Antarctica is dominated by ice, mainly two massive glacial ice sheets called the East and West Antarctic Ice Sheets. Unsurprisingly, these ice sheets have been losing mass in recent years. Two glaciers within these ice sheets – the Thwaites and Pine Island glaciers – are especially threatened. Scientists estimate that at the current melt rates, the ice sheets together will add as much as 3.4 meters to rising sea levels in the coming centuries.
Now, new research led by the University of Maine and the British Antarctic Survey has measured the rates of sea level change around Antarctica. The research shows something disturbing. The glaciers have been retreating at rates not seen for 5,500 years. Thwaites and Pine Island glaciers have lost 192,000 square kilometers and 162,300 square kilometers, respectively. These glaciers alone could add significantly to global sea level rises.
“We reveal that although these vulnerable glaciers were relatively stable during the past few millennia, their current rate of retreat is accelerating and already raising global sea level,” said study co-author Dr Dylan Rood, an expert in the Department of Earth Science and Engineering at Imperial College London.
“These currently elevated rates of ice melting may signal that those vital arteries from the heart of the West Antarctic Ice Sheet have been ruptured, leading to accelerating flow into the ocean that is potentially disastrous for future global sea level in a warming world. Is it too late to stop the bleeding?”
During the mid Holocene, more than 5,000 years ago, the earth’s climate was much warmer than it is today. Because of the warmer climate, the scientists wanted to look at the sea levels to compare them to what may be our future. To look at the sea levels, the researchers studied sea shells and penguin bones, indicators of sea levels. Using carbon dating, they were able to pinpoint these remains in time.
Interestingly, sea levels in Antarctica seemed to be lower during the warmer period while at the same time higher globally. This is because the weight of glacial ice pushes land down, causing it to ride lower in the water and ride higher when the ice melts away, relieving the pressure.
Overall, the researchers have been able to see a drop in sea levels for Antarctica as the glaciers melted but a rise in sea levels nearly everywhere else. To further understand the phenomenon and hopefully find possible solutions, the scientists plan to carry out more research.
The study is published in the journal Nature Geoscience.