A massive cavity that is two-thirds of the size of Manhattan and almost the height of the Chrysler Building is growing at the bottom of one of the world's most dangerous glaciers – a discovery that NASA scientists called "disturbing."
The hole, which is nearly 1,000 feet tall, was seen during the space agency's study of the disintegrating Thwaites Glacier in West Antarctica, NASA said Wednesday. It's big enough to contain 14 billion tons of ice, most of which has melted over the last three years.
Thwaites Glacier, one of the most difficult places to reach on Earth, is responsible for around 4% of the global sea rise. Scientists had long predicted the glacier was not tightly attached to the bedrock underneath it and expected to find some gaps.
Yet the immense size and fast-moving growth rate of the hole in Thwaites was called both "disturbing" and "surprising" by researchers.
"[The size of] a cavity under a glacier plays an important role in melting, "said the study's lead author Pietro Milillo." As more heat and water get under the glacier, it melts faster. "
Thwaites holds enough ice to raise the world's ocean just over 2 feet and backstops neighboring glaciers that are capable of rising sea levels and an additional 8 feet if all ice was lost.
The cavity was seen using NASA's Operation IceBridge, an airborne campaign starting in 2010 that studies connections between the polar regions and the global climate.
Researchers hope the new findings will help others prepare for fieldwork in the area to better understand the ice-ocean interactions.
"The findings highlight the need for detailed observations of the Antarctic glaciers' bottom in calculating how fast global sea levels will rise in response to climate change," according to the study by NASA's Jet Propulsion Laboratory.