Lennart Ramme
| Department | Climate Variability |
| Group | Director's Research Group (CVR) |
| Position | Postdoc |
| phone | +49 40 41173-162 |
| lennart.ramme@mpimet.mpg.de | |
| Room | B 216 |
Research Interests
In my research, I focus on the ocean's role in the global carbon cycle and the climate, investigating time scales from decades to millenia, over which the ocean is the dominant driver of the dynamics within the Earth system. The main tools I use are complex Earth system models like ICON-ESM and MPI-ESM, often in combination with idealized box models, which are helpful to understand individual processes within the system.
During my PhD, I studied these aspects in the context of the Marinoan snowball Earth and the supergreenhouse climate in its aftermath. One of the main outcomes of this work was the quantification of how the ocean responds to excessive amounts of atmospheric CO2 in a scenario of rapid warming during the deglaciation of a snowball Earth - in some ways an extreme version of modern climate change.
Currently, I am a post-doctoral researcher within the Horizon-EU project WorldTrans - Transparent Assessments for Real People. Here, I am looking into the evolution of the ocean carbon uptake in future scenarios of anthropogenic climate change, especially focusing on those scenarios that apply negative carbon emissions to mitigate climate change (like SSP1-1.9 and SSP5-3.4-over). Furthermore, as part of my current position, I am helping in the development of a climate module in the new system dynamcis-based integrated assessment model FRIDA.
More Information
Experience
2023 - 2026 Postdoctoral Reseacher
- Project: WorldTrans (Horizon Europe)
- Max Planck Institute for Meteorology, Hamburg, Germany
2019 - 2023 PhD student
- Thesis: "Snowball Earth aftermath: Ocean dynamics and carbon cycling under extreme greenhouse conditions"
- International Max-Planck Research School on Earth System Modelling (IMPRS-ESM), Hamburg, Germany
2016 Research Internship
- Modelling of seismological surface wave anisotropy around the Hawaiian mantle plume
- Institute for Geophysics, Scripps Institution of Oceanography, San Diego, USA
Education
2016 - 2018 M.Sc. Geophysics
- Thesis: "Horizontal convection at infinite Prandtl number" (in German)
- Westfälische Wilhelms Universität Münster, Münster, Germany
2013 - 2016 B.Sc. Geophysics
- Thesis: "Evolution of Plumes in a chemical background stratification" (in German)
- Westfälische Wilhelms Universität Münster, Münster, Germany
Published
Ramme, L., Ilyina, T. and Marotzke, J. (2024): Moderate greenhouse climate and rapid carbonate formation after Marinoan snowball Earth, Nat. Commun., 15, 3571, doi.org/10.1038/s41467-024-47873-6
Ramme, L. and Marotzke, J. (2022): Climate and ocean circulation in the aftermath of a Marinoan snowball Earth, Clim. Past, 18, 759–774, doi.org/10.5194/cp-18-759-2022
Linardakis, L., Stemmler, I., Hanke, M., Ramme, L., Chegini, F., Ilyina, T., and Korn, P. (2022): Improving scalability of Earth system models through coarse-grained component concurrency – a case study with the ICON v2.6.5 modelling system, Geosci. Model Dev., 15, 9157–9176, doi.org/10.5194/gmd-15-9157-2022
Mathis, M., Logemann, K., Maerz, J., Lacroix, F., Hagemann, S., Chegini, F., Ramme, L., Ilyina, T., Korn, P. and Schrum, C. (2022): Seamless integration of the coastal ocean in global marine carbon cycle modeling. J. Adv. Model. Earth Sy., 14, e2021MS002789, doi.org/10.1029/2021MS002789
Jungclaus, J. H., S. J. Lorenz, H. Schmidt, V. Brovkin, N. Brüggemann, F. Chegini, T. Cruger, P. De-Vrese, V. Gayler, M. A. Giorgetta, O. Gutjahr, H. Haak, S. Hagemann, M. Hanke, T. Ilyina, P. Korn, J. Kroger, L. Linardakis, C. Mehlmann, U. Mikolajewicz, W. A. Müller, J. E. M. S. Nabel, D. Notz, H. Pohlmann, D. A. Putrasahan, T. Raddatz, L. Ramme, R. Redler, C. H. Reick, T. Riddick, T. Sam, R. Schneck, R. Schnur, M. Schupfner, J.-S. v. Storch, F. Wachsmann, K.-H. Wieners, F. Ziemen, B. Stevens, J. Marotzke, and M. Claussen, 2022 (2022): The ICON Earth System Model version 1.0. Journal of Advances in Modeling Earth Systems, 14, e2021MS002813, doi.org/10.1029/2021MS002813, 2022
Ramme, L. and Hansen, U. (2019): Transition to time-dependent flow in highly viscous horizontal convection, Phys. Rev. Fluids, 4, 093501, doi.org/10.1103/PhysRevFluids.4.093501, 2019
Research Highlights
In my Phd Thesis, I have shown that the ocean plays a major role in the aftermath of the Marinoan snowball Earth. It's dynamic circulation removes any freshwater stratification within a few thousand years. At the same time, the ocean's chemical composition determines the evolution of the supergreenhouse climate, with possible scenarios ranging from a rapid decline to an intensification of the extreme greenhouse conditions.