I'll guess 3.7, which is nothing more than an eyeball estimate of the long term nonlinear trend. There really is nothing more to my guess than that.

Rick's point concerning the meaning "1 STD" (sexually transmitted or not:) is related to some other head scratching. The 1σ and 2σ bands on the Piomas graphs seem to only have meaning in the context of an assumed linear decline of the ice volume. But if the "true" trend should be represented an exponential or a Gompertz curve, it seems that the bands would be narrower (or am I wrong). Oh well, I do know one thing, σ is sigma, not omega! ;)

I would find the "regression to the mean" point to be more useful if I thought we knew what "the mean" means! As Ghoti Of Lod points out, when there is reason to believe that data are distributed randomly about a stable mean, "regression to the mean" is expected after a year like 2012. We don't have a stable mean. For all we know, 2008 was anamalously high.

In case you missed it (or, actually, to beat Wipneus to the punch!), the PIOMAS data for Dec. 2012 is out. No surprises, but it is worth noting that the mean Dec. 2012 ice volume estimate is lower than the mean ice volume estimate for SEPTEMBER for 1994 or any earlier year.

Lucas, IMHO, if you include phrases like "we need to convince the planet that we need to put the global economy into a depression of unknown duration, starting tomorrow" you are doing exactly what your worst enemies want you to do. The climate delayers and people who want to push Rube Goldberg geoengineering schemes (say, Bjorn Lomberg) LOVE to see the alternative cast in exactly this light. With that kind of talk (and I think it is simply incorrect) you are basically handing the reins over to the BAU folks. Besides, a depression that reduces economic activity by 25-33% would only reduce GHG emissions by 25-30% by itself. We would still have to transform our energy system and without the economic dynamism needed to do the job. Reduction of economic activity by, what? 80 - 90%, would kill just as many people as droughts, floods, desertification, etc. I think the kind of people Wayne is talking about (Joe Romm and his new associate Stephen Lacey, for example) are much closer to the only path you might convince people to move down.

idunno, I know Hans is just trolling, but to follow up, if methane from melting methane clathrates could be could be economically captured, it would be even better to disproportionate it, use the carbon-rich products as a chemical feedstock and only burn the hydrogen. Alas, I'm sure the methane from clathrates is far too dispersed to be a practical source.

The new dialog is not off to an auspicious beginning. I see that the hoary old "the Antarctic Sea Ice" trope has already been excreted on as a public comment. What is the use of having "experts" if they're not going to moderate the "public" comments and require some modicum of truth (Judith Curry's silly "anthropogenic percentages" are bad enough. It is hard to believe she actually made such an idiotic comment - perhaps she could enlighten her colleagues by publishing a derivation of her percentage). At any rate, the Antarctic nonsense was debunked on this web site on Sept. 22.

California universities may be in trouble now, but if you think that Texas universities are doing 'just fine' you're misinformed. Perry and his right-wing think tank anti-intellectuals (the Texas Public Policy Foundation) are actively working to dismantle Texas A&M and trying to sell it off the the "private sector". The University of Texas is putting up more resistance, but will likely knuckle under eventually. The UC system has much further to fall. Texas never had the breadth of quality that the UC system reached. Beyond UC Berkeley and UCLA, the UC system had quality schools at Davis, Santa Barbara, San Diego, and Irvine - Texas has nothing really comparable outside of Austin and College Station.

I'm a Texan and it seems that the only difference between being a Kansan and a Texan is that in Texas, Brownbackism is Perryism. Perryism is just a nakedly apparent, but runs even deeper because Perry has had twelve years to pack every statewide office, every Board of Regents and every nook and cranny where he can stick a corrupt functionary with his school chums.

Karl, Pretty much the same question as Klon Jay: I see from your recent comments that you think CO₂ is not the origin of climate change. (e.g., "AGW driven by CO₂ is just not looking logical with the factual information we have") Does that mean we'll soon see a groundbreaking paper from you that fleshes the idea out a bit - with conclusions actually supported by data? If so, what journal are you submitting to?

I need a clarification of terminology. What is a "warmist"? Is a "warmist" someone who regards the scientific consensus on the nature, seriousness, and rate of global warming as something to be worried about? Are the people who wrote the IPCC reports* "warmists"? Are the climate scientists shown in this video "warmists"? * You know, the reports that have so far seriously underestimated the rate of Arctic sea ice melt.

As it happens, I just sent Neven an e-mail concerning just the kind of graphical data that Whitebeard has suggested. Countering antarctic nonsense once and for all really requires a comarison of only three graphs. First, compare the decadal averages and full 33-year CT data on antarctic sea ice area, http://i713.photobucket.com/albums/ww133/Sane_Person/Arctic%20Meltdown/Antarctic_Ice_averages_zps781ade33.jpg with the decadal (and selected recent year) sea ice area data for the arctic, http://i713.photobucket.com/albums/ww133/Sane_Person/Arctic%20Meltdown/Arctic_Ice_Averages_zps44307409.jpg Nothing of statistical significance is going on as far as antarctic sea ice area is concerned - period - end of story. The last six years of antarctic ice shows nothing more than the degree of scatter about the long-term mean that one should expect from any arbitrarily selected six year interval in the antarctic ice record: http://i713.photobucket.com/albums/ww133/Sane_Person/Arctic%20Meltdown/Antarctic_Ice_last-6-years_zps4c0c19dd.jpg The response to a denier who dredges up an argument involving antarctic ice as a distraction from what is going on in the arctic is, basically, "Look at the graphs and answer the following question: If the arctic sea ice data showed the either the long- or near-term behavior that the antarctic sea ice data shows, do think that an Arctic Sea Ice blog would even exist?" Of course, you could go further and point out that antarctic land ice, like the Greenland land ice, has shown a very clear statistically significant decline over the past decade at least.

Neven, I took the liberty of updating the Climate Crocks figure, putting 2012 in its proper position: http://i713.photobucket.com/albums/ww133/Sane_Person/Arctic%20Meltdown/Sea_Ice_models_v_reality-2012.jpg You're welcome to it. (I'm assuming Peter Sinclair approves.)

LRC, A few comments: (1) The pharmaceutical industry is a miniscule player in CO₂ generation. If they had to switch to carbon-neutral feedstocks, it would not much affect the cost of pharmaceuticals because the cost of drugs is overwhelmingly determined by value added (research & production) and, sadly, marketing (on which they now spend more than research!). (2) The broader commodity-chemical industry does generate a significant fraction of all CO₂ (8% of world energy use), but the industry is not as intransigent about maintaining the status quo as the fossil fuel industry. Oil companies used to be big into chemicals, but now chemical companies are more separate and act as consumers of fossil fuels; the two businesses are not nearly as closely intertwined as they used to be. See this presentation to gain a perspective of Dow chemical view, for example: http://www.chem.tamu.edu/academics/fyp/lecture_series/slides/stevens.pdf

Joe Bastardi is a tough call. He is so ignorant of basic science, that it is difficult to tell if he is the sleaziest liar on the denier circuit, or just a pathetic poster boy for willful ignorance. As evidence for the latter, read his comments and the replies here: http://thinkprogress.org/climate/2012/03/11/442110/weatherbell-forecaster-joe-bastardi-denies-basic-physics-co2-cannot-cause-global-warming/ Be sure to note that he "contributes" to the comments on the thread - amazingly dumb.

Wipneus, I love your graphs! (They're posted outside my office - and I'm a chemistry professor.) I think you made a mistake in your update - you got September updated already in the monthly PIOMAS plots - your just needed to update August, of course. Keep up the excellent work.

Correction: The Scorpion and the Frog may not have originated with Aesop!

My question to Dr. Christy: Why do you lie? Umm...it is what they do? (c.f., Aesop: The Scorpion and the Frog) About the time that the North Pole goes ice free in August, you can expect the deniers to find the lost diaries of Captain Cook describing his observation of palm trees in Nome and an 'independent discovery' of a petrified catamaran used by Santa Claus in 1724.

One thing bothers me about PIOMAS plots: Their average always includes all data from 1979 to the year before. Why don't they choose a base period of 1979-2000 like NSIDC does with extents? I also can't see how their standard deviations can hold up; they've got both 2010 and 2011 more than 2σ below the mean for all of both years. Since there is only ~5% probability that any given measurement will fall outside of 2σ, how are their standard deviations getting huge?

Wbuawxman, Two dimensions are enough for any real 'merican. Thickness is a commie conspiracy.

"In fact the size of a typical molecule is comparable to UV light." No, Typical gas molecules are a few Angstroms across - that's X-rays, not UV.