National Geographic: An “alarming rate” of melting in the Antarctic Peninsula has finally snapped the ice bridge that held the Wilkins Ice Shelf in place, experts say. The 25-mile-long (40-kilometer-long) ribbon of sea ice that secured the Jamaica-size ice shelf (which is just out of view in the above pictures) to Antarctica had been “hanging by a thread” since August 2008 (above, top, in November 2008 in a European Space Agency satellite image). On Saturday, April 4, the bridge broke at its …