A new study has suggested that the infamous “Doomsday Glacier” in Antarctica, known as Thwaites Glacier, may not collapse as quickly as previously predicted. This glacier has earned its nickname due to the potential catastrophic consequences of its collapse, which could lead to significant flooding of coastlines worldwide. Thwaites Glacier is already responsible for contributing about 4% of the annual sea-level rise as it continues to lose ice.
One theory surrounding Thwaites Glacier suggests that it could collapse into the ocean in a rapid and cascading manner, similar to a row of dominoes falling. However, the recent study on the glacier’s susceptibility to marine ice cliff instability offers a glimmer of hope. While the findings do not indicate that Thwaites is completely stable, they do provide some insight into the potential future of this critical ice formation.
Polar scientist Mathieu Morlighem, who led the study, explains the importance of Thwaites Glacier and the implications of its possible collapse. The glacier drains a massive area of Antarctica’s ice sheet, covering approximately 74,000 square miles, which is larger than the state of Florida. Any snowflake that falls within this drainage system eventually contributes to the formation of icebergs in the ocean off Thwaites.
Currently, Thwaites Glacier is experiencing a slow-motion disaster. The bedrock beneath the glacier sits below sea level and slopes downward towards the interior of the ice sheet, causing the glacier to deepen as it moves inland. Once the glacier begins losing more ice than it gains from new snowfall, it becomes challenging to slow down its retreat due to this slope. With the climate warming, Thwaites is already retreating at an accelerating rate, posing significant concerns for future sea-level rise.
The potential collapse of Thwaites Glacier holds immense implications for global sea levels, as it contains enough ice to raise sea levels by over 2 feet. Additionally, if Thwaites were to destabilize, it could trigger the destabilization of neighboring glaciers, amplifying the impact on the West Antarctic Ice Sheet and, consequently, coastlines around the world.
One of the key concepts discussed in the study is marine ice cliff instability, a relatively new idea introduced by scientists in the past decade. Many glaciers around Antarctica have large floating extensions known as ice shelves, which provide support to the glacier and slow its flow into the ocean. However, with the rising temperatures, some of these ice shelves have collapsed rapidly, sometimes within a few weeks or months.
In the case of Thwaites Glacier, if its ice shelf were to collapse, it would expose a towering ice cliff facing the ocean, reaching over 200 feet in height in some areas. The theory of marine ice cliff instability suggests that if these ice cliffs collapse rapidly, it could set off a chain reaction of increasingly taller ice cliffs collapsing one after the other. However, the actual occurrence of marine ice cliff instability remains unobserved, leaving uncertainties about its potential impact.
The study conducted by Morlighem and his team aimed to explore the risk of marine ice cliff instability for Thwaites Glacier. Contrary to previous estimates, their results indicate that if the entire ice shelf of Thwaites collapsed today, the glacier’s ice front would not rapidly retreat inland due to marine ice cliff instability alone. Without the ice shelf, the glacier’s ice would flow faster towards the ocean, thinning the front of the glacier and resulting in lower ice cliffs.
The findings suggest that Thwaites Glacier may remain relatively stable at least through the year 2100, even in the scenario of an ice shelf collapse in 50 years. This challenges recent projections, including a worst-case scenario mentioned in the Intergovernmental Panel on Climate Change’s latest assessment report, which labeled the collapse of Thwaites as a “low likelihood” event.
Thwaites Glacier plays a critical role in the stability of the entire West Antarctic Ice Sheet, making it a focal point for researchers studying the impacts of climate change on polar regions. While the study’s results offer some reassurance regarding the glacier’s vulnerability to ice cliff failure, it does not discount the other mechanisms contributing to its retreat at an accelerating rate.
Apart from marine ice cliff instability, several processes make the Antarctic ice sheet unstable, with ice-ocean interactions being a significant factor in recent ice mass loss. Warm ocean currents penetrating beneath the ice shelves have been thinning the ice from below, weakening the ice shelves and accelerating the flow of ice streams. The intrusion of warm water from the Antarctic Circumpolar Current in the Amundsen Sea sector, where Thwaites Glacier is located, has been particularly concerning.
The impact of climate change on Antarctica cannot be understated, as human activities that warm the planet have far-reaching consequences on polar ice formations. The loss of ice in Antarctica contributes to rising sea levels, posing a threat to coastal regions worldwide. The choices made today regarding environmental policies and mitigation efforts will determine the rate at which sea levels rise and the extent of coastal flooding in the future.
In conclusion, the new study on Thwaites Glacier provides valuable insights into the potential risks associated with marine ice cliff instability and the glacier’s stability in the face of climate change. While the findings offer some hope for the future of Thwaites, they also underscore the complex interplay of factors driving ice loss in Antarctica. Continued research and monitoring of polar regions are crucial to understanding and mitigating the impacts of climate change on the world’s ice sheets and coastal regions.