An international team of geologists and climate scientists has documented the link between ice melt and sea level rise for the first time using evidence of a massive and abrupt calving of an iceberg that occurred in Antarctica thousands of years ago, at a time when the continent’s melting glaciers launched enough icebergs into the ocean to increase sea levels by nearly 13 feet in only 100 years.

The new study about Antarctica's melting glaciers, dating back 19,000 years to 9,000 years, is based on an analysis of new deep-sea sediment cores extracted from a region between the Falkland Islands in the South Atlantic Ocean on the Patagonian Shelf and the Antarctic Peninsula. The study, published in the journal Nature on Wednesday, reveals an unstable Antarctic ice sheet that can abruptly reorganize climate in the southern hemisphere and cause a rapid rise in sea levels.

“This is the first direct evidence that instabilities of the Antarctic ice sheet caused rapid sea level rise during the last glacial termination,” Peter Clark of Oregon State University and the study’s co-author, said in a statement.

Michael Weber of the University of Cologne in Germany and the study’s lead author, said in the statement: “One of the iceberg events in our data that is of particular interest took place 14,600 years ago and coincided with a huge ice-sheet melt, the famous Meltwater Pulse 1A, which according to previous studies led to a global sea level rise of about 4 meters within 100 years.” 

According to the study, natural climate warming led to the collapse of huge ice sheets on the frozen continent eight times in the past 20,000 years, and to determine what exactly triggered the disintegration of the ice sheets, the researchers conducted a series of climate-modeling experiments.

“An unusually strong flow of warm water toward Antarctica may have triggered these events,” Axel Timmermann, a professor at the International Pacific Research Center of the University of Hawaii, said in the statement. “Our model experiments reveal further that the associated melting in turn increased the warm water flow, thus providing a positive feedback. This is a perfect recipe for rapid sea level rise.”

The researchers also stated that measurements at Antarctica's biggest glaciers, such as Thwaites and Pine Island, suggest the ice sheet is close to a similar massive retreat, LiveScience reported.

According to researchers, Antarctica's glaciers have been shrinking since the last great ice age that ended nearly 22,000 years ago. The retreat of Antarctica's glaciers decreased until the twentieth century, when the melting quickened because of man-made climate change.