Every day we hear something new about the icy regions of our planet -- either Antarctica or the Arctic -- how global warming is slowly obliterating these ice-clad regions, and how they would impact our lives if we continue to pollute and cause global warming.
Amidst all this, in Antarctica, the East Antarctic ice sheet is always considered to be stable. However, the ancient melting data says otherwise.
Researchers looked at data from nearly 400,000 years ago when the Earth was around 1 to 2 degrees Celsius warmer than average. The ice melt could have raised the water levels by about 10 to 13 feet.?
The study looked specifically on the Wilkes Basin which is one of the several bowl-like basins at the edges of the ice sheet that¡¯s as big as France. Researchers from the University of California, Santa Cruz, University of Kansas and the University of Washington looked at three samples of subglacial sediment to see what minerals have accumulated beneath the ice historically.?
With the help of specific uranium isotopes that collect in regions where water and rock meet for an extended amount of time, researchers dated the opal and calcite in their samples that were taken from near the Pensacola Mountains and Elephant Moraine in East Antarctica. Ice that floats is known to trap isotopes in place in the sediment record, however, the open ocean can usually flush it out.?
These samples revealed that the East Antarctica hasn¡¯t been stable as long as researches have otherwise believed, in the past. Approximately 400,000 years ago, samples show that the ice levels dropped in the basin and caused the sea level to rise.?
First author Terrence Blackburn, assistant professor of Earth and planetary sciences at UC Santa Cruz explains, "Our data shows that the grounding line in the Wilkes Basin retreated 700 kilometres inland during one of the last really warm interglacials, when global temperatures were 1 to 2 degrees Celsius warmer than now. That probably contributed 3 to 4 meters to global sea level rise, with Greenland and West Antarctica together contributing another 10 meters."
He added, "We've opened the freezer door, but that block of ice is still cold and it's not going anywhere in the short term. To understand what will happen over longer time scales, we need to see what happened under comparable conditions in the past."
Reports in the past have already shown how fast the ice in the Antarctic is melting. A 2018 study revealed that just in the last five years between 2012 to 2017, Antarctica's ice sheet has shrunk and it has lost 219 billion tons of ice every single year -- triple the rate of ice melt before 2012.
A more recent study from March 2020 has revealed that this has only gotten worse, as researchers found that Antarctica and Greenland have lost a whopping 6.4 million tonnes of ice between the year 1992 and 2017.?
This has resulted in the sea levels to rise by 17.8mm or around 0.7 inches.?Researchers claim this can not only cause flooding in coastal areas but also cause coastal erosion which will eventually submerge the area underwater.?