The recent loss of sea ice in the Arctic is greater than any natural variation in the past 1½ millennia, a Canadian study shows.

"The recent sea ice decline … appears to be unprecedented," said Christian Zdanowicz, a glaciologist at Natural Resources Canada, who co-led the study and is a co-author of the paper published Wednesday online in Nature.

"We kind of have to conclude that there's a strong chance that there's a human influence embedded in that signal."

Arctic sea ice loss unprecedented in 1,450 years