GEOL 5700-4

Seminar in Paleoclimate
Rapid Warming, Ocean Acidification, and Anoxia: Lessons from the Past

Spring 2019

Archived past offerings:
Seminar in 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. The Earth and its oceans are currently undergoing rapid changes. In less than half a century, the base of the atmosphere has warmed by 0.9C and the top of the ocean has warmed by 0.7C. Sea level is rising at a rate of 30 cm per century. The ocean’s surface pH has dropped by 0.1 (a 25% increase in [H+]), and the whole ocean has lost >2% of its dissolved oxygen. The geologic record is replete with partial analogs for these shifts, and studying them may help us to anticipate what future changes are in store.

Expectations and grading: During the semester, each student will be required to make one formal AGU-style presentation on an assigned reading, and to lead the discussion of that reading. Each student will also be responsible for leading informal discussions of additional papers during the semester. Each week, 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 and discussion-leading (50%).

Meets: Thursdays 2:20-4, SEEC S124
Instructor: Tom Marchitto,
Office Hours: By appointment, SEEC S153C or Benson 435
Credits: 2

List of potential papers (pdf)


Course schedule (updated weekly)
We will only be discussing the papers with names assigned after them; the 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 28: pCO2 over the Phanerozoic
Foster et al. (2017) Future climate forcing potentially without precedent in the last 420 million years (Tom)
Witkowski et al. (2018) Molecular fossils from phytoplankton reveal secular pCO2 trend over the Phanerozoic (Tom)
Radiative forcing from change in CO2 (Foster's equation 6): Byrne and Goldblatt (2014) Radiative forcing at high concentrations of well-mixed greenhouse gases
Landmark use of epsilon-p to infer ancient pCO2: Popp et al. (1989) The post-Paleozoic chronology and mechanism of 13C depletion in primary marine organic matter

February 4: Mechanisms and feedbacks for high pCO2
Lyons et al. (2019) Palaeocene–Eocene Thermal Maximum prolonged by fossil carbon oxidation (Garrett)
van der Ploeg et al. (2018) Middle Eocene greenhouse warming facilitated by diminished weathering feedback (Tanya)
Seminal weathering paper #1: Walker, Hays, & Kasting (1981) A negative feedback mechanism for the long-term stabilization of Earth's surface temperature
Seminal weathering paper #2: Berner, Lasaga, & Garrels (1983) The carbonate-silicate geochemical cycle and its effects on atmospheric carbon dioxide over the past 100 million years

February 11: What's wrong with a little heat?
Fischer et al. (2018) Palaeoclimate constraints on the impact of 2 °C anthropogenic warming and beyond (Jonn)
Frieling et al. (2017) Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum (Riley)
On thermal tolerance in cold-blooded organisms: Sunday et al. (2010) Global analysis of thermal tolerance and latitude in ectotherms
It's not the heat, it's the humidity: Sherwood and Huber (2010) An adaptability limit to climate change due to heat stress

February 18: From mildly warm to hellish
Hoffman et al. (2017) Regional and global sea-surface temperatures during the last interglaciation (Alyssa)
Zambito & Benison (2013) Extremely high temperatures and paleoclimate trends recorded in Permian ephemeral lake halite (Peter)

February 25: Icehouse sea level
Dutton et al. (2015) Sea-level rise due to polar ice-sheet mass loss during past warm periods (Jody)
DeConto & Pollard (2016) Contribution of Antarctica to past and future sea-level rise (Wyatt)
Questioning the ice-cliff instability: Edwards et al. (2019) Revisiting Antarctic ice loss due to marine ice-cliff instability

March 4: Greenhouse sea level
Miller et al. (2005) The Phanerozoic Record of Global Sea-Level Change
Wendler & Wendler (2016) What drove sea-level fluctuations during the mid-Cretaceous greenhouse climate?
Exxon Vail curve: Vail et al. (1977) Seismic stratigraphy and global changes of sea level, Part 4: Global cycles of relative changes of sea level
Exxon Haq curve: Haq et al. (1987) Chronology of Fluctuating Sea Levels Since the Triassic

March 11: Acidification controls and history
Hönisch et al. (2012) The Geological Record of Ocean Acidification (Garrett)
Zeebe (2012) History of Seawater Carbonate Chemistry, Atmospheric CO2, and Ocean Acidification (Riley)
Paper that coined the term 'ocean acidification': Broecker and Clark (2001) A dramatic Atlantic dissolution event at the onset of the last glaciation
PETM, best known analog: Zachos et al. (2005) Rapid Acidification of the Ocean During the Paleocene-Eocene Thermal Maximum

March 18: Calcium carbonate levers and impacts
Ridgwell and Zeebe (2005) The role of the global carbonate cycle in the regulation and evolution of the Earth system (Tanya)
Kiessling and Simpson (2011) On the potential for ocean acidification to be a general cause of ancient reef crises
On the Precambrian role of silica and authigenic clay formation: Isson and Planavsky (2018) Reverse weathering as a long-term stabilizer of marine pH and planetary climate

March 25: Spring Break

April 1: The coming dissolution horizon
Sulpis et al. (2018) Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2 (Alyssa)
Boudreau et al. (2018) The role of calcification in carbonate compensation (Jonn)

April 8: Anoxia and big mass extinctions
Bartlett et al. (2018) Abrupt global-ocean anoxia during the Late Ordovician–early Silurian detected using uranium isotopes of marine carbonates
Penn et al. (2018) Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction (Wyatt)

April 15: Mesozoic Ocean Anoxic Events
Jenkyns (2010) Geochemistry of oceanic anoxic events (Jonn)
Ostrander et al. (2017) Constraining the rate of oceanic deoxygenation leading up to a Cretaceous Oceanic Anoxic Event (OAE-2: ~94 Ma)

April 22: Anthropocene hypoxia
Breitburg et al. (2018) Declining oxygen in the global ocean and coastal waters (Alyssa)
Ito et al. (2017) Upper ocean O2 trends: 1958–2015 (Tanya)

April 29: Final thoughts
Kast et al. (2019) Nitrogen isotope evidence for expanded ocean suboxia in the early Cenozoic (Garrett)
Nolan et al. (2018) Past and future global transformation of terrestrial ecosystems under climate change (Wyatt)
On the recent past and future of drought (bumped): Cook et al. (2018) Climate Change and Drought: From Past to Future