An iceberg twice the size of New York City will break off of Antarctica’s Brunt Ice Shelf, as a result of two growing fissures in the ice shelf that are on course to meet. NASA is tracking the process, which could take anywhere from days to months, according to the Washington Post.
The two fissures are now just over 1.5 kilometers apart. At over 1700 square kilometers, the size of the resulting iceberg would actually be smaller than other recent breakaways, including one in 2017 that was twice the size of Delaware at 5700 square kilometers. While it would be far from the largest iceberg to break away from Antarctica, it would be largest to break off of the Brunt Ice Shelf in a century.
The new fissure is also another sign of how climate change may be destabilizing Antarctic ice shelves, and it poses a potential threat to British research that has been conducted in the area since 1956. Britain’s nearby Halley Research Station has moved many times over the years, most recently in 2017, to avoid being cut off by one of the two fissures.
According to the British Antarctic Survey, there is no direct threat to the researchers in their new location, inland from the potential rift. But a spokesperson said they are monitoring the integrity of the shelf, and have ceased operations during the Antarctic winter, during which darkness and snowfall would make any potential rescue attempts much more difficult.
The long-term stability of the ice shelves has profound implications for rising sea levels around the world. A report last year warned that Antarctic ice is melting faster than ever, accelerating threefold in just the last five years, and threatening to drive sea level rise that could affect the world’s coastal cities.
Scientists currently warn that melting Antarctic ice could alone lead sea levels to rise over 25 centimeters by 2070.
But scientists caution that it’s difficult to attribute single events to climate change, and that iceberg calving is a natural process in Antarctica.
“I don’t think you can link one calving event to climate change,” said Helen Fricker, a glaciologist at the Scripps Institution of Oceanography. “That isn’t to say Antarctica isn’t undergoing rapid changes that are linked to climate change. But it’s in another region of Antarctica.”
On the western side of the continent, warming water temperatures are thinning ice shelves.
Scientists have only been observing ice shelves for about a century, and researchers are uncertain whether calving is speeding up on the Brunt shelf. They also don’t know why one of the fissures began growing for the first time in over 30 years.
According to NASA research scientist Christopher Shuman:
“The impact on the area is that these rifts have reactivated, and we’re not sure why. A new rift formed in what was thought to be a pretty stable ice shelf.”