csnavywx

IJIS extent in Antarctica is down to 2.25M, now at lowest on record with a 1-2 weeks to go on the melting season. NSIDC not far behind. Arctic extent up just 47k over the last 5 days. That may change after we get some cooler weather in a few days. Might even get a week of normal temps/climo weather in that region before that Pac jet extension and upcoming secondary SSW conspire to buckle the Pacific pattern again and likely build another AK/Pac side ridge.

Yeah, extent is fairly insensitive to basin-wide temp at this time of the year and is much more subject to temp swings on the edges (over the Bering, Ohktosk, Kara, Barents, etc). Much too early to make any calls there. Volume and very high basin temps are the big story of the refreeze season.

I'm more than willing to engage at length on this, but this phrasing leaves room for backsliding or goalpost-moving later. It also implies you have other objections besides the issue you raise. I want an intellectually honest conversation where there is no chance to drag the conversation through the weeds or possibility of engagement in an obstacle-course style argument where an endless stream of objections is thrown up after the first is countered. Basically, I'm trying to provoke you to think honestly about your position and set a standard that can be falsified*. Please provide the a full accounting of what it would take to convince you that it is human-caused climate change. The reason is that I want to know ahead of time if it's even possible to change your mind on the issue. If your personal standard is, for instance, too high (e.g. Earth must become Venus-like), then obviously no amount of data or argument will meet it and I've wasted my time. *Holding a scientifically-sound position means it includes the possibility of being falsified if a defined set of conditions are met. If it can't, it's speculative, hypothetical and/or faith-based and I'm not here to engage in that line of conversation.

Answering the question I pose above (in a way), this year is already considerably worse than any other in the basin with the slight exception of 2013, which also had a weak Pacific, though not quite as bad as this year. It's a bit deceiving though, as 2013 turned colder after the first few weeks and went very cold in February, something this year isn't likely to do -- so this likely opens up a wide gap even with that year. The volume differences outside the basin appear fairly minimal at this point (when comparing the actual thickness graphs) when compared to that year, so there's every reason to believe a 2009/2013 style summer won't be able to put up the numbers we saw in those years. If we continue with the ridiculous warmth for another 6 weeks, the ship will have likely sailed. It's a bit ironic, since fast FYI growth in a near MYI-less landscape was the last big buffer left to prevent a quick transition to a near-sea ice free state and this winter seems poised to largely erase that buffer. The Arctic is great at making fools out of prognosticators, so I'm not quite ready to throw my hat all-in on a new record, but I feel it's pretty safe to say that the chances have increased significantly at this point. A tie in volume with 2007 last year after a below-average summer increases confidence a bit too.

20K km^3 with a record small loss would still result in a minimum just below last year. A well below average loss of 17k (2013-style) would put it below 2012 volume. That's ballpark, though, and I'd like to get a comparison of basin-only volume losses (minus the peripheral areas like the Ohktosk, Bering, Hudson and St. Lawrence as they melt every year and starting below average in those areas doesn't mean much). Regardless, it's easy to see how a new record becomes much more likely with such low maximum volume.

Out of curiosity, what evidence would you have to see to convince you that it is mainly climate change? What standard would it have to meet?

Feb 1st update: Conditions continue to deteriorate vs other years. The longer range forecasts for the first 2 weeks of Feb. look terrible for almost the entire basin. Some improvement is forecast for the Bering Sea and Beaufort areas next week, meaning extent numbers are likely to climb back towards the pack: Volume gains will continue to be slow. We're on track for a -1700 to -1900 FDD freezing season (using 80N+ temps as baseline), far below any previous winter. With 2 weeks of hostile re-freeze conditions forecast, only about a month remains for significant volume gains heading into the melt season. Despite the one decent cold spell over on the Pacific side, the ice there is still quite thin: Time is running low for the peripheral seas. Without a recovery soon, these areas aren't likely to survive very long during the melting season without a 2009/2013 style summer. A below average (2016-like) June isn't going to cut it. With the sun returning in a few short weeks, any remaining open water likely will not freeze and will start absorbing insolation earlier than at any time seen in recent history.

In other news -- Antarctic sea ice extent is down to 2.51M on NSIDC, lowest on record for the date and 7th place against the all-time minimum of 2.26M set on 2/27/97. Area at 1.87M vs mins of 1.24M in 1993 and 1.50 in 1984.

Very cold conditions over the Bering and Okhotsk have allowed extent to catch up and pass 2006, offsetting losses on the Atlantic side. The Pacific side should warm up over the next two days and put a halt to any further advances there, but we should finally see a relaxation of the very warm conditions near the pole for a bit.

Stall speed again on extent. No net increase over the last 9 days. Will probably remain at/near the level it is now for another week with the upcoming warmth and storms as the Atlantic side is chewed up again for the umpteenth time this winter.

Another ice destroyer being modeled on the Atlantic side in a few days. Hits the Kara/Barents pretty hard, but pulls warm air all the way across the pole too. Might turbocharge Fram export depending on the track (a la recent runs of the Euro). At least the Chukchi gets a break from the relentless blowtorching.

Thanks for those links. Interesting results. Trick now will be pinpointing which mechanisms are most important and/or which are providing synergistic interactions or feedbacks. I have a feeling the Blue Ocean experiment was on to something, but we'll see with time.

That's pretty much how I envision getting the first near ice-free September day. Combine a winter like this one (with a finish below 3500) and a summer like 2007 and you're pretty much there. Maybe not quite -- but it's pretty close. That extra 30-40cm of missing ice growth on the edges will make all the difference in the world in getting the outer periphery to melt very early on, as in 2-3 weeks earlier. That puts the CAB under the gun in July rather than August -- with a higher sun angle and a longer period of time to heat the peripheral seas. Of course, it's going take a whopper of a summer to get this to happen this early, but in 10-15 years -- not so much. It seems the ability to get a warm enough winter to stifle ice growth enough to put away all of the ice in a single summer is close to being in reach. That was a topic of discussion on this board last year. I just didn't think we'd be seeing a winter this warm so early.

My main concern this year will be the Chukchi/Beaufort and Barents/Kara area. Ice in those areas is (very) abnormally thin and likely won't make it past ~80-100cm before spring. The fact that it took until the first week of January for the Chukchi to finally finish freezing over isn't a great sign. One bad weather spell in May/June will quickly erode what used to be a bulwark for the CAB. Gotta hope for a 2013 or 2014 style summer to get out of this one.

We have probably at least 6 weeks as Don alluded to. The sun has to return to the peripheral seas before max can be attained. Getting it in mid-January is nearly impossible as heat lag hasn't finished cycling off of the solstice.

Pretty speculative, but it could be an atmospheric heat transport feedback. There was a paper about a Blue Arctic Ocean experiment that showed an increasing propensity for AHT feedback with decreasing fall/early winter ice coverage and thickness. Makes me wonder if there's some sort of threshold behavior at work.

Yes, highly unusual. We've also matched the freezing degree day deficit of the entirety of the last (record warm) freezing season and it's only January. Completely unlike any other winter.

The Chukchi is finally closing. However, another monster ridge in the medium range on the OPs and Ensembles could put that in jeopardy. Amazing how little progress this freezing season has had. Coming up on January and the basin is still struggling to freeze or stay frozen.

93k loss over the past 2 days on Jaxa, similar on NSIDC. Remarkable losses and extraordinary temps on DMI -- yet again. We're getting close to January -- about halfway there. If the rest of this winter goes about the same as the first half, the pack will be in no condition to take punishment in the next melt season.

Ice pack is still getting the crap kicked out of it at the solstice. DMI 80N temps and overall Arctic temps on (yet) another surge and the Kara/Franz Joseph Island area is yet again losing ground. I think we've broken -900 FDD anomaly for the 80N region (not sure on the 66N+), but that's only 175 above ALL of last winter's record total and it's still December. If this keeps up, both the Pacific and Atlantic ice fronts aren't going to put up much resistance this spring. There just isn't going to be enough quality freezing days to build up a good pack at this rate.

The SAM went negative, so that's helped, but it doesn't explain everything. Pure speculation mode: I was wondering if there was a link with the Super Nino earlier this year. However, we didn't see this kind of response in 1998, so I'm having a hard time reconciling that. The big coastal polynyas this year might hold a clue. More warm CDW being directed at the continental margins would explain that.

Yeah, it's definitely not an error. Something rather odd going on down there this year, including the sudden reappearance of the Weddell Polynya.

We're at 8.3M. In order to avoid getting a new SIE low-max record, extent will have to increase by 5.7M before maximum. The record increase between now and maximum is 5.2M, set in 2012-2013. Still possible, but getting to be a tall order.

IJIS extent has opened up a huge lead. Down 46k yesterday (biggest drop in Nov in 10 years), which puts it about 750k behind 2012. 2012 rockets away shortly and is replaced by 2006 for previous lowest (which was the 2nd warmest winter behind last year). I suspect we'll get pretty close to 1M below the record before closing later in the month (2006 had quite the slowdown in Nov before speeding back towards the pack). Anomalies look to "revert" back to +10C above 80N and +6C over the Arctic Ocean as a whole, so we should see some resumption of freezing, if at a somewhat sluggish pace. The real story is the continuing lack of decent freezing degree day totals, which if it continues to be sustained, will put the hurt on spring thickness. Last year was a -650 anomaly (above the Arctic Circle) and -1075 (above 80N) or about 800 overall. A doubling of that anomaly to -1300/-2150 puts us in striking range of near ice-free conditions by summer's end as it causes thickness gains to drop below the critical ~1.7m threshold. I'm far from convinced that we'll get a doubling of those anomalies, but with the way it is going, it might get somewhat close. Speaking of which, there's another strat PV split forecasted in the medium range. Edit: My numbers are a bit off. Ice thickness growth= sqrt(FDD/804) Normal for the Arctic Ocean is 4500 FDD (5500 north of 80N). This equals about 2.2m of thickness growth overall (a bit more at the pole/near Greenland). A -1300 anomaly would drop this to 2.0m of thickness growth. A -2000 anomaly would drop this to 1.7m, which is where you would need to be to get ice-free conditions at the end of summer assuming a normal melt year. A 2007 or 2012 style melt year would require quite a bit less, of course. To achieve a 2500 FDD total for 1.7m of average thickness growth, the average temperature during the freezing season (Sept 15-April 15) would need to average -13 to -14C. That's the number we need to watch. If we keep getting crazy bursts of periodic warmth through say... February, I'd be worried. If it finally mean-reverts and gets closer to normal for a while, it won't be so bad.

Sea ice volume now tanking into record low territory (as of the end of Oct) on PIOMAS. I would suspect that the lack of FDD is continuing to eat away at SIV gains. Gotta wonder if there's a bit of "climate flickering" going on here. I thought the ridiculous +SAT anomalies would have started to back off by now.