Study reveals behavior of ice cliffs in Antarctica

With rising temperatures, the ice shelves that support the edges of the Antarctic ice sheet are melting and calving at record rates, leaving solid ice cliffs behind. The stability of these exposed cliffs can influence how Antarctica fragments and contributes to global sea-level rise ².

Scientists had assumed that the stability of an ice cliff depends mainly on its height. Cliffs taller than 100 meters should collapse under their own weight, exposing taller and inner cliffs that would also collapse. However, a recent study challenges this idea ².

Researchers from MIT and the Woods Hole Oceanographic Institution (WHOI) analyzed more than 15,330 ice cliffs in Antarctica, monitored by satellites over four years. They observed how these cliffs and the ice sheet evolved over time. They found that the cliffs that collapsed did so more quickly than scientific models predicted. However, these cliffs stabilized rapidly after collapse, without continuing to erode the ice sheet ^1,2.

The study also revealed that the height of the cliffs is highly correlated with the thickness of the mélange, water depth, and the presence of crevasses. These factors influence the stability of the cliffs and the speed at which they calve ¹.

Challenges and next steps

The results suggest that model projections may underestimate subannual calving rates of cliffs. However, potential instability depends on other factors besides the height of the cliffs. The research highlights the need to consider multiple parameters to predict the behavior of ice sheets ¹.