New Research Provides Insights into How Antarctic Ice Loss Has Accelerated
Recent research sheds light on the alarming acceleration of melting in Antarctica, indicating critical changes in the pinning points that anchor glaciers in place. Scientists, led by Dr. Bertie Miles from the University of Edinburgh, analyzed the transformation of bumps on the ice surface, representing pinning points, which play a crucial role in holding back glacier movement.
The study, published in the journal Nature, utilized a unique approach by examining the evolution of these pinning points over the past five decades. The researchers scrutinized the Antarctic ice shelves, which constitute 75% of the continent's coastline. These floating fronts of glaciers act as a braking mechanism against the flow of ice into the ocean, with pinning points serving as anchors.
The analysis revealed a concerning trend: half a century ago, minimal changes were observed in these pinning points; however, since 2000, over a third of them have significantly decreased in size, signifying a substantial escalation in melting. The pinning points can get caught in place, particularly in areas with shallow seafloors, impeding glacier ice flow and influencing sea-level rise.
"As we go through the decadal snapshots, you see these bumps in general getting smaller and sometimes completely disappearing," Dr. Miles told BBC News. "The thing to remember is that once an ice shelf loses contact with a pinning point, it's very difficult to regain contact, because you get a dynamical response in the ice: it starts to speed up and the grounding line - the line where the glacier is still touching the seabed - starts to retreat.”
Dr. Miles utilized the Landsat satellite imagery archive from 1973 to 2022 to create cloudless mosaics of Antarctica's coastline and track the changes in pinning points. The findings indicate that, over time, a growing percentage of these bumps are diminishing, and once lost, the contact with pinning points is challenging to regain.
The significance of this study lies in its departure from traditional methods of assessing ice shelf thinning. While satellite altimeters are commonly used for this purpose, offering a reliable technique spanning the last 30 years, the Landsat images allowed the researchers to extend observations by an additional two decades. This extended historical perspective provides a clearer understanding of when and where Antarctica's ice loss accelerated.
