Antarctica: The calving of Larsen C iceberg not linked to climate change, will have only marginal impact on sea levels

A trillion-tonne iceberg, considered one of the largest ever recorded, has broken away from Antarctica. With the calving of the 5,800 square kilometre iceberg, the Larsen C Ice Shelf has reduced in area by more than 12 percent, changing the landscape of the Antarctic Peninsula forever. The event occurred sometime between 10 and 13 July but researchers have been monitoring the growing rift in the West Antarctic ice shelf for years. “We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometres of ice,” professor Adrian Luckman of Swansea University in the UK told PTI. [caption id=“attachment_3808303” align=“alignleft” width=“380”] Representational image. Reuters[/caption] The breakaway iceberg, which is likely to be named A68, weighs more than a trillion tonnes. Its volume is twice that of Lake Erie, one of the Great Lakes. The final breakthrough of the rift was detected in data from NASA’s Aqua MODIS satellite instrument, which images in the thermal infrared at a resolution of one kilometre and confirmed by NASA’s Suomi VIIRS instrument. While icebergs calving from the Antarctic mainland is not a new phenomena. However, the sheer size of this iceberg has made the scientist community analyse the long term impact of the event. Ice sheet sliding into the sea is a bigger concern First of all, scientists say that the latest development may pose a serious hazard to ships around the South Pole. There is also a risk that Larsen C may eventually follow the example of its neighbour, Larsen B, which disintegrated in 2002. Seven years before Larsen B’s disintegration, the Larsen A too had broken away from the continent. Scientists believe the iceberg will later fragment into several pieces during the passage of time. The disintegration of Larsen C has always been in the offing, and could have been accelerated by global warming. A report on The New York Times took a larger view of the issue and links the event to the rising temperatures across the world. The report noted that scientists have been observing monumental changes in the polar regions since last few decades. The report, however, added that the calving of the iceberg pales in comparison to the threat from the West Antarctic Ice Sheet. The report said that while the new iceberg will not immediately raise sea levels, if the ice sheet covering the West Antarctic slides into the sea, then sea levels can rise by 17 feet. However, David Vaughan, glaciologist and director of science at British Antarctic Survey told Reuters, “If Larsen C now starts to retreat significantly and eventually collapses, then we will see another contribution to sea-level rise.” Global warming not responsible for the event Nevertheless, there are some researchers who do not link the event to global warming, suggesting that such events have taken place throughout earth’s history. They add that the calving was expected to take place any time in the future. “Although this is a natural event, and we’re not aware of any link to human-induced climate change, this puts the ice shelf in a very vulnerable position,” Martin O’Leary, a glaciologist on the Midas team, said in a statement. Christopher Shuman, a scientist with the Cryospheric Sciences Laboratory at NASA Goddard, also shared a similar view, telling Vox that there needs be more research to know whether the development will lead to destabilisation of the land ice, which can then contribute to the rise in sea levels. A report in Slate added that satellite images had been highlighting the rift since the 1980s. The report added that linking the development to global warming is just simplifying the phenomena of climate change. A report in news.com.au noted that there is a bigger threat from ice shelf declining rather than the calving of a iceberg. the report said, “Removal of the ice shelf causes glaciers to flow faster, increasing the rate at which ice moves from the land into the sea. This has a much larger effect on sea level than iceberg calving does.” However, there is no immediate threat to the world but the impact of the calving will be determined by whether the iceberg remains stable and not retreat and collapse in the future, a Vox report noted.