Articles | Volume 16, issue 5
https://doi.org/10.5194/cp-16-1953-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-16-1953-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
26 Oct 2020
Research article |
| 26 Oct 2020
| 26 Oct 2020
Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene
Gordon N. Inglis
CORRESPONDING AUTHOR
School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
Organic Geochemistry Unit, School of Chemistry, School of Earth Sciences, Cabot Institute for the Environment, University of Bristol, Bristol, UK
Fran Bragg
School of Geographical Sciences, University of Bristol, Bristol, UK
Natalie J. Burls
Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, USA
Marlow Julius Cramwinckel
Department of Earth Sciences, Utrecht University, Utrecht, the Netherlands
currently at: School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
David Evans
Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
Gavin L. Foster
School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
Matthew Huber
Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, USA
Daniel J. Lunt
School of Geographical Sciences, University of Bristol, Bristol, UK
Nicholas Siler
College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, USA
Sebastian Steinig
School of Geographical Sciences, University of Bristol, Bristol, UK
Jessica E. Tierney
Department of Geosciences, The University of Arizona, 1040 E 4th St., Tucson, USA
Richard Wilkinson
School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
currently at: School of Mathematical Sciences, University of Nottingham, Nottingham, UK
Eleni Anagnostou
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Agatha M. de Boer
Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
Tom Dunkley Jones
School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
Kirsty M. Edgar
School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
Christopher J. Hollis
GNS Science, Lower Hutt, New Zealand
David K. Hutchinson
Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
Richard D. Pancost
Organic Geochemistry Unit, School of Chemistry, School of Earth Sciences, Cabot Institute for the Environment, University of Bristol, Bristol, UK
Related authors
Appy Sluijs, Joost Frieling, Gordon N. Inglis, Klaas G. J. Nierop, Francien Peterse, Francesca Sangiorgi, and Stefan Schouten
Clim. Past, 16, 2381–2400, https://doi.org/10.5194/cp-16-2381-2020, https://doi.org/10.5194/cp-16-2381-2020, 2020
Short summary
Short summary
We revisit 15-year-old reconstructions of sea surface temperatures in the Arctic Ocean for the late Paleocene and early Eocene epochs (∼ 57–53 million years ago) based on the distribution of fossil membrane lipids of archaea preserved in Arctic Ocean sediments. We find that improvements in the methods over the past 15 years do not lead to different results. However, data quality is now higher and potential biases better characterized. Results confirm remarkable Arctic warmth during this time.
Iris Arndt, Jonathan Erez, David Evans, Tobias Erhardt, Adam Levi, and Wolfgang Müller
EGUsphere, https://doi.org/10.5194/egusphere-2025-3479, https://doi.org/10.5194/egusphere-2025-3479, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
This study explores daily geochemical variations in giant clam (Tridacna) shells from controlled, isotopically-labelled day-night growth experiments. Results show five times higher daytime calcification rates. Light availability and metabolic activity significantly influence elemental incorporation mechanisms. The findings enhance our understanding of clam geochemistry and growth dynamics, offering valuable insights for studies on past environmental changes.
Kirsty M. Edgar, Maria Grigoratou, Fanny M. Monteiro, Ruby Barrett, Rui Ying, and Daniela N. Schmidt
Biogeosciences, 22, 3463–3483, https://doi.org/10.5194/bg-22-3463-2025, https://doi.org/10.5194/bg-22-3463-2025, 2025
Short summary
Short summary
Planktic foraminifera are microscopic marine organisms whose calcium carbonate shells provide valuable insights into past ocean conditions. A promising means of understanding foraminiferal ecology and their environmental interactions is to constrain their key functional traits relating to feeding, symbioses, motility, calcification, and reproduction. Here we review what we know of their functional traits, key gaps in our understanding, and suggestions on how to fill them.
Amar Mistry, Dan Lunt, and Xin Ren
EGUsphere, https://doi.org/10.5194/egusphere-2025-2750, https://doi.org/10.5194/egusphere-2025-2750, 2025
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
The Antarctic Ice Sheet is melting and adding fresh water into the Southern Ocean, affecting the global climate system. Here, we conduct model experiments in which water is input into the Southern Ocean. We find a significant response of the climate system to this meltwater; however, the manner in which the Antarctic Ice Sheet loses mass does not strongly control this response. The implications are that Antarctic meltwater should be included in future climate model projections.
Mehdi Pasha Karami, Torben Koenigk, Shiyu Wang, René Navarro Labastida, Tim Kruschke, Aude Carreric, Pablo Ortega, Klaus Wyser, Ramon Fuentes Franco, Agatha M. de Boer, Marie Sicard, and Aitor Aldama Campino
EGUsphere, https://doi.org/10.5194/egusphere-2025-2653, https://doi.org/10.5194/egusphere-2025-2653, 2025
This preprint is open for discussion and under review for Earth System Dynamics (ESD).
Short summary
Short summary
This study uses a high-resolution global climate model to simulate future climate, focusing on the Arctic and North Atlantic. The model captures observed sea ice loss and Atlantic circulation trends, projecting a nearly ice-free Arctic by 2040. It introduces a new method to quantify deep water formation, revealing how different ocean regions contribute to the weakening of overturning circulation in a warming climate.
Lukas Jonkers, Tonke Strack, Montserrat Alonso-Garcia, Simon D'haenens, Robert Huber, Michal Kucera, Iván Hernández-Almeida, Chloe L. C. Jones, Brett Metcalfe, Rajeev Saraswat, Lóránd Silye, Sanjay K. Verma, Muhamad Naim Abd Malek, Gerald Auer, Cátia F. Barbosa, Maria A. Barcena, Karl-Heinz Baumann, Flavia Boscolo-Galazzo, Joeven Austine S. Calvelo, Lucilla Capotondi, Martina Caratelli, Jorge Cardich, Humberto Carvajal-Chitty, Markéta Chroustová, Helen K. Coxall, Renata M. de Mello, Anne de Vernal, Paula Diz, Kirsty M. Edgar, Helena L. Filipsson, Ángela Fraguas, Heather L. Furlong, Giacomo Galli, Natalia L. García Chapori, Robyn Granger, Jeroen Groeneveld, Adil Imam, Rebecca Jackson, David Lazarus, Julie Meilland, Marína Molčan Matejová, Raphael Morard, Caterina Morigi, Sven N. Nielsen, Diana Ochoa, Maria Rose Petrizzo, Andrés S. Rigual-Hernández, Marina C. Rillo, Matthew L. Staitis, Gamze Tanık, Raúl Tapia, Nishant Vats, Bridget S. Wade, and Anna E. Weinmann
J. Micropalaeontol., 44, 145–168, https://doi.org/10.5194/jm-44-145-2025, https://doi.org/10.5194/jm-44-145-2025, 2025
Short summary
Short summary
Our study provides guidelines improving the reuse of marine microfossil assemblage data, which are valuable for understanding past ecosystems and environmental change. Based on a survey of 113 researchers, we identified key data attributes required for effective reuse. Analysis of a selection of datasets available online reveals a gap between the attributes scientists consider essential and the data currently available, highlighting the need for clearer data documentation and sharing practices.
Himadri Saini, David K. Hutchinson, Josephine R. Brown, Russell N. Drysdale, Yanxuan Du, and Laurie Menviel
EGUsphere, https://doi.org/10.5194/egusphere-2025-1990, https://doi.org/10.5194/egusphere-2025-1990, 2025
Short summary
Short summary
This study examines how large ice sheets during the last Ice Age influenced global weather patterns. We found that the presence of these ice sheets affected rainfall patterns in regions like Eurasia and Australia. By altering wind and weather systems, they shifted the position of the tropical rainbelt and impacted the circulation of air in both the Northern and Southern Hemispheres. Our research helps us understand past climate changes and their potential effects on future climate patterns.
Peter K. Bijl, Kasia K. Sliwinska, Bella Duncan, Arnaud Huguet, Sebastian Naeher, Ronnakrit Rattanasriampaipong, Claudia Sosa-Montes de Oca, Alexandra Auderset, Melissa Berke, Bum Soo Kim, Nina Davtian, Tom Dunkley Jones, Desmond Eefting, Felix Elling, Lauren O'Connor, Richard D. Pancost, Francien Peterse, Pierrick Fenies, Addison Rice, Appy Sluijs, Devika Varma, Wenjie Xiao, and Yige Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2025-1467, https://doi.org/10.5194/egusphere-2025-1467, 2025
Short summary
Short summary
Many academic laboratories worldwide process environmental samples for analysis of membrane lipid molecules of archaea, for the reconstruction of past environmental conditions. However, the sample workup scheme involves many steps, each of which has a risk of contamination or bias, affecting the results. This paper reviews steps involved in sampling, extraction and analysis of lipids, interpretation and archiving of the data. This ensures reproducable, reusable, comparable and consistent data.
Flavia Boscolo-Galazzo, David Evans, Elaine M. Mawbey, William R. Gray, Paul N. Pearson, and Bridget S. Wade
Biogeosciences, 22, 1095–1113, https://doi.org/10.5194/bg-22-1095-2025, https://doi.org/10.5194/bg-22-1095-2025, 2025
Short summary
Short summary
Here we compare the Mg / Ca and oxygen isotope signatures for 57 recent to fossil species of planktonic foraminifera for the last 15 Myr. We find the occurrence of lineage-specific offsets in Mg / Ca conservative between ancestor-descendent species. Taking into account species kinship significantly improves temperature reconstructions, and we suggest that the occurrence of Mg / Ca offsets in modern species results from their evolution when ocean properties were different from today's.
Louise C. Sime, Rahul Sivankutty, Irene Malmierca-Vallet, Sentia Goursaud Oger, Allegra N. LeGrande, Erin L. McClymont, Agatha de Boer, Alexandre Cauquoin, and Martin Werner
EGUsphere, https://doi.org/10.5194/egusphere-2025-288, https://doi.org/10.5194/egusphere-2025-288, 2025
Short summary
Short summary
We used climate models to study how stable water isotopes in ice cores changed in the Arctic and Antarctica during the warm Last Interglacial (LIG) period. Whilst standard simulations underestimate polar warming, when the effects of ice sheet meltwater from the preceding deglaciation are included, there is a much better match with observations. Findings suggest that previous estimates of LIG Arctic warming were too high. Understanding these past polar changes can help improve future predictions.
Johan Liakka, Natalie S. Lord, Alan Kennedy-Asser, Daniel J. Lunt, Charles J. R. Williams, and Jens-Ove Näslund
Adv. Geosci., 65, 71–81, https://doi.org/10.5194/adgeo-65-71-2024, https://doi.org/10.5194/adgeo-65-71-2024, 2024
Short summary
Short summary
Future glaciations can affect the long-term safety of deep geological repositories for nuclear waste. This study introduces a simple method to assess frequency and duration of ice sheets over the next one million years at locations with past glaciations. The method considers uncertainties in human-caused CO2 emissions and climate change. It is easy to implement for any nuclear waste management organization that need to consider impacts of future ice sheets on long-term safety.
Yixuan Xie, Daniel J. Lunt, and Paul J. Valdes
Clim. Past, 20, 2561–2585, https://doi.org/10.5194/cp-20-2561-2024, https://doi.org/10.5194/cp-20-2561-2024, 2024
Short summary
Short summary
Desert dust plays a crucial role in the climate system; while it is relatively well studied for the present day, we still lack knowledge on how it was in the past and on its underlying mechanism in the multi-million-year timescale of Earth’s history. For the first time, we simulate dust emissions using the newly developed DUSTY1.0 model over the past 540 million years with a temporal resolution of ~5 million years. We find that palaeogeography is the primary control of these variations.
Nick R. Hayes, Daniel J. Lunt, Yves Goddéris, Richard D. Pancost, and Heather L. Buss
EGUsphere, https://doi.org/10.5194/egusphere-2024-2811, https://doi.org/10.5194/egusphere-2024-2811, 2024
Short summary
Short summary
The breakdown of volcanic rocks by water helps balance the climate of the earth by sequestering atmospheric CO2 . The rate of CO2 sequestration is referred to as "weatherability". Our modelling study finds that continental position strongly impacts CO2 concentrations, that runoff strongly controls weatherability, that changes in weatherability may explain long term trends in atmospheric CO2 concentrations, and that even relatively localised changes in weatherability may have global impacts.
Dominique K. L. L. Jenny, Tammo Reichgelt, Charlotte L. O'Brien, Xiaoqing Liu, Peter K. Bijl, Matthew Huber, and Appy Sluijs
Clim. Past, 20, 1627–1657, https://doi.org/10.5194/cp-20-1627-2024, https://doi.org/10.5194/cp-20-1627-2024, 2024
Short summary
Short summary
This study reviews the current state of knowledge regarding the Oligocene
icehouseclimate. We extend an existing marine climate proxy data compilation and present a new compilation and analysis of terrestrial plant assemblages to assess long-term climate trends and variability. Our data–climate model comparison reinforces the notion that models underestimate polar amplification of Oligocene climates, and we identify potential future research directions.
Sebastian Steinig, Wolf Dummann, Peter Hofmann, Martin Frank, Wonsun Park, Thomas Wagner, and Sascha Flögel
Clim. Past, 20, 1537–1558, https://doi.org/10.5194/cp-20-1537-2024, https://doi.org/10.5194/cp-20-1537-2024, 2024
Short summary
Short summary
The opening of the South Atlantic Ocean, starting ~ 140 million years ago, had the potential to influence the global carbon cycle and climate trends. We use 36 climate model experiments to simulate the evolution of ocean circulation in this narrow basin. We test different combinations of palaeogeographic and atmospheric CO2 reconstructions with geochemical data to not only quantify the influence of individual processes on ocean circulation but also to find nonlinear interactions between them.
Chris D. Fokkema, Tobias Agterhuis, Danielle Gerritsma, Myrthe de Goeij, Xiaoqing Liu, Pauline de Regt, Addison Rice, Laurens Vennema, Claudia Agnini, Peter K. Bijl, Joost Frieling, Matthew Huber, Francien Peterse, and Appy Sluijs
Clim. Past, 20, 1303–1325, https://doi.org/10.5194/cp-20-1303-2024, https://doi.org/10.5194/cp-20-1303-2024, 2024
Short summary
Short summary
Polar amplification (PA) is a key uncertainty in climate projections. The factors that dominantly control PA are difficult to separate. Here we provide an estimate for the non-ice-related PA by reconstructing tropical ocean temperature variability from the ice-free early Eocene, which we compare to deep-ocean-derived high-latitude temperature variability across short-lived warming periods. We find a PA factor of 1.7–2.3 on 20 kyr timescales, which is somewhat larger than model estimates.
Marci M. Robinson, Kenneth G. Miller, Tali L. Babila, Timothy J. Bralower, James V. Browning, Marlow J. Cramwinckel, Monika Doubrawa, Gavin L. Foster, Megan K. Fung, Sean Kinney, Maria Makarova, Peter P. McLaughlin, Paul N. Pearson, Ursula Röhl, Morgan F. Schaller, Jean M. Self-Trail, Appy Sluijs, Thomas Westerhold, James D. Wright, and James C. Zachos
Sci. Dril., 33, 47–65, https://doi.org/10.5194/sd-33-47-2024, https://doi.org/10.5194/sd-33-47-2024, 2024
Short summary
Short summary
The Paleocene–Eocene Thermal Maximum (PETM) is the closest geological analog to modern anthropogenic CO2 emissions, but its causes and the responses remain enigmatic. Coastal plain sediments can resolve this uncertainty, but their discontinuous nature requires numerous sites to constrain events. Workshop participants identified 10 drill sites that target the PETM and other interesting intervals. Our post-drilling research will provide valuable insights into Earth system responses.
Madeleine L. Vickers, Morgan T. Jones, Jack Longman, David Evans, Clemens V. Ullmann, Ella Wulfsberg Stokke, Martin Vickers, Joost Frieling, Dustin T. Harper, Vincent J. Clementi, and IODP Expedition 396 Scientists
Clim. Past, 20, 1–23, https://doi.org/10.5194/cp-20-1-2024, https://doi.org/10.5194/cp-20-1-2024, 2024
Short summary
Short summary
The discovery of cold-water glendonite pseudomorphs in sediments deposited during the hottest part of the Cenozoic poses an apparent climate paradox. This study examines their occurrence, association with volcanic sediments, and speculates on the timing and extent of cooling, fitting this with current understanding of global climate during this period. We propose that volcanic activity was key to both physical and chemical conditions that enabled the formation of glendonites in these sediments.
Mohd Al Farid Abraham, Bernhard David A. Naafs, Vittoria Lauretano, Fotis Sgouridis, and Richard D. Pancost
Clim. Past, 19, 2569–2580, https://doi.org/10.5194/cp-19-2569-2023, https://doi.org/10.5194/cp-19-2569-2023, 2023
Short summary
Short summary
Oceanic Anoxic Event 2 (OAE 2), about 93.5 million years ago, is characterized by widespread deoxygenated ocean and massive burial of organic-rich sediments. Our results show that the marine deoxygenation at the equatorial Atlantic that predates the OAE 2 interval was driven by global warming and associated with the nutrient status of the site, with factors like temperature-modulated upwelling and hydrology-induced weathering contributing to enhanced nutrient delivery over various timescales.
Elwyn de la Vega, Thomas B. Chalk, Mathis P. Hain, Megan R. Wilding, Daniel Casey, Robin Gledhill, Chongguang Luo, Paul A. Wilson, and Gavin L. Foster
Clim. Past, 19, 2493–2510, https://doi.org/10.5194/cp-19-2493-2023, https://doi.org/10.5194/cp-19-2493-2023, 2023
Short summary
Short summary
We evaluate how faithfully the boron isotope composition of foraminifera records atmospheric CO2 by comparing it to the high-fidelity CO2 record from the Antarctic ice cores. We evaluate potential factors and find that partial dissolution of foraminifera shells, assumptions of seawater chemistry, and the biology of foraminifera all have a negligible effect on reconstructed CO2. This gives confidence in the use of boron isotopes beyond the interval when ice core CO2 is available.
Alison J. Smith, Emi Ito, Natalie Burls, Leon Clarke, Timme Donders, Robert Hatfield, Stephen Kuehn, Andreas Koutsodendris, Tim Lowenstein, David McGee, Peter Molnar, Alexander Prokopenko, Katie Snell, Blas Valero Garcés, Josef Werne, Christian Zeeden, and the PlioWest Working Consortium
Sci. Dril., 32, 61–72, https://doi.org/10.5194/sd-32-61-2023, https://doi.org/10.5194/sd-32-61-2023, 2023
Short summary
Short summary
Western North American contains accessible and under-recognized paleolake records that hold the keys to understanding the drivers of wetter conditions in Pliocene Epoch subtropical drylands worldwide. In a 2021 ICDP workshop, we chose five paleolake basins to study that span 7° of latitude in a unique array able to capture a detailed record of hydroclimate during the Early Pliocene warm period and subsequent Pleistocene cooling. We propose new drill cores for three of these basins.
Xin Ren, Daniel J. Lunt, Erica Hendy, Anna von der Heydt, Ayako Abe-Ouchi, Bette Otto-Bliesner, Charles J. R. Williams, Christian Stepanek, Chuncheng Guo, Deepak Chandan, Gerrit Lohmann, Julia C. Tindall, Linda E. Sohl, Mark A. Chandler, Masa Kageyama, Michiel L. J. Baatsen, Ning Tan, Qiong Zhang, Ran Feng, Stephen Hunter, Wing-Le Chan, W. Richard Peltier, Xiangyu Li, Youichi Kamae, Zhongshi Zhang, and Alan M. Haywood
Clim. Past, 19, 2053–2077, https://doi.org/10.5194/cp-19-2053-2023, https://doi.org/10.5194/cp-19-2053-2023, 2023
Short summary
Short summary
We investigate the Maritime Continent climate in the mid-Piacenzian warm period and find it is warmer and wetter and the sea surface salinity is lower compared with preindustrial period. Besides, the fresh and warm water transfer through the Maritime Continent was stronger. In order to avoid undue influence from closely related models in the multimodel results, we introduce a new metric, the multi-cluster mean, which could reveal spatial signals that are not captured by the multimodel mean.
Louise C. Sime, Rahul Sivankutty, Irene Vallet-Malmierca, Agatha M. de Boer, and Marie Sicard
Clim. Past, 19, 883–900, https://doi.org/10.5194/cp-19-883-2023, https://doi.org/10.5194/cp-19-883-2023, 2023
Short summary
Short summary
It is not known if the Last Interglacial (LIG) experienced Arctic summers that were sea ice free: models show a wide spread in LIG Arctic temperature and sea ice results. Evaluation against sea ice markers is hampered by few observations. Here, an assessment of 11 climate model simulations against summer temperatures shows that the most skilful models have a 74 %–79 % reduction in LIG sea ice. The measurements of LIG areas indicate a likely mix of ice-free and near-ice-free LIG summers.
Caitlyn R. Witkowski, Vittoria Lauretano, Alex Farnsworth, Shufeng Li, Shi-Hu Li, Jan Peter Mayser, B. David A. Naafs, Robert A. Spicer, Tao Su, He Tang, Zhe-Kun Zhou, Paul J. Valdes, and Richard D. Pancost
EGUsphere, https://doi.org/10.5194/egusphere-2023-373, https://doi.org/10.5194/egusphere-2023-373, 2023
Preprint archived
Short summary
Short summary
Untangling the complex tectonic evolution in the Tibetan region can help us understand its impacts on climate, the Asian monsoon system, and the development of major biodiversity hotspots. We show that this “missing link” site between high elevation Tibet and low elevation coastal China had a dynamic environment but no temperature change, meaning its been at its current-day elevation for the past 34 million years.
Kasia K. Śliwińska, Helen K. Coxall, David K. Hutchinson, Diederik Liebrand, Stefan Schouten, and Agatha M. de Boer
Clim. Past, 19, 123–140, https://doi.org/10.5194/cp-19-123-2023, https://doi.org/10.5194/cp-19-123-2023, 2023
Short summary
Short summary
We provide a sea surface temperature record from the Labrador Sea (ODP Site 647) based on organic geochemical proxies across the late Eocene and early Oligocene. Our study reveals heterogenic cooling of the Atlantic. The cooling of the North Atlantic is difficult to reconcile with the active Atlantic Meridional Overturning Circulation (AMOC). We discuss possible explanations like uncertainty in the data, paleogeography and atmospheric CO2 boundary conditions, model weaknesses, and AMOC activity.
Julia E. Weiffenbach, Michiel L. J. Baatsen, Henk A. Dijkstra, Anna S. von der Heydt, Ayako Abe-Ouchi, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Mark A. Chandler, Camille Contoux, Ran Feng, Chuncheng Guo, Zixuan Han, Alan M. Haywood, Qiang Li, Xiangyu Li, Gerrit Lohmann, Daniel J. Lunt, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Gilles Ramstein, Linda E. Sohl, Christian Stepanek, Ning Tan, Julia C. Tindall, Charles J. R. Williams, Qiong Zhang, and Zhongshi Zhang
Clim. Past, 19, 61–85, https://doi.org/10.5194/cp-19-61-2023, https://doi.org/10.5194/cp-19-61-2023, 2023
Short summary
Short summary
We study the behavior of the Atlantic Meridional Overturning Circulation (AMOC) in the mid-Pliocene. The mid-Pliocene was about 3 million years ago and had a similar CO2 concentration to today. We show that the stronger AMOC during this period relates to changes in geography and that this has a significant influence on ocean temperatures and heat transported northwards by the Atlantic Ocean. Understanding the behavior of the mid-Pliocene AMOC can help us to learn more about our future climate.
Christopher J. Hollis, Sebastian Naeher, Christopher D. Clowes, B. David A. Naafs, Richard D. Pancost, Kyle W. R. Taylor, Jenny Dahl, Xun Li, G. Todd Ventura, and Richard Sykes
Clim. Past, 18, 1295–1320, https://doi.org/10.5194/cp-18-1295-2022, https://doi.org/10.5194/cp-18-1295-2022, 2022
Short summary
Short summary
Previous studies of Paleogene greenhouse climates identified short-lived global warming events, termed hyperthermals, that provide insights into global warming scenarios. Within the same time period, we have identified a short-lived cooling event in the late Paleocene, which we term a hypothermal, that has potential to provide novel insights into the feedback mechanisms at work in a greenhouse climate.
Flavia Boscolo-Galazzo, Amy Jones, Tom Dunkley Jones, Katherine A. Crichton, Bridget S. Wade, and Paul N. Pearson
Biogeosciences, 19, 743–762, https://doi.org/10.5194/bg-19-743-2022, https://doi.org/10.5194/bg-19-743-2022, 2022
Short summary
Short summary
Deep-living organisms are a major yet poorly known component of ocean biomass. Here we reconstruct the evolution of deep-living zooplankton and phytoplankton. Deep-dwelling zooplankton and phytoplankton did not occur 15 Myr ago, when the ocean was several degrees warmer than today. Deep-dwelling species first evolve around 7.5 Myr ago, following global climate cooling. Their evolution was driven by colder ocean temperatures allowing more food, oxygen, and light at depth.
Zixuan Han, Qiong Zhang, Qiang Li, Ran Feng, Alan M. Haywood, Julia C. Tindall, Stephen J. Hunter, Bette L. Otto-Bliesner, Esther C. Brady, Nan Rosenbloom, Zhongshi Zhang, Xiangyu Li, Chuncheng Guo, Kerim H. Nisancioglu, Christian Stepanek, Gerrit Lohmann, Linda E. Sohl, Mark A. Chandler, Ning Tan, Gilles Ramstein, Michiel L. J. Baatsen, Anna S. von der Heydt, Deepak Chandan, W. Richard Peltier, Charles J. R. Williams, Daniel J. Lunt, Jianbo Cheng, Qin Wen, and Natalie J. Burls
Clim. Past, 17, 2537–2558, https://doi.org/10.5194/cp-17-2537-2021, https://doi.org/10.5194/cp-17-2537-2021, 2021
Short summary
Short summary
Understanding the potential processes responsible for large-scale hydrological cycle changes in a warmer climate is of great importance. Our study implies that an imbalance in interhemispheric atmospheric energy during the mid-Pliocene could have led to changes in the dynamic effect, offsetting the thermodynamic effect and, hence, altering mid-Pliocene hydroclimate cycling. Moreover, a robust westward shift in the Pacific Walker circulation can moisten the northern Indian Ocean.
Arthur M. Oldeman, Michiel L. J. Baatsen, Anna S. von der Heydt, Henk A. Dijkstra, Julia C. Tindall, Ayako Abe-Ouchi, Alice R. Booth, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Mark A. Chandler, Camille Contoux, Ran Feng, Chuncheng Guo, Alan M. Haywood, Stephen J. Hunter, Youichi Kamae, Qiang Li, Xiangyu Li, Gerrit Lohmann, Daniel J. Lunt, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Gabriel M. Pontes, Gilles Ramstein, Linda E. Sohl, Christian Stepanek, Ning Tan, Qiong Zhang, Zhongshi Zhang, Ilana Wainer, and Charles J. R. Williams
Clim. Past, 17, 2427–2450, https://doi.org/10.5194/cp-17-2427-2021, https://doi.org/10.5194/cp-17-2427-2021, 2021
Short summary
Short summary
In this work, we have studied the behaviour of El Niño events in the mid-Pliocene, a period of around 3 million years ago, using a collection of 17 climate models. It is an interesting period to study, as it saw similar atmospheric carbon dioxide levels to the present day. We find that the El Niño events were less strong in the mid-Pliocene simulations, when compared to pre-industrial climate. Our results could help to interpret El Niño behaviour in future climate projections.
Peter K. Bijl, Joost Frieling, Marlow Julius Cramwinckel, Christine Boschman, Appy Sluijs, and Francien Peterse
Clim. Past, 17, 2393–2425, https://doi.org/10.5194/cp-17-2393-2021, https://doi.org/10.5194/cp-17-2393-2021, 2021
Short summary
Short summary
Here, we use the latest insights for GDGT and dinocyst-based paleotemperature and paleoenvironmental reconstructions in late Cretaceous–early Oligocene sediments from ODP Site 1172 (East Tasman Plateau, Australia). We reconstruct strong river runoff during the Paleocene–early Eocene, a progressive decline thereafter with increased wet/dry seasonality in the northward-drifting hinterland. Our critical review leaves the anomalous warmth of the Eocene SW Pacific Ocean unexplained.
Katherine A. Crichton, Andy Ridgwell, Daniel J. Lunt, Alex Farnsworth, and Paul N. Pearson
Clim. Past, 17, 2223–2254, https://doi.org/10.5194/cp-17-2223-2021, https://doi.org/10.5194/cp-17-2223-2021, 2021
Short summary
Short summary
The middle Miocene (15 Ma) was a period of global warmth up to 8 °C warmer than present. We investigate changes in ocean circulation and heat distribution since the middle Miocene and the cooling to the present using the cGENIE Earth system model. We create seven time slices at ~2.5 Myr intervals, constrained with paleo-proxy data, showing a progressive reduction in atmospheric CO2 and a strengthening of the Atlantic Meridional Overturning Circulation.
Charles J. R. Williams, Alistair A. Sellar, Xin Ren, Alan M. Haywood, Peter Hopcroft, Stephen J. Hunter, William H. G. Roberts, Robin S. Smith, Emma J. Stone, Julia C. Tindall, and Daniel J. Lunt
Clim. Past, 17, 2139–2163, https://doi.org/10.5194/cp-17-2139-2021, https://doi.org/10.5194/cp-17-2139-2021, 2021
Short summary
Short summary
Computer simulations of the geological past are an important tool to improve our understanding of climate change. We present results from a simulation of the mid-Pliocene (approximately 3 million years ago) using the latest version of the UK’s climate model. The simulation reproduces temperatures as expected and shows some improvement relative to previous versions of the same model. The simulation is, however, arguably too warm when compared to other models and available observations.
Ellen Berntell, Qiong Zhang, Qiang Li, Alan M. Haywood, Julia C. Tindall, Stephen J. Hunter, Zhongshi Zhang, Xiangyu Li, Chuncheng Guo, Kerim H. Nisancioglu, Christian Stepanek, Gerrit Lohmann, Linda E. Sohl, Mark A. Chandler, Ning Tan, Camille Contoux, Gilles Ramstein, Michiel L. J. Baatsen, Anna S. von der Heydt, Deepak Chandan, William Richard Peltier, Ayako Abe-Ouchi, Wing-Le Chan, Youichi Kamae, Charles J. R. Williams, Daniel J. Lunt, Ran Feng, Bette L. Otto-Bliesner, and Esther C. Brady
Clim. Past, 17, 1777–1794, https://doi.org/10.5194/cp-17-1777-2021, https://doi.org/10.5194/cp-17-1777-2021, 2021
Short summary
Short summary
The mid-Pliocene Warm Period (~ 3.2 Ma) is often considered an analogue for near-future climate projections, and model results from the PlioMIP2 ensemble show an increase of rainfall over West Africa and the Sahara region compared to pre-industrial conditions. Though previous studies of future projections show a west–east drying–wetting contrast over the Sahel, these results indicate a uniform rainfall increase over the Sahel in warm climates characterized by increased greenhouse gas forcing.
Nicolai Schleinkofer, David Evans, Max Wisshak, Janina Vanessa Büscher, Jens Fiebig, André Freiwald, Sven Härter, Horst R. Marschall, Silke Voigt, and Jacek Raddatz
Biogeosciences, 18, 4733–4753, https://doi.org/10.5194/bg-18-4733-2021, https://doi.org/10.5194/bg-18-4733-2021, 2021
Short summary
Short summary
We have measured the chemical composition of the carbonate shells of the parasitic foraminifera Hyrrokkin sarcophaga in order to test if it is influenced by the host organism (bivalve or coral). We find that both the chemical and isotopic composition is influenced by the host organism. For example strontium is enriched in foraminifera that grew on corals, whose skeleton is built from aragonite, which is naturally enriched in strontium compared to the bivalves' calcite shell.
Felipe S. Freitas, Philip A. Pika, Sabine Kasten, Bo B. Jørgensen, Jens Rassmann, Christophe Rabouille, Shaun Thomas, Henrik Sass, Richard D. Pancost, and Sandra Arndt
Biogeosciences, 18, 4651–4679, https://doi.org/10.5194/bg-18-4651-2021, https://doi.org/10.5194/bg-18-4651-2021, 2021
Short summary
Short summary
It remains challenging to fully understand what controls carbon burial in marine sediments globally. Thus, we use a model–data approach to identify patterns of organic matter reactivity at the seafloor across distinct environmental conditions. Our findings support the notion that organic matter reactivity is a dynamic ecosystem property and strongly influences biogeochemical cycling and exchange. Our results are essential to improve predictions of future changes in carbon cycling and climate.
Paul J. Valdes, Christopher R. Scotese, and Daniel J. Lunt
Clim. Past, 17, 1483–1506, https://doi.org/10.5194/cp-17-1483-2021, https://doi.org/10.5194/cp-17-1483-2021, 2021
Short summary
Short summary
Deep ocean temperatures are widely used as a proxy for global mean surface temperature in the past, but the underlying assumptions have not been tested. We use two unique sets of 109 climate model simulations for the last 545 million years to show that the relationship is valid for approximately the last 100 million years but breaks down for older time periods when the continents (and hence ocean circulation) are in very different positions.
Daniel J. Lunt, Deepak Chandan, Alan M. Haywood, George M. Lunt, Jonathan C. Rougier, Ulrich Salzmann, Gavin A. Schmidt, and Paul J. Valdes
Geosci. Model Dev., 14, 4307–4317, https://doi.org/10.5194/gmd-14-4307-2021, https://doi.org/10.5194/gmd-14-4307-2021, 2021
Short summary
Short summary
Often in science we carry out experiments with computers in which several factors are explored, for example, in the field of climate science, how the factors of greenhouse gases, ice, and vegetation affect temperature. We can explore the relative importance of these factors by
swapping in and outdifferent values of these factors, and can also carry out experiments with many different combinations of these factors. This paper discusses how best to analyse the results from such experiments.
Masa Kageyama, Sandy P. Harrison, Marie-L. Kapsch, Marcus Lofverstrom, Juan M. Lora, Uwe Mikolajewicz, Sam Sherriff-Tadano, Tristan Vadsaria, Ayako Abe-Ouchi, Nathaelle Bouttes, Deepak Chandan, Lauren J. Gregoire, Ruza F. Ivanovic, Kenji Izumi, Allegra N. LeGrande, Fanny Lhardy, Gerrit Lohmann, Polina A. Morozova, Rumi Ohgaito, André Paul, W. Richard Peltier, Christopher J. Poulsen, Aurélien Quiquet, Didier M. Roche, Xiaoxu Shi, Jessica E. Tierney, Paul J. Valdes, Evgeny Volodin, and Jiang Zhu
Clim. Past, 17, 1065–1089, https://doi.org/10.5194/cp-17-1065-2021, https://doi.org/10.5194/cp-17-1065-2021, 2021
Short summary
Short summary
The Last Glacial Maximum (LGM; ~21 000 years ago) is a major focus for evaluating how well climate models simulate climate changes as large as those expected in the future. Here, we compare the latest climate model (CMIP6-PMIP4) to the previous one (CMIP5-PMIP3) and to reconstructions. Large-scale climate features (e.g. land–sea contrast, polar amplification) are well captured by all models, while regional changes (e.g. winter extratropical cooling, precipitations) are still poorly represented.
Alan Huston, Nicholas Siler, Gerard H. Roe, Erin Pettit, and Nathan J. Steiger
The Cryosphere, 15, 1645–1662, https://doi.org/10.5194/tc-15-1645-2021, https://doi.org/10.5194/tc-15-1645-2021, 2021
Short summary
Short summary
We simulate the past 1000 years of glacier length variability using a simple glacier model and an ensemble of global climate model simulations. Glaciers with long response times are more likely to record global climate changes caused by events like volcanic eruptions and greenhouse gas emissions, while glaciers with short response times are more likely to record natural variability. This difference stems from differences in the frequency spectra of natural and forced temperature variability.
Zhongshi Zhang, Xiangyu Li, Chuncheng Guo, Odd Helge Otterå, Kerim H. Nisancioglu, Ning Tan, Camille Contoux, Gilles Ramstein, Ran Feng, Bette L. Otto-Bliesner, Esther Brady, Deepak Chandan, W. Richard Peltier, Michiel L. J. Baatsen, Anna S. von der Heydt, Julia E. Weiffenbach, Christian Stepanek, Gerrit Lohmann, Qiong Zhang, Qiang Li, Mark A. Chandler, Linda E. Sohl, Alan M. Haywood, Stephen J. Hunter, Julia C. Tindall, Charles Williams, Daniel J. Lunt, Wing-Le Chan, and Ayako Abe-Ouchi
Clim. Past, 17, 529–543, https://doi.org/10.5194/cp-17-529-2021, https://doi.org/10.5194/cp-17-529-2021, 2021
Short summary
Short summary
The Atlantic Meridional Overturning Circulation (AMOC) is an important topic in the Pliocene Model Intercomparison Project. Previous studies have suggested a much stronger AMOC during the Pliocene than today. However, our current multi-model intercomparison shows large model spreads and model–data discrepancies, which can not support the previous hypothesis. Our study shows good consistency with future projections of the AMOC.
Wolf Dummann, Sebastian Steinig, Peter Hofmann, Matthias Lenz, Stephanie Kusch, Sascha Flögel, Jens Olaf Herrle, Christian Hallmann, Janet Rethemeyer, Haino Uwe Kasper, and Thomas Wagner
Clim. Past, 17, 469–490, https://doi.org/10.5194/cp-17-469-2021, https://doi.org/10.5194/cp-17-469-2021, 2021
Short summary
Short summary
This study investigates the climatic mechanism that controlled the deposition of organic matter in the South Atlantic Cape Basin during the Early Cretaceous. The presented geochemical and climate modeling data suggest that fluctuations in riverine nutrient supply were the main driver of organic carbon burial on timescales < 1 Myr. Our results have implications for the understanding of Cretaceous atmospheric circulation patterns and climate-land-ocean interactions in emerging ocean basins.
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. Śliwińska, Paul A. Wilson, and Zhongshi Zhang
Clim. Past, 17, 269–315, https://doi.org/10.5194/cp-17-269-2021, https://doi.org/10.5194/cp-17-269-2021, 2021
Short summary
Short summary
The Eocene–Oligocene transition was a major climate cooling event from a largely ice-free world to the first major glaciation of Antarctica, approximately 34 million years ago. This paper reviews observed changes in temperature, CO2 and ice sheets from marine and land-based records at this time. We present a new model–data comparison of this transition and find that CO2-forced cooling provides the best explanation of the observed global temperature changes.
Annique van der Boon, Klaudia F. Kuiper, Robin van der Ploeg, Marlow Julius Cramwinckel, Maryam Honarmand, Appy Sluijs, and Wout Krijgsman
Clim. Past, 17, 229–239, https://doi.org/10.5194/cp-17-229-2021, https://doi.org/10.5194/cp-17-229-2021, 2021
Short summary
Short summary
40.5 million years ago, Earth's climate warmed, but it is unknown why. Enhanced volcanism has been suggested, but this has not yet been tied to a specific region. We explore an increase in volcanism in Iran. We dated igneous rocks and compiled ages from the literature. We estimated the volume of igneous rocks in Iran in order to calculate the amount of CO2 that could have been released due to enhanced volcanism. We conclude that an increase in volcanism in Iran is a plausible cause of warming.
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, and Bette L. Otto-Bliesner
Clim. Past, 17, 203–227, https://doi.org/10.5194/cp-17-203-2021, https://doi.org/10.5194/cp-17-203-2021, 2021
Short summary
Short summary
This paper presents the first modelling results from the Deep-Time Model Intercomparison Project (DeepMIP), in which we focus on the early Eocene climatic optimum (EECO, 50 million years ago). We show that, in contrast to previous work, at least three models (CESM, GFDL, and NorESM) produce climate states that are consistent with proxy indicators of global mean temperature and polar amplification, and they achieve this at a CO2 concentration that is consistent with the CO2 proxy record.
Tom Dunkley Jones, Yvette L. Eley, William Thomson, Sarah E. Greene, Ilya Mandel, Kirsty Edgar, and James A. Bendle
Clim. Past, 16, 2599–2617, https://doi.org/10.5194/cp-16-2599-2020, https://doi.org/10.5194/cp-16-2599-2020, 2020
Short summary
Short summary
We explore the utiliity of the composition of fossil lipid biomarkers, which are commonly preserved in ancient marine sediments, in providing estimates of past ocean temperatures. The group of lipids concerned show compositional changes across the modern oceans that are correlated, to some extent, with local surface ocean temperatures. Here we present new machine learning approaches to improve our understanding of this temperature sensitivity and its application to reconstructing past climates.
Michiel Baatsen, Anna S. von der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, and Henk A. Dijkstra
Clim. Past, 16, 2573–2597, https://doi.org/10.5194/cp-16-2573-2020, https://doi.org/10.5194/cp-16-2573-2020, 2020
Short summary
Short summary
Warm climates of the deep past have proven to be challenging to reconstruct with the same numerical models used for future predictions. We present results of CESM simulations for the middle to late Eocene (∼ 38 Ma), in which we managed to match the available indications of temperature well. With these results we can now look into regional features and the response to external changes to ultimately better understand the climate when it is in such a warm state.
Appy Sluijs, Joost Frieling, Gordon N. Inglis, Klaas G. J. Nierop, Francien Peterse, Francesca Sangiorgi, and Stefan Schouten
Clim. Past, 16, 2381–2400, https://doi.org/10.5194/cp-16-2381-2020, https://doi.org/10.5194/cp-16-2381-2020, 2020
Short summary
Short summary
We revisit 15-year-old reconstructions of sea surface temperatures in the Arctic Ocean for the late Paleocene and early Eocene epochs (∼ 57–53 million years ago) based on the distribution of fossil membrane lipids of archaea preserved in Arctic Ocean sediments. We find that improvements in the methods over the past 15 years do not lead to different results. However, data quality is now higher and potential biases better characterized. Results confirm remarkable Arctic warmth during this time.
Alan M. Haywood, Julia C. Tindall, Harry J. Dowsett, Aisling M. Dolan, Kevin M. Foley, Stephen J. Hunter, Daniel J. Hill, Wing-Le Chan, Ayako Abe-Ouchi, Christian Stepanek, Gerrit Lohmann, Deepak Chandan, W. Richard Peltier, Ning Tan, Camille Contoux, Gilles Ramstein, Xiangyu Li, Zhongshi Zhang, Chuncheng Guo, Kerim H. Nisancioglu, Qiong Zhang, Qiang Li, Youichi Kamae, Mark A. Chandler, Linda E. Sohl, Bette L. Otto-Bliesner, Ran Feng, Esther C. Brady, Anna S. von der Heydt, Michiel L. J. Baatsen, and Daniel J. Lunt
Clim. Past, 16, 2095–2123, https://doi.org/10.5194/cp-16-2095-2020, https://doi.org/10.5194/cp-16-2095-2020, 2020
Short summary
Short summary
The large-scale features of middle Pliocene climate from the 16 models of PlioMIP Phase 2 are presented. The PlioMIP2 ensemble average was ~ 3.2 °C warmer and experienced ~ 7 % more precipitation than the pre-industrial era, although there are large regional variations. PlioMIP2 broadly agrees with a new proxy dataset of Pliocene sea surface temperatures. Combining PlioMIP2 and proxy data suggests that a doubling of atmospheric CO2 would increase globally averaged temperature by 2.6–4.8 °C.
Marlow Julius Cramwinckel, Lineke Woelders, Emiel P. Huurdeman, Francien Peterse, Stephen J. Gallagher, Jörg Pross, Catherine E. Burgess, Gert-Jan Reichart, Appy Sluijs, and Peter K. Bijl
Clim. Past, 16, 1667–1689, https://doi.org/10.5194/cp-16-1667-2020, https://doi.org/10.5194/cp-16-1667-2020, 2020
Short summary
Short summary
Phases of past transient warming can be used as a test bed to study the environmental response to climate change independent of tectonic change. Using fossil plankton and organic molecules, here we reconstruct surface ocean temperature and circulation in and around the Tasman Gateway during a warming phase 40 million years ago termed the Middle Eocene Climatic Optimum. We find that plankton assemblages track ocean circulation patterns, with superimposed variability being related to temperature.
Erin L. McClymont, Heather L. Ford, Sze Ling Ho, Julia C. Tindall, Alan M. Haywood, Montserrat Alonso-Garcia, Ian Bailey, Melissa A. Berke, Kate Littler, Molly O. Patterson, Benjamin Petrick, Francien Peterse, A. Christina Ravelo, Bjørg Risebrobakken, Stijn De Schepper, George E. A. Swann, Kaustubh Thirumalai, Jessica E. Tierney, Carolien van der Weijst, Sarah White, Ayako Abe-Ouchi, Michiel L. J. Baatsen, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Ran Feng, Chuncheng Guo, Anna S. von der Heydt, Stephen Hunter, Xiangyi Li, Gerrit Lohmann, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Christian Stepanek, and Zhongshi Zhang
Clim. Past, 16, 1599–1615, https://doi.org/10.5194/cp-16-1599-2020, https://doi.org/10.5194/cp-16-1599-2020, 2020
Short summary
Short summary
We examine the sea-surface temperature response to an interval of climate ~ 3.2 million years ago, when CO2 concentrations were similar to today and the near future. Our geological data and climate models show that global mean sea-surface temperatures were 2.3 to 3.2 ºC warmer than pre-industrial climate, that the mid-latitudes and high latitudes warmed more than the tropics, and that the warming was particularly enhanced in the North Atlantic Ocean.
Cited articles
Abbot, D. S., Huber, M., Bousquet, G., and Walker, C. C.: High-CO2 cloud radiative forcing feedback over both land and ocean in a global climate model, Geophys. Res. Lett., 36, L05702, https://doi.org/10.1029/2008GL036703, 2009.
Anagnostou, E., John, E. H., Edgar, K. M., Foster, G. L., Ridgwell, A., Inglis, G. N., Pancost, R. D., Lunt, D. J., and Pearson, P. N.: Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate, Nature, 533, 380–384, https://doi.org/10.1038/nature17423, 2016.
Arnold, N. P., Tziperman, E., and Farrell, B.: Abrupt transition to strong superrotation driven by equatorial wave resonance in an idealized GCM, J. Atmos. Sci., 69, 626–640, 2012.
Barnet, J. S., Littler, K., Westerhold, T., Kroon, D., Leng, M. J., Bailey, I., Röhl, U., and Zachos, J. C.: A high-Fidelity benthic stable isotope record of late Cretaceous–early Eocene climate change and carbon-cycling, Paleoceanogr. Paleoclim., 34, 672–691, 2019.
Bijl, P. K., Schouten, S., Sluijs, A., Reichart, G.-J., Zachos, J. C., and Brinkhuis, H.: Early Palaeogene temperature evolution of the southwest Pacific Ocean, Nature, 461, 776–779, 2009.
Bragg, F. J., Paine, P., Saul, A., Lunt, D. J., Wilkinson, R., and Zammit-Mangion, A.: A Statistical Algorithm for Evaluating Palaeoclimate Simulations Against Geological Observations, Geoscientific Model Development, in preperation, 2020.
Byrne, B. and Goldblatt, C.: Radiative forcing at high concentrations of well-mixed greenhouse gases, Geophys. Res. Lett., 41, 152–160, 2014.
Caballero, R. and Huber, M.: Spontaneous transition to superrotation in warm climates simulated by CAM3, Geophys. Res. Lett., 37, L11701, https://doi.org/10.1029/2010GL043468, 2010.
Caballero, R. and Huber, M.: State-dependent climate sensitivity in past warm climates and its implications for future climate projections, P. Natl. Acad. Sci. USA, 110, 14162–14167, 2013.
Cramer, B. S., Toggweiler, J. R., Wright, J. D., Katz, M. E., and Miller, K. G.: Ocean overturning since the Late Cretaceous: Inferences from a new benthic foraminiferal isotope compilation, Paleoceanogr. Paleoclim., 24, PA4216, https://doi.org/10.1029/2008pa001683, 2009.
Cramwinckel, M. J., Huber, M., Kocken, I. J., Agnini, C., Bijl, P. K., Bohaty, S. M., Frieling, J., Goldner, A., Hilgen, F. J., Kip, E. L., Peterse, F., van der Ploeg, R., Rohl, U., Schouten, S., and Sluijs, A.: Synchronous tropical and polar temperature evolution in the Eocene, Nature, 559, 382–386, 2018.
Creech, J. B., Baker, J. A., Hollis, C. J., Morgans, H. E., and Smith, E. G.: Eocene sea temperatures for the mid-latitude southwest Pacific from Mg/Ca ratios in planktonic and benthic foraminifera, Earth Planet. Sci. Lett., 299, 483–495, 2010.
Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N., and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system, Q. J. Roy. Meteorol. Soc., 137, 553–597, 2011.
Dunkley Jones, T., Lunt, D. J., Schmidt, D. N., Ridgwell, A., Sluijs, A., Valdes, P. J., and Maslin, M.: Climate model and proxy data constraints on ocean warming across the Paleocene–Eocene Thermal Maximum, Earth Sci. Rev., 125, 123–145, 2013.
Dworkin, S. I., Nordt, L., and Atchley, S.: Determining terrestrial paleotemperatures using the oxygen isotopic composition of pedogenic carbonate, Earth Planet. Sci. Lett., 237, 56–68, 2005.
Edgar, K. M., Anagnostou, E., Pearson, P. N., and Foster, G. L: Assessing the impact of diagenesis on δ11B, δ13C, δ18O, Sr/Ca and B/Ca values in fossil planktic foraminiferal calcite, Geochim. Cosmochim. Acta, 166, 89–209, 2015.
Edgar, K. M., Pälike, H., and Wilson, P. A.: Testing the impact of diagenesis on the δ18O and δ13C of benthic foraminiferal calcite from a sediment burial depth transect in the equatorial Pacific, Paleoceanography, 28, 468–480, 2013.
Eley, Y. L., Thompson, W., Greene, S. E., Mandel, I., Edgar, K., Bendle, J. A., and Dunkley Jones, T.: OPTiMAL: A new machine learning approach for GDGT-based palaeothermometry, Clim. Past Discuss., https://doi.org/10.5194/cp-2019-60, in review, 2019.
Evans, D., Sagoo, N., Renema, W., Cotton, L. J., Müller, W., Todd, J. A., Saraswati, P. K., Stassen, P., Ziegler, M., Pearson, P. N., Valdes, P. J., and Affek, H. P.: Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry, P. Natl. Acad. Sci. USA, 115, 1174–1179, https://doi.org/10.1073/pnas.1714744115, 2018.
Farnsworth, A., Lunt, D., O'Brien, C., Foster, G., Inglis, G., Markwick, P., Pancost, R., and Robinson, S.: Climate sensitivity on geological timescales controlled by non-linear feedbacks and ocean circulation, Geophys. Res. Lett., 46, 9880–9889, https://doi.org/10.1029/2019GL083574, 2019.
Frieling, J., Gebhardt, H., Huber, M., Adekeye, O. A., Akande, S. O., Reichart, G. J., Middelburg, J. J., Schouten, S., and Sluijs, A.: Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum, Sci. Adv., 3, p.e1600891, https://doi.org/10.1126/sciadv.1600891, 2017.
Genest, C. and Zidek, J. V.: Combining probability distributions: a critique and an annotated bibliography, Stat. Sci., 1, 147–148, 1986.
Goldner, A., Herold, N., and Huber, M.: Antarctic glaciation caused ocean circulation changes at the Eocene – Oligocene transition, Nature, 511, 574–577, 2014.
Gutjahr, M., Ridgwell, A., Sexton, P. F., Anagnostou, E., Pearson, P. N., Pälike, H., Norris, R. D., Thomas, E., and Foster, G. L.: Very large release of mostly volcanic carbon during the Palaeocene–Eocene Thermal Maximum, Nature, 548, 573–577, https://doi.org/10.1038/nature23646, 2017.
Hansen, J., Sato, M., Russell, G., and Kharecha, P.: Climate sensitivity, sea level and atmospheric carbon dioxide, Philos. Trans. Royal Soc. A, 371, 20120294, https://doi.org/10.1098/rsta.2012.0294 2013.
Hegerl, G. C., Zwiers, F. W., Braconnot, P., Gillett, N. P., Luo, Y., Marengo Orsini, J., Nicholls, N., Penner, J. E., and Stott, P. A.: Understanding and attributing climate change, IPCC, 2007: Climate Change 2007: the physical science basis. contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007.
Herold, N., Buzan, J., Seton, M., Goldner, A., Green, J. A. M., Müller, R. D., Markwick, P., and Huber, M.: A suite of early Eocene (∼55 Ma) climate model boundary conditions, Geosci. Model Dev., 7, 2077–2090, https://doi.org/10.5194/gmd-7-2077-2014, 2014.
Hollis, C. J., Taylor, K. W. R., Handley, L., Pancost, R. D., Huber, M., Creech, J. B., Hines, B. R., Crouch, E. M., Morgans, H. E. G., Crampton, J. S., Gibbs, S., Pearson, P. N., and Zachos, J. C.: Early Paleogene temperature history of the Southwest Pacific Ocean: Reconciling proxies and models, Earth Planet. Sci. Lett., 349–350, 53–66, https://doi.org/10.1016/j.epsl.2012.06.024, 2012.
Hollis, C. J., Dunkley Jones, T., Anagnostou, E., Bijl, P. K., Cramwinckel, M. J., Cui, Y., Dickens, G. R., Edgar, K. M., Eley, Y., Evans, D., Foster, G. L., Frieling, J., Inglis, G. N., Kennedy, E. M., Kozdon, R., Lauretano, V., Lear, C. H., Littler, K., Lourens, L., Meckler, A. N., Naafs, B. D. A., Pälike, H., Pancost, R. D., Pearson, P. N., Röhl, U., Royer, D. L., Salzmann, U., Schubert, B. A., Seebeck, H., Sluijs, A., Speijer, R. P., Stassen, P., Tierney, J., Tripati, A., Wade, B., Westerhold, T., Witkowski, C., Zachos, J. C., Zhang, Y. G., Huber, M., and Lunt, D. J.: The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database, Geosci. Model Dev., 12, 3149–3206, https://doi.org/10.5194/gmd-12-3149-2019, 2019.
Huber, M. and Caballero, R.: The early Eocene equable climate problem revisited, Clim. Past, 7, 603–633, https://doi.org/10.5194/cp-7-603-2011, 2011.
Hutchinson, D. K., de Boer, A. M., Coxall, H. K., Caballero, R., Nilsson, J., and Baatsen, M.: Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1, Clim. Past, 14, 789–810, https://doi.org/10.5194/cp-14-789-2018, 2018.
Hyland, E. G. and Sheldon, N. D.: Coupled CO2-climate response during the early Eocene climatic optimum, Palaeogeogr. Palaeoclim. Palaeoecol., 369, 125–135, 2013.
Hyland, E. G., Sheldon, N. D., and Cotton, J. M.: Constraining the early Eocene climatic optimum: A terrestrial interhemispheric comparison, GSA Bull., 129, 244–252, https://doi.org/10.1130/B31493.1, 2017.
Inglis, G. N., Farnsworth, A., Lunt, D., Foster, G. L., Hollis, C. J., Pagani, M., Jardine, P. E., Pearson, P. N., Markwick, P., Galsworthy, A. M. J., Raynham, L., Taylor, K. W. R., and Pancost, R. D.: Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions, Paleoceanography, 30, 1000–1020, https://doi.org/10.1002/2014pa002723, 2015.
Inglis, G. N., Collinson, M. E., Riegel, W., Wilde, V., Farnsworth, A., Lunt, D. J., Valdes, P., Robson, B. E., Scott, A. C., Lenz, O. K., Naafs, B. D. A., and Pancost, R. D.: Mid-latitude continental temperatures through the early Eocene in western Europe, Earth Planet. Sci. Lett., 460, 86–96, https://doi.org/10.1016/j.epsl.2016.12.009, 2017.
IPCC: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp., 2013.
Keating-Bitonti, C. R., Ivany, L. C., Affek, H. P., Douglas, P., and Samson, S. D.: Warm, not super-hot, temperatures in the early Eocene subtropics, Geology, 39, 771–774, 2011.
Knutti, R., Rugenstein, M. A., and Hegerl, G. C.: Beyond equilibrium climate sensitivity, Nat. Geosci., 10, 727–736, 2017.
Lauretano, V., Littler, K., Polling, M., Zachos, J. C., and Lourens, L. J.: Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum, Clim. Past, 11, 1313–1324, https://doi.org/10.5194/cp-11-1313-2015, 2015.
Littler, K., Röhl, U., Westerhold, T., and Zachos, J. C.: A high-resolution benthic stable-isotope record for the South Atlantic: Implications for orbital-scale changes in Late Paleocene–Early Eocene climate and carbon cycling, Earth Planet. Sci. Lett., 401, 18–30, 2014.
Lunt, D. J., Dunkley Jones, T., Heinemann, M., Huber, M., LeGrande, A., Winguth, A., Loptson, C., Marotzke, J., Roberts, C. D., Tindall, J., Valdes, P., and Winguth, C.: A model–data comparison for a multi-model ensemble of early Eocene atmosphere–ocean simulations: EoMIP, Clim. Past, 8, 1717–1736, https://doi.org/10.5194/cp-8-1717-2012, 2012.
Lunt, D. J., Farnsworth, A., Loptson, C., Foster, G. L., Markwick, P., O'Brien, C. L., Pancost, R. D., Robinson, S. A., and Wrobel, N.: Palaeogeographic controls on climate and proxy interpretation, Clim. Past, 12, 1181–1198, https://doi.org/10.5194/cp-12-1181-2016, 2016.
Lunt, D. J., Huber, M., Anagnostou, E., Baatsen, M. L. J., Caballero, R., DeConto, R., Dijkstra, H. A., Donnadieu, Y., Evans, D., Feng, R., Foster, G. L., Gasson, E., von der Heydt, A. S., Hollis, C. J., Inglis, G. N., Jones, S. M., Kiehl, J., Kirtland Turner, S., Korty, R. L., Kozdon, R., Krishnan, S., Ladant, J.-B., Langebroek, P., Lear, C. H., LeGrande, A. N., Littler, K., Markwick, P., Otto-Bliesner, B., Pearson, P., Poulsen, C. J., Salzmann, U., Shields, C., Snell, K., Stärz, M., Super, J., Tabor, C., Tierney, J. E., Tourte, G. J. L., Tripati, A., Upchurch, G. R., Wade, B. S., Wing, S. L., Winguth, A. M. E., Wright, N. M., Zachos, J. C., and Zeebe, R. E.: The DeepMIP contribution to PMIP4: experimental design for model simulations of the EECO, PETM, and pre-PETM (version 1.0), Geosci. Model Dev., 10, 889–901, https://doi.org/10.5194/gmd-10-889-2017, 2017.
Lunt, D. J., Bragg, F., Chan, W.-L., Hutchinson, D. K., Ladant, J.-B., Niezgodzki, I., Steinig, S., Zhang, Z., Zhu, J., Abe-Ouchi, A., de Boer, A. M., Coxall, H. K., Donnadieu, Y., Knorr, G., Langebroek, P. M., Lohmann, G., Poulsen, C. J., Sepulchre, P., Tierney, J., Valdes, P. J., Dunkley Jones, T., Hollis, C. J., Huber, M., and Otto-Bliesner, B. L.: DeepMIP: Model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data, Clim. Past Discuss., https://doi.org/10.5194/cp-2019-149, in review, 2020.
Marchitto, T., Curry, W., Lynch-Stieglitz, J., Bryan, S., Cobb, K., and Lund, D.: Improved oxygen isotope temperature calibrations for cosmopolitan benthic foraminifera, Geochim. Cosmochim. Acta, 130, 1–11, 2014.
Masson-Delmotte, V., Schulz, M., Abe-Ouchi, A., Beer, J., Ganopolski, A., Gonzalez Rouco, J. F., Jansen, E., Lambeck, K., Luterbacher, J., Naish, T., Osborn, T., Otto-Bliesner, B., Quinn, T., Ramesh, R., Rojas, M., Shao, X., and Timmermann, A.: Information from Paleoclimate Archives, in: Climate Change 2013 – The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 383–464, 2014.
Pearson, P. N., Ditchfield, P. W., Singano, J., Harcourt-Brown, K. G., Nicholas, C. J., Olsson, R. K., Shackleton, N. J., and Hall, M. A.: Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs, Nature, 413, 481–487, 2001.
Pearson, P. N., van Dongen, B. E., Nicholas, C. J., Pancost, R. D., Schouten, S., Singano, J. M., and Wade, B. S.: Stable warm tropical climate through the Eocene Epoch, Geology, 35, 211–214, https://doi.org/10.1130/g23175a.1, 2007.
Rohling, E. J., Sluijs, A., Dijkstra, H. A., Köhler, P., van de Wal, R. S. W., von der Heydt, A. S., Beerling, D. J., Berger, A., Bijl, P. K., Crucifix, M., DeConto, R., Drijfhout, S. S., Fedorov, A., Foster, G. L., Ganopolski, A., Hansen, J., Hönisch, B., Hooghiemstra, H., Huber, M., Huybers, P., Knutti, R., Lea, D. W., Lourens, L. J., Lunt, D., Masson-Delmotte, V., Medina-Elizalde, M., Otto-Bliesner, B., Pagani, M., Pälike, H., Renssen, H., Royer, D. L., Siddall, M., Valdes, P., Zachos, J. C., Zeebe, R. E., and Members, P. P.: Making sense of palaeoclimate sensitivity, Nature, 491, 683–691, https://doi.org/10.1038/nature11574, 2012.
Sexton, P. F., Wilson, P. A., and Pearson, P. N.: Microstructural and geochemical perspectives on planktic foraminiferal preservation: “Glassy” versus “Frosty”, Geochem. Geophys. Geosyst., 7, Q12P19, https://doi.org/10.1029/2006GC001291, 2006.
Sexton, P. F., Norris, R. D., Wilson, P. A., Pälike, H., Westerhold, T., Röhl, U., Bolton, C. T., and Gibbs, S.: Eocene global warming events driven by ventilation of oceanic dissolved organic carbon, Nature, 471, 349–352, 2011.
Shaffer, G., Huber, M., Rondanelli, R., and Pedersen, J. O. P. J. G. R. L.: Deep time evidence for climate sensitivity increase with warming, Geophys. Res. Lett., 43, 6538–6545, 2016.
Sheldon, N. D.: Non-marine records of climatic change across the Eocene-Oligocene transition, The Late Eocene Earth – Hothouse, Icehouse, and Impacts, Geol. Soc. Am. Special Paper, 452, 241–248, 2009.
Sijp, W. P., England, M. H., and Huber, M.: Effect of the deepening of the Tasman Gateway on the global ocean, Paleoceanography, 26, PA4207, https://doi.org/10.1029/2011PA002143, 2011.
Stevens, B., Sherwood, S. C., Bony, S., and Webb, M. J.: Prospects for narrowing bounds on Earth's equilibrium climate sensitivity, Earth's Future, 4, 512–522, 2016.
Tierney, J. E. and Tingley, M. P.: A Bayesian, spatially-varying calibration model for the TEX86 proxy, Geochim. Cosmochim. Acta, 127, 83–106, 2014.
Westerhold, T., Röhl, U., Donner, B., and Zachos, J. C.: Global extent of early Eocene hyperthermal events: A new Pacific benthic foraminiferal isotope record from Shatsky Rise (ODP Site 1209), Paleoceanogr. Paleoclim., 33, 626–642, 2018.
Zachos, J. C., Dickens, G. R., and Zeebe, R. E.: An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics, Nature, 451, 279–283, 2008.
Zhu, J., Poulsen, C. J., and Tierney, J. E.: Simulation of Eocene extreme warmth and high climate sensitivity through cloud feedbacks, Sci. Adv., 5, EAAX1874, 2019.
Zhu, J., Poulsen, C. J., and Otto-Bliesner, B. L.: High climate sensitivity in CMIP6 model not supported by paleoclimate, Nat. Clim. Change, 10, 378–379, 2020.
Short summary
This paper presents estimates of global mean surface temperatures and climate sensitivity during the early Paleogene (∼57–48 Ma). We employ a multi-method experimental approach and show that i) global mean surface temperatures range between 27 and 32°C and that ii) estimates of
bulkequilibrium climate sensitivity (∼3 to 4.5°C) fall within the range predicted by the IPCC AR5 Report. This work improves our understanding of two key climate metrics during the early Paleogene.
This paper presents estimates of global mean surface temperatures and climate sensitivity during...
