Climate model sensitivity to atmospheric CO2 concentrations for the middle Miocene

Tong, Jessica; You, Yong‐Ouk; Müller, R. Dietmar; Seton, Maria

doi:10.1016/j.gloplacha.2009.02.001

Cited by 36 publications

(65 citation statements)

References 42 publications

(83 reference statements)

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“…The atmospheric CO 2 concentration during the middle Miocene is still highly debated (Cerling, 1991;Pagani et al, 1999Pagani et al, , 2009Pearson and Palmer, 2000;Royer et al, 2001;Kürschner et al, 2008;Kürschner and Kvacek, 2009;Tripati et al, 2009;Foster et al, 2012;Badger et al, 2013). Recent modelling studies concluded that higher-than-present pCO 2 is necessary to simulate a middle Miocene climate consistent with data (Tong et al, 2009;You et al, 2009;Henrot et al, 2010;Krapp and Jungclaus, 2011;Herold et al, 2011;Ha- mon et al, 2012). Moreover, using the model FOAMv1.5, Hamon et al (2012) showed that Miocene European climate and vegetation are more consistent with data when the pCO 2 is equal to 560 ppmv.…”

Section: Model and Experiments Designmentioning

confidence: 85%

“…Many authors have proposed a pCO 2 decrease as the main driver of the Middle Miocene Climatic Transition and cryospheric expansion in Antarctica (Kürschner et al, 2008;Kürschner and Kvacek, 2009;Tripati et al, 2009;Foster et al, 2012;Badger et al, 2013). The recently published sensitivity tests on Miocene pCO 2 indicate that a drawdown of this gas concentration could have been key in the MMCT (Tong et al, 2009;You et al, 2009;Henrot et al, 2010;Krapp and Jungclaus, 2011;Hamon et al, 2012). The climate sensitivity to such a CO 2 concentration drawdown was likely different from the present-day sensitivity, due to the oceanic changes induced by the Tethys seaway closure.…”

Section: Discussionmentioning

confidence: 99%

“…Most of them investigated the impact of varying pCO 2 on middle Miocene climate, and concluded that high pCO 2 is necessary to simulate climatic conditions consistent with data-based reconstructions (Tong et al, 2009;You et al, 2009;Henrot et al, 2010;Krapp and Jungclaus, 2011;Hamon et al, 2012). Henrot et al (2010) and Herold et al (2009) also performed sensitivity experiments on palaeogeography, but they did not study the impact of the eastern Tethys seaway closure.…”

Section: N Hamon Et Al: Tethys Seaway Closure and Middle Miocene CLmentioning

confidence: 99%

“…The Miocene vegetation is based on Wolfe (1985) and is the same as used in previous studies on middle Miocene climate (Tong et al, 2009;You et al, 2009;Herold et al, 2009;Hamon et al, 2012). Important changes compared to present-day vegetation are the absence of desert, the larger latitudinal expansion of tropical and subtropical forests as well as the replacement of ice by boreal forest in Greenland.…”

Section: Model and Experiments Designmentioning

confidence: 99%

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The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

et al. 2013

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Abstract. The Middle Miocene Climatic Transition (MMCT, approximately 14 Ma) is a key period in Cenozoic cooling and cryospheric expansion. Despite being well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was due the final closure of the eastern Tethys seaway and subsequent oceanic circulation reorganisation. The aim of the present study is to quantify the impact of varying Tethys seaway depths on middle Miocene ocean and climate, in order to better understand its role in the MMCT.We present four sensitivity experiments with a fully coupled ocean-atmosphere general circulation model. Our results indicate the presence of a warm and salty water source in the northern Indian Ocean when the eastern Tethys is deep open (4000 or 1000 m), which corresponds to the Tethyan Indian Saline Water (TISW) described on the basis of isotopic studies. This water source is absent in the experiments with shallow (250 m) and closed Tethys seaway, inducing strong changes in the latitudinal density gradient and ultimately the reinforcement of the Antarctic Circumpolar Current (ACC). Moreover, when the Tethys seaway is shallow or closed, there is a westward water flow in the Gibraltar Strait that strengthens the Atlantic Meridional Overturning Circulation (AMOC) compared to the experiments with deep-open Tethys seaway. Our results therefore suggest that the shoaling and final closure of the eastern Tethys seaway played a major role in the oceanic circulation reorganisation during the middle Miocene.The results presented here provide new constraints on the timing of the Tethys seaway closure and particularly indicate that, prior to 14 Ma, a deep-open Tethys seaway should have allowed the formation of TISW. Moreover, whereas the final closure of this seaway likely played a major role in the reorganisation of oceanic circulation, we suggest that it was not the main driver of the global cooling and Antarctica ice-sheet expansion during the MMCT. Here we propose that the initiation of the MMCT was caused by an atmospheric pCO 2 drawdown and that the oceanic changes due to the Tethys seaway closure amplified the response of global climate and East Antarctic Ice Sheet.

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Section: Model and Experiments Designmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: N Hamon Et Al: Tethys Seaway Closure and Middle Miocene CLmentioning

confidence: 99%

Section: Model and Experiments Designmentioning

confidence: 99%

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The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

et al. 2013

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“…The ocean model that they used furthermore had a flat bottom ocean at 5000 m depth. More recent climate modelling sensitivity experiments have particularly focused on the sensitivity of the Miocene climate to various atmospheric CO 2 concentrations using atmospheric models (Tong et al, 2009;You et al, 2009). Tong et al (2009) used the NCAR Community Atmosphere Model (CAM v.3.1) and Community Land Model (CLM v.3.0) coupled to a slab ocean to examine the sensitivity of the Middle Miocene climate to successive quasi-doubling of atmospheric CO 2 concentration (180 355 and 700 ppmv).…”

mentioning

confidence: 99%

Effects of CO<sup>2</sup>, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study

Henrot¹,

François

Favre

et al. 2010

Clim. Past

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Abstract. The Middle Miocene was one of the last warm periods of the Neogene, culminating with the Middle Miocene Climatic Optimum (MMCO, approximatively 17-15 Ma). Several proxy-based reconstructions support warmer and more humid climate during the MMCO. The mechanisms responsible for the warmer climate at the MMCO and particularly the role of the atmospheric carbon dioxide are still highly debated. Here we carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the absence of ice on the continents, the opening of the Central American and Eastern Tethys Seaways, the lowering of the topography on land, the effect of various atmospheric CO 2 concentrations and the vegetation feedback.Our results show that a higher than present-day CO 2 concentration is necessary to generate a warmer climate at all latitudes at the Middle Miocene, in agreement with the terrestrial proxy reconstructions which suggest high atmospheric CO 2 concentrations at the MMCO. Nevertheless, the changes in sea-surface conditions, the lowering of the topography on land and the vegetation feedback also produce significant local warming that may, locally, even be stronger than the CO 2 induced temperature increases. The lowering of the topography leads to a more zonal atmospheric circulation and allows the westerly flow to continue over the lowered Plateaus at mid-latitudes. The reduced height of the Tibetan Plateau notably prevents the development of a monsoon-like circulation, whereas the reduction of elevations of the North American and European reliefs strongly increases precipitation from northwestern to eastern Europe.Correspondence to: A.-J. Henrot (alexandra.henrot@ulg.ac.be)The changes in vegetation cover contribute to maintain and even to intensify the warm and humid conditions produced by the other factors, suggesting that the vegetationclimate interactions could help to improve the model-data comparison.

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Strong interannual variation of the Indian summer monsoon in the Late Miocene

et al. 2013

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Climate model sensitivity to atmospheric CO2 concentrations for the middle Miocene

Cited by 36 publications

References 42 publications

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

Effects of CO<sup>2</sup>, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study

Strong interannual variation of the Indian summer monsoon in the Late Miocene

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Climate model sensitivity to atmospheric CO2 concentrations for the middle Miocene

Cited by 36 publications

References 42 publications

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

Effects of CO&lt;sup&gt;2&lt;/sup&gt;, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study

Strong interannual variation of the Indian summer monsoon in the Late Miocene

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Effects of CO<sup>2</sup>, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study