This gaping polynya, which measures an area equivalent to the Netherlands, opened right in the middle of a sea which would have otherwise been completely covered in thick ice. Now that it is back, scientists have more sophisticated resources that enable them to improve their observations.
Sea ice and clouds blanket the Weddell Sea around Antarctica in this satellite image from September 25, 2017.
A preliminary analysis run by American scientists suggests that the Weddell Polynya should not occur again because of climate change at all.
"At that time, the scientific community had just launched the first satellites that provided images of the sea-ice cover from space", Dr Torge Martin of the GEOMAR Research Division explains of its initial discovery many decades ago.
The going theory, Moore said, is that ocean currents are lifting warmer waters from the ocean's depths up to the surface, where it's melting the ice.
Scientists are investigating how a polynya in Antarctica's Weddell Sea formed again after disappearing for 40 years. The Weddell Sea polynya is like "an oasis" for Antarctic sea mammals, says scientist Kent Moore.
It's larger than The Netherlands, and almost the size of Lake Superior.
As these ice gaps typically form in coastal regions, however, the appearance of a polynya "deep in the ice pack" is an unusual occurrence.
Polynyas allow heat to escape the ocean, cooling the top layer of water as it becomes colder and denser - allowing more warm water to rise and keep the hole open.
While its reappearance has spurred some questions, the experts say the processes driving it are relatively well- understood.
"This is like opening a pressure relief valve-the ocean then releases a surplus of heat to the atmosphere for several consecutive winters until the heat reservoir is exhausted", Lati added. & Gnanadesikan, A. Global atmospheric teleconnections and multidecadal climate oscillations driven by Southern Ocean convection.
Simulated temperature development in the area of the polynya is illustrated above.
Actually, this type of phenomena can be termed as polynya- an area of open water completely enclosed by sea ice. "The better we understand these natural processes, the better we can identify the anthropogenic impact on the climate system", said Professor Latif.
Blaming climate change for this giant hole is one alternative that the scientists have but according to Moore, that would be a premature thing.