Deeper than anticipated channels may accelerate the melting of the glacier from below.
The unstable Thwaites Glacier in West Antarctica may be losing its glacial cover more quickly than previously thought thanks to a network of channels that are finally visible on new seabed maps.
The researchers discovered that the channels are deeper and more intricate than previously believed, and they might be carrying warm ocean water all the way to the glacier’s base, where it might melt.
Researchers calculate that the Thwaites Glacier, which is the size of Florida, contributes roughly 4% of the current rise in world sea levels (SN: 1/7/20). Should the glacier completely melt, which some scientists predict may occur in the coming decades, sea levels might rise by almost 65 cm. An worldwide joint research project spanning five years is investigating how and when that collapse might happen.
Thwaites glacier and other glaciers are prevented from moving seaward by buttressing ice shelves, which are tongues of floating ice that protrude into the ocean, as well as by the structure of the seafloor, which can aid in stabilizing the glacier’s ice (SN: 4/3/18). However, the researchers demonstrate how the comparatively warm ocean waves may have a direct route to the Thwaites glacier’s underside in two new experiments that were published online in The Cryosphere on September 9.
Between January and March of 2019, scientists examined the seafloor surrounding the glacier and two nearby ice shelves using a range of aerial and vessel-based techniques, such as radar, sonar, and gravity measurements. The team was able to approximate the contour of the seafloor beneath the ice itself using those data.
Through these efforts, a rough sequence of deep troughs and high ridges that ranged in depth from 250 to 1,000 meters were discovered on the seafloor. The scientists discovered that one significant channel, which is over 800 meters deep, may be the conduit for warm water that flows from Pine Island Bay to the glacier’s submerged edge.