The sudden disappearance of a giant Antarctic lake that worries scientists

Gigantic lake in Antarctica suddenly disappeared in winter 2019, in a new sample of the effects of climate change in the colder parts of the Earth.

The discovery, made thanks to satellite observations analyzed by an international group of scientists, was presented in a study published in the journal Geophysical research letters.

The researchers believe that the lake, located in the Amery ice floe in East Antarctica, contained between 600 and 750 million cubic meters of water: more than all the water in Sydney Harbor or about twice the volume of San Diego Bay.

According to scientists, the huge reservoir probably became too heavy for the ice cap that supported it.

“We believe that the weight of the water accumulated in this deep lake has opened a crack in the pack ice below the lake, a process known as hydrofracture, which causes the water to flow into the ocean below, ”he told media. Scientific alert the glaciologist Roland warner, University of Tasmania.

According to satellite images, the lake emptied in three days, with a loss of water comparable to the flow of Niagara Falls, scientists say.

The phenomenon alarms scientists because when these lakes cross unstable ice shelves, this water is added directly to the volume of water in the ocean, which in turn directly impacts sea level rise.

NASA’s ICESat-2 satellite measurements also recorded changes in sea ice elevation due to water displacement, the affected region surrounding the lake rising up to 36 meters.

The increasing appearance of meltwater lakes and streams on the surface of Antarctica is widely regarded as evidence of climate change. Therefore, the researchers say that while at the moment we do not yet know if the hydrofracture events are linked to global warming, we must continue to study the phenomenon.

“The melting of Antarctica’s surface is expected to double by 2050, raising concerns about the stability of other ice shelves.”, write the researchers in their study, noting that “Processes such as hydrofracture and bending remain little studied, and ice cap models still do not include a realistic treatment of these processes.”

After the lake disappeared in winter 2019, the lake started to fill again when the thaw resumed in the summer of 2020, reaching a maximum flow of over 1 million cubic meters of water per day flowing into the frozen cavity that was left behind, called the sinkhole.

It is not entirely clear whether this new lake will also disappear due to the ice fractures., or when it could happen, but it is possible that the meltwater accumulated in the sinkhole is already draining into the ocean.

“It appears the divide was briefly reopened during the 2020 summer thaw season, so this is definitely a system to consider.”Warner said.

“This event raises new questions about how common are these deep ice-covered lakes on ice shelves and how they evolve ”, concludes the researcher.

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