Francesco, Regarding your belief in many contrarians' favourite zombie idea, Jevons Paradox, your version of it was: "it's long known that any increase in (energy) efficiency in an open large market leads to an increase in consumption of the relevant resource (oil in this case)." This is directly contradicted by the very Wikipedia article you linked to, which states: "First, in the context of a mature market such as for oil in developed countries, the direct rebound effect is usually small, and so increased fuel efficiency usually reduces resource use, other conditions remaining constant.[6][9][10]" "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." - Mark Twain

@Brian Wind If you're going to rant, would you mind not deploying the phrase "But seriously...." in the middle of it? It makes it difficult for those of us who mght be unwilling to let you speak for everyone here about what we all 'know' to respond to everything you wrote up until then, either partially or fully in jest.

@Devi869 Ummm... how do you handle the cognitive dissonance of believing both "No cap and trade nonsense. No taxes." and "Do the simple thing, tax all fossil fuels on the planet with 5%."?

And "solutions" we have seen in my part of the world, windmills and solar panels, are not a solution, since they look like crap! Says Espen who if marooned on a desert island would presumably refuse to be rescued by an ugly boat.

Also, if this came to pass, would this not amount to a new record for extent and area? I'm not sure it would - your ice stronghold certainly contains some area that was open water on 9/24/2007. Of course, it also excludes some areas that still had 15% or more ice cover on 9/24/2007. A better area measuring tool than my eyeballs is required to answer the question. That said, if there's anything I've learned following Arctic sea ice fairly closely for a few seasons, it's that just because the Beaufort, Chukchi and/or East Siberian seas and adjacent parts of the Arctic Basin contain large areas of fragile looking, low concentration ice in late July or early August doesn't mean it's all going to melt away by September. Maybe it will this time. I certainly think it could if the weather for the next couple of months turns out highly favourable to melting. But a lot of ice has managed to survive the melt season despite looking ready to melt away in a flash for weeks on end just in the last couple of years. It could well happen again this year.

In order for the total sea ice area to hit a new record low, then given that there will be some small patches of ice left in areas such as the Canadian Archipelago and the Greenland Sea, the total in the AB needs to go down to closer to 2 million than 2.5 million. Looking at your first link, it appears the current record low from last year was set without the total in the AB going below ~2.4 million so it's not clear why you think something less than 2.4 million but closer to 2.5 million than 2 million won't suffice.

It's sobering that the Beitsch et al, prediction has dropped from 4.7+/-1.3 M km2 when they submitted to 4.3 +/- 0.7 posted online today. Though that does, I suppose, also demonstrate just how sensitive these estimates can be to short term acceleration/deceleration - a few days or a week of slow change and that estimate might bounce right back up again. None of the other individuals or groups submitting to SIO update their estimate daily, do they>

Maybe my browsers are withholding the latest data from me but are you sure about that, Lodger?

Will Crump, "The lines in the graphs above are drawn using Arctic wide data. Implicit in the drawing of these graphs is an assumption that all regions in the Arctic are declining at the same rate." No, that assumption isn't implicit in the graphs anymore than an assumption that all American citizens always grow richer or poorer at the same rate is implicit in a graph of US economic growth. If you want to repeat your theory ad nauseum, fine, but could you spare us obvious nonsense like that?

crandles, No doubt we can both be wrong on some aspect of this and inexpert in solidarity with each other. I agree, that isn't the shape of ice edge I'd intuitively expect from compaction. Hopefully it's been a clear day and visible imagery will allow someone to enlighten us as to what's actually happened there.

crandles, Looking at today's preliminary Bremen concentration map compared to yesterday's map, I think "Big compaction day in the Beaufort." is a much better explanation that your suggestion. The only plausible alternative I can see is that a whole lot of the edge spread out to less than 15% concentration while refreezing simultaneously filled in a lot of polynyas, which really doesn't sound very plausible when I try saying it out loud.

Peter McGrath, Quoting one Peter McGrath "...I for one like to read a balanced point of view so why should that stop me reading this Jon,..." Also quoting the same Peter McGrath "This isn't a balanced website..." I think the reason why you might want to stop reading this blog is obvious based on those two statements. But if you want to punish yourself by forcing yourself to read things you don't like, I have no objection.

Since Neven focuses on 2005 to present, I'll point out that in 2003 the first uptick in JAXA extent wasn't until September 12th. It was of 64375 and was followed by another uptick of 74688 the next day and yet the minimum still hadn't been reached, although it came on the 18th and was only about 9000 lower than the value for the 11th. Peter McGrath - if you can't handle someone making a simple observation about the observational data, perhaps you should stay off the climate blogs. Or at least stay quiet - now we know reality is getting under your skin :)

Great stuff. However, regarding "The downside of this thin, young and unstable ice is that it's difficult to find appropriate ice floes for our operations on the ice.", I can sadly think of another downside to that.

Paul, It's okay for Gavin Schmidt to call the product JAXA sea ice extent but forbidden for Lucia? I think you're getting a little bit (actually, quite a bit) ridiculous now.

How about "Until the outsides are melted, the center is more protected than it would be if no ice at all formed outside the center during the winter."? Can we all agree on that, with the possible exception of William Crump, who appears to believe that a mystical barrier isolates the Arctic Basin from the surrounding seas? Also, crandles, I think there are simply a variety of ways, none of them yet effective, of trying to persuade Mr. Crump that his idea is foolish.

William, This is no doubt somewhat unfair (after all, as far as I know no one anticipated the 2007 melt season) but if it were December 2006 and you had the 1981-2006 portion of the Tivy chart of Central Arctic Ocean September sea ice area you linked to as your only basis for predicting when, if ever, the September area would drop to ~2.1M square kms, you would probably have concluded that it would take at least a few decades and might well never happen. You certainly wouldn't have predicted that it would happen the very next year. As I said, no one that I know of looking at all available Arctic data did (although props to Maslowski for having the courage to make his initial observation years before then about what would happen if trends continued) but I do think it is fair to say that also considering the trends in area and extent up to then for the Arctic as a whole would have given you greater awareness that there was a significant decrease in Arctic sea ice going on and made you more cautious about predicting that ~2.1M couldn't happen anytime soon, i.e. for that specific imagined test of predictive ability, considering data covering all the northern hemisphere sea ice would have outperformed considering only data covering the ice in the Central Arctic Basin.

Will Crump, When you say "We are well above 2007 level on this graph.", does that mean you have an archived copy of a Cryosphere Today arctic basin area graph covering the 2007 melt season? Or is that freely available somewhere on the CT web site and I just haven't noticed? Or out there in the blogosphere somewhere, in which case a link would be nice. Cheers.

To be fair, Nick also proposed a somewhat lopsided bet in his favour if we assume your description of his position is accurate.

Paul, You've designed a bet that has a higher expected value for you based on your stated position than it does for Nick based on his stated position. I wouldn't blame him, if this bet isn't to have a zone of results in which neither of you wins or loses, for insisting on a threshold enough lower than 4.60 to equalise that.

Widget or not, it might be fun to do some retrospective analysis comparing the track record of predictions here compared to various mechanical strategies (average for the date in the JAXA record, same as the day before, same as the day before plus or minus the difference between that day and the preceding day, usw). I think there's a decent argument to be made that many of the predictions here are read as more confident than is truly warranted, which may contribute to making us look excessively alarmist in the eyes even of a neutral observer.

Probably not news to very many readers here but I'll note that from August 9th to August 18th, 2011 extent caught up 226,093 square kilometers on 2007. With 2007's lead currently 244,063, I'm still in the camp of not completely writing off the possibility of a new record JAXA extent minimum this year.

A question for sea ice experts generally - can any of you explain why the ice floes in the picture illustrating http://thinkprogress.org/romm/2011/08/09/291467/as-melting-artic-sea-ice-opens-up-oil-and-gas-resources-secretary-salazar-backs-offshore-drilling/ are so angular, in contrast to the more rounded, irregular shapes of ice floes we're accustomed to seeing in the Healy webcam. Is it because these have been broken up by wave or some other mechanical action rather than melting or is there some other explanation?

Okay, I should know better than to put a period after a URL.

"Monnett manages a $50m budget. The integrity enquiry is likely to have more to do with his managing of funds than with the veracity or validity of his scientific findings." Not an unreasonable supposition but it seems to be contradicted by the exerpts from Dr. Monnett's interview with the investigators available at http://www.peer.org/docs/doi/7_28_11_Scientific_Misconduct_Complaint.pdf. Apparently, they were focused on the publication about the drowned polar bears.