Ice is melting so fast in the Arctic that the North Pole will be in the open sea in 30 years, according to a team of leading climatologists. Ships will be able to sail over the top of the world and tourists will be able visit what was, until climate change, one of planet’s most inaccessible landscapes. Researchers assessing the impact of carbon emissions on the world’s climate have calculated that late summer in the Arctic will be ice-free by 2040 or earlier - well within a lifetime. Some ice would still be found on coastlines, notably Greenland and Ellesmere...