Iceberg

When an iceberg reaches warm waters, the new climate attacks it from all sides. On the iceberg surface, warm air melts snow and ice into pools called melt ponds that can trickle [blank] the iceberg and widen cracks. At the same time, warm water laps at the iceberg's edges, melting the ice and causing chunks of ice to break off. On the underside, warmer waters melt the iceberg from the bottom up. Icebergs [blank] a danger to ships [blank] the North Atlantic and the waters around Antarctica. After the Titanic sank near Newfoundland in 1912, the United States and twelve other countries formed the International Ice Patrol to warn ships of icebergs in the North Atlantic. The International Ice Patrol uses aeroplanes and radar to track icebergs that float into major shipping lanes. The U.S. National Ice Center uses satellite data to [blank] icebergs near Antarctica. However, it only tracks icebergs larger than 500 square meters (5,400 square feet).