Image: Sentinel 2 satellite image, meltwater ponds on the Amery Ice Shelf.
Credit: Copernicus Sentinel 2 data, processed by Pete Tuckett
Research involving the University of Liverpool has discovered a trend of increasing surface meltwater in East Antarctica.
In an ambitious new study, they produced the first Antarctic-wide, high-resolution monthly dataset of surface meltwater using satellite images.
The research raises questions about the future behaviour of the ice sheet because surface meltwater is predicted to become increasingly important for Antarctic mass-loss as atmospheric temperatures rise.
Increased meltwater ponding
The research, published in the journal Nature Climate Change, reveals a significant increase in the amount of meltwater ponding on the ice surface around the vast East Antarctic ice sheet, and more variability from one year to the next. This comprehensive study, utilising cloud computing to analyse over 133,000 satellite images, highlights the growing influence of atmospheric warming on the continent’s ice sheets.
It shows that surface meltwater covered an average of 3732 km² – more than twice the area of Greater London – across Antarctica each melt season. While meltwater area varied significantly across the continent and between years, the research uncovered a concerning result: the ice sheet surface in East Antarctica may be becoming more susceptible to meltwater ponding.
Led by the University of York, the research involves researchers from the University of Liverpool, the universities of Sheffield, Leeds and the British Antarctic Survey.
Antarctica matters to us all
Dr Pete Tuckett, from the University of York, explained that the research has significant potential to change the way policymakers see the Antarctic continent and underlines the speed of change in its ice sheets.
He said: “Antarctica has traditionally been considered too cold for substantial amounts of surface melting to take place. Our study shows that not only does surface meltwater exist around large parts of the Antarctic margin, the amount of surface meltwater in East Antarctica is increasing”.
The Antarctic Ice Sheet contains enough water to raise global sea level by around 58 metres, and researchers are keen to understand what impact continued increases in global atmospheric temperature will have on the future behaviour of the ice sheet.
James Lea, a Professor of Glaciology at the University of Liverpool and UKRI Future Leaders Fellow, is a co-author of the study.
He said: “This study provides an incredibly important insight into how meltwater around Antarctica varies. This is crucial for understanding Antarctic ice sheet stability, as we know meltwater ponding can cause ice shelf collapse. When these floating ice shelves disintegrate they can release substantial volumes of grounded ice into the ocean from upstream ocean contributing to global sea level rise.”
“The data analysis for this study is no mean feat – by analysing literally tens of thousands of satellite images we’ve been able to show in detail where and why meltwater coverage is changing across the entire Antarctic continent.”
“Due to the way the Earth’s gravity field works, ice loss from Antarctica has an outsized effect on sea level change in the UK and across the northern hemisphere. The information in this study is invaluable for identifying the areas that are potentially at greatest risk and understanding what impacts our generation needs to start planning for.”
Ponded meltwater is a critical factor in ice sheet stability. It can lead to ice-shelf breakup through water-driven cracking, enhance localised melting, and influence the movement of ice on land (‘grounded ice’), potentially accelerating its flow towards the ocean.
Dr Tuckett added: “It is key that this new dataset is now combined with climate models, other satellite observations, and on-the-ground measurements to better understand the underlying causes of the increased meltwater ponding in East Antarctica and its potential future impacts on ice sheet stability and sea-levels.
“Understanding where and why surface meltwater is changing in Antarctica is crucial for predicting the continent’s future contribution to our oceans. It’s a global story.”
Professor Lea holds a prestigious UKRI Future Leaders Fellowship which aims to improve knowledge of both future global sea level change and understand the risks to future polar shipping routes.
The paper ‘Continent-wide mapping shows increasing sensitivity of East Antarctica to meltwater ponding’ is published in the journal Nature Climate Change.
IMAGE:
Sentinel 2 satellite image, meltwater ponds on the Amery Ice Shelf.
Credit: Copernicus Sentinel 2 data, processed by Pete Tuckett