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Matthew Huber
Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, Lafayette, IN 47907, USA

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Journal article
Published: 26 August 2021 in Sustainability
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Climate change and variability is affecting maize (Zea mays L.) production in eastern Ethiopia but how farmers perceive the challenge and respond to it is not well documented. A study was conducted to analyze smallholder maize farmers’ perception of climate change/variability and identify their adaptation approaches and barriers for adaptation in the eastern highlands of Ethiopia. Meteorological data were assessed to provide evidence of the perceived change. A survey was conducted in six major maize-producing kebeles with a total of 364 respondents. A multi-stage sampling method was employed for selecting the sample units for the study. The data were analyzed using descriptive statistics and a multinomial logit model. The results indicated that 78% of the sampled smallholder maize farmers perceived increasing temperatures while 83% perceived decreasing amounts of rainfall. About 75% of the farmers indicated that they became aware of climate change and variability from their own experience and perceived deforestation as the main cause. The farmers perceived that drought, diseases and pests, dwindling soil fertility, and declining crop yields were the major impacts of climate change that affected maize production. The farmers’ major adaptation practices include adjusting planting dates, using improved maize varieties, intercropping, recommended mineral fertilizers, supplementary irrigation, and soil and water conservation measures. Econometric analysis revealed that low educational level, shortage of land, large family sizes, age, lack of access to irrigation water, lack of access to credit, and lack of access to extension services were the most important barriers to climate change adaptation in the area. It is concluded that farmers cultivating maize in the study area have perceived climate change and use certain adaptation strategies to counter its negative impacts on maize production. This implies that policies should be geared towards strengthening farmers’ efforts to adapt to climate change and alleviate the existing barriers in promoting adaptation strategies for enhancing the productivity of maize.

ACS Style

Helen Teshome; Kindie Tesfaye; Nigussie Dechassa; Tamado Tana; Matthew Huber. Smallholder Farmers’ Perceptions of Climate Change and Adaptation Practices for Maize Production in Eastern Ethiopia. Sustainability 2021, 13, 9622 .

AMA Style

Helen Teshome, Kindie Tesfaye, Nigussie Dechassa, Tamado Tana, Matthew Huber. Smallholder Farmers’ Perceptions of Climate Change and Adaptation Practices for Maize Production in Eastern Ethiopia. Sustainability. 2021; 13 (17):9622.

Chicago/Turabian Style

Helen Teshome; Kindie Tesfaye; Nigussie Dechassa; Tamado Tana; Matthew Huber. 2021. "Smallholder Farmers’ Perceptions of Climate Change and Adaptation Practices for Maize Production in Eastern Ethiopia." Sustainability 13, no. 17: 9622.

Article
Published: 28 July 2021
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Wet bulb globe temperature (WBGT) is a widely applied heat stress index. However, most applications of WBGT within the heat stress impacts literature do not use WBGT at all, but one of the ad hoc approximations, typically the simplified WBGT (sWBGT) or the environmental stress index (ESI). Surprisingly little is known about how well these approximations work for the global climate and climate change settings that they are being applied to. Here we assess the bias distribution as a function of temperature, humidity, wind speed and radiative conditions of both sWBGT and ESI relative to a well-validated, explicit physical model for WBGT developed by Liljegren, within an idealized context and the more realistic setting of ERA5 reanalysis data. sWBGT greatly overestimates heat stress in hot-humid areas. ESI has much smaller biases in the range of standard climatological conditions. However, both metrics may substantially underestimate extreme heat especially over subtropical dry regions. These systematic biases demonstrate that sWBGT-derived estimates of heat stress and its health and labor consequences are significantly overestimated over much of the world today. We recommend discontinuing the use of sWBGT. ESI may be acceptable for assessing average heat stress or integrated impact over a long period like a year, but less suitable for health applications, extreme heat stress analysis, or as an operational index for heat warning, heatwave forecasting or guiding activity modification at workplace. Nevertheless, Liljegren’s approach should be preferred over these ad hoc approximations and we provide a Python implementation to encourage its widespread use.

ACS Style

Qinqin KongiD; Matthew HuberiD. Explicit calculations of Wet Bulb Globe Temperature compared with approximations and why it matters for labor productivity. 2021, 1 .

AMA Style

Qinqin KongiD, Matthew HuberiD. Explicit calculations of Wet Bulb Globe Temperature compared with approximations and why it matters for labor productivity. . 2021; ():1.

Chicago/Turabian Style

Qinqin KongiD; Matthew HuberiD. 2021. "Explicit calculations of Wet Bulb Globe Temperature compared with approximations and why it matters for labor productivity." , no. : 1.

Journal article
Published: 24 May 2021 in Paleoceanography and Paleoclimatology
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The Miocene epoch, spanning 23.03‐5.33Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300‐600ppm and were potentially higher during the Miocene Climatic Optimum (16.75‐14.5Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker‐than‐modern equator‐to‐pole temperature difference. Here we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model‐data agreement, highlight robust mechanisms operating across Miocene modelling efforts, and regions where differences across experiments result in a large spread in warming responses. Prescribed CO2 is the primary factor controlling global warming across the ensemble. On average, elements other than CO2, such as Miocene paleogeography and ice sheets, raise global mean temperature by ∌ 2, with the spread in warming under a given CO2 concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to ∌1.2 times a CO2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference datasets represent the state‐of‐art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi‐model, multi‐proxy comparison attempted so far. This study serves to take stock of the current progress towards simulating Miocene warmth while isolating remaining challenges that may be well served by community‐led efforts to coordinate modelling and data activities within a common analysis framework.

ACS Style

N. J. Burls; C. D. Bradshaw; A. M. De Boer; N. Herold; M. Huber; M. Pound; Y. Donnadieu; A. Farnsworth; A. Frigola; E. Gasson; A. S. von der Heydt; D. K. Hutchinson; G. Knorr; K. T. Lawrence; C. H. Lear; X. Li; G. Lohmann; D. J. Lunt; A. Marzocchi; M. Prange; C. A. Riihimaki; A.‐C. Sarr; N. Siler; Z. Zhang. Simulating Miocene Warmth: Insights From an Opportunistic Multi‐Model Ensemble (MioMIP1). Paleoceanography and Paleoclimatology 2021, 36, 1 .

AMA Style

N. J. Burls, C. D. Bradshaw, A. M. De Boer, N. Herold, M. Huber, M. Pound, Y. Donnadieu, A. Farnsworth, A. Frigola, E. Gasson, A. S. von der Heydt, D. K. Hutchinson, G. Knorr, K. T. Lawrence, C. H. Lear, X. Li, G. Lohmann, D. J. Lunt, A. Marzocchi, M. Prange, C. A. Riihimaki, A.‐C. Sarr, N. Siler, Z. Zhang. Simulating Miocene Warmth: Insights From an Opportunistic Multi‐Model Ensemble (MioMIP1). Paleoceanography and Paleoclimatology. 2021; 36 (5):1.

Chicago/Turabian Style

N. J. Burls; C. D. Bradshaw; A. M. De Boer; N. Herold; M. Huber; M. Pound; Y. Donnadieu; A. Farnsworth; A. Frigola; E. Gasson; A. S. von der Heydt; D. K. Hutchinson; G. Knorr; K. T. Lawrence; C. H. Lear; X. Li; G. Lohmann; D. J. Lunt; A. Marzocchi; M. Prange; C. A. Riihimaki; A.‐C. Sarr; N. Siler; Z. Zhang. 2021. "Simulating Miocene Warmth: Insights From an Opportunistic Multi‐Model Ensemble (MioMIP1)." Paleoceanography and Paleoclimatology 36, no. 5: 1.

Journal article
Published: 27 April 2021 in Paleoceanography and Paleoclimatology
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The Miocene epoch (23.03–5.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned towards modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∌2 Myr greenhouse interval – the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO2, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO2 (∌400–600 ppm), the MCO has been suggested as a particularly appropriate analogue for future climate scenarios, and for assessing the predictive accuracy of numerical climate models – the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re‐interpretation of proxies, which might mitigate the model‐data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here we review the state‐of‐the‐art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modelling studies.

ACS Style

M. Steinthorsdottir; H. K. Coxall; A. M. de Boer; M. Huber; N. Barbolini; C. D. Bradshaw; N. J. Burls; S. J. Feakins; E. Gasson; J. Henderiks; A. E. Holbourn; S. Kiel; M. J. Kohn; G. Knorr; W. M. KĂŒrschner; C. H. Lear; D. Liebrand; D. J. Lunt; T. Mörs; P. N. Pearson; M. J. Pound; H. Stoll; C. A. E. Strömberg. The Miocene: The Future of the Past. Paleoceanography and Paleoclimatology 2021, 36, 1 .

AMA Style

M. Steinthorsdottir, H. K. Coxall, A. M. de Boer, M. Huber, N. Barbolini, C. D. Bradshaw, N. J. Burls, S. J. Feakins, E. Gasson, J. Henderiks, A. E. Holbourn, S. Kiel, M. J. Kohn, G. Knorr, W. M. KĂŒrschner, C. H. Lear, D. Liebrand, D. J. Lunt, T. Mörs, P. N. Pearson, M. J. Pound, H. Stoll, C. A. E. Strömberg. The Miocene: The Future of the Past. Paleoceanography and Paleoclimatology. 2021; 36 (4):1.

Chicago/Turabian Style

M. Steinthorsdottir; H. K. Coxall; A. M. de Boer; M. Huber; N. Barbolini; C. D. Bradshaw; N. J. Burls; S. J. Feakins; E. Gasson; J. Henderiks; A. E. Holbourn; S. Kiel; M. J. Kohn; G. Knorr; W. M. KĂŒrschner; C. H. Lear; D. Liebrand; D. J. Lunt; T. Mörs; P. N. Pearson; M. J. Pound; H. Stoll; C. A. E. Strömberg. 2021. "The Miocene: The Future of the Past." Paleoceanography and Paleoclimatology 36, no. 4: 1.

Editorial
Published: 08 April 2021 in Paleoceanography and Paleoclimatology
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Once a year we take the opportunity to thank the reviewers whose difficult, important work is never sufficiently recognized. This year is special. Due to the vicissitudes of COVID19, submissions were up just as reviewing came at a higher personal cost than ever before. Reviewers had to dig deep and make real sacrifices to respond to the community's needs for critical, thorough reviews aiming to improve manuscripts, while simultaneously dealing with very difficult personal and professional circumstances. Without their intense, robust, and helpful attention, all the science we do would be diminished. Ulla and I would like to express our gratitude and appreciation for your efforts this year and our hope for improvement in 2021 and beyond.

ACS Style

Matthew Huber; Ursula (Ulla) Röhl. Thank You to Our 2020 Peer Reviewers. Paleoceanography and Paleoclimatology 2021, 36, 1 .

AMA Style

Matthew Huber, Ursula (Ulla) Röhl. Thank You to Our 2020 Peer Reviewers. Paleoceanography and Paleoclimatology. 2021; 36 (4):1.

Chicago/Turabian Style

Matthew Huber; Ursula (Ulla) Röhl. 2021. "Thank You to Our 2020 Peer Reviewers." Paleoceanography and Paleoclimatology 36, no. 4: 1.

Preprint content
Published: 04 March 2021
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The opening of the Tasmanian Gateway during the Eocene and further deepening in the Oligocene is hypothesized to have reorganized ocean currents, preconditioning the Antarctic Circumpolar Current (ACC) to evolve into place. However, fundamental questions still remain on the past Southern Ocean structure. We here present reconstructions of latitudinal temperature gradients and the position of ocean frontal systems in the Australian sector of the Southern Ocean during the Oligocene. We generated new sea surface temperature (SST) and dinoflagellate cyst data from the West Tasman margin, ODP Site 1168. We compare these with other records around the Tasmanian Gateway, and with climate model simulations to analyze the paleoceanographic evolution during the Oligocene. The novel organic biomarker TEX86- SSTs from ODP Site 1168, range between 19.6 – 27.9°C (± 5.2°C, using the linear calibration by Kim et al., 2010), supported by temperate and open ocean dinoflagellate cyst assemblages. The data compilation, including existing TEX86-based SSTs from ODP Site 1172 in the Southwest Pacific Ocean, DSDP Site 274 offshore Cape Adare, DSDP Site 269 and IODP Site U1356 offshore the Wilkes Land Margin and terrestrial temperature proxy records from the Cape Roberts Project (CRP) on the Ross Sea continental shelf, show synchronous variability in temperature evolution between Antarctic and Australian sectors of the Southern Ocean. The SST gradients are around 10°C latitudinally across the Tasmanian Gateway throughout the early Oligocene, and increasing in the Late Oligocene. This increase can be explained by polar amplification/cooling, tectonic drift, strengthening of atmospheric currents and ocean currents. We suggest that the progressive cooling of Antarctica and the absence of mid-latitude cooling strengthened the westerly winds, which in turn could drive an intensification of the ACC and strengthening of Southern Ocean frontal systems.

ACS Style

Frida Hoem; Suning Hou; Matthew Huber; Francesca Sangiorgi; Henk Brinkhuis; Peter Bijl. Oligocene sea-surface temperature gradients in the Southern Ocean related to Tasmanian Gateway widening: New TEX86 paleothermometry, dinoflagellate cyst data and climate model comparisons. 2021, 1 .

AMA Style

Frida Hoem, Suning Hou, Matthew Huber, Francesca Sangiorgi, Henk Brinkhuis, Peter Bijl. Oligocene sea-surface temperature gradients in the Southern Ocean related to Tasmanian Gateway widening: New TEX86 paleothermometry, dinoflagellate cyst data and climate model comparisons. . 2021; ():1.

Chicago/Turabian Style

Frida Hoem; Suning Hou; Matthew Huber; Francesca Sangiorgi; Henk Brinkhuis; Peter Bijl. 2021. "Oligocene sea-surface temperature gradients in the Southern Ocean related to Tasmanian Gateway widening: New TEX86 paleothermometry, dinoflagellate cyst data and climate model comparisons." , no. : 1.

Journal article
Published: 02 March 2021 in Journal of Geophysical Research: Atmospheres
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Vegetation growth plays a crucial role in the carbon cycle and climate change mitigation. However, the relative contribution of hydroclimatic variables (relative humidity, terrestrial water storage, day and night‐time land surface temperatures) on vegetation growth of agricultural and non‐agricultural areas at the global scale remains unexplored. Using satellite‐based datasets, we examined the changes in Normalized Difference Vegetation Index (NDVI) and the four hydroclimatic variables during 2003‐2014. Also, the relative contribution of the four hydroclimatic variables on vegetation growth in agricultural and non‐agricultural areas was estimated. A significant (p‐value < 0.05) greening has occurred in the agricultural regions of India and Brazil during 2003‐2014. Whereas in non‐agriculture areas, a considerable greening occurred only in India and China during the 2003‐2014 period. Among the four hydroclimatic variables, both day‐time and night‐time land surface temperature are the significant contributors of vegetation growth in the two‐thirds of the global landmass. Terrestrial water storage is a substantial contributor to the vegetation growth in the tropics and sub‐tropics. Night‐time land surface temperature is strongly associated with the vegetation growth in the colder regions. The hydroclimatic variables do not explain the considerable amount of the total variance of vegetation growth over the agricultural areas in China, which is due to human agricultural management practices. Generally, the response of hydroclimate variables on vegetation growth in the agricultural and non‐agricultural areas has significant implications in many areas, including food security, carbon sequestration, water resource management, and climate change. This article is protected by copyright. All rights reserved.

ACS Style

Akarsh Asoka; Brian Wardlow; Tadesse Tsegaye; Matthew Huber; Vimal Mishra. A Satellite‐Based Assessment of the Relative Contribution of Hydroclimatic Variables on Vegetation Growth in Global Agricultural and Nonagricultural Regions. Journal of Geophysical Research: Atmospheres 2021, 126, 1 .

AMA Style

Akarsh Asoka, Brian Wardlow, Tadesse Tsegaye, Matthew Huber, Vimal Mishra. A Satellite‐Based Assessment of the Relative Contribution of Hydroclimatic Variables on Vegetation Growth in Global Agricultural and Nonagricultural Regions. Journal of Geophysical Research: Atmospheres. 2021; 126 (5):1.

Chicago/Turabian Style

Akarsh Asoka; Brian Wardlow; Tadesse Tsegaye; Matthew Huber; Vimal Mishra. 2021. "A Satellite‐Based Assessment of the Relative Contribution of Hydroclimatic Variables on Vegetation Growth in Global Agricultural and Nonagricultural Regions." Journal of Geophysical Research: Atmospheres 126, no. 5: 1.

Review
Published: 28 January 2021 in Climate of the Past
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The Eocene–Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring ∌34 million years ago (Ma) and lasting ∌790 kyr. The change is marked by a global shift in deep-sea ÎŽ18O representing a combination of deep-ocean cooling and growth in land ice volume. At the same time, multiple independent proxies for ocean temperature indicate sea surface cooling, and major changes in global fauna and flora record a shift toward more cold-climate-adapted species. The two principal suggested explanations of this transition are a decline in atmospheric CO2 and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. Here we review and synthesise proxy evidence of palaeogeography, temperature, ice sheets, ocean circulation and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of climate model simulations of temperature change across the EOT. The simulations compare three forcing mechanisms across the EOT: CO2 decrease, palaeogeographic changes and ice sheet growth. Our model ensemble results demonstrate the need for a global cooling mechanism beyond the imposition of an ice sheet or palaeogeographic changes. We find that CO2 forcing involving a large decrease in CO2 of ca. 40 % (∌325 ppm drop) provides the best fit to the available proxy evidence, with ice sheet and palaeogeographic changes playing a secondary role. While this large decrease is consistent with some CO2 proxy records (the extreme endmember of decrease), the positive feedback mechanisms on ice growth are so strong that a modest CO2 decrease beyond a critical threshold for ice sheet initiation is well capable of triggering rapid ice sheet growth. Thus, the amplitude of CO2 decrease signalled by our data–model comparison should be considered an upper estimate and perhaps artificially large, not least because the current generation of climate models do not include dynamic ice sheets and in some cases may be under-sensitive to CO2 forcing. The model ensemble also cannot exclude the possibility that palaeogeographic changes could have triggered a reduction in CO2.

ACS Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. de Boer; Michiel Baatsen; Anna von der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. The Eocene–Oligocene transition: a review of marine and terrestrial proxy data, models and model–data comparisons. Climate of the Past 2021, 17, 269 -315.

AMA Style

David K. Hutchinson, Helen K. Coxall, Daniel J. Lunt, Margret Steinthorsdottir, Agatha M. de Boer, Michiel Baatsen, Anna von der Heydt, Matthew Huber, Alan T. Kennedy-Asser, Lutz Kunzmann, Jean-Baptiste Ladant, Caroline H. Lear, Karolin Moraweck, Paul N. Pearson, Emanuela Piga, Matthew J. Pound, Ulrich Salzmann, Howie D. Scher, Willem P. Sijp, Kasia K. ƚliwiƄska, Paul A. Wilson, Zhongshi Zhang. The Eocene–Oligocene transition: a review of marine and terrestrial proxy data, models and model–data comparisons. Climate of the Past. 2021; 17 (1):269-315.

Chicago/Turabian Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. de Boer; Michiel Baatsen; Anna von der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. 2021. "The Eocene–Oligocene transition: a review of marine and terrestrial proxy data, models and model–data comparisons." Climate of the Past 17, no. 1: 269-315.

Article
Published: 18 January 2021
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The Miocene epoch, spanning 23.03-5.33Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300-600ppm and were potentially higher during the Miocene Climatic Optimum (16.75-14.5Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker-than-modern equator-to-pole temperature difference. Here we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model-data agreement, highlight robust mechanisms operating across Miocene modelling efforts, and regions where differences across experiments result in a large spread in warming responses. Prescribed CO2 is the primary factor controlling global warming across the ensemble. On average, elements other than CO2, such as Miocene paleogeography and ice sheets, raise global mean temperature by ~ 2℃, with the spread in warming under a given CO2 concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to ~1.2 times a CO2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference datasets represent the state-of-art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi-model, multi-proxy comparison attempted so far. This study serves to take stock of the current progress towards simulating Miocene warmth while isolating remaining challenges that may be well served by community-led efforts to coordinate modelling and data activities within a common analysis framework.

ACS Style

Natalie J Burls; Catherine Bradshaw; Agatha Margaretha De Boer; Nicholas Herold; Matthew Huber; Matthew Pound; Yannick Donnadieu; Alexander Farnsworth; Amanda Frigola Boix; Edward G. W. Gasson; Anna Von Der Heydt; David Karel Hutchinson; Gregor Knorr; Kira T Lawrence; Caroline H. Lear; Xiangyu Li; Gerrit Lohmann; Daniel J. Lunt; Alice Marzocchi; Matthias Prange; Catherine Anne Riihimaki; Anta-Clarisse Sarr; Nicholas Siler; Zhongshi Zhang. Simulating Miocene warmth: insights from an opportunistic Multi-Model ensemble (MioMIP1). 2021, 1 .

AMA Style

Natalie J Burls, Catherine Bradshaw, Agatha Margaretha De Boer, Nicholas Herold, Matthew Huber, Matthew Pound, Yannick Donnadieu, Alexander Farnsworth, Amanda Frigola Boix, Edward G. W. Gasson, Anna Von Der Heydt, David Karel Hutchinson, Gregor Knorr, Kira T Lawrence, Caroline H. Lear, Xiangyu Li, Gerrit Lohmann, Daniel J. Lunt, Alice Marzocchi, Matthias Prange, Catherine Anne Riihimaki, Anta-Clarisse Sarr, Nicholas Siler, Zhongshi Zhang. Simulating Miocene warmth: insights from an opportunistic Multi-Model ensemble (MioMIP1). . 2021; ():1.

Chicago/Turabian Style

Natalie J Burls; Catherine Bradshaw; Agatha Margaretha De Boer; Nicholas Herold; Matthew Huber; Matthew Pound; Yannick Donnadieu; Alexander Farnsworth; Amanda Frigola Boix; Edward G. W. Gasson; Anna Von Der Heydt; David Karel Hutchinson; Gregor Knorr; Kira T Lawrence; Caroline H. Lear; Xiangyu Li; Gerrit Lohmann; Daniel J. Lunt; Alice Marzocchi; Matthias Prange; Catherine Anne Riihimaki; Anta-Clarisse Sarr; Nicholas Siler; Zhongshi Zhang. 2021. "Simulating Miocene warmth: insights from an opportunistic Multi-Model ensemble (MioMIP1)." , no. : 1.

Journal article
Published: 15 January 2021 in Climate of the Past
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We present results from an ensemble of eight climate models, each of which has carried out simulations of the early Eocene climate optimum (EECO, ∌ 50 million years ago). These simulations have been carried out in the framework of the Deep-Time Model Intercomparison Project (DeepMIP; http://www.deepmip.org, last access: 10 January 2021); thus, all models have been configured with the same paleogeographic and vegetation boundary conditions. The results indicate that these non-CO2 boundary conditions contribute between 3 and 5 ∘C to Eocene warmth. Compared with results from previous studies, the DeepMIP simulations generally show a reduced spread of the global mean surface temperature response across the ensemble for a given atmospheric CO2 concentration as well as an increased climate sensitivity on average. An energy balance analysis of the model ensemble indicates that global mean warming in the Eocene compared with the preindustrial period mostly arises from decreases in emissivity due to the elevated CO2 concentration (and associated water vapour and long-wave cloud feedbacks), whereas the reduction in the Eocene in terms of the meridional temperature gradient is primarily due to emissivity and albedo changes owing to the non-CO2 boundary conditions (i.e. the removal of the Antarctic ice sheet and changes in vegetation). Three of the models (the Community Earth System Model, CESM; the Geophysical Fluid Dynamics Laboratory, GFDL, model; and the Norwegian Earth System Model, NorESM) show results that are consistent with the proxies in terms of the global mean temperature, meridional SST gradient, and CO2, without prescribing changes to model parameters. In addition, many of the models agree well with the first-order spatial patterns in the SST proxies. However, at a more regional scale, the models lack skill. In particular, the modelled anomalies are substantially lower than those indicated by the proxies in the southwest Pacific; here, modelled continental surface air temperature anomalies are more consistent with surface air temperature proxies, implying a possible inconsistency between marine and terrestrial temperatures in either the proxies or models in this region. Our aim is that the documentation of the large-scale features and model–data comparison presented herein will pave the way to further studies that explore aspects of the model simulations in more detail, for example the ocean circulation, hydrological cycle, and modes of variability, and encourage sensitivity studies to aspects such as paleogeography, orbital configuration, and aerosols.

ACS Style

Daniel J. Lunt; Fran Bragg; Wing-Le Chan; David K. Hutchinson; Jean-Baptiste Ladant; Polina Morozova; Igor Niezgodzki; Sebastian Steinig; Zhongshi Zhang; Jiang Zhu; Ayako Abe-Ouchi; Eleni Anagnostou; Agatha M. De Boer; Helen K. Coxall; Yannick Donnadieu; Gavin Foster; Gordon N. Inglis; Gregor Knorr; Petra M. Langebroek; Caroline H. Lear; Gerrit Lohmann; Christopher J. Poulsen; Pierre Sepulchre; Jessica E. Tierney; Paul J. Valdes; Evgeny M. Volodin; Tom Dunkley Jones; Christopher J. Hollis; Matthew Huber; Bette L. Otto-Bliesner. DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data. Climate of the Past 2021, 17, 203 -227.

AMA Style

Daniel J. Lunt, Fran Bragg, Wing-Le Chan, David K. Hutchinson, Jean-Baptiste Ladant, Polina Morozova, Igor Niezgodzki, Sebastian Steinig, Zhongshi Zhang, Jiang Zhu, Ayako Abe-Ouchi, Eleni Anagnostou, Agatha M. De Boer, Helen K. Coxall, Yannick Donnadieu, Gavin Foster, Gordon N. Inglis, Gregor Knorr, Petra M. Langebroek, Caroline H. Lear, Gerrit Lohmann, Christopher J. Poulsen, Pierre Sepulchre, Jessica E. Tierney, Paul J. Valdes, Evgeny M. Volodin, Tom Dunkley Jones, Christopher J. Hollis, Matthew Huber, Bette L. Otto-Bliesner. DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data. Climate of the Past. 2021; 17 (1):203-227.

Chicago/Turabian Style

Daniel J. Lunt; Fran Bragg; Wing-Le Chan; David K. Hutchinson; Jean-Baptiste Ladant; Polina Morozova; Igor Niezgodzki; Sebastian Steinig; Zhongshi Zhang; Jiang Zhu; Ayako Abe-Ouchi; Eleni Anagnostou; Agatha M. De Boer; Helen K. Coxall; Yannick Donnadieu; Gavin Foster; Gordon N. Inglis; Gregor Knorr; Petra M. Langebroek; Caroline H. Lear; Gerrit Lohmann; Christopher J. Poulsen; Pierre Sepulchre; Jessica E. Tierney; Paul J. Valdes; Evgeny M. Volodin; Tom Dunkley Jones; Christopher J. Hollis; Matthew Huber; Bette L. Otto-Bliesner. 2021. "DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data." Climate of the Past 17, no. 1: 203-227.

Journal article
Published: 23 December 2020 in Climate of the Past
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The early and late Eocene have both been the subject of many modelling studies, but few have focused on the middle Eocene. The latter still holds many challenges for climate modellers but is also key to understanding the events leading towards the conditions needed for Antarctic glaciation at the Eocene–Oligocene transition. Here, we present the results of CMIP5-like coupled climate simulations using the Community Earth System Model (CESM) version 1. Using a new detailed 38 Ma geography reconstruction and higher model resolution compared to most previous modelling studies and sufficiently long equilibration times, these simulations will help to further understand the middle to late Eocene climate. At realistic levels of atmospheric greenhouse gases, the model is able to show overall good agreement with proxy records and capture the important aspects of a warm greenhouse climate during the Eocene. With a quadrupling of pre-industrial concentrations of both CO2 and CH4 (i.e. 1120 ppm and ∌2700 ppb, respectively, or 4 × PIC; pre-industrial carbon), sea surface temperatures correspond well to the available late middle Eocene (42–38 Ma; ∌ Bartonian) proxies. Being generally cooler, the simulated climate under 2 × PIC forcing is a good analogue for that of the late Eocene (38–34 Ma; ∌ Priabonian). Terrestrial temperature proxies, although their geographical coverage is sparse, also indicate that the results presented here are in agreement with the available information. Our simulated middle to late Eocene climate has a reduced Equator-to-pole temperature gradient and a more symmetric meridional heat distribution compared to the pre-industrial reference. The collective effects of geography, vegetation, and ice account for a global average 5–7 ∘C difference between pre-industrial and 38 Ma Eocene boundary conditions, with important contributions from cloud and water vapour feedbacks. This helps to explain Eocene warmth in general, without the need for greenhouse gas levels much higher than indicated by proxy estimates (i.e. ∌500–1200 ppm CO2) or low-latitude regions becoming unreasonably warm. High-latitude warmth supports the idea of mostly ice-free polar regions, even at 2 × PIC, with Antarctica experiencing particularly warm summers. An overall wet climate is seen in the simulated Eocene climate, which has a strongly monsoonal character. Equilibrium climate sensitivity is reduced (0.62 ∘C W−1 m2; 3.21 ∘C warming between 38 Ma 2 × PIC and 4 × PIC) compared to that of the present-day climate (0.80 ∘C W−1 m2; 3.17 ∘C per CO2 doubling). While the actual warming is similar, we see mainly a higher radiative forcing from the second PIC doubling. A more detailed analysis of energy fluxes shows that the regional radiative balance is mainly responsible for sustaining a low meridional temperature gradient in the Eocene climate, as well as the polar amplification seen towards even warmer conditions. These model results may be useful to reconsider the drivers of Eocene warmth and the Eocene–Oligocene transition (EOT) but can also be a base for more detailed comparisons to future proxy estimates.

ACS Style

Michiel Baatsen; Anna S. Von Der Heydt; Matthew Huber; Michael A. Kliphuis; Peter K. Bijl; Appy Sluijs; Henk A. Dijkstra. The middle to late Eocene greenhouse climate modelled using the CESM 1.0.5. Climate of the Past 2020, 16, 2573 -2597.

AMA Style

Michiel Baatsen, Anna S. Von Der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, Henk A. Dijkstra. The middle to late Eocene greenhouse climate modelled using the CESM 1.0.5. Climate of the Past. 2020; 16 (6):2573-2597.

Chicago/Turabian Style

Michiel Baatsen; Anna S. Von Der Heydt; Matthew Huber; Michael A. Kliphuis; Peter K. Bijl; Appy Sluijs; Henk A. Dijkstra. 2020. "The middle to late Eocene greenhouse climate modelled using the CESM 1.0.5." Climate of the Past 16, no. 6: 2573-2597.

Journal article
Published: 08 December 2020 in Paleoceanography and Paleoclimatology
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Many explanations for Eocene climate change focus on the Southern Ocean – where tectonics influenced oceanic gateways, ocean circulation reduced heat transport, and greenhouse gas declines prompted glaciation. To date, few studies focus on marine vertebrates at high latitudes to discern paleoecological and paleoenvironmental impacts of this climate transition. The Tertiary Eocene La Meseta (TELM) Formation has a rich fossil assemblage to characterize these impacts; Striatolamia macrota, an extinct (†) sand tiger shark, is abundant throughout the La Meseta Formation. Body size is often tracked to characterize and integrate across multiple ecological dimensions. †Striatolamia macrota body size distributions indicate limited changes during TELMs 2 – 5 based on anterior tooth crown height (n = 450, mean = 19.6 ± 6.4mm). Similarly, environmental conditions remained stable through this period based on ÎŽ18OPO4 values from tooth enameloid (n = 42; 21.5 ± 1.6‰), which corresponds to a mean temperature of 22.0 ± 4.0°C. Our preliminary ΔNd (n = 4) results indicate an early Drake Passage opening with Pacific inputs during TELM 2 – 3 (45 – 43 Ma) based on single unit variation with an overall radiogenic trend. Two possible hypotheses to explain these observations are (1) †S. macrota modified its migration behavior to ameliorate environmental changes related to the Drake Passage opening, or (2) the local climate change was small and gateway opening had little impact. While we cannot rule out an ecological explanation, a comparison with climate model results suggests that increased [CO2] produces warm conditions that also parsimoniously explain the observations.

ACS Style

Sora L. Kim; Sarah S. Zeichner; Albert S. Colman; Howie D. Scher; JĂŒrgen Kriwet; Thomas Mörs; Matthew Huber. Probing the Ecology and Climate of the Eocene Southern Ocean With Sand Tiger Sharks Striatolamia macrota. Paleoceanography and Paleoclimatology 2020, 35, 1 .

AMA Style

Sora L. Kim, Sarah S. Zeichner, Albert S. Colman, Howie D. Scher, JĂŒrgen Kriwet, Thomas Mörs, Matthew Huber. Probing the Ecology and Climate of the Eocene Southern Ocean With Sand Tiger Sharks Striatolamia macrota. Paleoceanography and Paleoclimatology. 2020; 35 (12):1.

Chicago/Turabian Style

Sora L. Kim; Sarah S. Zeichner; Albert S. Colman; Howie D. Scher; JĂŒrgen Kriwet; Thomas Mörs; Matthew Huber. 2020. "Probing the Ecology and Climate of the Eocene Southern Ocean With Sand Tiger Sharks Striatolamia macrota." Paleoceanography and Paleoclimatology 35, no. 12: 1.

Journal article
Published: 26 October 2020 in Nature Geoscience
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Intensive irrigation in India has been demonstrated to decrease surface temperature, but the influence of irrigation on humidity and extreme moist heat stress is not well understood. Here we analysed a combination of in situ and satellite-based datasets and conducted meteorological model simulations to show that irrigation modulates extreme moist heat. We found that intensive irrigation in the region cools the land surface by 1 °C and the air by 0.5 °C. However, the decreased sensible heat flux due to irrigation reduces the planetary boundary layer height, which increases low-level moist enthalpy. Thus, irrigation increases the specific and relative humidity, which raises the moist heat stress metrics. Intense irrigation over the region results in increased moist heat stress in India, Pakistan, and parts of Afghanistan—affecting about 37–46 million people in South Asia—despite a cooler land surface. We suggest that heat stress projections in India and other regions dominated by semi-arid and monsoon climates that do not include the role of irrigation overestimate the benefits of irrigation on dry heat stress and underestimate the risks. Intensive irrigation in India cools the land surface, but increases the moist heat stress in South Asia, according to an analysis of observational datasets and meteorological models.

ACS Style

Vimal Mishra; Anukesh Krishnankutty Ambika; Akarsh Asoka; Saran Aadhar; Jonathan Buzan; Rohini Kumar; Matthew Huber. Moist heat stress extremes in India enhanced by irrigation. Nature Geoscience 2020, 13, 722 -728.

AMA Style

Vimal Mishra, Anukesh Krishnankutty Ambika, Akarsh Asoka, Saran Aadhar, Jonathan Buzan, Rohini Kumar, Matthew Huber. Moist heat stress extremes in India enhanced by irrigation. Nature Geoscience. 2020; 13 (11):722-728.

Chicago/Turabian Style

Vimal Mishra; Anukesh Krishnankutty Ambika; Akarsh Asoka; Saran Aadhar; Jonathan Buzan; Rohini Kumar; Matthew Huber. 2020. "Moist heat stress extremes in India enhanced by irrigation." Nature Geoscience 13, no. 11: 722-728.

Research article
Published: 26 October 2020 in Climate of the Past
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Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required to estimate the sensitivity of the climate system to CO2 forcing through Earth's history. Previous GMST estimates for the latest Paleocene and early Eocene (∌57 to 48 million years ago) span a wide range (∌9 to 23 ∘C higher than pre-industrial) and prevent an accurate assessment of climate sensitivity during this extreme greenhouse climate interval. Using the most recent data compilations, we employ a multi-method experimental framework to calculate GMST during the three DeepMIP target intervals: (1) the latest Paleocene (∌57 Ma), (2) the Paleocene–Eocene Thermal Maximum (PETM; 56 Ma), and (3) the early Eocene Climatic Optimum (EECO; 53.3 to 49.1 Ma). Using six different methodologies, we find that the average GMST estimate (66 % confidence) during the latest Paleocene, PETM, and EECO was 26.3 ∘C (22.3 to 28.3 ∘C), 31.6 ∘C (27.2 to 34.5 ∘C), and 27.0 ∘C (23.2 to 29.7 ∘C), respectively. GMST estimates from the EECO are ∌10 to 16 ∘C warmer than pre-industrial, higher than the estimate given by the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (9 to 14 ∘C higher than pre-industrial). Leveraging the large “signal” associated with these extreme warm climates, we combine estimates of GMST and CO2 from the latest Paleocene, PETM, and EECO to calculate gross estimates of the average climate sensitivity between the early Paleogene and today. We demonstrate that “bulk” equilibrium climate sensitivity (ECS; 66 % confidence) during the latest Paleocene, PETM, and EECO is 4.5 ∘C (2.4 to 6.8 ∘C), 3.6 ∘C (2.3 to 4.7 ∘C), and 3.1 ∘C (1.8 to 4.4 ∘C) per doubling of CO2. These values are generally similar to those assessed by the IPCC (1.5 to 4.5 ∘C per doubling CO2) but appear incompatible with low ECS values (<1.5 per doubling CO2).

ACS Style

Gordon N. Inglis; Fran Bragg; Natalie J. Burls; Margot J. Cramwinckel; David Evans; Gavin L. Foster; Matthew Huber; Daniel J. Lunt; Nicholas Siler; Sebastian Steinig; Jessica E. Tierney; Richard Wilkinson; Eleni Anagnostou; Agatha M. de Boer; Tom Dunkley Jones; Kirsty M. Edgar; Christopher J. Hollis; David K. Hutchinson; Richard D. Pancost. Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene. Climate of the Past 2020, 16, 1953 -1968.

AMA Style

Gordon N. Inglis, Fran Bragg, Natalie J. Burls, Margot J. Cramwinckel, David Evans, Gavin L. Foster, Matthew Huber, Daniel J. Lunt, Nicholas Siler, Sebastian Steinig, Jessica E. Tierney, Richard Wilkinson, Eleni Anagnostou, Agatha M. de Boer, Tom Dunkley Jones, Kirsty M. Edgar, Christopher J. Hollis, David K. Hutchinson, Richard D. Pancost. Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene. Climate of the Past. 2020; 16 (5):1953-1968.

Chicago/Turabian Style

Gordon N. Inglis; Fran Bragg; Natalie J. Burls; Margot J. Cramwinckel; David Evans; Gavin L. Foster; Matthew Huber; Daniel J. Lunt; Nicholas Siler; Sebastian Steinig; Jessica E. Tierney; Richard Wilkinson; Eleni Anagnostou; Agatha M. de Boer; Tom Dunkley Jones; Kirsty M. Edgar; Christopher J. Hollis; David K. Hutchinson; Richard D. Pancost. 2020. "Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene." Climate of the Past 16, no. 5: 1953-1968.

Journal article
Published: 28 September 2020 in Proceedings of the National Academy of Sciences
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Falling atmospheric CO2levels led to cooling through the Eocene and the expansion of Antarctic ice sheets close to their modern size near the beginning of the Oligocene, a period of poorly documented climate. Here, we present a record of climate evolution across the entire Oligocene (33.9 to 23.0 Ma) based on TEX86sea surface temperature (SST) estimates from southwestern Atlantic Deep Sea Drilling Project Site 516 (paleolatitude ∌36°S) and western equatorial Atlantic Ocean Drilling Project Site 929 (paleolatitude ∌0°), combined with a compilation of existing SST records and climate modeling. In this relatively low CO2Oligocene world (∌300 to 700 ppm), warm climates similar to those of the late Eocene continued with only brief interruptions, while the Antarctic ice sheet waxed and waned. SSTs are spatially heterogenous, but generally support late Oligocene warming coincident with declining atmospheric CO2. This Oligocene warmth, especially at high latitudes, belies a simple relationship between climate and atmospheric CO2and/or ocean gateways, and is only partially explained by current climate models. Although the dominant climate drivers of this enigmatic Oligocene world remain unclear, our results help fill a gap in understanding past Cenozoic climates and the way long-term climate sensitivity responded to varying background climate states.

ACS Style

Charlotte L. O’Brien; Matthew Huber; Ellen Thomas; Mark Pagani; James R. Super; Leanne E. Elder; Pincelli M. Hull. The enigma of Oligocene climate and global surface temperature evolution. Proceedings of the National Academy of Sciences 2020, 117, 25302 -25309.

AMA Style

Charlotte L. O’Brien, Matthew Huber, Ellen Thomas, Mark Pagani, James R. Super, Leanne E. Elder, Pincelli M. Hull. The enigma of Oligocene climate and global surface temperature evolution. Proceedings of the National Academy of Sciences. 2020; 117 (41):25302-25309.

Chicago/Turabian Style

Charlotte L. O’Brien; Matthew Huber; Ellen Thomas; Mark Pagani; James R. Super; Leanne E. Elder; Pincelli M. Hull. 2020. "The enigma of Oligocene climate and global surface temperature evolution." Proceedings of the National Academy of Sciences 117, no. 41: 25302-25309.

Review
Published: 18 May 2020
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ACS Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. De Boer; Michiel Baatsen; Anna Von Der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. Supplementary material to "The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons". 2020, 1 .

AMA Style

David K. Hutchinson, Helen K. Coxall, Daniel J. Lunt, Margret Steinthorsdottir, Agatha M. De Boer, Michiel Baatsen, Anna Von Der Heydt, Matthew Huber, Alan T. Kennedy-Asser, Lutz Kunzmann, Jean-Baptiste Ladant, Caroline H. Lear, Karolin Moraweck, Paul N. Pearson, Emanuela Piga, Matthew J. Pound, Ulrich Salzmann, Howie D. Scher, Willem P. Sijp, Kasia K. ƚliwiƄska, Paul A. Wilson, Zhongshi Zhang. Supplementary material to "The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons". . 2020; ():1.

Chicago/Turabian Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. De Boer; Michiel Baatsen; Anna Von Der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. 2020. "Supplementary material to "The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons"." , no. : 1.

Review
Published: 18 May 2020
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The Eocene-Oligocene transition (EOT) from a largely ice-free greenhouse world to an icehouse climate with the first major glaciation of Antarctica was a phase of major climate and environmental change occurring ~34 million years ago (Ma) and lasting ~500 kyr. The change is marked by a global shift in deep sea ή18O representing a combination of deep-ocean cooling and global ice sheet growth. At the same time, multiple independent proxies for sea surface temperature indicate a surface ocean cooling, and major changes in global fauna and flora record a shift toward more cold-climate adapted species. The major explanations of this transition that have been suggested are a decline in atmospheric CO2, and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. This work reviews and synthesises proxy evidence of paleogeography, temperature, ice sheets, ocean circulation, and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of model simulations of temperature change across the EOT. The model simulations compare three forcing mechanisms across the EOT: CO2 decrease, paleogeographic changes, and ice sheet growth. We find that CO2 forcing provides by far the best explanation of the combined proxy evidence, and based on our model ensemble, we estimate that a CO2 decrease of about 1.6× across the EOT (e.g. from 910 to 560 ppmv) achieves the best fit to the temperature change recorded in the proxies. This model-derived CO2 decrease is consistent with proxy estimates of CO2 decline at the EOT.

ACS Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. De Boer; Michiel Baatsen; Anna Von Der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons. 2020, 1 -71.

AMA Style

David K. Hutchinson, Helen K. Coxall, Daniel J. Lunt, Margret Steinthorsdottir, Agatha M. De Boer, Michiel Baatsen, Anna Von Der Heydt, Matthew Huber, Alan T. Kennedy-Asser, Lutz Kunzmann, Jean-Baptiste Ladant, Caroline H. Lear, Karolin Moraweck, Paul N. Pearson, Emanuela Piga, Matthew J. Pound, Ulrich Salzmann, Howie D. Scher, Willem P. Sijp, Kasia K. ƚliwiƄska, Paul A. Wilson, Zhongshi Zhang. The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons. . 2020; ():1-71.

Chicago/Turabian Style

David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. De Boer; Michiel Baatsen; Anna Von Der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. ƚliwiƄska; Paul A. Wilson; Zhongshi Zhang. 2020. "The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons." , no. : 1-71.

Journal article
Published: 17 May 2020 in Paleoceanography and Paleoclimatology
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We reconstruct sea surface temperatures (SSTs) at Deep Sea Drilling Project Site 608 (42.836°N, 23.087°), north of the Azores Front, and Ocean Drilling Program Site 982 (57.516°N, 15.866°), under the North Atlantic Current, in order to track Miocene (23.1–5.3 Ma) development of North Atlantic surface waters. Mean annual SSTs from TEX86 and Uk’37 proxy estimates at both sites were 10°‐15°C higher than modern through the Miocene Climatic Optimum (MCO; 17–14.5 Ma). During the global cooling of the Middle Miocene Climate Transition (MMCT; ~14.5–12.5 Ma), SSTs at mid‐latitude Site 608 cooled by ~6°C, whereas high‐latitude Site 982 cooled by only ~2°C, resulting in an ~ 4 myr collapse of the SST gradient between the two sites. This regional pattern is inconsistent with an increased latitudinal surface temperature gradient, as generally associated with global cooling episodes linked to decreasing pCO2 levels. Instead, the pattern is best explained by enhanced ocean heat transport into the high‐latitude North Atlantic superimposed on the global cooling trend, probably due to enhanced Atlantic Meridional Overturning Circulation and/or a stronger North Atlantic Current. During global late Miocene cooling (~8–7 Ma), surface waters cooled by ~6°C at Site 982 while minimal change occurred at Site 608, re‐establishing the North Atlantic SST gradient. The collapse and re‐emergence of the SST gradient between the middle‐ and high‐latitude North Atlantic suggests that interaction between changes in regional ocean circulation and the global response to changes in greenhouse gas concentration was important in Miocene climate evolution.

ACS Style

James R. Super; Ellen Thomas; Mark Pagani; Matthew Huber; Charlotte L. O'Brien; Pincelli M. Hull. Miocene Evolution of North Atlantic Sea Surface Temperature. Paleoceanography and Paleoclimatology 2020, 35, 1 .

AMA Style

James R. Super, Ellen Thomas, Mark Pagani, Matthew Huber, Charlotte L. O'Brien, Pincelli M. Hull. Miocene Evolution of North Atlantic Sea Surface Temperature. Paleoceanography and Paleoclimatology. 2020; 35 (5):1.

Chicago/Turabian Style

James R. Super; Ellen Thomas; Mark Pagani; Matthew Huber; Charlotte L. O'Brien; Pincelli M. Hull. 2020. "Miocene Evolution of North Atlantic Sea Surface Temperature." Paleoceanography and Paleoclimatology 35, no. 5: 1.

Preprint content
Published: 23 March 2020
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When the Earth warms, the high latitudes often warm more than the low latitudes, a phenomenon commonly known as high latitude amplification. Although high latitude amplification has been observed by both climate data and models, the trajectory of high latitude amplification in our future changing climate is uncertain. Pacific-wide reconstructions of sea surface temperature variability from past climates are important for establishing the historical records of high latitude amplification. Multiple extratropical temperature records have been established for the past 10 million years (Myr). However, it is debated whether the warmest end member, the Western Pacific Warm Pool (WPWP), warmed during the late Miocene (~12 to 5 million years ago, Ma) and Pliocene (5 to 3 Ma). Here we present new multi-proxy, multi-site paleotemperature records from the WPWP. These results, based on lipid biomarkers and foraminiferal Mg/Ca, unequivocally show warmer temperatures in the past, and a secular cooling over the last 10 Myr. We combine these new data, along with the previously established paleotemperature records, to reveal a persistent pattern of change in the Pacific described by a high latitude amplification factor of ~1.7, which does not seem to be affected by the major climate changes over the past 10 Myr. The evolution of spatial temperature gradients in the Pacific is also evident in climate model output and instrumental observations covering the last 160 years, and thus appears to be a robust and predictable feature of the climate system. These results therefore confirm that climate models can capture the major features of past climate change, providing increased confidence in their predictions of future patterns that are likely to be similar to those reconstructed here.

ACS Style

Xiaoqing Liu; Matthew Huber; Gavin L Foster; R Mark Leckie; Yi Ge Zhang. Persistent high latitude amplification over the past 10 million years. 2020, 1 .

AMA Style

Xiaoqing Liu, Matthew Huber, Gavin L Foster, R Mark Leckie, Yi Ge Zhang. Persistent high latitude amplification over the past 10 million years. . 2020; ():1.

Chicago/Turabian Style

Xiaoqing Liu; Matthew Huber; Gavin L Foster; R Mark Leckie; Yi Ge Zhang. 2020. "Persistent high latitude amplification over the past 10 million years." , no. : 1.

Preprint content
Published: 09 March 2020
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ACS Style

Michiel Baatsen; Anna S. Von Der Heydt; Matthew Huber; Michael A. Kliphuis; Peter K. Bijl; Appy Sluijs; Henk A. Dijkstra. Supplementary material to "The middle-to-late Eocene greenhouse climate, modelled using the CESM 1.0.5". 2020, 1 .

AMA Style

Michiel Baatsen, Anna S. Von Der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, Henk A. Dijkstra. Supplementary material to "The middle-to-late Eocene greenhouse climate, modelled using the CESM 1.0.5". . 2020; ():1.

Chicago/Turabian Style

Michiel Baatsen; Anna S. Von Der Heydt; Matthew Huber; Michael A. Kliphuis; Peter K. Bijl; Appy Sluijs; Henk A. Dijkstra. 2020. "Supplementary material to "The middle-to-late Eocene greenhouse climate, modelled using the CESM 1.0.5"." , no. : 1.