Since 1990, the surface area affected by these extreme events has been expanding by about 2.8 million km² per decade. At the same time, the amount of water released from melting ice has surged. Between 1950 and 2023, extreme melt events produced an average of 12.7 gigatons of water per decade. Since 1990, that figure has jumped to 82.4 gigatons per decade, marking a sixfold increase.

Record-Breaking Melt Events Are Becoming More Common

Most of the most intense melting episodes have occurred in recent decades. Seven of the ten most extreme events on record have taken place since 2000, including major events in August 2012, July 2019, and July 2021. These events stand out because they have no comparable dynamic precedents, highlighting how unusual current conditions have become.

The study also shows that each extreme event is now producing more meltwater than similar events in the past. Since 1990, meltwater output during these episodes has risen by 25% compared to the 1950-1975 period when examining cases with similar anticyclonic and cyclonic air mass circulation. When considering all extreme events together, the increase reaches as high as 63%. This points to a strong thermodynamic effect, meaning rising temperatures are intensifying the melting beyond what atmospheric circulation alone would explain.

Northern Greenland Emerges as a Key Hotspot

The northern part of Greenland is now one of the regions most affected by these changes, emerging as a major hotspot for extreme melting. Looking ahead, projections under high greenhouse gas emission scenarios suggest that by the end of the century, the most intense meltwater anomalies could increase by as much as threefold.

New Methods Reveal Drivers Behind Intensifying Melt

The research was led by Josep Bonsoms, a postdoctoral researcher and professor in the Department of Geography at the University of Barcelona, with contributions from Marc Oliva, also a professor in the department. Conducted as part of the Antarctic, Arctic and Alpine Environments (ANTALP) Research Group, the study examined extreme melting events recorded between 1950 and 2023.

To better understand what is driving these changes, the team used a novel classification method that combines types of anticyclonic and cyclonic air mass circulation with a regional climate model. This approach allowed researchers to separate thermodynamic influences, which are linked to atmospheric warming, from dynamic influences tied to atmospheric circulation patterns.

Global Implications and Growing Strategic Importance

As global attention increasingly focuses on Greenland due to rapid environmental changes and their geopolitical implications, these findings carry added weight. Bonsoms, the article's lead author, says that "the rapid transformation of the ice sheet not only has global environmental consequences, such as sea level rise and possible alterations in ocean circulation, but also places the Arctic at the centre of new strategic, economic and territorial dynamics."

Understanding the processes that intensify extreme melting is critical for anticipating future risks and shaping informed policy decisions. The study is part of the GRELARCTIC project led by the UB ANTALP research group, with Marc Oliva as principal investigator, and was supported by an award from the ICREA Academia program.