Increasingly frequent calving events

Evidence of accelerated melting of Antarctic glaciers

The large cracks running along the edge of the Pine Island Glacier are the result of the gradual rise in temperatures. These cracks weaken glaciers, resulting in more frequent glacier calving. Credits: ESA

As global temperatures rise due to global warming, the Antarctic ice is becoming brittle and undergoing accelerated melting in recent years. And recently, one of the largest glaciers in Antarctica, the Pine Island Glacier, was an example: a piece the size of Malta (or twice that of Washington DC) has come off in the sea. The other giant glacier nearby, that of Thwaites, could soon suffer the same fate.The Pine Island Glacier, one of the fastest melting glaciers in Antarctica, has just lost another huge chunk of ice in the sea, continuing a trend of rapid melting that has become an almost annual occurrence over the past decade. Scientists at Copernicus, the European Union's Earth observation program, have been closely monitoring the glacier since large cracks appeared near its edge in October 2019.Yesterday, these cracks finally cut a piece of the glacier (a process called calving glacier), releasing giant pieces of fresh icebergs into the nearby Amundsen Sea. In total, the largest piece is approximately twice the size of Washington (DC) in surface area (over 350 square kilometers), which is equivalent to the area of ​​Malta.The recent calving alone is not so surprising or particularly threatening to the global sea level; calving is a normal part of the life of ice formations with sections floating on the water. Because the ice at the edge of the glacier was already floating, this ice does not directly contribute to the rise in sea level when it inevitably melts.However, over the past two decades, calving events have occurred much more frequently at the Pine Island Glacier and the nearby Thwaites Glacier (also known as the “Doomsday Glacier”) as the surrounding ocean warms. due to global warming.While large calving events occurred at the Pine Island Glacier every four to six years, they have now become near-annual events, according to NASA.Over the past decade, huge chunks of the glacier have come off in 2011, 2013, 2015, 2017, 2018 and now in 2020. As a result, the ice shelves of Pine Island and Thwaites are retreating inside. land faster than new ice can form.Scientists fear that this persistent retreat is a sign that an accelerated melting cycle is underway: as relatively warm seawater flows over the newly exposed edges of an ice shelf, the melt accelerates, the ice shelf stretches and thins, and calving becomes more and more likely.According to NASA, the region around the two glaciers contains enough vulnerable ice to raise the ocean by 1.2 meters. The new Pine Island icebergs calved just days after scientists reported the hottest temperature on record in Antarctica. On Thursday, February 6, temperatures near a research base on the northern edge of the continent reached 18.3 ° C, reported the World Meteorological Organization (WMO). The previous record was 17.5 ° C, established in March 2015.