Irregular update, this might be the last one comparing early years (1980s, 1990s) to this year. As was very likely expected by all the regular contributors of this forum the CT SIA numerical decline continued after the previous update and so -

Tomorrow is likely the day when 2013 5-day weighted average passes the minimum of the 1980s. The earliest minimum in the available record (CT SIA for Arctic) is on 2nd of September (1992 and 2005, 39 days to go) and the latest is the oddball year 1995 on 29th of September (66 days to go, 5 days later than anyother year). Minimum of 1990s is 4,7804 Mkm^{2} on Sept-9th and minimum for 2000s is 3,9504 Mkm^{2} also on Sept-9th (46 days to go)

Average daily loss from Jul-23rd (five day smooth is 2 days late) to Sept-9th has been 43153,9287 km^{2} during the 2010s thus far. This would give 2013 a drop of 2,071388 Mkm^{2} from the 23th of July value and this would make a minimum of 3,163104 Mkm^{2} (the 6th smallest). 2010-2012 have hurled past the 1990s minimum in few days on average (actually this might happen in 1-3 days, so I'll have to think some other way of comparing 2013 to the early record) and passed under 2000s minimum on August 4th (possible update here is thus on Aug 6th)

2013 is now about 18Â¼ days ahead the long term average

2013 is now approximately 3Â½ days behind the 2010-2012 average

2013 is now almost 9 days ahead the 2000s average

2013 is now ~24Â¾ days ahead the 1990s average

2013 is now c.47 days ahead the 1980s average

Average losses/day graph. Shamelessly cherrypicking 1985 as the starting point for another graph tells that since 1985 the arctic ice has lost on average almost 306 km^{2}/day more each year during Jul 23rd - Sept 12th. I don't know if this is a proper value for GHG-effect, anyway, this value should be calculated from the volumes.

For some light entertainment, calculated (again, last time was in 2009 if i recall correctly) what would happen if 2013 started to equal maximum losses from previous years every day from here on. Result: total loss of Ice on Sept 17th (image not included, check yourself), on the other hand, if 2013 would do maximum gains/minimum melts from now on the melt should end in two days and the value for Sept 12 would be 6,4579 Mkm^{2} (again, no image included) and the historical maximum would be passed on Nov 7th. Also checked how many record days 2013 has thus far. This is equal, 4 maximum gain/minimum loss days vs. 4 minimum gains/maximum loss days. However the sum of these record days is -601884,531 km^{2}, so it's not like there's been no changes in the extreme value distributions.

what someone might want to check is whether land temperature developments above 30 north (ferrel-polar cells of atmospheric circulation) correlates to the average loss image, I've no idea where to find that data.

(modified) as there is a slight trend to increasing losses during this time of year did a Jim Pettit -style graph 'if 2013 behaves like recent years what'll happen?' Included the above, estimated trend in the calculus. This doesn't change the result much as can be seen. 2013 would have to start to behave like a badass 2008 to get near a new record. On the other hand, it might just behave like 2013 behaves and that might be alltogether a different thing. 2 out of six realizations put 2013 challenging second spot in minimums so at least (inserting own opinion) 33% chance of 2nd smallest minimum.

Cherrypicking the steepest trendline I dare, ;-) 2013 still does not yield a new record but ends up some 333000km2 short of it. But still, 2013 has been behaving unlike anything seen previously. (not changing my vote, voting possibly ended already?)

(Modified 26.07.2013) A dubious excercise on Global CT SIA. Ordered numbers separately for each year, then took the difference of smallest and largest value of each set of values (so this is a mix of separate dates from different years) and got the R^{2} shown in the right bottom corner. As can be seen from the main image, ordered values of global sea ice have been decreasing, but if one looks only variance, someone (read: 'deniers') might conclude that Southern Ocean Ice balances the decrease in Arctic Ocean, which is clearly not the case.

(Modified 06.08.2013)

4th image: not sure if I did this correctly (ah, pretty sure that there's some glitch in it but anyway it shouldn't change the shape of things...), and what does this tell. Global daily values divided by daily averages, then multiplied by yearly averages and again divided by the average of the whole record. Then took 11 year means from the record where it was possible and smoothed the ends by ever shortening averages. Then shaded the ends of the graph indicating the increase in statistical uncertainty.

Now what happened in 1999? Again this is calculated after the fact, so it doesn't mean people (or just graduated students of limited statistical capabilities) should have been shouting that "Increase in Antarctic Sea Ice won't match the loss in the Arctic Sea Ice, thus the albedo will decrease!". Anyway 11 years is such a long time that an ocean current might notice it, but the sun it isn't. Can this be connected to the 1998 el Nino somehow? Did the southern ocean start to increase its heat content in 1999?