West Antarctic Ice Sheet retreat in the context of ENSO variability

Lead Research Organisation: British Antarctic Survey
Department Name: Science Programmes


Satellite observations show rapid changes in the rate of ice loss from West Antarctica, but attribution of their cause is uncertain and requires modelling of the full ice-ocean system. Recent studies highlight the influence of El Niño Southern Oscillation (ENSO) on this important contribution to sea level. The hypothesised mechanism is through changes in ice-shelf melting, attributed to wind-forced variation in the depth of the oceanic thermocline that separates cooler surface waters from warmer Circumpolar Deep Water beneath. To improve upon detailed forecasts of West Antarctic ice using steady climate forcing, we propose novel experiments using a new synchronously coupled ice/ocean model that can continuously compute the response of the ice sheet to highly-variable oceanic forcing driven by ENSO. We seek to quantify: (1) the probability that 20th Century retreat of West Antarctic ice was triggered by ENSO; (2) the probability that sequential strong La Niña events could halt the retreat happening now; (3) formal attribution of changes in the West Antarctic Ice Sheet to ENSO or anthropogenic trends in zonal winds; and (4) the impact of ENSO and anthropogenic trends on predicted extremes of 21st Century sea level used for coastal planning decisions.

Planned Impact

By reducing uncertainty around the interaction between oceans and ice sheets, and the future contribution of Antarctica to sea level rise, the proposed research will benefit:
1) The Environment Agency in management of the coastal environment.
2) Government departments, e.g. Treasury, BEIS, in making decisions about resource allocation.
3) Other partners in the UK RIDE forum in understanding the risks of climate change and assessing options for avoiding or managing such risks. See https://nerc.ukri.org/research/partnerships/ride/ for details of the RIDE forum.
4) Business and industry in making investment decisions about long-lived infrastructure projects.
5) Local Authorities in making planning decisions.
6) The general public in allowing them to make informed decisions about energy use, and in playing an active and informed role in debates about coastal management, climate change, and the allocation of resources by government.


10 25 50
Description This award has led to a better understanding of the influence of ocean upon the Antarctica ice sheet through development of a new parameterisation of sub-ice-shelf melting and a new method of coupling ocean models to ice flow models. These advances will be described in later publications.
Exploitation Route Once the method of coupling ice and ocean models is further developed it will help to improve simulations used to make projections of global sea level.
Sectors Communities and Social Services/Policy



Description The main academic papers are only being finished now, so it is still too early for most of the non-academic impact to have been realised. Alex Bradley has done some filming for a documentary. Further impact will be added here in future submissions.
First Year Of Impact 2023
Sector Environment
Impact Types Societal

Description Towards an Antarctic digital twin for instantaneous decision-making (A).
Amount £78,215 (GBP)
Funding ID 2021DTUC3Hosking 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 12/2021 
End 04/2022
Title WAVI Ice Sheet Model 
Description WAVI is a Wavelet-based, Adaptive-grid, Vertically-integrated, Ice-sheet model. See Github for details: https://github.com/RJArthern/WAVI.jl 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? Yes  
Impact The model has recently been used to provide a training dataset for a new multifidelity approach. This work was presented at NeurIPS 2022. https://neurips.cc/Conferences/2022/ScheduleMultitrack?event=65895 
URL https://github.com/RJArthern/WAVI.jl
Description Outreach activity. Filming undertaken as input for documentary. 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Filming by Alex Bradley as possible input to a forthcoming documentary.
Year(s) Of Engagement Activity 2022
URL https://www.maximusfilm.de/de