A giant slab of ice almost four times the size of New York City has sheared off from the frozen edge of Antarctica into the Weddell sea, becoming the largest iceberg afloat in the world. The Guardian reports that the newly calved berg, designated A-76 by scientists, was spotted in recent satellite images captured by the Copernicus Sentinel-1 mission, the European Space Agency said in a statement posted on its website with a photo of the 4,320 sq km oblong ice sheet. Periodic calving off of large chunks of those shelves is part of a natural cycle. But some ice shelves along the Antarctic peninsula have undergone rapid disintegration in recent years, a phenomenon scientists believe may be related to climate change.