Giant iceberg breaks off Antarctic glacier
Published Thursday, February 13, 2020 2:12AM EST
The Pine Island Glacier recently spawned an iceberg over 300 square kilometres that very quickly shattered. This image, captured Tuesday by the Copernicus Sentinel-2 mission, shows the freshly broken bergs in detail. (European Space Agency)
A story about a glacier shedding mass at the edge of the world, threatening to raise ocean levels and potentially contribute to untold environmental change.
Sound familiar? That's because it probably is. But if you weren't paying attention before, it probably is worth doing so now.
An iceberg has broken off Pine Island Glacier (PIG) on the edge of Antarctica, according to satellite images taken Tuesday by the European Space Agency (ESA).
And it's a big one. At more than 300 square kilometres (116 square miles), the iceberg was almost as big as Atlanta and roughly the same size as Malta -- although it very quickly fragmented.
"What you are looking at is both terrifying and beautiful," Mark Drinkwater, head of the Earth and Mission Sciences Division at the ESA, told CNN.
"It is clear from these images (that the Pine Island Glacier) is responding to climate change dramatically," he added.
While icebergs calving from glaciers is a natural process, Drinkwater made it clear that the rate of melting and calving being seen in West Antarctica is greater than anything observed in the satellite record.
He pointed to an "imbalance" in the glacial system, which meant the impacts of warming temperatures, warmer ocean water and declining of snowfall were not allowing the glacier to replenish itself.
Pine Island Glacier, along with its neighbor Thwaites Glacier, effectively act as arteries connecting the West Antarctic ice sheet to the ocean. The region holds enough ice to raise global sea levels by 1.2 metres, or 4 feet, according to NASA.
Earlier this month, the ESA's Copernicus Sentinel satellite mission captured cracks appearing and "rapidly" growing over a number of days.
And only a few days later, the glacier, also referred to as PIG, "spawned piglets," ESA said -- in a process known as calving -- and "many large" icebergs were formed. The largest of them was so big, it was even given a name: B-49.
Drinkwater suggested this was due to the continuing instability of the ice shelf, with greater levels of warm water under the glacier causing even greater disruption at the base of it.
This phenomenon of calving isn't new for Pine Island Glacier, according to the ESA.
Two large rifts in PIG were spotted in 2019 and scientists have kept a close eye on the cracks and changes.
But it has been losing ice over the past 25 years. "Since the early 1990s, the Pine Island Glacier's ice velocity has increased dramatically to values which exceed 10 meters (or 30 feet) a day," the space agency said in a news release.
"Its floating ice front, which has an average thickness of approximately 500 meters, has experienced a series of calving events over the past 30 years, some of which have abruptly changed the shape and position of the ice front," the ESA said.
The changes to the glacier have been mapped by ESA-built satellites since the 1990s, with calving events occurring multiple times since 1992.
The satellite images come as a research base on the tip of Antarctica recorded the hottest temperature on record for the continent. Last week, a region in the North West reached over 18 degrees Celsius (65 degrees Fahrenheit) -- almost a full degree higher than the previous record from five years ago.
"Sea level rise can have huge economic and societal impacts. ... We have been crying out for instruments like this," Drinkwater said. "These satellites are showing how much mass has been lost."
He said he hopes the images would continue to be an "eye in the sky" to monitor glacial change and improve public knowledge.