When massive blocks of ice detach from glaciers, it is known as calving. This process is one of the main ways that glaciers lose mass, and has long been a dramatic visualization of changes in ice sheets. There have been some enormous calving events that can destabilize ice shelves, and are a major source of uncertainty when it comes to forecasting future increases in sea levels. In 2017, an iceberg roughly the size of Delaware, which was around 5,800 square kilometers (2,239 square miles) was calved in Antarctica, for example.
The pace of glacier loss has been increasing in recent years as the planet gets warmer, but extreme calving events are still relatively rare, and they are difficult to predict. A new study has investigated the links between climate change and the calving of massive icebergs.
In this work, the researchers assessed focused on smaller datasets, and zeroed in on the one largest iceberg that formed in every year between 1976 and 2023. Some of the icebergs that were calved were as much as 11,000 square kilometers (4,247 square miles). This work showed that the surface area of the annual largest iceberg actually decreased slightly over time. The rate of extreme calving events was also not found to increase. The study has been reported in Geophysical Research Letters.
The study authors suggested that such massive calving events may not be a direct consequences of climate change.
Other research in unrelated studies has shown that the rate of smaller calving events has increased, however. Antarctica's ice is being lost in a process akin to 'death by a thousand cuts,' the study authors noted. Smaller calving events could be a much bigger driver of Antarctica ice loss.
There could be larger calving events in the future as well, the study noted. Although an increase in the frequency of extreme calving events is not anticipated, an unusually gargantuan iceberg could form at some point, which could be about the size of Switzerland at around 38,827 square kilometers (14,991 square miles).
Sources: Eos, Geophysical Research Letters
