Periodic Reporting for period 1 - CliMoTran (Comprehensive Climate Modeling of the Mid-Pleistocene Transition)
Okres sprawozdawczy: 2021-10-01 do 2023-09-30
Anthropogenic climate forcing has initiated an unprecedentedly rapid and extensive change of the Earth system and climate. Therefore, it is crucial to gain a better understanding of Earth’s climate system, its changes, and internal processes. The geological past provides a wealth of natural experiments that allow to decipher the triggers and feedback mechanisms that affect climate variability on various timescales. One of the most intriguing climate transitions occurred about one million years ago when the periodicity of ice ages slowed down from 41,000 to 100,000-year cycles, without any discernible changes in the orbital parameters. This shift, known as the Mid-Pleistocene Transition, was accompanied by an increase in the amplitude of glacial-interglacial climate variability, substantially larger continental ice-sheets during peak glacial conditions, and a shift from symmetric to strongly asymmetric cycles. The overarching objective of the CliMoTran project is to unravel the driving processes behind this unique transition in Earth’s climate system through comprehensive climate modeling. The project aims to investigate the impacts of changes in ocean circulation and internal ice sheet dynamics on triggering this enigmatic climate transition. In conclusion, the findings of CliMoTran enhance our understanding of the climate system as a whole and help improve predictions of future climate under the evolving boundary conditions caused by anthropogenic greenhouse gas emissions.
The CliMoTran project has successfully achieved all of its main research objectives, which include coupling an ice-sheet to the Bern3D model and simulating glacial-interglacial cycles, testing hypotheses responsible for the Mid-Pleistocene Transition, investigating the interplay between different mechanisms and their sensitivities, and reconciling a transient model simulation of the past 1.5 million years with paleoceanographic and paleoclimatic reconstructions. Specifically, the effect of internal ice sheet parameters has been explored in shaping the evolution of continental ice volume during the Mid-Pleistocene Transition. These objectives contribute to the overarching goal of CliMoTran, which is to provide Earth scientists with a powerful tool to investigate past and future climate and advance the understanding of the relevant driving processes of climate change. The findings have been disseminated in a wide range of international scientific conferences and workshops as well as communicated to the general public through a number of outreach activities.
The specific training objectives of the CliMoTran project were also achieved, which aimed to enhance the researcher’s skills and knowledge in climate science and Earth system modeling. These objectives included gaining expertise in high-performance computing/programming, training in climate modeling at multiple levels of complexity, understanding, modifying, and interpreting model experiments of the Bern3D Earth System Model of intermediate complexity, and learning to evaluate ice-core and geochemical reconstructions of past climate/ocean parameters and set them in context to model experiments. These achievements have prepared the researcher for a future career in academia.
The project also successfully achieved its results on communication and dissemination, project management, and publication of results. A significant effort was placed on open access publishing.
The specific training objectives of the CliMoTran project were also achieved, which aimed to enhance the researcher’s skills and knowledge in climate science and Earth system modeling. These objectives included gaining expertise in high-performance computing/programming, training in climate modeling at multiple levels of complexity, understanding, modifying, and interpreting model experiments of the Bern3D Earth System Model of intermediate complexity, and learning to evaluate ice-core and geochemical reconstructions of past climate/ocean parameters and set them in context to model experiments. These achievements have prepared the researcher for a future career in academia.
The project also successfully achieved its results on communication and dissemination, project management, and publication of results. A significant effort was placed on open access publishing.
In CliMoTran, a three-dimensional dynamic ice sheet model has been coupled to an Earth system model of intermediate complexity, which presents a unique tool to investigate various aspects of the Earth system during past and future climate change. Potential future research avenues that can be pursued with this framework extend beyond the scientific focus of CliMoTran and include abrupt climate events on centennial to millennial timescales, such as Heinrich and Dansgaard-Oeschger Events, glacial terminations, and the future climate evolution under continued anthropogenic forcing.
A series of sensitivity tests targeting the MPT have assessed two main aspects: changes in deep ocean circulation and hence carbon storage, and a regime shift in internal ice sheet dynamics. These processes were examined both individually and in combination, as well as their magnitude has been investigated. Through comparisons of simulated with reconstructed proxies assessing the driving processes at play during the MPT a new framework for this climate transition has been built. The findings are currently being prepared for publication in a high-impact journal and are expected to be submitted in the coming months forming CliMoTran’s legacy.
A series of sensitivity tests targeting the MPT have assessed two main aspects: changes in deep ocean circulation and hence carbon storage, and a regime shift in internal ice sheet dynamics. These processes were examined both individually and in combination, as well as their magnitude has been investigated. Through comparisons of simulated with reconstructed proxies assessing the driving processes at play during the MPT a new framework for this climate transition has been built. The findings are currently being prepared for publication in a high-impact journal and are expected to be submitted in the coming months forming CliMoTran’s legacy.