Simulation of the Middle Miocene Climate Optimum

You, Yong‐Ouk; Huber, Matthew; Müller, R. Dietmar; Poulsen, Christopher J.; Ribbe, Joachim

doi:10.1029/2008gl036571

Cited by 202 publications

(186 citation statements)

References 34 publications

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“…According to numerical simulation of You et al (2009), the global annual mean surface temperature at around 15 Ma were about 3°C higher than today, and the meridional temperature gradient on the northern hemisphere was less pronounced than present. Indeed, European mid-latitudes proxy-data for that time indicate 9 to 12°C warmer temperatures in the annual mean than today (Böhme, 2003;Mosbrugger et al, 2005;Ivanov and Böhme, in press).…”

Section: Discussionmentioning

confidence: 99%

Miocene precipitation in Europe: Temporal trends and spatial gradients

Böhme

Winklhofer²,

Ilg

2011

Palaeogeography, Palaeoclimatology, Palaeoecology

133

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It is known from present-day climates that both temporal and spatial variations in precipitation can be more pronounced than those in temperature and thus influence ecosystems and human society in more substantial way. However, very little is known about such variations in the past. Here we present an analysis of 206 palaeoprecipitation data from two twelve million year long proxy records of precipitation for Southwest (Calatayud-Teruel basin) and Central Europe (Western and Central Paratethys), spanning the late Early and Middle to Late Miocene (17.8-5.3 Ma) at a temporal resolution of about 80 kyr and 200 kyr, respectively. The estimates of precipitation are based on the ecophysiological structure of herpetological assemblages. The results show that precipitation variations in both regions have large amplitudes during the Miocene with comparable temporal trends at longer time scales. With locally 300 mm up to more than 1000 mm more rainfall per year than present, the early Langhian and the Tortonian were relatively wet periods, whereas the late Langhian and late Serravallian were relatively dry, with up to 300 to 500 mm less precipitation than present. The most humid time intervals were the early and middle Tortonian washhouse climate periods. Overall, our data suggest that the latitudinal precipitation gradient in Europe from the Middle to Late Miocene were highly variable, with a general tendency towards a reduced gradient relative to present day values. The gradient decreases during cooling periods and increases during warming periods, similar to results from simulations of future climate change. Interestingly, the precipitation gradient was reversed during the second washhouse climate period and the Early Messinian, which may have causes a negative hydrologic balance in the Eastern Paratethys during the latter time. Yet, our reconstructed gradient curve shows no direct correlation with the global temperature signal from oxygen isotopes, which implies a non-linear regional response. Our results further suggest that major fluctuations in the precipitation gradient can be responsible for shifts in ecosystem distribution, and particularly, for faunal turnover in South Western Europe.

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Section: Discussionmentioning

confidence: 99%

Miocene precipitation in Europe: Temporal trends and spatial gradients

Böhme

Winklhofer²,

Ilg

2011

Palaeogeography, Palaeoclimatology, Palaeoecology

133

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“…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 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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“…The Miocene climate exhibited marked changes including the Mid-Miocene Climatic Optimum (MMCO, *15-17.0 Ma [2]) during which temperatures were inferred to be *3-8°C higher than preindustrial level [3,4]. The mechanisms leading to the MMCO are still debated [2], but evidence points to an increase in the concentration of atmospheric CO 2 [4].…”

Section: Introductionmentioning

confidence: 99%

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

Lebreton-Anberrée

et al. 2016

Science Bulletin

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The Mid-Miocene Climatic Optimum (MMCO; *15-17 Ma) was one of the short-term climatic warm events that punctuated the Cenozoic long-term cooling trend. Because there are very few terrestrial records of this event, most of our understanding comes from marine cores. In this report, we first present new palaeomagnetic data that revises the dating of our 400 m-thick lacustrine section in Wenshan (Yunnan), previously thought to be Late Miocene. These new data suggest an older age, ca. 15.2-16.5 Ma, coinciding with the MMCO. We measured d 13 C on bulk organic matter (d 13 C org ), total organic carbon (TOC), total nitrogen (TN) and C/N ratios at a high sample resolution to: (1) reconstruct the palaeoenvironmental changes in the lake catchment area, and (2) infer mechanisms responsible for these changes. Our results show that all four geochemical parameters demonstrate that a strong environmental change occurred around the middle of the section, shortly after the C5Cn/C5Br geomagnetic reversal and the Early/Middle Miocene boundary at 15.97 Ma. We propose that the environmental shift may be due to a combination of a change in climate, which became cooler, together with a change in organic matter cycling within the lake. This study provides a new insight into the MMCO and demonstrates that although the MMCO was generally a warm event, it was also a time of climatic instability and abrupt environmental changes.Keywords Yunnan Á Mid-Miocene Climatic Optimum Á Bulk organic carbon isotopes (d 13 C org ) Á C/N ratio Á TOC Electronic supplementary material The online version of this article

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Simulation of the Middle Miocene Climate Optimum

Cited by 202 publications

References 34 publications

Miocene precipitation in Europe: Temporal trends and spatial gradients

Miocene precipitation in Europe: Temporal trends and spatial gradients

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

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

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