A huge cavity that is two-thirds the size of Manhattan and nearly the height of the Chrysler Building is growing at the bottom of one of the most dangerous glaciers in the world – a discovery NASA scientists called "disturbing."
The hole, which is nearly 300 meters high, was seen during the space agency's study of the disintegrating Thwaites glacier in western Antarctica, NASA said on Wednesday. It is large enough to contain 14 billion tonnes of ice, most of which has melted in the last three years.
Thwaites Glacier, one of the most difficult places to reach on Earth, accounts for about 4 percent of the global sea's rise. Scientists have long predicted that the glacier was not well attached to the underlying rock bed and hoped to find some gaps.
However, the immense size and rapid growth rate of the Thwaites hole were called "disturbing" and "surprising" by researchers.
"[The size of] a cavity under a glacier plays an important role in melting, "said lead study author Pietro Milillo. As more heat and water under the glacier, it melts faster. "
The Thwaites have enough ice to raise the world's ocean just over 2 feet and protect neighboring glaciers that are capable of raising sea level by another 8 feet if all ice is lost.
The cavity was seen using NASA's IceBridge Operation, an airborne campaign begun in 2010 that studies connections between the polar regions and the global climate.
Researchers hope the new findings will help others who are preparing for field work in the area to better understand ice-ocean interactions.
"The findings highlight the need for detailed observations of the bottom of the Antarctic glaciers to calculate how quickly the global sea level will increase in response to climate change," according to the NASA Jet Propulsion Laboratory study.