The study, led by researchers from the Antarctic Research Centre at Te Herenga Waka—Victoria University of Wellington, highlights the rising risks for Antarctica’s ice shelves as the climate warms.

“Our findings show Antarctic surface melting is not only increasing but spreading into new parts of the continent. This trend will continue if we keep doing business as usual. Just to stabilise melt at current levels, significant cuts in greenhouse gas emissions will likely be needed,” said study co-author Professor Nicholas Golledge, a climate scientist at the university.

The study used climate models to predict how much surface ice would melt under different emissions scenarios. Results showed a stark difference between low- and high-emissions futures.

“Under a scenario in which global temperatures rise by approximately 3.5 to 4°C above pre-industrial levels, increased surface melting around the continent will leave ice shelves much more vulnerable to rapid collapse and sea-level rise. In an extreme scenario where warming rises above 4°C, the risk of rapid collapse becomes even more pronounced,” said Professor Golledge.

Modelling showed temperature rises of about 3.5 to 4°C would likely see future surface melt extend southward into regions that have historically been largely unaffected, with an additional 1.58 million km² estimated to experience melting by 2100.

Under medium- and high-emissions scenarios, melt rates would continue to accelerate and remain well above current levels by the end of the century.

Results showed only a low-emissions pathway would be likely to stabilise future melt at present-day levels. Under this pathway, increases in global average temperatures would need to be well below 2°C above pre-industrial levels.

“These findings underscore the urgency of reducing emissions. Strong mitigation could stabilse melt, while weaker action leaves Antarctica exposed to rapidly escalating change. We know sea-level rise resulting from ice-sheet collapse would have major implications for coastal communities in Aotearoa New Zealand. Given our long coastline, we’re particularly vulnerable to rising seas,” said Professor Golledge.

Expanding surface melt would not only affect the stability of the Antarctic ice shelves but would also likely result in other ecosystem changes.

“Surface melting increases water availability in summer, which may alter surface conditions. One flow-on effect is the new opportunities this could create for colonisation by invasive species in parts of the continent,” he said. 

The study is published in the journal Nature Communications. The work was funded by a Rutherford Discovery Fellowship from the Royal Society of New Zealand—Te Apārangi.