+1

Hi John C. "From my vantage point, the storm is absolutely necessary in order to limit sun radiation reaching the sea ice and open water in the highest north." That's a thin reed to try and grab ahold of, but I'll take it. To me, it seems about all we have right now.

Lots of discussion on the forums about that Cyclone. Things start getting really exciting over the Eastern Kara and Barents in 36-48 hours. Models are also suggesting over-all surviving arctic snow cover is going to get clobbered hard. Albedo all across the arctic is dropping fast. The storm is actually one of the scenarios (early precipitation stripping snow, increasing heat uptake) we were afraid of and discussed earlier in the forums.

SimonF, this year, we may be making a serious run at "Ice Free"; certainly to get well under 4000KM3 of volume. As indicated above, come over to the forums to see and follow the mixture of fascination and terror in our discussions.

There is a very high level of attention being paid to this in the forums. Consensus there agrees with consensus here. Weak ice, high winds, big trouble. Now we wait and see how it plays out this weekend.

Greetings to all - lively discussion as usual. We have indeed sadly passed the point where momentum will take us past key thresholds of CO2 which will cause massive changes in our climate. Similarly, we must act now to prevent the changes from being even more monstrous. As pointed out we have a two pronged approach which must be followed - reduction in production of CO2 and mitigation to reduce its effects. The path to reduction is quite obvious but has some nuances which bear examination. In particular reducing habitat destruction - which both releases carbon and reduces sinks - is something which must be pursued. Mitigation is much trickier, as geoengineering on the required massive scale can have similarly massive and undesirable unintended consequences. In particular active strategies such as solar shields or carbon injection may have environmental consequences which could be as or more destructive than the CO2 itself. Compound that risk with the sheer scale of resources and energy required to implement them and they become far less attractive. We do need mitigation, but my intuition is that will be by way of bio rather than mechanical engineering - as an example, organisms tailored to use photosynthesis to pull CO2 out of the atmosphere on a massive scale, but which themselves can be turned on or off by way of trace nutrients required for their growth. It can even be more mundane than that; simply reforestation and active agriculture with the expressed intent of maximizing biomass production, most of which goes straight back into the ground from which we pulled carbon in the first place. Sadly, it *will* take centuries to accomplish, either way, but hopefully fast enough to avoid the worst consequences of our current trajectory.

Concur on both counts Werther. I'd be very surprised if I did the calculation based on the DMI graph and found us less than a thousand degree days behind where we should be. That's just for 80N and above. What's happening elsewhere in the Arctic takes the astounding and transforms it into the staggering.

"Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification." And Colorado Bob's reference now lays it out in black and white. It may be over except for the shouting.

Hey Vidd; Not sure I'd call it a number 1 suspect, but I certainly wouldn't dismiss it having an impact. We'd have to quantify it over time as a derivative function of decreasing insolation as we approached and passed the equinox. I'm not quite certain where to start there, but that'd be a bunch of number crunching. What strikes me as a side effect of lower ice coverage (and lower albedo) is the effect it had on atmospheric circulation. Combined with the El Nino heat, I'd imagine open water (providing energy to storms locally) supporting circulation which would transfer of heat from lower latitudes. We'll be studying this year's weather for quite a while, I think.

It seems very quiet in here for the very dramatic phase we are in. 'Tis cause it's the forums and the right place for the discussion ;) For those of you wondering what Vidd is alluding to, here's a link to a post in one of the forums where discussion is on-going: http://forum.arctic-sea-ice.net/index.php/topic,1611.msg92652.html#msg92652

Robert S - A lot of the current thinking on the forums is that the coverage expansion is driven in part by fresher surface water, and increased snowfall due to the large volumes of moisture being imported into the Arctic. Snow being fresh, remains frozen in the -1.0 to -1.8 degree water. The water being somewhat fresher then forms additional ice around the slush on the surface. It wouldn't be too hard to get 10-20CM of this, which could be piled up further, but still increase both area and extent significantly. However, it is very different from what we would see with a "hard" freeze with temperatures well below -10C.

Witold, you make some interesting points and highlight some of the problems we face trying to articulate how the Arctic is changing. As Extent has been so critical a metric for so long in understanding the Arctic, changing how we use it presents a challenge, both cognitively and scientifically. That said, working up a study over time of say, 90%+ extent ice might prove very illuminating and might highlight just how the ice being measured by the metric has changed. (...starts contemplating data sets to download...)

Dan Ellis-Jones; I recommend this forum to you where there are active discussions of Permafrost. http://forum.arctic-sea-ice.net/index.php/board,20.0.html

Good post, Neven. Following weather, I'm in agreement, beating 2012 is less probable than it was a month ago. That said, I wish I could quantify it, but It seems like we're seeing more rain over the pack than in the past. That's a lot of energy and I think another wild card we need to stay aware of, along with the elevated SST's we're seeing. Even with the cloudiness, it still speaks to much higher total enthalpy in the Arctic. Each year that increases, that improves the probability that the "pendulum" will swing wide and give us a 2012-like year.

Ice Bridge this year showed that there is a fair amount of older ice that's relatively thick - especially hard up against the Canadian Arctic. However, it's far from consistent, and there's lots of ice they examined which is far thinner. It's playing out everywhere; the only areas I've seen recently which resemble the old "Mesh Pack" are to the north of the Lincoln Sea, and even those are not especially secure. I'm rather concerned.

Picking up from where Kevin left off. I think the key problems we wrestle with understanding changes in melt are three fold: 1) Limited detail in our data 2) Large numbers of related variables 3) Limited understanding of how they interact. We really have only *3* relatively constant factors - Annual insolation, net CO2 forcing and convective heat transfer from the earth. All of these vary by less than 1% a year. CO2 forcing has the largest variability over the last 30 years, but the impact of that change is far more indirect. Even with the most powerful computing engines ever created, we can't skillfully see ahead more than a few days, much less a season. Short term, almost like watching a pot coming to a boil, we have to fall back on a certain amount of intuition, and extrapolation from the paucity of long term data we have in our hands. We know the pot *will* come to a boil. That's calculable from the mechanics of heat being applied. What we're trying to do is akin to determining what the surface of the water will look like getting there.

Chris and Susan - yes, that storm brewing up off of the US Eastern seaboard is alarming. Water temperatures there are already running in the upper 20's to almost 30C. That heat translating into the Greenland/Norwegian/Barents seas via storm systems will make a big problem worse.

"...There is now some 200,000 km^2 of open water in the Beaufort (150,000 wide-open, and 50,000 in large polynia)..." And here you succinctly summarize the fear I've had since I first saw that water starting to open up almost a month ago. While a lot of the heat isn't getting dumped directly into the ice as it would with melt ponds, it is completely changing the seasonal balance, and creating a killing ground for ice which gets swept into it. The high pressure system reenergizing the gyre will do exactly that, and appears to be primed to continue to do so for the foreseeable future, all the while clear skies are dumping that 450W/M/Second into the water, and off-shore air flow draws more heat in from the land. And now, with hundreds of KM of fetch, we will start seeing more wave action and Ekman pumping as well. It's hard to imagine how the melt season could have gotten off to a worse start. So much heat, so early....

Concur bobcobb - way too early, and last year there was a lot of excitement. The uncertainty of it is why most of us think in terms of probabilities now. In that regard, while a predicted new minimum wasn't reached, for many off us, the 2015 result was dead on in the middle of the range of possibilities we saw; in fact a bit lower than many. To wit: Last year we saw a 15-20% chance of passing 2012. This year, at this point, I'd say we have at least double that, based on the last 10 years melt behavior. That's not because of any particular change in the melt season - we can reach that with rather modest melt numbers. Considering current conditions and short term weather predictions, there's a lot of pressure to presume more. I don't think it's a difficult stretch to imagine it.

Fortunately, that particular flood is headed towards the Caspian, which can use the water. There were Colorado-style flash floods down near the Black Sea as well - 30-40CM of rainfall in 24 hours. http://www.telegraph.co.uk/news/picturegalleries/worldnews/9386813/Flash-floods-in-Russia-leave-more-than-170-people-dead.html It *is* reasonable to conclude that there is a lot more moisture being carried north, and what we see here is a side effect of that. I'm not finding a lot about what's happening in northern drainage basins to the Arctic, but if what we see here is any indication, it won't be good.

Forgot the link: http://nsidc.org/arcticseaicenews/

No recovery Dean. There's considerable discussion of the satellite problems over on the forums. The NSIDC has in fact retracted it's April data, and is working on building from other satellites of the same mark. The IJIS numbers, which use a completely different device show no recovery.

Two other features worth mentioning here regarding weather. Along with the persistent high over the Pacific side of the CAB, we have not as strong but somewhat persistent low pressure over the Barents and Bering - something which has been true for several days and will continue to be a feature. Both are the product of low pressure systems running NE along the continental margins and then stalling over the (comparatively) warm peripheral Arctic seas. The effect is to amplify air movement - two dipoles if you will - which are boosting the power of the 1040-ish high pressure system, and which also steer winds westward along the N Alaskan coast, and SouthWestward across the CAB towards the Fram and Victoria island gaps. Export into warm Greenland and Barents Seas water is going to be very high over the next few days - on the order of 100's of thousands of KM2. What will replace that exported ice will be very thin, and disappear within weeks, exposing central portions of the basin to significantly reduced albedo. As Neven said, hope for clouds and cool weather. We will need them.

".... The choices as always aboard the World’s Best are yours. How will you write your story on board?" I have insufficient words. What astonishing narcissism.

Glenn Doty, I appreciate your perspective but will respectfully disagree. The cruise(s) planned are moneymaking affairs capitalizing on self-indulgent voyeurism. While I have no problem with that in principle when it is taking money out of the pockets of those who have it and should know better, it doesn't work here. It's not just the rich being affected. Local communities will be hit hard. Local governments are scrambling to find money to deal with the influx of tourists. National governments are having to spend money on hardware and training to insure the passenger's safety. In short, money isn't just coming out of the passenger's pockets. For practical purposes, the cruise is being subsidized by governments and communities, without any choice on their part. It is a monstrous distraction, which in fact will steer resources *away* from researchers trying to get things done during the short season they have. It's not helping, and the problem while political is still harmful.