One of the reasons for the importance of the existing ice shelves in the Antarctic Ocean is that they act as a brake on the movement of the Antarctic glaciers. If these platforms did not exist, the ice from these glaciers would move to the ocean more quickly and melt more easily, which would have a major impact on the rise in water levels on a global scale.
In recent years, a reduction in surface area has been observed at various points on the Antarctic ice shelves and several studies warn that climate change (with increased water temperature) is related to this phenomenon and may increase its scope in the coming decades.
Another effect most likely related to climate change is the alterations in ocean currents, observed in various areas of the planet. A study led by experts from Hokkaido University (Japan) has updated data on this phenomenon and concludes that current alterations in ocean currents in the Antarctic region endanger the stability of existing ice shelves. Consequently, the collapse (decrease) of these large ice sheets would facilitate the loss of ice from the glaciers and would have effects on the rise in sea level. The results of this new research have been published (April 11) in the journal Nature Communications.
The authors have observed that the interaction between ocean currents and water from the bottom of the ocean influences the arrival of warm water to the surface (or at lower depths). “This process is accelerating and substantially contributing to the melting of ice shelves in the Amundsen Sea, West Antarctica. These ice shelves are rapidly destabilizing and contributing to sea level rise,” highlights the summary of results. from the team led by Taewook Park and Yoshihiro Nakayama, involving experts from the Korea Polar Research Institute, Hokkaido University and Seoul National University.
The authors have used advanced ocean modeling techniques to investigate the forces that affect ice shelves and cause them to weaken. Unlike previous hypotheses that linked ice shelf melting primarily to winds over the Southern Ocean, this study highlights the important role that interactions between meandering ocean currents and the ocean floor play in driving the melting process. .
The Pine Island and Thwaites ice shelves are among the most rapidly changing in Antarctica and are of particular interest due to their vulnerability to warming ocean waters. They act as huge barriers that prevent the glaciers behind them from flowing into the ocean. However, its rapid melting and possible collapse represent a significant threat to coastal communities around the world due to the resulting rise in global sea level, the summary of results published by Hokkaido University indicates in an educational way.
The study focused on the role of a layer of warm water beneath the frigid surface waters, known as “modified circumpolar deep water,” in the melting of these ice shelves. “The intensity and trajectory of ocean currents surrounding ice shelves directly govern the influx of warm water, intricately determining its melting rate,” explains Professor Taewook. This shows the importance of the ocean in understanding and addressing the impacts of climate change.
The researchers paid attention to the “thermocline depth,” which is the depth of the interface between warmer deep waters and colder surface waters. Variations in the depth of the thermocline significantly affect the influx of warm water onto ice shelves. Until now, intensified westerly winds north of the Amundsen Sea were believed to drive ocean currents across the shelf, bringing warmer water into the ice shelf’s cavities. This phenomenon is particularly pronounced during El Niño events, according to the results of the new study.
