A new study led by the British Antarctic Survey (BAS) warns that increased melting of West Antarctica's ice shelves is unavoidable in the coming decades, regardless of efforts to reduce greenhouse gas emissions. The findings suggest that future sea-level rise may exceed current UN projections.
The study, published in Nature Climate Change, is the first to directly simulate how ocean warming will affect Antarctic ice shelves under different emission scenarios. It finds that the Amundsen Sea off West Antarctica will warm roughly three times faster than historical rates through the rest of this century, leading to rapid ice shelf melting.
Ice shelves, which are floating extensions of glaciers, play a crucial role in holding back the grounded ice behind them. As they melt, the glaciers can accelerate, releasing more ice into the ocean. The West Antarctic Ice Sheet holds enough ice to raise global sea levels by about 5 metres (16 feet), and its collapse could be triggered by these processes.
Lead author Dr Kaitlin Naughten emphasised that while strong action on emissions can slow long-term sea-level rise, it cannot prevent the near-term melting. The study highlights the vulnerability of Thwaites Glacier, often called the 'doomsday glacier', whose grounding line is already retreating by over 1 km per year in some areas.
The UN's Intergovernmental Panel on Climate Change (IPCC) had previously projected a sea-level rise of 0.28–1.01 metres by 2100, but noted deep uncertainties around ice-sheet processes. This new research suggests those estimates may be exceeded, putting hundreds of millions of people at risk of coastal flooding.
