The underwater storms in spiral accelerate the melting of the ice shelves of Pine Island and Thwaites, the two most critical Antarctic glaciers for the future of the sea level.
This was revealed by a study published in Nature Geosciences that delved into this phenomenon, which has been little analyzed until now.
Apparently, these oceanic eddies transform the thawing dynamics in Antarctica in real-time.
Eddies and storms that erode glaciers in hours
The underwater storms, technically known as submesoscales, are oceanic eddies that quickly alter their course and cause an intense mixing of waters of different temperatures.
“Imagine them as small water eddies spinning at high speed, like when water is stirred in a cup,” explained Mattia Poinelli, from the University of California.
However, in the ocean, these phenomena reach up to 9.6 kilometers in extent.
They form when warm and cold water meet, generating turbulences similar to those that occur in the atmosphere.
The eddies move under the ice shelves, removing warmer water from the ocean floor. This increases the melting of the vulnerable ice base.
“We are observing the ocean in very short time scales, similar to those of the weather. This is unusual for Antarctic studies,” noted Yoshihiro Nakayama, assistant professor of engineering at Dartmouth College.
A self-reinforcing cycle
The scientists determined that the underwater storms contributed, along with other short-duration processes. They added to cause 20% of the melting in nine months.
“Quantifying the precise contribution of the storms alone is difficult due to their chaotic nature,” acknowledged Poinelli.
However, he emphasized that “these events seem to play an important role in short periods.”
The most concerning finding is the existence of a feedback cycle. When the storms erode the ice, the amount of freshwater and cold water entering the ocean increases.
This mixes with the saline and warmer water from the bottom, which increases the turbulence and accelerates the melting rate.
“This positive feedback cycle could gain intensity in a warmer climate,” warned Lia Siegelman, a scientist at the Scripps Institution of Oceanography.
Antarctic storms, a risk for glaciers and sea level
The Thwaites glacier, nicknamed the “glacier Doomsday” (of Doomsday), is considered the most dangerous in the world. This is due to its ability to abruptly raise ocean levels.
The Antarctic ice shelves play a vital role:
- They contain the glaciers and slow their flow into the ocean
- They act as a plug for the West Antarctic ice sheet
- They prevent the massive collapse of continental ice
The collapse of Thwaites would be especially alarming, as it contains enough water to raise sea levels by more than 60 centimeters.
If it becomes completely destabilized, the sea level could rise up to three meters, affecting millions of people in coastal areas.
Tiago Dotto, a researcher at the UK’s National Oceanography Centre, described the magnitude of the melting revealed by the study as “astonishing”.
“The study is important because it sheds light on the role of small oceanic formations in the melting of the base of the ice shelves,” he stated.
The urgency for more real data
Because the Antarctic ice shelves are among the most remote and difficult-to-access places on the planet, scientists largely rely on computer simulations.
“These types of studies are intriguing, but they are computer models,” highlighted David Holland from New York University. Therefore, he emphasized the urgency of obtaining more real data.
Ted Scambos, from the Earth Science and Observation Center at the University of Colorado in Boulder, emphasized that “hundreds of factors have a similar importance to the decomposition of the ice sheet.”
“Studying these small-scale oceanic phenomena is the next frontier. This is fundamental regarding the interactions between the ocean and the ice,” concluded Siegelman.
The scientist made it clear that it is imperative to collect more data over seasons and years. This is necessary to fully understand how underwater storms vary.
