Here is a question that has troubled me. Water has a much lower Albedo than ice, and so open water will absorb more heat during the sunny summer supplying a positive feedback. But in winter this dark water radiates more heat. So the extra open water during the dark period this winter is a negative feedback allowing more heat to escape from the arctic. Is this significant or isn't it?

Dang, my apologies, http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20070904.jpg

I had hoped the comparison would copy. The other half is here: http://igloo.atmos.uiuc.edu/cgi-bin/test/testimage.2.sh?first=19790905.png&second=20070904.jpg

Question. Why is most of the ice retreat on the Pacific side? Is it Greenland or what? http://igloo.atmos.uiuc.edu/cgi-bin/test/testimage.2.sh?first=19790905.png&second=20070904.jpg

Open water does absorb more heat from insolation, but also radiates more heat back. This reradiation continues day and night. What is the net heat budget for open water?

Insolation, not insulation

Right now atmospheric CO2 is roughly 400 ppm. That means the energy budget ( insulation -radiation) is positive. First question: If we held CO2 to present levels, at what temperature does this value become zero? If this is too high for human life we are already finished. Secondly: methane and CO2 are escaping from melting permafrost. The rate is a function of temperature and its escape increases temperature. Thus this feedback seems to be exponential. If this is so, it makes little difference that the present value is small. Greenhouse gases and temperature will continue to increase ever more swiftly to a maximum temperature, far about humn tolerance. Second question: what can stop this feedback from producing runaway global warming? Third question: If the answer to 2 is “nothing but reduction of CO2 levels,” then, are there any viable methods for CO2 recapture. If the answer to the third question is “no,” then kiss your ass goodbye.

What about the debris thrown up around the craters? Would that be there if a methane bubble just burst, or more likely, leaked, from melting permafrost?

If you compare CT for 6/1/2014 with the same day in 2007 the difference in the condition of the ice is startling.

As a big picture guy I see it like this: AGW means more heat coming in than going out. Most of this extra heat is outside the arctic. Heat always moves from hot to cold. Melting arctic ice is a measure of how fast this heat moves from hot to cold. This happens primarily through winds and currents. Cold coming down from the arctic is heat moving into the arctic. Record cold temperatures in the temperate zone means record heat transported into the arctic.

Here is a good talk from an economist on peak oil.it's long at over an hour, but quite clear. http://energypolicy.columbia.edu/events-calendar/global-oil-market-forecasting-main-approaches-key-drivers

I don't think you are an alarmist. I am an alarmist. I think it is already too late. The carbon we have already put into the atmosphere will continue to heat the world for what, twenty, thirty more years? We can already see permafrost melt , albedo reduction, and the release of methane as positive feedbacks. Guy Mcpherson has cataloged other positive feed-backs. http://guymcpherson.com/2013/01/climate-change-summary-and-update/ So the warming will continue far beyond that, even if we stopped using fossil fuels today. The time for taking this problem seriously is past. Enjoy your life, what is left of it. Of course I am open to any reasonable argument that provides hope, provided it is reasonable. I have children

The question I have not seen answered directly is this: Did the "rebound" of 2013 result from a change of albedo that actually caused radiation from the earth to exceed insolation, or did it result from weather that drove the excess heat somewhere other than the arctic. Clearly if the first is true it represents a pause in global warming.

oops. My mistake.

Perhaps this is slightly off topic, but I believe there is something wrong with the bot at the right hand corner of the page. According to calculations provided by (excuse it) Wikipedia, the Hiroshima Bomb released 2x10 to the 13 joules. A lightning bolt contains 5x10to the 9 joules. Yet the bot claims the extra heat is equivalent to 3.6 x 10 to the 9 bombs but only 4.6 x 10 to the 8 lightning bolts.What gives?

The big question for 2013 (in my humble opinion) is: did changes in air and water circulation prevent heat from moving from warmer climes into the arctic, or did changes in cloud cover, ice extent, and snow cover cause long wave radiation from the earth to exceed insolation?

If ice loss can increase planetary heat loss through long wave radiation from open water so that it exceeds heat gain through insolation, wouldn't this put an upper bound on global warming?

Would it be possible for warm water to slip into the inland lake to hollow out a huge ice dome from which waterfalls from the melt ponds above would pour forth. Cool!

As a mathematician I look at it from a slightly different slant. From what I understand clathrate release as methane is a function of pressure and temperature. The question is, is this a continuous function. Put another way: are the clathrate deposits physically continuous so that an increase in surrounding temperature will produce an increase in methane release. If so, since methane is already being released, and the temperature rise we are already committed to is perhaps 1 degree more than we have now, that further temperature increase will release more methane which will launch runaway greenhouse climate warming since every temperature increase will release more methane. Only if the temperature can rise at some point without further methane release is there even the remotest chance of some humanly endurable temperature plateau. I have no idea what this function is.

The idea that "they" are going to be aroused is simply self-justifying. How aroused are people who write on this blog? What do we do? Knowing doesn't count as doing. Writing here doesn't count either. Is it doing something to write and hope others will see it and do something? There's no solution within the present lumbering system. Surely we all know that. Find something it can now do well other than blow things up. I myself seriously doubt there now is anything humans can do about global warming, but surely if there is it must be a highly organized world-wide extremely radical response. It requires the end of industrial civilization. Does anyone think the government is up to the job?

Neven This is the reason I think the start and end dates haven't changed much. There is a clear pattern of the colors shifting to the left, but not the end points http://i137.photobucket.com/albums/q210/Sekerob/Climate/ArcticSIEDaysMillionStepMelts.png

Does anyone have a theory as to why the beginning and end of the melt season have remained more or less the same since 1979 even though so much more ice is melting?

@ Paddy I do not deny that a volume increase is possible, but since the radiation budget is positive and growing larger, it becomes less and less likely. It can only happen through a slowing of heat transfer to the ice while the gradient in the NH hot to cold grows ever larger. Remember, the earth is hotter every year. This gradient smooths out with the melt, for heat used in melt, rather than affect temperature, is then stored as latent heat or, in an expression I like to use to tweak physicists, heat that's not hot.

Mathematicians, like me, are (by definition) lazy. Most of what goes on here seems like too much work to me. I am a 1 and will stay that way. Global warming because of increases in greenhouse gases is a scientific theory that says the radiation budget, the difference between insolation and radiation, is positive and growing larger as more greenhouse gases accumulate. This extra heat always moves from warmer to colder, and most of what is discussed on this site is observations of the mechanisms of this movement. And of course heat melts ice. The real question is not about extent or area, both poor proxies for the amount of ice, but volume. Even volume is only a proxy given the variability in mass of a volume of ice due to its condition. I note that volume has only increased in one year since 2001. This makes sense to me given that the radiation budget must be quite large by now and growing larger every year. What could cause a volume increase? There have been reductions in insolation and increases in radiation, but these are the result of long standing conditions. Prior to the accumulation of human generated greenhouse gases the radiation budget must have been very nearly in balance (zero), the ice amount going up and down at random, these changes due to long standing conditions, must also be small, at least during the period of stable climate in the recent past. So I think the only possibility for volume increase is the result of the rate of movement of heat to the colder areas, mostly the arctic (in the NH). The only year of increase was 2008 after the huge drop in 2007. Therefore I guess that that huge drop was a result of heat moving into the arctic far faster than the usual rate. 2007 was, notoriously, a “perfect storm” for ice melt. However 2012 was not such a perfect storm. On the contrary, while it was happening many said it was a relatively bad or at least average year for melt (heat movement into the arctic). Therefore, I do not think the conditions are right for a volume rebound this year. What extent will be, given the slushy condition of the ice, is anybody's guess, but if crowd source averaging can get it right I guess the science, such as it is, is superfluous,