Antarctica’s vast ice sheet appears flat to the human eye, but beneath the ice lies a surprising landscape of steep mountains, valleys, and meandering rivers. Although the ice rises 13,400 feet above sea level near its center, the true topography beneath is hidden, influencing the ice sheet’s behavior. As climate change accelerates, scientists are uncovering the impact of these hidden rivers, which may play a significant role in the future of Antarctica’s glaciers and sea level rise.
For decades, scientists have used ice-penetrating radar and gravity measurements to explore the landscape under Antarctica’s ice sheets. These surveys have revealed mile-high mountains, valleys, canyons, and subglacial lakes. Water from melting ice, due to geothermal heat and friction, accumulates in these lakes, which are connected by rivers.
These rivers behave in unusual ways, driven by both gravity and the immense pressure of the ice above. In some cases, water can even flow uphill, further complicating the dynamics of these subglacial systems.
Subglacial Rivers Speed Up Glacier Movement and Accelerate Ice Shelf Melting Process
Through years of detailed mapping, researchers discovered that the fastest-moving glaciers in Antarctica, such as the Thwaites and Pine Island glaciers, have extensive subglacial water systems. The presence of water beneath these glaciers reduces friction, allowing the ice to move more quickly.
Additionally, the geothermal heat from the landscape below these glaciers provides the necessary meltwater. This interaction accelerates the movement of glaciers, contributing to the loss of ice from Antarctica and influencing sea level rise.
Hidden Subglacial Rivers in Antarctica Could Accelerate Ice Loss and Sea Level RiseSubglacial rivers also play a role in the rapid melting of ice shelves. These floating ice slabs help slow the flow of glaciers into the ocean. However, unexpected hot spots on the ice shelves, where melting occurs much faster than anticipated, have puzzled scientists.
Recent research uncovered that these melting spots correspond to areas where subglacial rivers flow into the ocean, increasing the rate of melting. The freshwater from these rivers interacts with dense seawater, creating turbulent waterfalls that bring warm, salty water into contact with the ice, accelerating its breakdown.
Underestimating Ice Loss and the Hidden Impact of Subglacial Rivers on Sea Levels
Current computer models used to predict ice loss and sea level rise do not fully account for the effects of subglacial rivers. A study in 2024 revealed that river-driven melting would increase the ice loss from East Antarctica’s Totten Glacier, which holds enough ice to raise global sea levels by 12 feet. The study projected a 30% increase in ice loss by 2100 compared to models that exclude subglacial river effects. This suggests that current predictions of ice sheet collapse and sea level rise may be underestimating future changes.
The new research on subglacial rivers extends beyond static models, considering how these rivers will evolve as the ice sheet thins. By 2100, the flow of water from beneath the Totten Glacier could increase nearly five-fold, leading to an even faster glacier retreat.
The speed of water flow could reach up to three feet per second, similar to fast-moving rivers in the western United States. This increased water flow would amplify the turbulence when it meets ocean water, resulting in accelerated ice melting and thinning, particularly around key regions of the ice shelf.
The accelerated melt due to subglacial river dynamics may destabilize ice shelves and hasten their collapse. Areas of increased water flow create weak points in the ice shelf, potentially causing it to break apart sooner than anticipated. The increased rate of melting could lead to significant shifts in sea level rise projections.
Researchers warn that, as our understanding of subglacial features improves, we may be vastly underestimating the amount of water beneath the ice, leading to more conservative sea level rise predictions. Understanding these processes is critical for accurate future climate models and projections of global sea level changes.
