text: In this Aug. 15, 2019, photo, a boat navigates at night next to a large iceberg in eastern Greenland. Summer 2019 is hitting Greenland hard with record-shattering heat and extreme melt. By the end of the summer, about 440 billion tons (400 billion metric tons) of ice, maybe more, will have melted or calved off Greenland's giant ice sheet, scientists estimate. (AP Photo/Felipe Dana