New study reveals how responsive the Greenland ice sheet is to climate change – more so than models predict
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Stretching approximately 1.7 million square kilometres, the Greenland Ice Sheet covers about 80 per cent of the island’s surface. While large in size, this huge body of ice is extremely sensitive to small changes in the climate, more so than models have predicted.
In a new paper published by Charles University, Czechia, and the University of Oulu, Finland, researchers found evidence linking widespread methane release from beneath the ice sheet to an episode of warming around 4,000 years ago, known as the Holocene Thermal Maximum.
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To reach their conclusion, scientists collected samples along a 2,000-kilometre-long transect of the western margin of the Greenland Ice Sheet and used analysis to identify the origin and age of the methane within. Such findings imply that the ice sheet retreated significantly inside its present margins after the last ice age, allowing boreal and tundra vegetation to grow in the newly exposed areas. This was subsequently overridden by advancing ice during the subsequent colder period. The retreat suggests a highly dynamic ice sheet, one that is far more sensitive to climate change than previously thought, with clear implications for its future behaviour.
‘“Our study reveals startling insights into just how responsive the Greenland ice sheet is to climate change. That it abruptly retreated to a configuration much smaller than present under levels of Arctic warming on a par with that ongoing today is a bleak reminder of its future committed loss to global sea-level rise and coastal flooding, if we can’t get our act together to curb greenhouse gas emissions, said co-author Professor Alun Hubbard from the University of Oulu.
‘The ultimate irony is that as it retreats, the ice sheet itself further contributes to those methane emissions.’
In recent years, international scientific discussion has increasingly highlighted the so-called hidden methane phenomenon: evidence that methane reservoirs beneath glaciers may be released as glaciers retreat. Researchers warn that they may represent a climate-warming feedback mechanism. At present, these emissions are not significant at the global scale, but that can change as rates of deglaciation increase.
How fast is the Greenland Ice Sheet melting?
Every year, the Greenland Ice Sheet is losing around 266–270 billion metric tons of ice, equivalent to approximately 0.6–0.8 millimetres of global sea level rise annually. If the Greenland Ice Sheet were to melt completely, global sea levels would rise by approximately seven metres.
As Geographical reported in 2025, the Greenland Ice Sheet is cracking more amid climate change, with crevasses increasing in both size and depth at the fast-flowing edges of the ice sheet.
However, beyond measuring Greenland’s ice loss, scientists are also trying to understand the wider ripple effects of a warming Arctic.
This summer, an international team of scientists will head to Greenland to discover how quickly the ice sheet’s melting glaciers are pushing the Atlantic Ocean towards a critical climate tipping point.
This fieldwork is part of a five-year project that brings together 17 partners led by the British Antarctic Survey (BAS). Through this fieldwork – where drones, marine robots, satellites, and other equipment will be used – researchers hope to gain a better understanding of how much meltwater is being released from Greenland’s fjord glaciers and how this influences ocean circulation and the global climate system.
Currently, scientists don’t have a clear idea of how Greenland’s fjord glaciers interact with the surrounding ocean, with the 200 or so narrow fjords impossible to capture in global computer models.
