Threats from the Arctic

USCGC Polar Sea at Iceberg B-15A on Jan. 29, 2001 (wikimedia; NSF/Josh Landis )USCGC Polar Star backs and rams through dense ice off the Antarctic coast, Jan. 15, 2017. (U.S. Coast Guard photo by Chief Petty Officer David Mosley)USCGC is the abbreviation for United...