A study led by the University of Barcelona and published in the journal Nature Communications shows that climate change has profoundly altered extreme episodes of melting of the Greenland ice sheet: it has made them more frequent, more extensive and more intense. Since 1990, the area affected by extreme melting episodes has increased at a rate of 2.8 million km² per decade. And the production of water from ice melt has increased six-fold: while in the period 1950-2023 it was 12.7 gigatons per decade, since 1990 this figure has risen to 82.4 gigatons per decade.
Seven of the ten most extreme melting episodes have occurred since 2000, including the record-breaking events of August 2012, July 2019 and July 2021, which have no comparable dynamic precedents, underscoring their exceptional nature. The study notes a clear thermodynamic intensification of extreme melting events, with more water being produced in each one: since 1990, this water production has increased by 25% compared to the 1950-1975 period when comparing episodes with equivalent anticyclonic and cyclonic air mass circulation, and by up to 63% when analysing all extreme episodes as a whole.
The most affected area is northern Greenland, which is emerging as one of the main hotspots. Future projections under high greenhouse gas emission scenarios indicate that by the end of the century, extreme anomalies in meltwater production could increase up to threefold.
The study was led by Josep Bonsoms, a researcher and postdoctoral professor at the Department of Geography at the University of Barcelona, and included the participation of Marc Oliva, professor in the same department. Developed within the framework of the Antarctic, Arctic and Alpine Environments (ANTALP) Research Group, the study analyses extreme melting events recorded between 1950 and 2023 using an innovative classification methodology: the type of anticyclonic and cyclonic air mass circulation is combined with a regional climate model. This approach has made it possible to differentiate the role of thermodynamic factors (associated with atmospheric warming) from dynamic factors (related to atmospheric circulation) in the intensification of melting episodes.
