Articles | Volume 20, issue 3
https://doi.org/10.5194/cp-20-495-2024
© Author(s) 2024. 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-20-495-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
13 Mar 2024
Research article |
| 13 Mar 2024
| 13 Mar 2024
CO2-driven and orbitally driven oxygen isotope variability in the Early Eocene
Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, USA
Christopher J. Poulsen
Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, USA
Department of Earth Sciences, University of Oregon, Eugene, OR 97403, USA
Jiang Zhu
Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80301, USA
Jessica E. Tierney
Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA
Jeremy Keeler
Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, USA
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EGUsphere, https://doi.org/10.5194/egusphere-2026-3595, https://doi.org/10.5194/egusphere-2026-3595, 2026
This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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Simulating warm paleoclimates increases our understanding of the mechanisms that drive climatic change and tipping points. The Miocene Epoch, specifically the Miocene Climatic Optimum, has been identified as a particularly valuable past warm climate to simulate, meriting the design of a coordinated Miocene Model Intercomparison Project. Here we synthesize the latest available literature and present the experimental design for coordinated Miocene simulations and sensitivity studies.
Daniel J. Lunt, Nicky M. Wright, Bram Vaes, Ulrich Salzmann, James W. B. Rae, Thomas Hickler, David K. Hutchinson, Julia Brugger, Jiang Zhu, Sebastian Steinig, A. Nele Meckler, Gordon N. Inglis, David Evans, Agatha M. de Boer, Bette L. Otto-Bliesner, Natalie Burls, Yurui Zhang, Appy Sluijs, Tammo Reichgelt, Igor Niezgodzki, Katrin Meissner, Jean-Baptiste Ladant, Fanni D. Kelemen, Matthew Huber, David R. Greenwood, Mattias Green, Flavia Boscolo-Galazzo, Manuel Tobias Blau, and Michiel Baatsen
Geosci. Model Dev., 19, 6143–6166, https://doi.org/10.5194/gmd-19-6143-2026, https://doi.org/10.5194/gmd-19-6143-2026, 2026
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The early Eocene, about 50 million years ago, was a super-warm period of Earth's history, with high concentrations of carbon dioxide in the atmosphere. Here, we provide a framework and experimental design for climate modellers to carry out a coordinated project, simulating this period. This is the second phase of this project, and here we provide updated maps of the Earth's mountains and ocean floor, and vegetation, to enable more accurate modelling.
Fanni Dóra Kelemen, Richard Lohmann, Jiang Zhu, and Bodo Ahrens
Clim. Past, 22, 505–516, https://doi.org/10.5194/cp-22-505-2026, https://doi.org/10.5194/cp-22-505-2026, 2026
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The arrangement of continents and oceans strongly affects climate by shaping large-scale circulation patterns. We study, how early Eocene geography (53.5 Ma) influenced mid-latitude storms and persistent high-pressure systems, focusing on the West Siberian Sea and absent Antarctic Circumpolar Current. The climate model simulation of the early Eocene, shows a more balanced hemispheric distribution, through increased northern and decreased southern mid-latitude storm activity compared to today.
Tancrède P. M. Leger, Jeremy C. Ely, Christopher D. Clark, Sarah L. Bradley, Rosie E. Archer, and Jiang Zhu
The Cryosphere, 19, 5719–5761, https://doi.org/10.5194/tc-19-5719-2025, https://doi.org/10.5194/tc-19-5719-2025, 2025
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This study uses state-of-the-art computer simulations to better constrain the Greenland-Ice-Sheet's evolution over the past 24,000 years. By comparing model results with geological data, it reveals when and why the ice sheet grew and shrank, helping to improve future predictions of sea level rise and climate change.
Magali Verkerk, Thomas J. Aubry, Chris Smith, Peter O. Hopcroft, Michael Sigl, Jessica E. Tierney, Kevin Anchukaitis, Matthew Osman, Anja Schmidt, and Matthew Toohey
Clim. Past, 21, 1755–1778, https://doi.org/10.5194/cp-21-1755-2025, https://doi.org/10.5194/cp-21-1755-2025, 2025
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Large volcanic eruptions can trigger global cooling, affecting human societies. Using ice-core records and simple climate model to simulate volcanic effect over the last 8500 years, we show that volcanic eruptions cool the climate by 0.12 °C on average. By comparing model results with temperature recorded by tree rings over the last 1000 years, we demonstrate that our models can predict the large-scale cooling caused by volcanic eruptions and can be used in cases of large eruptions in the future.
Xiaodong Zhang, Brett J. Tipple, Jiang Zhu, William D. Rush, Christian A. Shields, Joseph B. Novak, and James C. Zachos
Clim. Past, 20, 1615–1626, https://doi.org/10.5194/cp-20-1615-2024, https://doi.org/10.5194/cp-20-1615-2024, 2024
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This study is motivated by the current anthropogenic-warming-forced transition in regional hydroclimate. We use observations and model simulations during the Paleocene–Eocene Thermal Maximum (PETM) to constrain the regional/local hydroclimate response. Our findings, based on multiple observational evidence within the context of model output, suggest a transition toward greater aridity and precipitation extremes in central California during the PETM.
Sarah L. Bradley, Raymond Sellevold, Michele Petrini, Miren Vizcaino, Sotiria Georgiou, Jiang Zhu, Bette L. Otto-Bliesner, and Marcus Lofverstrom
Clim. Past, 20, 211–235, https://doi.org/10.5194/cp-20-211-2024, https://doi.org/10.5194/cp-20-211-2024, 2024
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The Last Glacial Maximum (LGM) was the most recent period with large ice sheets in Europe and North America. We provide a detailed analysis of surface mass and energy components for two time periods that bracket the LGM: 26 and 21 ka BP. We use an earth system model which has been adopted for modern ice sheets. We find that all Northern Hemisphere ice sheets have a positive surface mass balance apart from the British and Irish ice sheets and the North American ice sheet complex.
Jonathan King, Jessica Tierney, Matthew Osman, Emily J. Judd, and Kevin J. Anchukaitis
Geosci. Model Dev., 16, 5653–5683, https://doi.org/10.5194/gmd-16-5653-2023, https://doi.org/10.5194/gmd-16-5653-2023, 2023
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Paleoclimate data assimilation is a useful method that allows researchers to combine climate models with natural archives of past climates. However, it can be difficult to implement in practice. To facilitate this method, we present DASH, a MATLAB toolbox. The toolbox provides routines that implement common steps of paleoclimate data assimilation, and it can be used to implement assimilations for a wide variety of time periods, spatial regions, data networks, and analytical algorithms.
Andrew Gettelman, Hugh Morrison, Trude Eidhammer, Katherine Thayer-Calder, Jian Sun, Richard Forbes, Zachary McGraw, Jiang Zhu, Trude Storelvmo, and John Dennis
Geosci. Model Dev., 16, 1735–1754, https://doi.org/10.5194/gmd-16-1735-2023, https://doi.org/10.5194/gmd-16-1735-2023, 2023
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Clouds are a critical part of weather and climate prediction. In this work, we document updates and corrections to the description of clouds used in several Earth system models. These updates include the ability to run the scheme on graphics processing units (GPUs), changes to the numerical description of precipitation, and a correction to the ice number. There are big improvements in the computational performance that can be achieved with GPU acceleration.
Martin Renoult, Navjit Sagoo, Jiang Zhu, and Thorsten Mauritsen
Clim. Past, 19, 323–356, https://doi.org/10.5194/cp-19-323-2023, https://doi.org/10.5194/cp-19-323-2023, 2023
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The relationship between the Last Glacial Maximum and the sensitivity of climate models to a doubling of CO2 can be used to estimate the true sensitivity of the Earth. However, this relationship has varied in successive model generations. In this study, we assess multiple processes at the Last Glacial Maximum which weaken this relationship. For example, how models respond to the presence of ice sheets is a large contributor of uncertainty.
Ryan A. Green, Laurie Menviel, Katrin J. Meissner, Xavier Crosta, Deepak Chandan, Gerrit Lohmann, W. Richard Peltier, Xiaoxu Shi, and Jiang Zhu
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Short summary
In this study, we use climate modeling to investigate the relative impact of CO2 and orbit on Early Eocene (~ 55 million years ago) climate and compare our modeled results to fossil records to determine the context for the Paleocene–Eocene Thermal Maximum, the most extreme hyperthermal in the Cenozoic. Our conclusions consider limitations and illustrate the importance of climate models when interpreting paleoclimate records in times of extreme warmth.
In this study, we use climate modeling to investigate the relative impact of CO2 and orbit on...
