Antarctica has lost 12,820 square kilometers of grounded ice over three decades—an area nearly 10 times the size of Greater Los Angeles—according to new research that reveals accelerating retreat threatening coastal cities worldwide.
The ice sheet has been retreating from the grounding line at an average rate of 442 square kilometers per year, according to the study published in Proceedings of the National Academy of Sciences. The grounding line marks where ice sheets lift off bedrock and begin floating on ocean water, making it a critical indicator of ice sheet stability and future sea level rise.
West Antarctica Bears Heaviest Losses
While 77 percent of Antarctica's coastline has remained stable since 1996, the remaining 23 percent is experiencing aggressive retreat, concentrated primarily in West Antarctica's vulnerable glaciers. Eric Rignot, UC Irvine Distinguished Professor and NASA Jet Propulsion Laboratory senior research scientist, led the multinational research team.
"Where warm ocean water is pushed by winds to reach glaciers, that's where we see the big wounds" in Antarctica, Rignot explained. Smith Glacier has retreated 42 kilometers, Pine Island Glacier 33 kilometers, and the notorious Thwaites Glacier—often called the "Doomsday Glacier"—has pulled back 26 kilometers. The Amundsen Sea and Getz sectors show retreat ranging from 10 to 40 kilometers.
Implications for Global Sea Level Rise
The findings provide crucial benchmarks for ice sheet models projecting future sea level rise. Climate scientists emphasize that models must replicate this 30-year observational record to demonstrate credibility before being used for coastal planning.
