Greenland's ice loss, seen through two different calculations
· BehindLines newsroom
Greenland has ended a thirtieth consecutive annual cycle with less ice than it had at the start. An analysis published on 27 October by two climate scientists in Carbon Brief puts that finding in context: even a relatively moderate season can extend a lasting trend of mass loss.
Two estimates of the same season
Martin Stendel and Ruth Mottram, of the Danish Meteorological Institute, report a loss of about 135 billion tonnes during the twelve months ending in August 2026. Their method combines results from three climate models.
Their article also cites a different estimate, about 173 billion tonnes, from the Geological Survey of Denmark and Greenland, GEUS. The figures come from different approaches to the same annual balance. They should neither be added together nor described as two successive losses.
GEUS presented its estimate on 1 September. It describes monitoring that brings together weather stations, satellites, GPS measurements, aerial observations and model calculations. Both publications agree that the overall balance is negative, despite differing estimates of its size.
The surface is only part of the picture
Snow adds mass to the ice sheet. Melting and water flowing away remove it at the surface. But the total balance also includes ice carried towards the sea by glaciers and icebergs breaking off. Snow accumulating at the surface can therefore coexist with an overall loss.
A cool start to summer is consequently insufficient evidence that the ice sheet is recovering. Seasonal weather affects the outcome without cancelling the other processes that remove ice.
A continuing trend, without inventing a record
GEUS stresses that the 2025-2026 season was not among the largest annual losses. The striking finding is the uninterrupted deficit since the 1996-1997 cycle. Carbon Brief notes that climatologists generally examine thirty-year periods to distinguish climate change from natural variability.