Doomsday Glacier's Eastern Ice Shelf Weakening Rapidly
The Thwaites Glacier in West Antarctica, often referred to as the "Doomsday Glacier" due to its potential impact on global sea levels, is undergoing significant and rapid changes. A new study, published in the Journal of Geophysical Research: Earth Surface, highlights the accelerating disintegration of the Thwaites Eastern Ice Shelf (TEIS), a crucial component of the glacier system. The research, led by Debangshu Banerjee from the Centre for Earth Observation Science (CEOS) at the University of Manitoba, along with Dr. Karen Alley and Dr. David Lilien, utilizes two decades of satellite observations to detail the shelf's structural decline.
The Thwaites Glacier is immense, and its complete collapse could raise global sea levels by several feet. The TEIS, a floating ice shelf, acts as a buttress, slowing the flow of ice from the mainland into the ocean. This buttressing effect is critical to maintaining the stability of the entire glacier. However, the new study reveals that the TEIS is weakening at an alarming rate.
Fracture Growth and Ice Dynamics
The research team analyzed satellite imagery, ice-flow speed measurements, and GPS data from 2002 to 2022 to understand how fractures formed and evolved within the TEIS shear zone. Their findings indicate that the growth of these fractures has significantly weakened the shelf's connection to a critical pinning point at its northern edge. This pinning point previously helped anchor the ice shelf, but now appears to be contributing to its instability.
The study identified four distinct stages in the weakening process. Initially, long fractures aligned with the direction of ice flow appeared. These were followed by shorter fractures cutting across the flow. As the fractures grew, they weakened the connection to the pinning point, causing the ice upstream to accelerate. This acceleration, in turn, led to further damage, creating a dangerous positive feedback loop.
A Strengthening Feedback Loop
The positive feedback loop is a key finding of the study. As fractures increase, ice flow accelerates. This faster flow then causes more fractures, further weakening the ice shelf. This accelerating cycle has played a significant role in the recent decline of the TEIS and highlights the precarious state of the glacier. Understanding this feedback mechanism is crucial for predicting the future behavior of the Thwaites Glacier and its impact on sea levels.
Implications for Sea-Level Rise
The weakening and potential collapse of the Thwaites Eastern Ice Shelf have profound implications for global sea-level rise. If the floating ice shelves of Antarctica continue to deteriorate, the Antarctic Ice Sheet could contribute substantially to future sea-level rise. This could lead to coastal inundation, displacement of populations, and significant economic disruption worldwide.
The study's findings underscore the urgent need for continued monitoring and research on the Thwaites Glacier and other vulnerable ice shelves in Antarctica. By understanding the processes driving ice shelf collapse, scientists can improve projections of sea-level rise and inform strategies for mitigating the impacts of climate change.
International Collaboration
This research is a product of the TARSAN (Thwaites-Amundsen Regional Survey and Network) project, part of the International Thwaites Glacier Collaboration (ITGC), a joint effort between the United States and the United Kingdom. The ITGC brings together leading glaciologists and researchers from around the world to study the Thwaites Glacier and its surrounding environment. The collaboration aims to improve our understanding of the glacier's dynamics and its potential impact on global sea levels.
