Adrift at sea: on the calving of Antarctica's trillion-ton iceberg

The separation of a massive iceberg shows how precarious the Antarctic ecosystem is

July 15, 2017 12:02 am | Updated December 03, 2021 12:43 pm IST

The dramatic but inevitable calving of a trillion-ton iceberg from the Larsen C Ice Shelf in Antarctica raises the question, did a warming atmosphere have a significant impact on the process? Scientists from Project MIDAS, a U.K.-based Antarctic research project that has been looking at the ice shelf for many years, have said the formation of icebergs is natural, and no link to human-induced climate change was available in this case. Yet, the impact of such a loss on the stability of the ice shelf itself may not be benign. Should it disintegrate, glaciers normally feeding into the floating shelf may have nothing to restrain them, and could then contribute to sea level rise, possibly at a slow rate. Such fears are based on the unambiguous data on the thinning of the Larsen Ice Shelf. Researchers said in 2003 that Antarctic Peninsula ice shelves retreated each year since 1980 by about 300 This erosion has been interspersed by two previous collapses of smaller ice shelves, Larsen A in 1995 and Larsen B in 2002, the latter providing strong evidence of subsequent accelerated glacier flow into the sea. While any negative impact of the latest event will likely be felt years or decades later, it highlights the need to stop continued warming of the planet from man-made carbon emissions.

Antarctica is a climate stabilising factor, and the importance of the marine West Antarctic ice sheet was highlighted by U.S. scientists over four decades ago. In the context of rising emissions from the burning of fossil fuels, a cautionary note was sounded, on warming seas hastening the melting of the shelves that hold its great mass. Indeed, the point made was that except for man-made causes, there was no anticipated factor in the natural geological cycle that would disturb Antarctica. The separation of an iceberg almost 6,000 sq. km in size from the ice shelf shows the importance of such alarms. Fortunately, newer satellite technologies, which were not available during earlier instances of iceberg calving, will help in the study of the fragile peninsular region and Antarctica as a whole. Among the stark effects of changes could be a shift in biodiversity: species like emperor penguins which depend on sea ice to complete their life cycle are at risk if ice cover declines. Any dramatic changes will only add to the worry of irreversible effects of climate change, given that the Arctic and Greenland have also been losing ice cover. Clearly, the loss of a massive portion of the Larsen C Ice Shelf marks another milestone in the evolution of this remote region. Yet, the lack of long-term data on Antarctica, as opposed to other regions, makes it difficult to arrive at sound conclusions. What is clear is that the last pristine continent should be left well alone, with a minimum of human interference, even as research efforts are intensified to study the impact of human activities in the rest of the world on this wilderness.

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