The Larsen C iceberg detachment taking place has drawn widespread attention because many in the public have speculated that it happened as a consequence of global warming. The dimensions of the iceberg, as large as the state of Delaware, lend a cataclysmic quality to what is happening, but glaciologists are not uniformly convinced this is cause for alarm. This is an example of events that are part of the constant maintenance of the rough mass balance of Antarctica’s cryosphere. The shedding of this particular iceberg compensates for the addition of snow Antarctica continually acquires. As new frozen material accumulates, it pushes ice off the continent. Some of this ice melts where it comes in contact with the ocean, and some of it breaks off as large icebergs every few decades.
Our laboratory’s extensive research indicates that the calving of the iceberg, the changing surface height of the Larsen C Ice Shelf, and observed summer melt events are consistent with what glaciologists expect to happen as Antarctica responds to natural climate variability. Ice shelves, interacting with the dynamic atmospheric and ocean systems, are one element of the larger, complex climate system.
This is not to take away from other areas in Antarctic that definitely merit alarm. Antarctic ice shelves overall are seeing accelerated thinning, and the ice sheet is losing mass in key sectors of Antarctica. Continuing losses might soon turn into an irreversible decline and several feet of damaging global sea level rise. However, as far as we can tell, this calving event for Larsen C is part of the normal evolution of an ice sheet.
– Helen Amanda Fricker, glaciologist and professor of geophysics at Scripps Institution of Oceanography at the University of California San Diego. Fricker tracked the drift path of the 1986 Larsen C iceberg with passive microwave imagery, and has studied calving processes on other ice shelves since the early 2000s.
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