Back to the Future: Ice Sheet collapse, ocean circulation showdown and abrupt climate change

Are you passionate about climate research and keen to tackle one of the greatest climate challenges of today? Are you keen to develop advanced research skills that can equip you for a wide range of future careers? For these reasons and more, you may be an ideal candidate to apply for a studentship with project VERIFY: Out Of Sample Testing For Early Warning Systems Using Past Climate, funded by the UK’s Advanced Research + Invention Agency (ARIA*). <br /> <br /> For this PhD, you will perform state-of-the-art ice sheet and climate model simulations of Earth’s most recent ice sheet collapse and reorganisation of Atlantic Ocean circulation to test and improve forecasts of crossing tipping points in the Greenland ice sheet and North Atlantic Ocean in the future. <br /> <br /> The fully funded scholarship is available in the School of Earth and Environment at the University of Leeds to begin in October 2025. The PhD is open to UK applicants and covers tuition fees and a maintenance stipend for three and a half years, as well as a Research Training Support Grant (RTSG) of £7,000 to fund research travel, training, conferences etc. The maintenance stipend is £20,780 in the year 2025/26.

<p><strong>Background</strong></p> <p>It is currently uncertain how the Greenland ice sheet will respond to current and future climate change, but we know that there were times in the past when the ice sheet, or parts of it, collapsed. Such an influx of cold, fresh water to the North Atlantic would be highly disruptive to the circulations that keep North American and European climates mild. Thus, we know that a collapse of the Greenland ice sheet would have dramatic consequences, globally, but exactly what those consequences are and when they might be triggered, is highly uncertain, with much disagreement among climate and ice sheet model projections.  </p> <p paraeid="{29d07962-2d8d-46f7-accf-a1ac7a2121d4}{152}" paraid="686296233">The problem is that modern observations are too short and do not capture large enough changes to sufficiently test or calibrate the models, making it hard for decision makers to understand or act on the threat. The solution is to test models against the last known episode of major ice sheet collapse and reorganisation of Atlantic Ocean circulation, 8,200 years ago, when accelerated ice sheet melt in the Hudson Bay region disrupted the North Atlantic, inducing a century-long Northern Hemisphere cooling of several °C. Touted as the “Goldilock’s” event for benchmarking future North Atlantic change, this so-called ‘8.2 kyr event’ has quantified forcing and abundant palaeoclimatic (ancient climate) records for testing model responses.  </p> <p paraeid="{29d07962-2d8d-46f7-accf-a1ac7a2121d4}{152}" paraid="686296233">This project aims to exploit the 8.2 kyr event to inform forecasts of future Greenland and North Atlantic ‘tipping’, performing new model simulations and merging the outputs with observational records using state-of-the-art techniques in artificial intelligence and machine learning. </p> <p paraeid="{29d07962-2d8d-46f7-accf-a1ac7a2121d4}{152}" paraid="686296233"><strong>The PhD </strong></p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{27}" paraid="2030060382">Using advanced uncertainty quantification, this project will combine complex climate and ice sheet models with geological records of Earth’s most recent ice sheet collapse and reorganisation of Atlantic Ocean circulation 8,200 years ago to provide ‘out of sample’ constraints on Earth System tipping, improving confidence in future climate projections. </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{41}" paraid="438661766">Efficient experimental design (e.g. sequential sampling) will be used to expand the outputs from the UK Earth Systems Model (UKESM, a flagship complex model with interactive ice sheets) and drive ice sheet model simulations (BISICLES) of the 8.2 kyr event, varying uncertain model parameters and surface mass balance forcing. Advanced Gaussian process emulators (statistical models used in artificial intelligence/machine learning) will be applied to learn the relationships between uncertain model inputs and past/future ice sheet change. This will be used to optimally exploit information from models and real world data to better understand and project future tipping events in the Greenland ice sheet and North Atlantic Ocean. Implausibility metrics will rule out unrealistic models within uncertainty, producing a probability distribution of plausible ice sheet change, including meltwater forcing of North Atlantic Ocean circulation change. </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{117}" paraid="698826354">These tools will be used to answer exciting research questions chosen by the postgraduate researcher with support from the project supervisors and wider VERIFY project team, for example: </p> <ul> <li paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{133}" paraid="1393970265">What were the mechanisms that controlled the Hudson Bay ice saddle collapse 8,200 years ago? </li> <li paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{157}" paraid="1840640068">How much meltwater did the event produce? </li> <li paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{165}" paraid="427546531">What was the impact on the North Atlantic? </li> </ul> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">The PhD outputs will feed directly into other parts of Project VERIFY (e.g. a new early warning system for climate tipping) and the project may also investigate the usefulness of the 8.2 kyr event as a real-world ‘storyline’ to help decision-makers prevent or adapt to future climate change. </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999"><strong>Project VERIFY</strong></p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">With this PhD Scholarship, you will be part of the Project VERIFY team, with access to a wide array of expertise and bespoke training. Our vision is to observe and understand massive changes (so-called tipping events) in the climate of the North Atlantic, namely the Greenland Ice Sheet and Subpolar Gyre, in the recent and geological past. Embedded in nine institutions internationally, Project VERIFY brings together experts in modern and palaeo-climate dynamics, high resolution and complexity modelling, data science and statistics, decision making and communication. The project will develop Digital Twins of these past events that will serve as a testbed for verifying whether this tipping behavior can be predicted using Early Warning Systems (EWSs), forming a crucial component of an £81m ARIA-funded effort to develop these systems in the North Atlantic region. In Project VERIFY, you will be part of a team of seven PhD students (plus postdocs and more senior researchers) working in a diverse array of disciplines, including social sciences, Earth System Modelling, ice and sediment core geochemistry, and dynamical systems and statistical analysis. As an ARIA R&D Creator, you will also benefit from involvement in the broader ‘Forecasting Tipping Points’ programme, which seeks to build an early warning system capable of providing the information, understanding and time we need to accelerate proactive climate adaptation and mitigation. As part of the Project VERIFY team, you will be at the heart of this effort, working within a network of 27 international teams in a collaborative effort to detect the earliest signs of climate tipping points. </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">*ARIA is an R&D funding agency created to unlock technological breakthroughs that benefit everyone. Created by an Act of Parliament and sponsored by the Department for Science, Innovation and Technology, ARIA fund teams of scientists and engineers to pursue research at the edge of what is scientifically and technologically possible.</p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999"><strong>Further reading</strong></p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">Gregoire LH, Morrill C. 2021. The 8.2 kyr event: Benchmarking climate model sensitivity to ice-sheet melt. Past Global Changes Magazine. 76-77 29.2 <a href="http://dx.doi.org/10.22498/pages.29.2.76" rel="noreferrer noopener" target="_blank">http://dx.doi.org/10.22498/pages.29.2.76</a>  </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">Gandy N, Astfalck LC, Gregoire LJ, Ivanovic RF, Patterson VL, Sherriff-Tadano S, Smith RS, Williamson D, Rigby R. 2023. De-Tuning Albedo Parameters in a Coupled Climate Ice Sheet Model to Simulate the North American Ice Sheet at the Last Glacial Maximum. Journal of Geophysical Research: Earth Surface. 128.8 <a href="http://dx.doi.org/10.1029/2023jf007250" rel="noreferrer noopener" target="_blank">http://dx.doi.org/10.1029/2023jf007250</a> </p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999">Matero ISO, Gregoire LJ, Ivanovic RF, Tindall JC, Haywood AM. 2017. The 8.2 ka cooling event caused by Laurentide ice saddle collapse. Earth and Planetary Science Letters. 205-214 473 <a href="http://dx.doi.org/10.1016/j.epsl.2017.06.011" rel="noreferrer noopener" target="_blank">http://dx.doi.org/10.1016/j.epsl.2017.06.011</a></p> <p paraeid="{74b0a949-fd04-4d14-8423-26b642786d6e}{175}" paraid="1057771999"><a href="https://www.aria.org.uk/opportunity-spaces/scoping-our-planet/forecasting-tipping-points/" rel="noreferrer noopener" target="_blank">ARIA Forecasting Tipping Points Programme</a>, including the <a href="https://www.aria.org.uk/media/wxrnowvq/aria-forecasting-climate-tipping-points-programme-thesis.pdf" rel="noreferrer noopener" target="_blank">Programme Thesis</a> </p>

<p>Formal applications for research degree study should be made online through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University's website</a>. You will need to create a login ID with a username and PIN. </p> <ul> <li>For ‘Application type’ please select ‘Research Degrees – Research Postgraduate’.</li> <li>The admission year for this project is 2025/2026 Academic Year. You will need to select your ‘Planned Course of Study’ from a drop-down menu.</li> <li>For this project, scroll down and select ‘PhD Earth and Environment Full-time’.</li> <li>The project start date for this project is 1st October 2025, please use this as your Proposed Start Date of Research.</li> <li>You will also need to provide: copies of certificates and transcripts for your academic qualifications; a copy of your CV and a personal statement which outlines your interest in the project you are applying for, why you have chosen it and how your skills map onto the requirements of the project. You will also need to provide two references. It is your responsibility to provide these references. More information on how to apply is available on our website <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">here</a>. </li> <li><strong>Please state clearly in the research information section that the research degree you wish to be considered for is ‘Back to the Future: Ice Sheet collapse, ocean circulation showdown and abrupt climate change’ as well as <a href="https://environment.leeds.ac.uk/see/staff/1347/dr-ruza-ivanovic">Ruza Ivanovic</a> as your proposed supervisor. </strong></li> </ul> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

The minimum entry requirements for PhD study are a 2.1 honours Bachelor degree, or equivalent, or a good performance in a Master's level course in Physics, Mathematics, Oceanography, Meteorology, Climate Sciences, Earth/Environmental/Geographical Sciences, Engineering, Computer Sciences or related disciplines.<br /> <br /> Experience in computer programming (.e.g. Python, Fortran, C++, MATLAB, R...) or numerical modelling is highly desirable. Candidates with either strong/numerical programming skills or a good background in glaciology or climate science would be well suited to this project.<br /> <br /> Applicants who are uncertain about the requirements for a particular research degree are advised to contact the PGR Admissions team prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<p><strong>Information about the Award</strong></p> <p>We are offering 1 full-time PhD scholarship in the School of Earth and Environment for one UK candidate, covering a maintenance grant matching UKRI maintenance stipend (£20,780 per year in 2025/26) and UK tuition fees for three and a half years, as well as a Research Training Support Grant (RTSG) of £7,000, subject to satisfactory progress.</p> <p><strong>Duration of the Award</strong></p> <p>Full-time (3.5 years). The award will be made for one year in the first instance and renewable for a further period of up to two years, subject to satisfactory academic progress. </p> <ul> <li>Applicants must not have already been awarded or be currently studying for a doctoral degree. </li> <li>Awards must be taken up by 1st October 2025. </li> <li>Applicants must live within a reasonable distance of the University of Leeds whilst in receipt of this scholarship.</li> </ul> <p><strong>If you are unsure whether you are eligible for Home fees/funding, please see our <a href="https://www.leeds.ac.uk/undergraduate-fees/doc/fee-assessment">fee assessment page</a>.</strong></p>

<p>For further information please contact Ruza Ivanovic (<a href="mailto:R.Ivanovic@leeds.ac.uk">R.Ivanovic@leeds.ac.uk</a>) or the Postgraduate Research Admissions team (<a href="mailto:env-pgr@leeds.ac.uk?subject=%E2%80%8BBack%20to%20the%20Future%3A%20Ice%20Sheet%20collapse%2C%20ocean%20circulation%20slowdown%20and%20abrupt%20climate%20change">env-pgr@leeds.ac.uk</a>).</p>