A recent study by a team of researchers from the International Thwaites Glacier Collaboration (ITGC) has found that the Thwaites Eastern Ice Shelf – the last floating extension of Thwaites into the ocean - is rapidly destabilising due to widening cracks, not melting from below as previously thought.
Since 2016, cracks, or "rifts," in the ice shelf have been rapidly spreading and deepening, especially during the Southern Hemisphere’s spring season (Sep-Nov). These rifts have sped up the ice shelf’s movement by about 70%, with the central part now moving nearly three metres a day, compared to just under two metres a day in 2019. This acceleration also affected the structural integrity of the ice shelf, and since 2020 has contributed to the formation of large gaps filled with icy debris. Additionally, recent loss of sea ice around the ice shelf has allowed part of its western edge to detach from its main anchoring point on the seafloor.
Sensors placed along the ice for the study, which was published in September 2024 in the Journal of Glaciology, have shown that despite warming ocean waters, melting beneath the shelf is surprisingly low. This is likely because there’s a layer of buoyant freshwater below the ice that keeps warm ocean water from directly melting the ice from underneath.
What these findings as well as further computer modelling suggests is that, while warm ocean waters are preconditioning ice loss in West Antarctica, it is the ongoing internal destabilisation that now poses the greatest threat to the Thwaites Eastern Ice Shelf. The ice shelf is in its final phase of disintegration as these cracks grow, independent of melting from below.
Lead author of the study, Dr Christian Wild from Oregon State University says:
“We anticipated that the Thwaites Eastern Ice Shelf would break up within the next decade, but never so quickly – it’s like watching the final act of a disaster unfolding.”
This discovery highlights the complexity of Antarctic ice dynamics and amplifies concerns over the future stability of Thwaites Glacier, whose complete collapse could significantly raise global sea levels.
Wild, Christian T., Samuel B. Kachuck, Adrian Luckman, Karen E. Alley, Meghan A. Sharp, Haylee Smith, Scott W. Tyler, et al. Rift Propagation Signals the Last Act of the Thwaites Eastern Ice Shelf despite Low Basal Melt Rates. Journal of Glaciology, 2024, 1–18. https://doi.org/10.1017/jog.2024.64.
