Ocean and climate response to North Atlantic seaway changes at the onset of long-term Eocene cooling

Vahlenkamp, Maximilian; Niezgodzki, Igor; Vleeschouwer, David De; Lohmann, Gerrit; Bickert, Torsten; Pälike, Heiko

doi:10.1016/j.epsl.2018.06.031

Cited by 37 publications

(61 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among studies using Eocene geographies, some find similar results with a shift in deep convection zones and AABW strengthening in response to Antarctic Ice Sheet building (Goldner et al, 2014;Kennedy et al, 2015;Kennedy-Asser et al, 2019). However, model gateway opening experiments yield different results concerning the stability of deep convection in the Weddell Sea and show that the response might be model dependent and/or rely on paleogeographic differences, notably in the North Atlantic-Arctic area (Hutchinson et al, 2019;Vahlenkamp et al, 2018).…”

Section: Intermediate/deep Ocean Changesmentioning

confidence: 99%

“…Previous model studies using modern geography indicate the onset of NADW formation following DP opening (Mikolajewicz et al, 1993;Nong et al, 2000;Sijp et al, 2009;Sijp & England, 2004Toggweiler & Bjornsson, 2000;Yang et al, 2014). Several geographic changes might, however, be necessary to simulate the onset of NADW formation, notably the closure of the Panama Seaway and the closure of the Arctic-Atlantic gateway (Bice et al, 2000;Hutchinson et al, 2018Hutchinson et al, , 2019Roberts et al, 2009;Vahlenkamp et al, 2018;Yang et al, 2014). As discussed in details by Ladant et al (2018), there is significant variability in NADW reconstruction among model studies, and the geometry and depth of the Panama Seaway are likely instrumental in the existence of NADW in models using a modern geography (Ladant et al, 2018;Mikolajewicz et al, 1993;Sepulchre et al, 2014;Zhang et al, 2012).…”

Section: Circulation Changes and The Absence Of Nadwmentioning

confidence: 99%

“…In experiments with an Eocene paleogeography, the connection between the Arctic Ocean and the North Atlantic has been described as a controlling factor in the onset of NADW formation (Hutchinson et al, 2018(Hutchinson et al, , 2019Roberts et al, 2009;Vahlenkamp et al, 2018). In these experiments, a connection between both basins hampers deep convection in the North Atlantic because of Arctic freshwater inputs.…”

Section: Circulation Changes and The Absence Of Nadwmentioning

confidence: 99%

“…However, the existence of North Pacific Deep Water in the Late Cretaceous/Paleogene Ocean is still debated. Indeed, North Pacific sinking is absent from several recent Eocene ESM simulations (Baatsen et al, 2020;Farnsworth et al, 2019;Kennedy et al, 2015;Lunt et al, 2016;Vahlenkamp et al, 2018). Additionally, recent ε Nd samples from the tropical and equatorial Pacific Ocean argue against the possibility of deepwater formation in the North Pacific until at least the latest Cretaceous (Haynes et al, 2020).…”

Section: Paleoceanography and Paleoclimatologymentioning

confidence: 99%

“…Conversely, DP opening in the low-resolution FOAM general circulation model produces a smaller impact in terms of temperature and ocean circulation in an Eocene configuration with high CO 2 levels compared to a modern one (Zhang et al, 2010(Zhang et al, ). et al, 2015Kennedy-Asser et al, 2019;Vahlenkamp et al, 2018). These studies describe an ACC with a moderate intensity during the Eocene/Oligocene (around 4 to 46.2 Sv; Kennedy et al, 2015), which strengthens as a result of pCO 2 decrease, Antarctic Ice Sheet formation, and opening of the Southern Ocean (up to 89 Sv; Hill et al, 2013;Kennedy et al, 2015;Ladant et al, 2014a;Lefebvre et al, 2012;Zhang et al, 2010).…”

Section: Introductionmentioning

confidence: 96%

See 4 more Smart Citations

Quantifying the Effect of the Drake Passage Opening on the Eocene Ocean

Toumoulin

Donnadieu

Ladant

et al. 2020

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

The opening of the Drake Passage (DP) during the Cenozoic is a tectonic event of paramount importance for the development of modern ocean characteristics. Notably, it has been suggested that it exerts a primary role in the onset of the Antarctic Circumpolar Current (ACC) formation, in the cooling of high‐latitude South Atlantic waters and in the initiation of North Atlantic Deep Water (NADW) formation. Several model studies have aimed to assess the impacts of DP opening on climate, but most of them focused on surface climate, and only few used realistic Eocene boundary conditions. Here, we revisit the impact of the DP opening on ocean circulation with the IPSL‐CM5A2 Earth System Model. Using appropriate middle Eocene (40 Ma) boundary conditions, we perform and analyze simulations with different depths of the DP (0, 100, 1,000, and 2,500 m) and compare results to existing geochemical data. Our experiments show that DP opening has a strong effect on Eocene ocean structure and dynamics even for shallow depths. The DP opening notably allows the formation of a proto‐ACC and induces deep ocean cooling of 1.5°C to 2.5°C in most of the Southern Hemisphere. There is no NADW formation in our simulations regardless of the depth of the DP, suggesting that the DP on its own is not a primary control of deepwater formation in the North Atlantic. This study elucidates how and to what extent the opening of the DP contributed to the establishment of the modern global thermohaline circulation.

show abstract

Section: Intermediate/deep Ocean Changesmentioning

confidence: 99%

Section: Circulation Changes and The Absence Of Nadwmentioning

confidence: 99%

Section: Circulation Changes and The Absence Of Nadwmentioning

confidence: 99%

Section: Paleoceanography and Paleoclimatologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 3 more Smart Citations

Quantifying the Effect of the Drake Passage Opening on the Eocene Ocean

Toumoulin

Donnadieu

Ladant

et al. 2020

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

show abstract

Proxy-Model Comparison for the Eocene-Oligocene Transition in Southern High Latitudes

Tibbett

Burls

Hutchinson

et al. 2022

Preprint

View full text Add to dashboard Cite

The Eocene-Oligocene Transition (EOT) marks the shift from greenhouse to icehouse conditions at 34 Ma, when a permanent ice sheet developed on Antarctica. Climate modeling studies have recently assessed the drivers of the transition globally. Here we revisit those experiments for a detailed study of the southern high latitudes in comparison to the growing number of mean annual sea surface temperature (SST) and mean air temperature (MAT) proxy reconstructions, allowing us to assess proxy-model temperature agreement and refine estimates for the magnitude of the pCO forcing of the EOT. We compile and update published proxy temperature records on and around Antarctica for the late Eocene (38-34 Ma) and early Oligocene (34-30 Ma). Compiled SST proxies cool by up to 3°C and MAT by up to 4°C between the timeslices. Proxy data were compared to previous climate model simulations representing pre- and post-EOT, typically forced with a halving of pCO. We scaled the model outputs to identify the magnitude of pCO change needed to drive a commensurate change in temperature to best fit the temperature proxies. The multi-model ensemble needs a 30 or 33% decrease in pCO, to best fit MAT or SST proxies respectively, a difference of just 3%. These proxy-model intercomparisons identify pCO as the primary forcing of EOT cooling, with a magnitude (-200 or -243 ppmv) approaching that of the pCO proxies (-150 ppmv). However individual model estimates span -66 to -375 ppmv, thus proxy-model uncertainties are dominated by model divergence.

show abstract

Revisiting the geographical extent of exceptional warmth in the Early Paleogene Southern Ocean

Frieling

Bohaty

Cramwinckel

et al. 2022

Preprint

View full text Add to dashboard Cite

To assess zonal temperature and biogeographical patterns in the Paleogene of the Southern Ocean, we present new multi-proxy air and sea surface temperature data for the latest Paleocene (˜57-56 Ma) and the Paleocene-Eocene Thermal Maximum (PETM; ˜56 Ma) from the northern margin of the Australo-Antarctic Gulf (AAG). The various proxies document the well-known late Paleocene gradual warming and, superimposed, two late Paleocene pre-cursor warming events, hundreds of kyrs prior to the PETM. Remarkably, however, air and sea surface temperature reconstructions for the AAG and SW Pacific during the latest Paleocene, PETM and Early Eocene Climatic Optimum (˜53-49 Ma) show similar trends and, within proxies, similar absolute temperatures. The record implies that the exceptional warmth previously recorded in the SW Pacific extended westward into the AAG. This contrasts with the modeled circulation and temperature patterns. We suggest that simulations of ocean circulation underestimate heat transport in the SW Pacific due insufficient resolution, not allowing for mesoscale eddy-related heat transport. We argue for a systematic approach to tackle model and proxy biases in marginal marine settings, including assessment of underexplored factors as high-latitude proxy mechanisms to confidently assess temperature in these non-analogue climates.

show abstract

Ocean and climate response to North Atlantic seaway changes at the onset of long-term Eocene cooling

Cited by 37 publications

References 93 publications

Quantifying the Effect of the Drake Passage Opening on the Eocene Ocean

Quantifying the Effect of the Drake Passage Opening on the Eocene Ocean

Proxy-Model Comparison for the Eocene-Oligocene Transition in Southern High Latitudes

Revisiting the geographical extent of exceptional warmth in the Early Paleogene Southern Ocean

Contact Info

Product

Resources

About