The sensitivity of the Southern Ocean carbon sink to physical changes under modern and projected climate states

About the research project

The Southern Ocean connects ocean basins [Rintoul , 2011], ventilates the global deep ocean [Williams et al., 2023], and absorbs a disproportionate share of the anthropogenic heat and carbon that would otherwise remain in the atmosphere [Frölicher et al., 2015]. As a nexus of tightly coupled atmosphere, ocean, sea ice, and biogeochemical processes, the Southern Ocean’s future influence on the global climate system depends critically on how these interactions respond to ongoing warming, which is currently driving rapid changes in the physical state of the Southern Ocean [e.g. Purich and Doddridge, 2023; Silvano et al., 2025].

The Southern Ocean accounts for 40-50% of the anthropogenic CO2 taken up by the global ocean, making it the single largest carbon sink in the modern ocean [DeVries, 2014]. Large- and small-scale physical processes in the Southern Ocean – including the formation and propagation of inter- mediate, dense, and bottom waters, freshwater fluxes associated with sea ice and ice shelf processes, and the biological pump – regulate the redistribution of heat, carbon, and tracers across ocean basins. Through these mechanisms and others, local Southern Ocean dynamics mediate global climate feedbacks. Projections indicate that the Southern Ocean carbon sink may weaken under future warming, but this trajectory is not certain [Le Quéré et al., 2007; Olivier and Haumann, 2025]. Understanding the sensitivities of the Southern Ocean carbon sink is therefore critical for refining climate projections and informing policy aimed at protecting this natural carbon reservoir.

This project seeks to quantify the sensitivity of the Southern Ocean carbon sink to sea ice, circulation, and biogeochemical variables and to assess how these sensitivities shape carbon sink function under future net-zero emissions scenarios, with a particular focus on sensitivity to abrupt changes in physical state.

References

DeVries, T., GBC, 28 (7), 631–647, 2014.

Frölicher, T. L., et al., Journal of Climate, 2015.

Le Quéré, C., et al., Science, 316 (5832), 1735–1738, 2007.

Olivier, L., and F. A. Haumann, Nature Climate Change, 15 (11), 1219–1225, 2025.

Purich, A., and E. W. Doddridge, Communications Earth & Environment, 4 (1), 314, 2023.

Rintoul, S. R., The Southern Ocean in the Earth System, 2011.

Silvano, A., et al., PNAS, 122 (27), e2500440,122, 2025.

Williams, R. G., et al., Philosophical Transactions of the Royal Society A, 381 (2249), 20220,062, 2023.

Primary supervisor

Meet Doctor Edward Doddridge

Funding

The successful applicant will receive a scholarship which provides:

• a living allowance stipend co-funded with ARC of $34,315 per annum for 3.5 years
• a relocation allowance of up to $2,000
• a tuition fees offset covering the cost of tuition fees for up to four years (domestic applicants only)

A tuition fee offset may be offered to eligible international applicants following competitive assessment 

As part of the application process you may indicate if you do not wish to be considered for scholarship funding.

Additional Funding

This project comes with additional funding for travel and conferences.

Other funding opportunities and fees

For further information regarding other scholarships on offer, and the various fees for undertaking a research degree, please visit our Scholarships and fees on research degrees page.

Eligibility

Applicants should review the Higher Degree by Research minimum entry requirements.

Ensure your eligibility for the scholarship round by referring to our Key Dates.

Additional eligibility criteria specific to this project/scholarship:

• Applications are open to Domestic, International, and Onshore applicants
• English language score must be above minimum entry requirements for this project

Selection criteria

The project is competitively assessed and awarded. Selection is based on academic merit and suitability to the project as determined by the College.

Additional essential selection criteria specific to this project:

• Hons/MSc degree in science or engineering, ideally but not exclusively a physical or computational science.
• Interest and ability in the analysis of complex systems
• Experience in scientific writing, demonstrated by the production of a thesis or published manuscript
• Scientific programming experience, preferably in Python.
• Burning desire to understand how the world works.

Additional desirable selection criteria specific to this project:

• Background in oceanography or meteorology
• Familiarity with running numerical models
• Familiarity with high performance computing

Application process

1. Select your project, and check that you meet the eligibility and selection criteria, including citizenship;
2. Contact Doctor Edward Doddridge to discuss your suitability and the project's requirements; and
3. In your application:
   • Copy and paste the title of the project from this advertisement into your application. If you don’t correctly do this your application may be rejected.
   • Submit a signed supervisory support form, a CV including contact details of 2 referees and your project research proposal.
4. Apply prior to 1 August 2026.

Full details of the application process can be found under the ' How to apply ' section of the Research Degrees website.

Following the closing date applications will be assessed within the College. Applicants should expect to receive notification of the outcome by email by the advertised outcome date.

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