NEW LONDON, Conn. — About 1,000 icebergs drifted into the North Atlantic shipping lanes this year, marking the fourth consecutive “extreme” ice season, U.S. Coast Guard officials said Thursday. The Connecticut-based Coast Guard International Ice Patrol, which monitors iceberg danger in the North Atlantic and warns ships, held its annual meeting in New London to discuss 2017 and look ahead to 2018. Greenland glaciers are retreating, and storms broke up significant amounts of sea ice in 2017, freeing many icebergs, said Cmdr.