AS THE extent of Arctic ice approaches its summer minimum, it is clear that it has yet again shrunk to one of the smallest areas in recent decades – albeit not by quite as much as last year’s record-breaking low (see diagram). How much can be blamed on climate change, and how much on normal weather variation?
In 2007, Arctic ice reached an all-time low, opening the North-West Passage, a sea route along the north coast of Canada, for the first time on record. Climatologists now think a major factor was natural variations in the weather: temperatures were unusually…
