How stable is the Greenland ice sheet? A view from the past

Are you passionate about climate or glaciology 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.

For this PhD, you will perform cutting-edge ice sheet simulations to test mechanisms of Greenland ice sheet collapse, evaluated against records of real events from the past, to improve predictions of when and how abrupt changes in Greenland may be triggered in the future.

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.

Background

One of the greatest sources of uncertainty in predictions of 21^st Century sea level change is the Greenland ice sheet. Future warming will certainly increase ice sheet melting, the evidence is that it already is, but exactly how much ice will be lost, by what mechanisms and, critically, when those mechanisms will be triggered remains unknown.

We know from times in the past when climate was similar or only slightly warmer than today, known as ‘interglacials’, that Greenland is capable of great resilience to warm conditions, remaining relatively stable in size during some interglacial periods. Yet during long interglacials, even moderate warming can lead to the collapse of parts of the ice sheet, causing metres of sea level rise. Finding out when and how those tipping points are crossed – the difference between maintaining a relatively constant Greenland ice volume and losing whole sectors of the ice sheet – is key to confidently predicting future Greenland evolution. The problem is that modern observations are too short and do not capture large enough changes to sufficiently test or calibrate models of ice sheet change to make sure they accurately capture Greenland ice sheet behaviour over centuries. The past interglacials offer a solution: real world data from known episodes of Greenland ice sheet collapse that can be contrasted with known periods of ice sheet stability to test and improve the models, reaching new levels of understanding, and providing the best confidence in forecasts of when and how we might cross tipping points in the Greenland ice sheet in the future.

The PhD

Using advanced uncertainty quantification, this project will drive state-of-the-art ice sheet models with climate output from the most detailed and complex climate models to comprehensively assess when and how Greenland tipping events are triggered. The simulations will be combined with records of Greenland ice sheet conditions during past interglacials, testing periods when the ice underwent pronounced deglaciation and contrasting these with periods when we know the ice sheet was relatively stable.

Efficient experimental design will be used to perform strategic short simulations of the UK Earth Systems Model (UKESM, a flagship complex climate model with interactive ice sheets) and MAR (regional high resolution atmosphere model) for a range of past climatic conditions. Machine learning and/or statistical interpolation will be used to produce multi-millennia climate forcing for driving Greenland ice sheet model simulations (BISICLES) of past interglacials. Uncertain model parameters will be varied to determine which model configurations best match records of past Greenland ice sheet evolution and thus improve confidence in our projections of future change.

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:

• Under what conditions does the Greenland ice sheet remain stable or crosses a tipping point?
• Are the UKESM, MAR and BISICLES models able to reproduce changes in the Greenland ice sheet during past interglacials ?
• How does information from past interglacials inform future sea level projections?

The PhD outputs will feed directly into other parts of Project VERIFY (e.g. a Digital Twins of past abrupt ice sheet and climate change, and a new early warning system for climate tipping).

Project VERIFY

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 ten 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 behaviour can be predicted using Early Warning Systems (EWSs), forming a crucial component of a wider programme of 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. You will also benefit from involvement in the broader research 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.