Iceberg A23a has run aground on the wildlife-rich island of South Georgia, which could prevent penguins from accessing food and impact Earth's major cooling system. Vast slabs of ice are constantly breaking off Antarctica's ice shelves but most splinter into fragments as soon as they begin floating free in the warmer ocean surrounding the continent. But A23a has persisted for a long time. It calved off the Ronne-Filchner ice shelf a vast floating sill of ice in Antarctica's Weddell Sea back in