Scientists have gained a more precise understanding of the timing and location of Antarctica's ice melting by studying changes in the formations of bumps on its surface, which indicate where glaciers are anchored. Over the past 50 years, there has been a significant increase in the reduction of these frozen moorings, known as "pinning points," with more than a third diminishing in size since 2000. This research, detailed in Nature, highlights the escalating impact of Antarctic ice loss on global sea-level rise.

The focus of the study was on the ice shelves surrounding 75% of Antarctica's coastline, which act as crucial barriers, impeding the flow of ice into the ocean. However, many of these shelves, particularly in the western part of the continent, are thinning due to the intrusion of warm water. This thinning weakens their ability to restrain the movement of glacier ice behind them.

Using data from the Landsat satellite series, researchers analyzed changes in the shape of these pinning points over three periods from 1973 to 2022. They observed a trend of decreasing bump sizes, indicating ice shelf thinning and weakening. This approach offers insights into ice loss patterns beyond the limitations of traditional satellite techniques, which only cover the past three decades.

By extending the observation period, the study revealed that significant ice loss was already occurring in certain regions, such as Pine Island and Thwaites glaciers in West Antarctica, as early as the 1970s. This contrasts with other areas, like the Amundsen Sea sector, where thinning became evident only in the 1990s.

The significance of pinning points in providing structural support to ice shelves was highlighted by Prof. Helen Fricker from the Scripps Institution of Oceanography. She compared them to flying buttresses supporting buildings, emphasizing their role in propping up the ice sheet and the consequences of their destabilization.