Weather is chaotic. The big ice loss of 2007 is mirrored by the ice gain of 2013 -- up to a point. The trend is still definitely for loss. The NSIDC method of using "ice extent" is mistaken. Using a metric created after the loss of the Titanic which is meant to be a navigational aid to ships crossing the Atlantic, does not seem correct for understanding Arctic Ice conditions for climate study. I believe we are still on course for an ice free Arctic summer within the next 7 years. It is unimportant whether it is 2016 or 2020 or even 2025. What is important to watch is the Winter maximum. When that reaches zero, then the Arctic ocean temps rise quickly. As the Arctic ocean temp rises, the ocean conveyor begins to shut down. As it shuts down, the ocean starts becoming anoxic. As it becomes anoxic, we get nearer to re-creating paleo conditions associated with extinction events. I was recently told by Prof. Wadhams that the strength of the conveyor has already diminished a bit.

Excellent research and post. Thanks.

I do not doubt that ice volume is the ONLY reliable predictor of what is going on in the Arctic. In 2000, it was reported that the US Navy submarine data showed that the summer ice went from 17ft thick to 9ft thick from 1979 to about 1996. I did a simple extrapolation and calculated zero thick Arctic ice by 2017. At the time, all the models were predicting 2060 to 2100. So, far that little computation has proven more accurate than the super computers. [BTW. After a long email correspondence with Maslowsky, he was the first to predict 2020 as the data of zero ice. I like to think I helped him in that.] Now since PIOMAS seems to be predicting things better, I presume they have figured out why there was the loss of ice thickness from 1979 to 1996, when loss of albedo was not an issue. I was always curious about that. I figured it had to be warmer currents under the ice, since the melting seemed to be happening from below. I would love to hear from someone who knows about that.

nice blog. Great to see one not hijacked by the denier idiots. Have you guys talked about methane yet? Simelitov reported kilometer wide plumes coming from the ocean floor 8 months ago. Methane is 100 times more powerful GHG than methane. etc. I think things are going to get much worse much faster than has been predicted.

As I understand it, PIOMASS is a model that is used by the Navy to project where their subs can surface in the Arctic without encountering damaging ice. The need to be very cautious about damaging a sub, or the expense of sending it someplace where it cannot surface, leads me to believe that PIOMASS probably overstates its ice projections. Therefore, I do not recognize it as a valid climate model. Thank you