CU Boulder Team Uncovers Rapid Retreat of Antarctica’s Hektoria Glacier
A research team from the University of Colorado Boulder has identified a process that led to the remarkable retreat of the Hektoria Glacier in Antarctica, which lost approximately half its mass in just two months. This unprecedented retreat, recorded between January 2022 and March 2023, marks the fastest decline of a grounded glacier ever documented.
During a detailed study of Antarctic glaciers, Naomi Ochwat, a research affiliate at CU Boulder, observed that the Hektoria Glacier retreated faster than any other glacier she had encountered. The grounded glacier, which rests on bedrock, retreated an estimated 15.5 miles during the observation period. Ochwat’s investigation aimed to uncover the reasons behind this rapid retreat and its implications for the broader Antarctic ice sheet.
Significance of the Findings
Ochwat noted that if this rapid retreat mechanism were to occur on larger glaciers, it could lead to substantial changes in the ice sheet and contribute to sea level rise. “This process, if it could occur on a much larger glacier, then it could have significant consequences for how fast the ice sheet can change as a whole,” she stated. “That could be problematic for sea level rise.”
The Hektoria Glacier, measuring approximately 8 miles across and 20 miles long, is considered relatively small in the context of Antarctica. While the immediate impact of its retreat on global sea levels is minor—equating to fractions of a millimeter—it’s the underlying mechanisms that have drawn researchers’ attention. Ted Scambos, a senior research scientist at CU Boulder, emphasized the importance of understanding how other regions of Antarctica might react if they experience similar conditions.
Mechanisms Behind the Retreat
The glacier’s retreat was significantly influenced by the loss of fast ice, which previously supported the glacier’s ice tongue. As temperatures rose, this layer of fast ice disintegrated, leading to the destabilization of the glacier’s floating ice tongue. Scambos explained that the incoming water thinned the glacier further, causing the ice resting on bedrock to rise. This resulted in water pushing beneath the glacier, creating pressure that led to the calving of large ice slabs.
Ochwat described the phenomenon as a domino effect, where the breaking off of one slab triggered subsequent collapses. “The mechanism, this ice plain area that thins and starts to float and causes a rapid retreat, is something that hasn’t been seen before,” she noted.
The team’s research utilized satellite-derived data, including images and elevation measurements, to analyze the glacier’s behavior. This approach revealed that the rapid retreat was primarily attributed to the ice plain calving process rather than atmospheric or oceanic factors.
The findings suggest that glaciers resting on ice plains can be particularly susceptible to destabilization. Historical research indicates that during the last ice age, Antarctic glaciers with similar characteristics retreated at rates of hundreds of meters per day, providing context for the Hektoria Glacier’s recent behavior.
The Hektoria Glacier’s retreat, as documented by the CU Boulder team, represents the fastest observed decline of a grounded glacier. Scambos remarked, “It meant this grounded glacier lost ice faster than any glacier had in the past. It’s important to identify various other areas in Antarctica where this process might happen.”
Global Implications
Ice sheets are critical indicators of climate change, as they store vast amounts of water. If released into the ocean, this water can significantly contribute to rising sea levels. According to the National Oceanic and Atmospheric Administration (NOAA), nearly 30% of the U.S. population resides in coastal areas vulnerable to flooding and erosion due to sea level rise. Globally, eight of the ten largest cities are located near coastlines, according to the U.N. Atlas of the Oceans.
Ochwat emphasized the interconnectedness of Antarctic changes and global consequences, stating, “What happens in Antarctica does not stay in Antarctica. It’s really important to research these things because there’s so much we don’t know and so much that could have profound effects for us.”
The CU Boulder team’s findings highlight the urgent need for continued research into glacial dynamics in Antarctica, as understanding these processes is essential for predicting future sea level changes and their potential impact on global populations.
