Greenland’s ice sheet lost an estimated 105 billion tonnes of ice during the 2024–25 season with scientists warning that the increasing spread of darkened ice is creating a self reinforcing cycle that could accelerate future melting.
Satellite observations showed that during the summer of 2025, large areas of Greenland’s ice sheet became visibly darker as black carbon, dust and other impurities accumulated on the surface after seasonal snow melted away. The darker surface absorbed more sunlight instead of reflecting it, intensifying melting through a process known as the albedo feedback.
According to researchers, the melt season reached an exceptional peak between July 7 and July 20 when melting extended across much of the ice sheet. For three consecutive days, more than 80% of Greenland’s ice surface experienced melting, reaching a maximum of 81.2% the highest level recorded since satellite observations began in 1981.
Scientists also noted that the 2025 melt season began earlier than usual, with southern Greenland experiencing significant melting in spring. Sea ice in northwestern Greenland also broke up earlier than normal, affecting traditional seasonal activities such as Indigenous narwhal hunting.
Researchers say wildfire smoke from North America may have contributed to the surface darkening by depositing black carbon on the ice, further reducing its reflectivity and enhancing melt rates.
Although the 2025 season was not the most severe on record, scientists describe it as significant because it highlights how moderate melt seasons can still trigger powerful climate feedbacks. Greenland has now experienced nearly three decades of continuous annual ice loss with the last year of overall ice gain recorded in 1995–96.
The Greenland Ice Sheet is one of the world’s largest freshwater reservoirs, and its continued melting contributes to global sea level rise while adding freshwater to the North Atlantic Ocean, which may influence regional ocean circulation and weather patterns.
Researchers emphasize that while the ice sheet continues to regain some mass during winter snowfall, the increasing frequency of widespread melt events and the expansion of surface darkening underscore the need for continued monitoring to better understand future climate risks.