Even as some parts of West Antarctica rapidly melt, raising sea level, large swaths of the ice remain stable for the time being. Scientists have now explored one of those stable spots — an isolated nook where the ocean meets the ice. There, the team found the underside of the ice sculpted into strange grooves, ripples and globes.
This environment is “really at the edge” between melting and freezing, says planetary scientist Justin Lawrence. The delicate balance between these two processes is shaping the ice into those strange textures — similar to the way that minerals dissolve and recrystallize to form the beautiful shapes inside limestone caverns.
The result, at Kamb Ice Stream, is that massive cracks in the underside of the ice appear to be freezing back together as the beach ball–sized globes fill in the crevasses from above, Lawrence and colleagues report March 2 in Nature Geoscience.
This refreezing differs from what’s happening at Antarctica’s Thwaites Glacier. There, scientists recently reported that these cracks, known as basal crevasses, are instead sites of rapid melting (SN: 2/15/23).
Understanding what is happening at Kamb will help scientists predict how large parts of the Antarctic coastline that are not currently vulnerable might respond as the world continues to warm due to human-caused climate change. Here’s what’s different about Kamb.
Supercold water underlies the ice at Kamb, slowing melting
In December 2019, two teams of researchers from New Zealand and the United States visited the Kamb Ice Stream — a type of glacier that consists of a channel of faster-moving ice surrounded by slower ice.
Kamb, like much of the rest of the West Antarctic Ice Sheet, rests on a bed that is hundreds of meters below sea level. The New Zealand team used hot water to melt a narrow hole through the ice, just downstream of the “grounding zone,” where the glacier lifts off its muddy bed and floats on the…
Read the full article here