Antarctica’s ice shields are being measured in detail for the first time, revealing a clear link to global sea level rise. Since 1997, surface area reductions have occurred on more than 40 ice platforms along the coast, with many showing substantial loss. Researchers report that 28 of these platforms shed more than half their ice during the same period, signaling accelerated change in the region.
A broad view of 68 of the continent’s 162 floating shelves indicates notable decline. The study, published in a respected science journal, notes that 29 shelves expanded between 1997 and 2021, while 62 remained largely unchanged and three displayed mass loss. While these shifts are important, scientists caution that the picture is not yet a clear trend across all shelves. Science developments are ongoing.
The meltwater from these large inland glaciers ultimately reaches the sea. Climate researchers point to Antarctica and nearby Greenland as major sources of sea level rise that could persist for decades, possibly centuries, if the current pace continues. The consequences extend beyond ocean height to changes in ocean density and salinity, with potential impacts on marine life and broader ocean systems.
“Knowing exactly how much ice was lost from these floating shields helps illuminate how Antarctica has evolved”, commented a leading ice scientist from the University of Colorado.
The study provides new details about freshwater melt in the Amundsen Sea, a critical region for sea level rise in Antarctica. This not only affects how high the ocean stands but also alters its density and salinity, with implications for marine biodiversity and other ocean processes.
The role of frozen platforms
Ice shelves behave like shields, floating extensions that slow the flow of large glaciers into the ocean. The study’s lead author emphasizes the importance of understanding how these shields influence glacier movement toward the water.
The researchers estimate that Antarctic ice shelves lost about 8.3 trillion tons of ice over a 25-year span, roughly 330 billion tons per year. This rate aligns with earlier estimates and reinforces concerns about regional stability.
The study’s lead author, glaciologist Benjamin Davison of the University of Leeds, notes that the total ice loss is less about a single number and more about regional patterns. The findings highlight strong losses on the Antarctic Peninsula and four western glaciers, each shedding more than a billion tonnes.
Some areas experienced drastic reductions; for example, the Wordie Ice Shelf near the peninsula has lost extensive mass since 1997, turning into only a fragment of its former self. Larsen A and Larsen B shelves also show steep declines, while Larsen C lost a large portion of its ice mass. The overall pattern underscores the uneven nature of recent changes across different shelves.
The most dramatic loss has occurred at the Thwaites Ice Shelf, a key part of a major glacier system. Thwaites has shed roughly 70 percent of its mass in the Amundsen Sea since 1997, a figure that alarms many observers because of its influence on regional stability and global sea levels.
Davison notes that shelves on the eastern side of the continent show increases in area less quickly than the western shelves melt, a pattern linked to prevailing weather that keeps eastern waters relatively cooler. Still, the trend on the western side continues to drive overall change.
Reference work: Science Advances, 2021, doi: 10.1126/sciadv.adi0186 (citation: Science Advances, 2021). Findings summarized by the journal and subsequent analyses provide a clearer view of how these floating platforms shape Antarctic dynamics.
This evolving picture underscores the need for ongoing monitoring of ice shelves and their responses to climate shifts across the region (citation: Antarctic Climate Research Group). The research illustrates how regional processes can influence the global climate system and emphasizes the value of continued international collaboration in polar science.