What they are sort of saying is that previous cold periods have been preceded by short periods of warming.
This winter has been ...
Cold, and there was no warming for the past 10 years or so.
What that *could* mean is that the previous warming was the normal "pre-glacial" (read Ice Age) warming, which peaked 10 years ago or so. Now we could be heading into that next "glacial period". Historically speaking, we are overdue.
(The more "wiggly" nature of the data at times closer to the present is due to more data, that is samples closer together in time)
Dress warmly.