CAPIE is biased high due to the 2 or 3-day lag of CT data, right?

Chris, I think you might mean this: http://www.arcus.org/search-program/seaiceoutlook/2012/summary

Paddy, Greenland melt has *already* taken off: http://nsidc.org/greenland-today/

I see on days 4-6 (June 25th - 27th) a "reversed dipole" anomaly. I guess this means a "pause" in Fram Strait export?

I went ahead and sent in the snow-based estimate of 3.26 M km^2 based on TOPAZ4 and explained in more detail on the forum. I have stuck to June 13th as the date to use for snow cover, first for consistency, second to avoid dependence on long-range weather forecasts, and third, because it seems the correlation begins to degrade after that due to the slow-melt years "catching up".

If that low going into Alaska pulls the ice in the Bering southwards, I think there is enough cold air to cause the open water space that would be formed to freeze back over. This will increase extent considerably.

It's nice to see that you live in a place WITHOUT crazy zoning and construction permit restrictions and red tape that make it a huge headache to build your own house like in the US cities :)

I'm pretty sure that the correlation for September has the causation mostly the other way: Open water at high latitudes leads to a warm September.

It seems to me that the snow cover in June does a good job of foreshadowing the ice cover in September. Ice without snow by June 20th does not survive the season, almost without exception, and ice that still has snow cover on July 1st of a given year is likely to make it to the next season.

Just Freakin' call the max already, will ya?

It might be nice to have near-real-time maps (along with gridded data) of things like heat required to fully melt sea ice /sq meter, ice albedo, and upper ocean layer sensible heat content / sq. m. , etc. These would allow other scientists to make predictions using their own methods without the latter being too complicated, while retaining the "semi-empirical" and relatively transparent/easy-to-understand starting points. Plus, the models could be more easily cast into a form which works with a manageable parameter set.

3.05 M km^2 large areas of low concentration in the middle of the icepack spell serious bottom melt later in the season. This should more than overcome the 'slow start'.

Very interesting that there are so many negative correlation values. I think the approach of Kaleschke and Spreen in their "Sea Ice Outlook 2010" (see also ftp://ftp-projects.zmaw.de/seaice/prediction/ ) is better, and reduces artifacts of ice in areas that will be gone by September no matter what (e.g. Hudson Bay, Bering Sea). But they haven't updated their ongoing outlooks page to include 2013 yet :(

And to add to my previous comment, range/error bars will be somewhere between 2011 and 2012.

I think 3.75 M km^2 is reasonable. Not as high as 2011 (since the snow over Siberian sector is going faster than in 2011 and the ice concentration over European Russia sector is lower) but not quite as low as 2012 (snow melt is behind, season started off colder, PIOMAS volume higher).

Just put me in for 3.5, since the data necessary for me to analyse further (as I explained in my previous post) won't be around until after the deadline.

With no buoy data AT ALL on the Siberian side of the Arctic Ocean, it's hard to know just how thin the ice over there has become. Buoys in other areas are returning first year ice thicknesses in the range of ~140 cm at max. If the ice in those areas is really only 140 cm thick, then virtually the entire Siberian sector up to 83-85 degrees North is destined to disappear by September. Given that the Alaska side in the last 3 years has pretty consistently melted up to 80 degrees North or so and the Atlantic side up to 82 or 83, I think it will do at least that this year. So I'm going to shoot (tentatively) for just a hair below 2012, near 3.5 M km^2 for NSIDC September monthly extent. My guess has the potential for revision on the basis of the timing of melt onset in June. If the snow is all gone before June 16 as seen on MODIS, reduce my guess to 3.0 M km^2. If the Siberian sector still has a good snow cover on June 20, increase my guess to 4.0 M km^2 as the area might survive the summer. And if it makes it June 25, I'm going to go for 4.5 but I doubt that will happen.

PIOMAS has updated.

Andy Celsius himself set 0ºC as the boiling point of tap water and 100ºC as the freezing point. Other way 'round my friend, other way 'round.

Crandles said: The price of carbon once stood at 32 euros per tonne.” That article has now been extended. Where now? Doubt the committee will propose a carbon tax instead. The EU central banks perhaps ought to buy (and subsequently destroy) carbon permits on the open market in order to target a certain price level, which would be increased slowly, over time. If it works for bond prices, why wouldn't it also work for carbon permit prices?

R. Gates, Have you not read the P. Rampal et al. paper "IPCC climate models do not capture Arctic sea ice drift acceleration : Consequences in terms of projected sea ice thinning and decline " ? I think it is the increased drift speeds of ice as it thins that accounts for the vast majority of model failure, not an increase in ocean heat advection from lower latitudes. The rest of the discrepancy can be (maybe?) accounted for by the snow albedo feedback, given that the models also seriously underestimate NH snow cover retreat in May and June. (or even multiyearice-albedo feedback???)

Chris, As a large part of the volume loss of 2010 was the loss of thick MYI driven into the Siberian sector I don't think a re-run will occur. I don't think this is right. In the spring of 2008, a whole lot more MYI had been advected into the southern part of the Beaufort Gyre than in 2010, and yet the volume loss that spring and summer was much lower, if we believe PIOMAS. Something else must be invoked in order to explain the loss of 2010. I suspect it had to do with large April temperature anomalies across the Arctic Ocean in 2010, but without the ability to "tweak" the weather and re-run PIOMAS to see the effect, I cannot say for sure.

Doomcomessoon, In recent years, any openings forming after the middle of May do not refreeze again. Openings forming earlier than mid-May often do freeze back over, but if this happens very late in the season, the ice will be thin and nearly transparent, so will melt very quickly once the season gets going. The cracks we had opening up in February and earlier this month have plenty of time and plenty of cold temperatures to freeze over, so expect them to act more or less like any other first-year ice would this season.

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf/nowcast/icespddrf2013031718_2013032500_035_arcticicespddrf.001.gif Are you ready for the big one ?

Bob, Now, let's compare easy (cheap) oil to electricity for transportation. An EV uses about 0.3 kWh/mile. Average US electricity prices are $0.12/kWh. So $0.04/mile. To drive for four cents in a 50 MPG gasmobile you'd need to find $2 gallon fuel. Except that you are ignoring the effects of wear and tear in both cases, the more miles you drive the sooner the car will need servicing, and the sooner it will need to be replaced. Gasoline cars usually cost at least twice as much per mile as you would think if you only look at fuel cost. I am not as familiar with electric cars...