Influence of the opening of the Drake Passage on the Cenozoic Antarctic Ice Sheet: A modeling approach

Cristini, Luisa; Grosfeld, Klaus; Butzin, Martin; Lohmann, Gerrit

doi:10.1016/j.palaeo.2012.04.023

Cited by 34 publications

(29 citation statements)

References 25 publications

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“…Various studies have shown that changes in the ocean dynamics across the EOT may influence the Antarctic climate conditions as well as the total meridional heat transport [e.g. Huber and Nof, 2006;Cristini et al, 2012]. In our model, the atmospheric meridional heat transport to Antarctica during summer increases with the local meridional temperature gradient, which is maintained predominately by the Antarctic surface conditions.…”

Section: Discussionmentioning

confidence: 79%

The impact of climate‐vegetation interactions on the onset of the Antarctic ice sheet

Liakka

Colleoni

Ahrens

et al. 2014

Geophysical Research Letters

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A global coupled atmosphere/vegetation model and a dynamic ice sheet model were employed to study the impact of climate‐vegetation interactions on the onset of the Antarctic ice sheet during the Eocene‐Oligocene transition. We found that the CO2 threshold for Antarctic glaciation is highly sensitive to the prevailing vegetation. In our experiments, the CO2 threshold is less than 280 ppm if the Antarctic vegetation is dominated by forests and between 560 and 1120 ppm for tundra and bare ground conditions. The large impact of vegetation on inception is attributed to the ability of canopies to shade the snow‐covered ground, which leads to a weaker snow albedo feedback and higher summer temperatures. However, the overall effect of canopy shading on the Antarctic climate also depends on features like local cloudiness and atmospheric meridional heat transport. Our results suggest that vegetation feedbacks on climate are crucial for the timing of the Antarctic glaciation.

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Section: Discussionmentioning

confidence: 79%

The impact of climate‐vegetation interactions on the onset of the Antarctic ice sheet

Liakka

Colleoni

Ahrens

et al. 2014

Geophysical Research Letters

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“…It is not clear which of the two gateways was the last barrier for the ACC [ Barker et al , ; Bijl et al , ]. While this causality is not crucial if one is mainly interested in the exchange of water masses between the Pacific and the Atlantic, it is important for the much discussed impact of these seaways on Antarctic glaciation [ Kennett , ; Toggweiler and Bjornsson , ; DeConto and Pollard , ; Barker et al , ; Zhang et al , ; Sijp et al , ; Cristini et al , ; Lefebvre et al , ; Goldner et al , ].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Central American Seaway and Drake Passage on ocean circulation and neodymium isotopes: A model study

et al. 2014

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The sensitivity of the neodymium isotopic composition (ϵNd) to tectonic rearrangements of seaways is investigated using an Earth System Model of Intermediate Complexity. The shoaling and closure of the Central American Seaway (CAS) is simulated, as well as the opening and deepening of Drake Passage (DP). Multiple series of equilibrium simulations with various intermediate depths are performed for both seaways, providing insight into ϵNd and circulation responses to progressive throughflow evolutions. Furthermore, the sensitivity of these responses to the Atlantic Meridional Overturning Circulation (AMOC) and the neodymium boundary source is examined. Modeled ϵNd changes are compared to sediment core and ferromanganese (Fe‐Mn) crust data. The model results indicate that the North Atlantic ϵNd response to the CAS shoaling is highly dependent on the AMOC state, i.e., on the AMOC strength before the shoaling to shallow depths (preclosure). Three scenarios based on different AMOC forcings are discussed, of which the model‐data agreement favors a shallow preclosure (Miocene) AMOC (∼6 Sv). The DP opening causes a rather complex circulation response, resulting in an initial South Atlantic ϵNd decrease preceding a larger increase. This feature may be specific to our model setup, which induces a vigorous CAS throughflow that is strongly anticorrelated to the DP throughflow. In freshwater experiments following the DP deepening, ODP Site 1090 is mainly influenced by AMOC and DP throughflow changes, while ODP Site 689 is more strongly influenced by Southern Ocean Meridional Overturning Circulation and CAS throughflow changes. The boundary source uncertainty is largest for shallow seaways and at shallow sites.

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“…In the atmosphere, their sink via photolytic destruction in the stratosphere limits their lifetimes to a few thousand years (Ravishankara et al, 1993). The compounds do dissolve in the the ocean and can be used as tracers of ocean circulation, but we are unaware of studies indicating how long these chemicals might survive and/or be detectable in ocean sediment given some limited evidence for microbial degradation in anaerobic environments (Denovan & Strand, 1992).…”

Section: International Journal Of Astrobiology 145mentioning

confidence: 99%

“…Notably, the Eocene Thermal Maximum 2 event (ETM-2), and at least four other peaks are characterized by significant negative carbon isotope excursions, warming and relatively high sedimentation rates driven by increases in terrigenous input (D'Onofrio et al, 2016). Arctic conditions during ETM-2 show evidence of warming, lower salinity and greater anoxia (Sluijs et al, 2009).…”

Section: Eocene Eventsmentioning

confidence: 99%

The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?

Schmidt

Frank

2018

International Journal of Astrobiology

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If an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record. We then propose tests that could plausibly distinguish an industrial cause from an otherwise naturally occurring climate event.

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Influence of the opening of the Drake Passage on the Cenozoic Antarctic Ice Sheet: A modeling approach

Cited by 34 publications

References 25 publications

The impact of climate‐vegetation interactions on the onset of the Antarctic ice sheet

The impact of climate‐vegetation interactions on the onset of the Antarctic ice sheet

Influence of the Central American Seaway and Drake Passage on ocean circulation and neodymium isotopes: A model study

The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?

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