Search for a project

Legacy of a warming world: Simulating ice sheet melt

Dr Lauren Gregoire (SEE), Dr Ruza Ivanovic (SEE), Prof Andrew Shepherd (SEE), Dr Louise Sime (BAS)

Project partner(s): British Antarctic Survey and CPOM (CASE)

Contact email: l.j.gregoire@leeds.ac.uk

This project will develop novel methods for efficiently and accurately simulating ice sheet surface melt to improve simulations of past and future ice sheet evolution.

Figure 1: Future projections of the Greenland ice sheet under different scenarios of greenhouse gas emissions (Alley et al., 2005).

The unprecedented climate changes we are currently experiencing are causing ice sheets to melt and sea levels to rise. The greenhouse gas emissions in the next century will likely trigger major retreat of the Greenland and Antarctic ice sheets that will last for thousands of years.

An often overlooked fact is that many places around the world are experiencing the effects of past ice sheet retreat; the ground is still adjusting to the retreat of ice sheets since the last ice age (21 thousand years ago). For example, Southern England and the Netherlands are lowering, adding to the threat from sea level rise due to warming oceans and melting glaciers. Knowledge of past ice sheet evolution is therefore needed to constrain rates of this so-called ‘postglacial isostatic adjustment’ (i.e. changes in surface elevation caused by past ice sheets). Furthermore, constraining the past evolution of Greenland and Antarctica is also critical for disentangling the signals of past and current ice changes in present-day satellite observations.

To constrain past, present and future ice sheets and sea level rise we need to simulate the evolutions of ice sheets over thousands of years. Ground-breaking developments have recently been made to the modelling of ice sheet dynamics, but accurately simulating surface mass balance is still proving challenging. Determining snow accumulation and melt requires information from general circulation models of climate, which have errors and biases at high latitudes (see Gregoire et al, 2016). It also requires running high-resolution regional models alongside models of ice sheet dynamics, but such models are computationally expensive. To simulate ice sheet mass balance over thousands of years or longer time scales, we urgently need a method that efficiently simulates the response in snow accumulation and melt to climate change while correcting for known biases in high latitude climate.  

Objectives

The aims of this project are twofold:

  1. A new method for simulating the surface mass balance of ice sheets will be developed. The method will combine models of climate, regional energy mass balance and ice sheet dynamics with statistical methods for downscaling climate (increasing the spatial resolution) and quantifying model uncertainties. This will enable us to build an efficient, statistical model for surface mass balance that can be coupled to the latest generation of ice sheet models.
  2. The new model will then be applied to simulating the evolution of past and future ice sheets, which could include:

    • projecting the evolution of the Greenland ice sheet over the next 1000 years
    • Simulating the contributions of ice sheets to past abrupt sea level changes (such as the Meltwater Pulse 1a, a 14-18 m sea level rise in 340 years, 14,500 years ago).

Figure 2: This project will use the BISICLES model which enable efficient and accurate simulation of ice sheets dynamics, thanks to its adaptive grid.

Potential for high impact

The novelty of the developed ice sheet modelling techniques provides this project with great potential for making exciting scientific discoveries. By unlocking the potential to accurately and efficiently simulate surface mass balance, this new tool will allow us to quantify uncertainty in projections of future ice sheet evolution and sea level change over thousands of years. This will reveal the legacy of our current greenhouse gas emissions on ice sheets and sea level, and determine whether these changes are reversible. The new method also has the potential to correct major errors in current simulations of past ice sheet evolution, thus revealing properties of the solid earth and enabling us to disentangle the satellite signals of past and present ice sheet mass balance changes. The student will develop a highly sought-after, multidisciplinary skill-set, contributing towards the development of an interdisciplinary field of research that is at the forefront of glaciology. By the nature of this work, and due to its timeliness, there is strong potential for the PhD candidate to influence the direction of international research being carried out on this theme, and to thus establish a world-renowned reputation for innovative science.

Training

This interdisciplinary project will provide the successful PhD candidate with highly valued and sought-after skills in numerical ice sheet and climate modelling and a broad knowledge of the Earth System. This will equip the student with the necessary expertise to become a next generation glaciologist, ready to carry out their own programme of innovative scientific research.

The student will benefit from working within the dynamic and multidisciplinary Palaeo@Leeds and Physical Climate Change research groups; as well as collaborating with international experts in ice sheets and sea level rise. There will be opportunities to present results at major, international conferences, e.g. AGU (San Francisco), EGU (Vienna) and attend residential summer-schools (e.g. in Italy, USA, UK) and in-house workshops and courses.

Partnership with the British Antarctic Survey, CASE award

The British Antarctic Survey and Centre for Polar Observation and Modelling will be a partner for this project and provide additional research funding. This partnership will also provide access to data, training and opportunities to work with scientists at the British Antarctic survey, including the CASE supervisor Louise Sime.

Entry requirements

A good first degree (1 or high 2i), or a good Masters degree in a physical, mathematical or geological discipline, such as mathematics, physics, geophysics, engineering or meteorology. Experience in programming (eg. Fortran, Matlab, python, C …) and/or statistics is of advantage.

Further information

Watch: Modelling ice sheet retreat.

Read: Short story about the BISICLES ice sheet model (LBL web page), Rapid sea level rise triggered by ice saddle collapse.

Cornford, S. L. et al. 2015. Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate, The Cryosphere, 9, 1579-1600.

Gregoire, L.J., et al. 2012. Deglacial rapid sea level rises caused by ice-sheet saddle collapses. Nature 487, 219–222.

Gregoire, L.J. et al. 2016. Abrupt Bølling warming and ice saddle collapse contributions to the Meltwater Pulse 1a rapid sea level rise. Geophys. Res. Lett. 2016GL070356. doi:10.1002/2016GL070356

Alley, R.B., Clark, P.U., Huybrechts, P., Joughin, I., 2005. Ice-Sheet and Sea-Level Changes. Science 310, 456–460. doi:10.1126/science.1114613.

Hanna, E., et al. 2011. Greenland Ice Sheet surface mass balance 1870 to 2010 based on Twentieth Century Reanalysis, and links with global climate forcing, J. Geophys. Res., 116, doi:10.1029/2011JD016387.

Fettweis, X., 2007. Reconstruction of the 1979–2006 Greenland ice sheet surface mass balance using the regional climate model MAR. The Cryosphere 1, 21–40. doi:10.5194/tc-1-21-2007.

Related undergraduate subjects:

  • Applied mathematics
  • Atmospheric science
  • Computer science
  • Computing
  • Earth science
  • Earth system science
  • Environmental science
  • Geography
  • Geological science
  • Geophysical science
  • Geophysics
  • Geoscience
  • Materials science
  • Mathematics
  • Mechanical engineering
  • Meteorology
  • Natural sciences
  • Oceanography
  • Physical geography
  • Physical science
  • Physics
  • Remote sensing
  • Statistics