It's still open, but down to 4 months.
As you might recall, the DRH is the period back about 16 years ago where the linear trend of the HadCRUT4 surface temperature data from there to the present falls below "warming," where "warming" means a statistical significance of less than 95%.
In short, it's the longest period from where someone could technically say there's been no (surface) warming.
As I wrote last December, it's the little dip in this graph around 1997-1998 where the trend dips slightly and the 2σ error bars touch the x-axis. (All error bars are calculated by ordinary least squares, which is what I believe Phil Jones did when he made his statement(s)).
|HadCRUT4 surface trend from indicated month to Dec 2012|
Now this graph looks like this, which isn't a whole lot different:
Whereas the lowest statistical significance in the DRH last December was 92%, now it's 93.4%. Not a lot of "plateau" to hang you hat on.
Of course, once the DRH does close, scoffers will just move up their period up to 2001 or somewhere and say there's been no warming since then. Which is what some are already doing.
But that's numerology, not physics. In physics you first define what you want to calculate -- in this case it is "climate," where you define "climate" as some long-term average of weather, three decades at least -- and then you calculate "climate." Scoffers are calculating first and trying to define afterward, but that is mindless numerology, not science.
For more, see Skeptical Science's "Did global warming stop in