You realize that we don’t really know much about the Earth when a whole lake just up and disappears. This phenomenon happened in Antarctica when a massive, icy lake just disappeared. No one knew why and how it happened. Scientists estimated that the lake disappeared sometime during the 2019 Antarctic Winter. It only took them around 2 years to actually come up with a plausible theory on what actually could have happened.
It was estimated that around 600-750 million cubic meters of water just disappeared on the Amery Ice Shelf in East Antarctica. That’s a lot of water and it happened in Antarctica so you can rule out simple evaporation. The disappearance was discovered by a team of scientists, including several minds from the Scripps Institution of Oceanography at the University of California San Diego.
The researchers have now published a study of their findings in the journal, Geophysical Research Letters, last Friday. The authors used images of a satellite to estimate when the event actually happened. They narrowed the window down to a week or less in June. The lake disappearance left a crater in its place. This kind of surface depression is called an ice doline.
According to lead author Roland Warner, “We believe the weight of water accumulated in this deep lake opened a fissure in the ice shelf beneath the lake, a process known as hydrofracture, causing the water to drain away to the ocean below”. Roland is a glaciologist with the Australian Antarctic Program Partnership at the University of Tasmania.
The event was also captured by NASA’s ICESat-2 satellite. Repeat orbits from the satellite helped determine that the ice surface has fallen as much as 80 meters in the doline cavity. The lake’s surroundings rose up as much as 36 meters on the other hand. According to co-author Helen Amanda Fricker, “It is exciting to see ICESat-2 show us details of processes that are occurring on the ice sheet at such fine spatial scale”.
Helen is a glaciologist at Scripps Institution of Oceanography. She’s studied active sub-glacial lakes for a long time. She further explained that “Since surface meltwater on ice shelves can cause their collapse which ultimately leads to sea-level rise when grounded ice is no longer held back, it’s important to understand the processes that weaken ice shelves”.
A phenomenon like this could become more frequent in the future. As global warming increases, ice shelves will heat up more and more and eventually melt.