparison and Synthesis of Sea-Level and Deep-Sea Temperature Variations Over the Past 40 Million Years
Anagnostou et al. (2020) Proxy evidence for state-dependence of climate sensitivity in the Eocene greenhouse
Inglis et al. (2020) Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene
Sharoni and Halevy (2023) Rates of seafloor and continental weathering govern Phanerozoic marine phosphate levels
Henkes et al. (2018) Temperature evolution and the oxygen isotope composition of Phanerozoic oceans from carbonate clumped isotope thermometry