VUB Study: Amplifying Feedbacks Could Lead to the Near-Complete Disappearance of the Greenland Ice Sheet
No ice left by the year 3000, with a potential contribution of more than 7 metres to sea-level rise
Greenland, which has been prominently in the news in recent days, hosts a vast ice sheet. If it melts, it will become one of the largest contributors to global sea-level rise. Under a high-emissions scenario, the Greenland Ice Sheet is expected to largely disappear over time, with far-reaching consequences. This is the conclusion of a new study by Chloë Paice and colleagues, published in the scientific journal The Cryosphere. The Greenland Ice Sheet contains enough ice to raise global sea levels by approximately 7.4 metres and has been losing mass at an accelerating rate since the 1990s. Roughly half of this loss is due to surface melt, while the other half results from ice calving where the ice sheet meets the ocean.
Despite increasing observations and improved models, significant uncertainty remains about the long-term behaviour of the ice sheet and its precise interactions with the climate system. Until now, long-term projections have mainly relied on global climate models, which can inadequately represent key processes over Greenland, such as precipitation and wind patterns. In this new study, the researchers therefore adopted a different approach by coupling a Greenland ice-sheet model with a regional climate model specifically designed for polar regions.
Using this coupled framework, the researchers performed simulations under a future scenario of strong warming and high greenhouse gas emissions, known as SSP5-8.5. The simulations cover the next three hundred years, after which the climate was held constant while the coupled models continued to run until the year 3000. This allowed the team, for the first time, to investigate in detail the role of amplifying feedback mechanisms between the ice sheet and the atmosphere over very long timescales.
“Our results show that it is not just about how much ice melts, but especially about how the ice sheet and the atmosphere interact,” says lead author Chloë Paice. During the first centuries of the simulations, a stabilising feedback dominates, driven mainly by changes in wind speeds. Altered wind patterns around the margins of the ice sheet temporarily reduce melt rates, slightly slowing mass loss.
Over time, however, this picture changes fundamentally. From around the year 2300 onwards, amplifying feedbacks become dominant. The most important of these is the so-called melt–elevation feedback: as the ice sheet thins and its surface lowers, surface temperatures rise, further accelerating melting. At the same time, higher temperatures cause an increasing fraction of snowfall to fall as rain. Total precipitation also decreases, because a lower ice sheet induces less uplift, cooling and condensation of air. As a result, the accumulation of new ice is strongly reduced.
In addition, the simulations show increasing amounts of atmospheric water vapour and cloud cover, leading to extra warming over the ice sheet. Together, these processes result in an accelerating loss of ice mass. In simulations that fully include these feedbacks, the Greenland Ice Sheet loses nearly all of its ice by the end of the thousand-year period, with a potential contribution to global sea-level rise of more than seven metres.
“We find that the feedbacks between the ice sheet and the atmosphere ultimately become so strong that, under a high-warming scenario, the ice sheet largely loses its stability,” Paice explains. “Simulations that do not include these interactions significantly underestimate the total mass loss.”
The study highlights the importance of explicitly including ice-sheet–atmosphere feedbacks in long-term sea-level rise projections. It demonstrates that high-resolution regional climate models are crucial for accurately representing these processes. Combined with the currently observed acceleration in mass loss, the results suggest that, under sustained high warming, the Greenland Ice Sheet could largely disappear in the long term, with profound consequences for coastal regions worldwide.
More information
Chloë Paice: Chloë.Marie.Paice@vub.be
https://tc.copernicus.org/articles/20/309/2026/
