Where did the small nudge come from? Well in fact the northern Hemisphere has been simply warmer for the past four decades and this so far appears to be a cyclical shift from the southern Hemisphere and completely able to reverse. Possibly more heat from the gulf stream is now ending up in the Arctic which explains the rapid collapse of our sea ice as well.
A very nice bit of effort here.
january 13, 2016
An iceberg that cleaved off the Greenland ice sheet. Photo by Joe Raedle/Getty Images.