According to NASA, this is a "disturbing" discovery.
Scientists from the US agency have found a gigantic cavity growing at "an explosive rate" at the bottom of the Thwaites glacier in western Antarctica.
The hole is 350 meters high, 4 km wide and 10 km long, and it is estimated that it contained 14 billion tons of ice.
The huge fissure is an indication that the glacier's mass is disintegrating and could cause a rise in sea level faster than expected.
"The size of the cavity under a glacier plays an important role in its melting," explained Pietro Millilo, a researcher at NASA's Jet Propulsion Laboratory (JPL).
The Thwaites Glacier is similar in size to the state of Florida (about 170,000 square km) and is currently responsible for about 4% of the rise in sea level globally.
If the entire glacier melted, the water level would rise by about 65 centimeters.
But its collapse would in turn affect other glaciers that, when completely melted, would increase the ocean level by another 2.4 meters.
Between the years 1900 and 2016, the sea level has risen between 16 and 21 cm.
Thwaites is one of the most vulnerable glaciers in Antarctica, and scientists seek to understand the mechanisms that explain their changes.
A key factor is determining the boundary or line where the glacier ceases to be on solid rock and floats on the ocean.
In the same way that a stranded ship can float again when its cargo is removed, a glacier that loses ice can float on the rock to which it was previously attached, NASA explained in a statement.
"In the eastern part of the glacier, that border is made up of channels one km wide, which act like fingers that extend under the glacier to melt it from the bottom," Millilo said.
"Thanks to a new generation of satellites, we can finally see what is happening in detail."
The cavity was revealed by radars that penetrate the ice with their signals and are part of NASA's IceBridge operation ("Ice Bridge"), which studies the connections between the polar regions and the global climate.
The cavity in the Thwaites Glacier is 350 meters high, 4 km wide and 10 km long.
NASA noted that the Thwaites glacier is one of the most difficult to reach places on Earth, which since this year is being investigated by scientists from the United States and the United Kingdom.
The initiative, called the International Thwaites Glacier Collaboration, will last five years and is the largest joint mission between the two countries in Antarctica in more than 70 years.
Antarctica as a whole is losing ice at a rate six times faster than four decades ago, according to a study published by NASA in the journal of the United States Academy of Sciences, Proceedings of the National Academy of Sciences.
The frozen continent lost about 40 billion tons of ice each year between 1979 and 1989.
But that number rose to about 252 billion tons of ice annually as of 2009, according to the study.
Aerial view of Thwaites Glacier
IMAGE SOURCE, NASA
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