Iceberg the size of Singapore breaks from Antarctica to roam the ocean
By Rich McCormick Nov 20, 2013, 10:20pm EST
Image NASA Earth Observatory | Source NASA Earth Observatory
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NASA's Earth Observatory says that a vast chunk of ice the size of Singapore has broken away from Antarctica, and may soon start drifting in the Southern Ocean. Named B-31 by the US National Ice Center, the slab of ice is 21 miles by 12 miles in size and now floating in Pine Island Bay, south-west of the southern tip of Chile.
Scientists noticed a massive crack in the ice in July
Infrared and radar images showed a crack separating B-31 cracked from the rest of Antarctica in July of this year, but the ice has only recently started moving away from the coast. The new iceberg is set to remain in Pine Island Bay for now, but if the bay clears of ice by the annual sea ice minimum early next year, then it could drift out into the Southern Ocean. There, the iceberg is likely to get caught up in one of two currents swirling around the continent depending on the length of its underwater keel: either the counter-clockwise "coastal counter current," or the larger clockwise "circumpolar current." NASA scientist emeritus Robert Bindschadler explains how the iceberg will choose its direction. "Where it is going depends on the deeper currents into which its keel extends. If you ever throw a stick into a mountain stream, you would see an erratic flow as it spins, accelerates, and decelerates. This iceberg is like a very, very big stick."
A team of UK researchers is now using a £50,000 ($80,400) grant to track the iceberg using satellites. If the iceberg does make it out into the wider sea — a process that may take years, according to NASA glaciologist Kelly Brunt — it could threaten shipping lanes, reports The Telegraph. If it moves too far north, it could melt quickly, causing a build up of fresh water on top of the denser sea water, and affecting the speed of the ocean's currents.
Iceberg B-31 is 50 percent larger than other icebergs seen in the area
NASA's cryosphere program manager, Tom Wagner, says that the calving of a new iceberg is not necessarily a surprise. The Pine Island Glacier that birthed iceberg B-31 is one of Antarctica's most active, moving at a rate of around four kilometers a year (2.4 miles a year) and calving icebergs every "five or six years." But B-31 is surprising in its size: it's around 270 square miles in size, 50 percent larger than icebergs previously observed in the area. Its creation could be seen to back up the hypothesis that warmer waters are weakening ice shelves in this area of the Antarctic. Weakened shelves lead to increased ice flow that in turn could cause higher water levels and, eventually, coastal flooding around the world.