In a chilly twist to the narrative on climate change, researchers have uncovered that contrary to popular belief, the size of the largest icebergs calving from Antarctica has not increased over the last 47 years. This revelation comes from a team of scientists who’ve been diving deep into satellite data to understand the dynamics of these icy giants.
For those of us who might not know, “calving” is when huge chunks of ice break off from ice shelves to form icebergs. It’s like nature’s own dramatic ice show, but with real stakes for our planet’s climate.
Using a statistical tool called extreme value theory (EVT), which is like a crystal ball for predicting rare events, they looked at every year’s biggest iceberg from 1976 to 2023. Here’s what they found: despite global warming concerns, the data showed no upward trend in the surface area of these behemoths. In fact, the largest iceberg on record, named A68, which calved off the Larsen C Ice Shelf in 2017, was not an outlier when viewed through the lens of this 47-year dataset. It measured about 5,800 square kilometers, which might sound massive, but in the grand scheme of things, it’s just part of the cycle.
To put this into perspective, if you think of Antarctica like a giant ice cube, the parts that break off, or calve, are like the chips that fall off when it starts to melt. But here’s the twist: these chips haven’t been getting any bigger. The study calculates that even a once-in-a-century calving event would only yield an iceberg about the size of Switzerland, or roughly 38,827 square kilometers. That’s a lot, but it’s within what has been seen before.
One might ask, “Why does this matter?” Well, icebergs are not just floating hazards; they’re key players in the Earth’s climate system. When they break off, they not only reduce the size of the ice shelves but also impact ocean circulation and marine life. The researchers noted that while the size of individual icebergs isn’t growing, the frequency of smaller calving events might be increasing, leading to what they describe as “death by a thousand cuts” for the ice shelves.
Reference
MacKie, E. J., Millstein, J., & Serafin, K. A. (2024). 47 Years of Large Antarctic Calving Events: Insights From Extreme Value Theory. Geophysical Research Letters, 51(23), e2024GL112235. https://doi.org/10.1029/2024GL112235
