In just 15 years, the Arctic Ocean may be ice-free in summer, study says

Read MoreIt’s one of the most aggressive timelines and, if correct, is one of the more direct signs that humans are warming the Earth’s climate at an even more dramatic pace than expected.It’s one of the most aggressive timelines and, if correct, is one of the more direct signs that humans are warming the Earth’s climate at an even more dramatic pace than expected.