A research team from the University of Colorado Boulder has identified a remarkable phenomenon causing the rapid retreat of the Hektoria Glacier in Antarctica. This glacier has experienced the fastest recorded retreat of any grounded glacier, losing approximately half of its mass over a two-month period from January to March 2023.
Monitoring efforts led by research affiliate Naomi Ochwat revealed that the Hektoria Glacier retreated nearly 15.5 miles during this brief timeframe. Intrigued by the glacier’s unprecedented movement, Ochwat sought to understand the underlying mechanisms contributing to this accelerated retreat.
Significance of the Findings
Ochwat emphasized that the processes observed in the Hektoria Glacier could have serious implications for ice sheet dynamics across Antarctica. “If this process were to occur on a much larger glacier, it could significantly affect how quickly the ice sheet changes,” she stated. This potential for rapid change raises concerns about contributions to sea level rise.
While the Hektoria Glacier is relatively small by Antarctic standards, measuring about 8 miles across and 20 miles long, its retreat has revealed critical insights. According to senior research scientist Ted Scambos, the glacier’s retreat equates to only fractions of a millimeter in terms of sea level rise. However, the study’s findings prompt further investigation into other regions of Antarctica that may exhibit similar rapid retreat characteristics under comparable conditions.
The glacier was previously supported by a layer of fast ice, which is ice that adheres to the coastline and stabilizes the glacier’s floating ice tongue. As warmer conditions caused this thin layer of fast ice to break away, the glacier’s ice tongue began to disintegrate in the ocean.
Unique Calving Process Discovered
The research team discovered that the unique calving process occurring at the ice plain beneath the glacier was the primary driver of its rapid retreat. As water thinned the glacier, the ice resting on bedrock began to rise, creating pressure that led to the breaking off of large ice slabs. Scambos described this phenomenon as akin to “dominoes falling over backwards,” highlighting its unexpected nature.
“The important aspect is this mechanism of the ice plain that thins and begins to float, causing rapid retreat,” Ochwat noted, emphasizing the significance of this newly observed process. This phenomenon had not been seen before and suggests that glaciers resting on ice plains can be easily destabilized.
The team utilized satellite-derived data for their study, including images and elevation data, providing a comprehensive view of the glacier’s condition. Historical records indicate that between 15,000 and 19,000 years ago, glaciers with similar characteristics retreated substantially, offering context to the current findings.
Scambos remarked, “Hektoria’s retreat is the fastest for a grounded glacier that has ever been observed or reported in research.” He urged the scientific community to identify other areas in Antarctica where this calving process might occur, given its implications for global sea levels.
Ice sheets are critical to understanding potential sea level rise, as they store vast amounts of water. According to the National Oceanic and Atmospheric Administration, nearly 30% of the U.S. population resides in coastal areas where rising sea levels can lead to flooding and increased storm hazards. Globally, eight of the ten largest cities are located near coastlines, as noted by the United Nations Atlas of the Oceans.
Ochwat concluded, “What happens in Antarctica does not stay in Antarctica, which is why it’s crucial to research these processes. There is still much we do not know, and the potential consequences could be profound.” This study underscores the urgent need for continued research into glacial dynamics in Antarctica and their far-reaching impacts on global sea levels.
