A meltwater lake on the 79°N Glacier in Greenland has triggered lasting cracks and ice uplift, according to a new study published in The Cryosphere. Researchers from the Alfred Wegener Institute investigated how global warming caused the lake’s formation and its subsequent impact on the glacier.
The 79°N Glacier is one of three remaining floating tongues of the Greenland ice sheet, which has been losing mass since the mid-1990s. In 1995, a meltwater lake formed on the glacier’s surface, and over the years, it caused repeated drainage events through cracks in the ice. These events lifted the glacier upwards, forming a subglacial lake beneath the ice.
The researchers observed that the lake’s water repeatedly drained through channels and cracks, causing massive amounts of fresh water to reach the edge of the glacier tongue towards the ocean. This phenomenon has led to the formation of triangular fracture fields with cracks in the ice, which are shaped differently from all previous lake drainages.
The study suggests that the frequent drainages have forced the glacier system into a new state, raising questions about whether the system can absorb this amount of water and influence the drainage itself. The researchers found that the material behavior of the glacier plays a role in the formation of cracks and channels, with the ice behaving like an extremely thick fluid that flows slowly over the substrate.
The findings have important implications for understanding the behavior and effects of cracks in glaciers, particularly when it comes to the development of lakes on the 79°N Glacier. As atmospheric temperatures continue to rise, the fracture surfaces are becoming more frequent and affecting a larger area of the glacier.
This study provides crucial data for integrating cracks into ice sheet models and researching how they form and influence glaciers. The researchers will continue to work with scientists from TU Darmstadt and the University of Stuttgart on modeling and understanding the behavior of cracks in glaciers.
Source: https://phys.org/news/2025-08-meltwater-lake-79n-glacier-triggers.html