At a Glance

The cavity is two-thirds the size of Manhattan.The NASA-led team were surprised by the size of the cavity, which once contained 14 billion tons of ice. The cavity highlight the need for further observations to have a better idea of just how fast sea levels will rise.

A massive cavity two-thirds the size of Manhattan was discovered growing at the bottom of Thwaites Glacier in West Antarctica, which does not bode well for the survival of the disintegrating glacier.

Using ice-penetrating radar from NASA's — an airborne campaign launched in 2010 that studies connections between the polar regions and the global climate — the NASA-led team discovered the hole that's big enough to have contained 14 billion tons of ice.

"We have suspected for years that to the bedrock beneath it," co-author Eric Rignot of the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, California, said in a press release. "Thanks to a new generation of satellites, we can finally see the detail."

The researchers say the Florida-sized cavity under the glacier highlights the need for more detailed observations of Antarctic glaciers to better understand just how fast sea levels will rise as a result of climate change, according to a press release.

"Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades," Rignot said.

(MORE: Greenland's Ice Sheet Melt Rate Is 'Off the Charts,' Study Says)

Lead author Pietro Milillo of JPL says the size of the cavity under the glacier "plays an important role in melting."

"As more heat and water get under the glacier, it melts faster," he said.

Milillo told weather.com that the discovery was also surprising because "it highlights that ice-ocean interactions are more complex than previously understood."

Thwaites glacier is one of the most difficult places on Earth to reach. It is currently responsible for approximately 4 percent of global sea level rise and holds enough ice to raise the world ocean a little over 2 feet. Should Thwaites and other neighboring glaciers melt, sea levels would rise up to 10 feet, according to the press release.

While Thwaites is certainly a difficult place to reach, a five-year expedition by the to study the glacier will begin this summer. The collaboration includes the U.S. National Science Foundation and British National Environmental Research Council.