According to new research, Antarctic glaciers may be more susceptible to changes in sea temperature than previously believed.
Under the enormous Thwaites glacier, the British Antarctic Survey and the US Antarctic program placed sensors and an underwater robot to track melting.
Thwaites, a glacier the size of Britain, is among those undergoing rapid change.
Scientists are extremely concerned about its vulnerability to climate change because if it melted completely, the sea levels would rise by half a meter.
According to the new research, even small amounts of melting have the potential to advance a glacier's eventual disappearance.
One of the largest investigations ever conducted anywhere on the White Continent includes the joint survey at Thwaites.
The glacier's "grounding line," or the location where ice flowing off the land and along the seabed floats up to form a huge platform, has receded 14 km since the late 1990s.
Due to the seabed's landward slope, this grounding line retreat is already occurring in some locations at a rate of over a kilometer per year.
Scientists from the British Antarctic Survey (BAS) dropped sensors into the water below during the new study.
They discovered less melting than they had anticipated at those higher temperatures; a layer of fresh water was protecting against further losses even though warmer water circulates beneath the shelf.
Worryingly, they also learned through computer modeling that a glacier's retreat was not primarily influenced by the amount of melting.
The low melt rate is good, but how the melt rate changes is more important, according to BAS oceanographer Dr. Pete Davis. "We need to speed up the melting process to force an ice shelf out of equilibrium. Therefore, even a slight increase in the melt rate has the potential to cause rapid retreat. ".
The observations that showed less melting than anticipated came from flat, uniform areas of the glacier's underside.
Images taken by the underwater robot Icefin for the US Antarctic program during the same joint survey, however, revealed that situations were frequently much more complicated.
According to Cornell University researcher Britney Schmidt, who controlled Icefin under Thwaites using a video monitor and a games console controller, "what we could see is that instead of this kind of flat ice that we had all pictured, there were all kinds of staircases and cracks in the ice that weren't really expected.".
The British Antarctic Survey (BAS) used a hot-water drill to drill a small hole through 600 meters of ice so they could lower the torpedo-shaped Icefin beneath Thwaites. After that, the winched down the tethered sub to start its exploration.
Dr. Schmidt's group made five separate dives, bringing the robot all the way up to the grounding line of the glacier.
Icefin's onboard sensors revealed that the influx of warm water from the wider ocean is specifically eroding the bottom of Thwaites in these locations.
According to Dr. Schmidt, "basically, the warm water is getting into the weak spots and making them even weaker.". "What this enables us to do now is incorporate this kind of data into our predictive models to comprehend how and when the ice shelf will break down. ".
Dr. Davis added that the Thwaites glacier's lessons are almost certainly applicable to all the other retreating glaciers in the area.
This week, the scholarly journal Nature published two papers outlining the research. Both of them concentrate on the borehole profilers, while one on Icefin.
Prof. David Vaughan, the former director of science at BAS and one of the authors on the Icefin paper, passed away last week, according to the polar agency.
Prof. Vaughan had established a strong reputation as one of the top glaciologists in the world over the course of more than 35 years.
He supported the UK-US Thwaites project and co-led it until he had to step down due to illness.
His final excursion south was to visit the research that was the subject of the two papers published on Wednesday.
Professor Helen Fricker, of the University of California, San Diego's Scripps Institution of Oceanography, is currently in Antarctica. David was a brilliant, considerate, and charismatic scientist who served as an inspiration to a lot of people, she said. He was a pioneer in the field and provided crucial geophysical insights into the Antarctic ice sheet's evolution.
He led with class, grace, humor, and compassion and actively encouraged young scientists, particularly those from underrepresented groups. He was a true hero in the field of polar science and will be sorely missed. ".
