2024-OU2 Reconstructing 30 million years of past climate change

Project highlights

Join a highly interdisciplinary, international group of researchers and modellers working on diverse aspects of climate and Earth system change in the past, present and future
Develop a unique and powerful computational model to investigate a wide range of questions about past climate change and its impact on species evolution
Contribute new data and insight with potentially important implications for the critical societal challenges of climate change and biodiversity loss.

Overview

Climate is a critical driver for the evolution and extinction of species, and existing patterns of terrestrial biodiversity can only be fully explained through the effects of climate variations reaching back tens of millions of years. Over the last 30 million years, a principal driving factor for such change has been the evolution of the Earth’s crust, including the rise of the Himalayan-Tibetan and Andes ranges, the slow drift of continents and the opening and closing of ocean gateways between them. Superimposed on these tectonically induced variations are climatic oscillations on timescales of tens to hundreds of millennia driven by cyclical changes in the shape of the Earth’s orbit and the resulting growth and decay of the great polar ice caps and ice sheets. On even shorter, decadal to millennial timescales, nonlinear feedbacks internal to the ocean-climate dynamical system can sometimes drive almost equally large variations. At all timescales, the carbon cycle feeds back on these changes, sometimes amplifying and sometimes attenuating the variability by driving changes in atmospheric CO2.

We know a great deal about past temporal variations in climate from ocean and lake sediment cores, but the spatial variations in climate, from tropical rainforests to arid deserts and mountain and polar ice, are comparably dramatic, and these changes can only be fully described and explained by computer models of the Earth system. Unfortunately, the huge complexity of the system means that projecting and analysing changes over the multi-million year timescales important for species evolution with the spatial detail required to assess the suitability of local habitats that drives that evolution, is effectively impossible using conventional modelling techniques.

This project will build on recently developed techniques that combine conventional Earth system model simulation with a range of spatio-temporal statistical simulation approaches (Holden et al. 2019, Thomson et al. 2021) to produce integrated reconstructions of Earth’s climate change and decadal to millennial variability reaching back tens of millions of years, with the spatial resolution required to understand the effects on biodiversity evolution.

Figure 1: Modelled climate of the Last Glacial Maximum 21,000 years ago from the PLASIM-GENIE model (Holden et al. 2019) compared to data from Hijmans et al. Int. J. Climatol., (2005). Panels (a) and (c) show maximum and minimum temperature and precipitation at the Last Glacial Maximum. Panels (b) and (d) show the corresponding present-day observed climatology. LGM climate is derived by applying modelled change to this present-day climatology. The project will extend simulations with the same model back to 30 million years ago.

Host

The Open University

Theme

Climate and Environmental Sustainability

Supervisors

Project investigator

Neil Edwards, [email protected]

Co-investigators

Philip Holden, [email protected]

Luke Mander, [email protected]

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
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Methodology

A large ensemble of climate simulations will be developed with the intermediate complexity Earth system model PLASIM-GENIE (Holden et al. 2016) spanning the range of CO2, orbital and paleogeographic states relevant to the last 30 million years. Paleogeographic inputs will come from simulations carried out by collaborators in the University of Sydney. The climate simulations will be used to construct a stochastic model, or emulator, of the climate response to arbitrary input conditions, by decomposing the climate into a series of characteristic spatial patterns. The emulator will then be used to reconstruct global climate over many millions of years at very low computational cost. Modes of internal variability on shorter timescales will be incorporated into the emulator using techniques that preserve simulated climate variance. Finally, simplified representations species evolution will be used to infer potential impacts on changing patterns of biodiversity.

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

All Faculty PhD students will be provided with extensive training opportunities through the Open University graduate school and STEM Faculty programmes including core research and outreach skills in the first year and more specifically targeted training needs at later stages. This will include training in communicating their research to a range of different audiences, through a range of channels from academic publication to social media.

The student will also receive training in using the PLASIM-GENIE Earth system modelling framework; in statistical emulation using Gaussian Process models; and other numerical, statistical, or data processing methods required for the project. These are likely to include: experimental design for computer experiments, Bayesian calibration, R statistical software and data visualisation.

Partners and collaboration

Sabin Yahirovic in the University of Sydney is an expert on modelling tectonic evolution of the Earth’s crust and will collaborate on supplying paleogeographic inputs to the climate models.

Thiago Rangel at the Federal University of Goiás in Brazil is an expert on modelling the evolution of biodiversity, and will collaborate on estimating the potential effects of long-term climate variability on species evolution in the final stage of the project.

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here:

For any enquiries related to this project please contact Neil Edwards, [email protected].

To apply to this project:

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
Your application materials, including the CENTA application form 2024, your CV and the Open University application form must be emailed to [email protected]. Instructions on how to apply to the Open University are to be found on https://www5.open.ac.uk/stem/environment-earth-ecosystem-sciences/research/phd-students/current-opportunities-and-how-apply, please ensure you read this webpage before applying as you will need to obtain the relevant OU application form from here. Please quote CENTA 2022-OU2 when completing the application form.

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.

Possible timeline

Year 1

Year 1: tasks. Setting up and running Oligocene, Miocene and Pliocene climate model simulations and validating output projections against existing observational data and model simulations from the literature.

Year 2

Year 2: tasks. Constructing statistical framework for spatio-temporal emulation of the climate simulations and incorporation of shorter-term variability, construction of the long-term climate model emulator. Preparation of manuscripts describing paleoclimate simulations for publication.

Year 3

Year 3: tasks. Creating long-term climate reconstructions with the emulator and developing a simplified methodology to estimate potential effects on species evolution; presenting results at international conferences; writing up results for thesis and further publishable papers.