Over the past few days, Arctic sea ice extent has braked dramatically in the daily loss rate and now has made a sharp right turn, which is rather unusual. Here’s the JAXA extent:
And here is a close up view, note the 2011 red line:
That turn is unique to the record since 2002. Note that in 2007, there was also a turn, though brief, and then melt accelerated.
It is also showing up in the NSIDC plot:
But what is really most interesting is the plot from DMI, which show not only a turn, but a reversal:
What does this mean? The short answer is, probably nothing. When we approach the minimum, and the ice pack becomes more fractured and scattered, it also becomes more susceptible to the vagaries of local and regional wind and weather.
WUWT regular and contributor “Just the facts” suggested in comments that:
One factor appears to be the Greenland Sea, where sea ice began to grow on July 15th and has been trending above average since then.
Source: ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/plots/r07_Greenland_Sea_ts.png
On the other hand, looking at the most recent comparison with 2007, the Arctic ice cover looks a bit more soupy in 2011:
Air temperature is above freezing throughout the Arctic….
…as is fairly normal for this time of year:
Clearly, at present, air temperature in the Arctic is not in any way climatologically abnormal, so the reasons for the current extent being low and making erratic turns must lie elsewhere. Wind, soot deposition/albedo, ocean currents, etc. all factor in.
So, while we may have temporarily avoided a new record minimum (as many in the “Serreze death spiral” camp said we are headed to) there’s still the possibility that the plots will turn to the left again, and resume or even accelerate. It all depends on the weather, and the outcome could go either way at this point. Historically, we have about 7 more weeks before the turn upwards as the Arctic begins the slow re-freeze.
Still, it makes for interesting observation and discussion. The WUWT sea ice page has all the latest stats, updated as soon as they are made available.
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UPDATE: Bill Illis runs his own database, and offers this interesting view in comments.
The last 21 days are the lowest melt since 1973 in my database over the same period. The total ice extent is still well-below average but there are very few periods in the record where the trend is so different than normal for an extended period of time like the current period is.
Matching up a few different datasets back to 1972.
UPDATE2: In the meantime, while extent loss slows, the NSIDC “death spiral team” tries to make a case for a record low average for July, while at the same time admitting that On July 31, 2011 Arctic sea ice extent was 6.79 million square kilometers (2.62 million square miles). This was slightly higher than the previous record low for the same day of the year, set in 2007.
Arctic sea ice at record low for July
Arctic sea ice extent averaged for July 2011 reached the lowest level for the month in the 1979 to 2011 satellite record, even though the pace of ice loss slowed substantially during the last two weeks of July. Shipping routes in the Arctic have less ice than usual for this time of year, and new data indicate that more of the Arctic’s store of its oldest ice disappeared.
Figure 1. Arctic sea ice extent for July 2011 was 7.92 million square kilometers (3.06 million square miles). The magenta line shows the 1979 to 2000 median extent for that month. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data.
—Credit: National Snow and Ice Data CenterHigh-resolution image
Overview of conditions
Average ice extent for July 2011 was 7.92 million square kilometers (3.06 million square miles). This is 210,000 square kilometers (81,000 square miles) below the previous record low for the month, set in July 2007, and 2.18 million square kilometers (842,000 square miles) below the average for 1979 to 2000.
On July 31, 2011 Arctic sea ice extent was 6.79 million square kilometers (2.62 million square miles). This was slightly higher than the previous record low for the same day of the year, set in 2007. Sea ice coverage remained below normal everywhere except the East Greenland Sea.
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” I think this season differs to previous seasons for which we have JAXA data in. In previous seasons there was still a degree of compaction in the remaining ice to limit the impact of ice melt on extent loss. 100% sea ice concentrations will not display as much extent loss for the same rate of ice melt as 50% sea ice concentrations”
Exactly. And there is very little 100% compaction left even compared to `07 at this time. And we still have at least 7 weeks left in the melt season.
Arctic sea ice may approach record low: NSIDC:
http://www.bloomberg.com/news/2011-08-05/arctic-sea-ice-may-approach-record-low-after-biggest-july-melt.html
Werner Brozek says:
August 4, 2011 at 5:22 pm
you have set me thinking now! – and to be honest I am too busy at work to check up on my likely poorly remembered ‘facts’, but isn’t there a wind chill effect/factor – on the basis of latent heat of evaporation at the ice surface? if the ice melts, the surface water will be evaporated by the wind thereby causing a cooling? my brain hurts just trying to remember this stuff from many years ago……….but I just seem to recall that a wet surface exposed to wind will cause the surface to be cooled as the moisture evaporates……….and I am now wondering if the energy for the evaporation simply all comes from the wind itself……….argh, how embarassing – why can’t I remember this stuff?
Mike Jonas says:
August 4, 2011 at 8:54 pm
Here’s a serious question : Why are we watching Arctic ice extent so avidly?
I think one reason is because one of the alarmist theories is that once the Arctic is ice free we will reach some sort of “tipping point” where warming will then accelerate.
While I doubt that will actually happen (and I wouldn’t mind seeing a couple of years of an ice-free Arctic as confirmation), some support for their tipping point position comes from the DMI temperature graphs. Temps during the winter are all over the lot, ranging from 20 degrees above trend to 20 degrees below trend at various random times. During summer though, anyone can forecast the DMI temperature within one degree just by stating the long-term average.
I view this as the ice controlling the air temperature. As long as there’s ice, air temps are constrained by the ice taking energy from the air for melting. But once the ice is gone, what will happen to air temps? Tipping point?
I doubt it (very much), but like I said I really wouldn’t mind a real-world experiment happening so we could put the nonsense to rest (or move to higher ground.)
Everyone’s spacial awareness ability took a sharp left turn after the economic downturn. Or was that a right turn? I’m sure an answer will turn up.
“While I doubt that will actually happen (and I wouldn’t mind seeing a couple of years of an ice-free Arctic as confirmation),”
I would`nt. The Arctic controls weather patterns over North America. The less ice there is, the more havoc it will cause for farmers/agriculture.
R. Gates says:
August 4, 2011 at 12:11 pm
Don’t know what you mean “greatest factor the atmosphere has going for it”.
Well, you pretty much ran with the point I was trying to make – that wind is likely a greater “driver” in Arctic ice melt than air temperature alone. And no, I’m not discounting atmospheric heat in the production of that wind, just as SST should not be discounted in that same wind production. But ultimately, as you appear to eventually acknowledge, ocean heat “drives” ice melt moreso than the atmosphere.
DMI (Aug. 5) showing a deep decline towards `07 levels again. Even the `07 ice on this date was much healthier than it is now. Much more compaction over a much wider area. I`m afraid the “soupy” ice that is left is going to disappear like mist over a lake after the sun rises.
Two big days after the run of low ice loss days on Jaxa have made the graph go off it’s small ledge
AO looks set to be below zero for next 2 weeks. High pressure at the moment over the central arctic.
Andy
Something seems to have happened to the Bremen Antarctic Sea Ice Extent graph as is took a sudden nose dive today and went straight down on us. Maybe their attention was focused on the Arctic and they haven’t seen it yet? 😉
Or perhaps a huge iceberg the size of New Zealand has broken off and is now heading for New York ( only to meet it’s ultimate demise at the hands of Bruce Willis armed with a hair dryer)
Not surprising that the Greenland Sea ice coverage is higher – the strong currents southward carry a large load of sea ice. It is extremely doubtful that the sea ice extent in the Arctic is making a rebound, as suggested by the headline to this blog. From the NSDC:
“Ice loss slowed towards the end of July as a high-pressure cell centered over the northern Beaufort Sea broke down and a series of low-pressure systems moved over the central Arctic Ocean. This change brought cooler conditions and likely pushed the ice apart into a thinner but more extensive ice cover.”
What’s important to look at is the volume of sea ice! And, as usual, this blog cherry picks. You guys must be blind not to see what is happening.
High pressure back over the main Arctic ice region, so only going to aid further melt.
http://www.uni-koeln.de/math-nat-fak/geomet/meteo/winfos/arcisoTTPPWW.gif
Not suprising since the AO has become quite negative again over recent days.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.obs.gif
Now forecasting rather negative AO period over at least the next week, so good sign for significant melting in areas especially less than 60 percent ice cover.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
From wolfheinl on August 6, 2011 at 7:37 am:
What’s important to note is the loss of Arctic sea ice really doesn’t matter much. Read this February 9, 2011 post:
Arctic “death spiral” actually more like “zombie ice”
The Arctic Ocean is where the planet sheds a lot of heat into space. When more sea ice is lost in the summer, more heat is lost into space from the open water. If we do get an “ice-free Arctic” in the summer then we’ll lose a whole lot of heat until the insulating blanket of ice reforms in the winter, and the Arctic will recover within 2 years due to this extreme heat dumping. If you’re worried about “runaway global warming” then you should be glad there is less ice as that means the planet is getting more cooling.
Of course natural systems tend to have lag times that we short-lived humans find irritating, on the order of decades to far longer. Overshot tends to be the norm. The Arctic Ocean is dumping lots of heat, but the evidence is mounting that we are in global cooling, the “heat reserves” are getting dumped. But still, it’s not the runaway global warming so you should be happy with it. Right? ☺
From Julian Flood on August 4, 2011 at 5:02 am:
(BTW Sorry for the delay, stuff happened.)
For such human-scale interactions, it is to be expected that theory follows real-world observations and the resulting “common sense” view. From my driving experience I can testify to how distracted driving leads to increased accidents and near-misses, and how “both hands on the wheel” is best. From the local TV news, by the reports of accidents involving use of a cell phone (including texting) it can easily be inferred that such increases the dangers of driving. Other reports, usually mentioned in conjunction with “no cell phones while driving” laws, confirm the hazards of talking on a cell phone are equivalent to control adjustments like with the sound system, while others have confirmed that hands-free and hands-on phone use are about the same as they both are distractions.
Actually Wikipedia says RHD was shown to be safer, but the data is old, they say it’s from 1969 research. Examining the source reveals the work was started in 1961, thus using data 50+ years old. It was noted:
No research using more-current data is known, and vehicles have changed greatly since then, with power steering as noted, increased use of automatic transmissions (no shifting while driving), more and more-complex center-mounted controls, the US slowed down (55mph national speed limit in the 1970’s), etc. Further research needed, indeed.
Rare to find a new vehicle on the American market without it though, at least among those with more than three wheels. 😉
About the “soupy” ice, and whether it will all melt away in the next few weeks: I had a look at 2007, and what happened between this time of year and the sea ice minimum, which in 2007 came fairly late in September.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=08&fd=07&fy=2007&sm=09&sd=25&sy=2007
It looks like there was more consolidation than melting, as a significant part of the ice appears to have thickened up in the lead-up to minimum.
So fears (?? why “fears” ??) that the remaining ice will melt away may possibly be misplaced. If it behaves as in 2007 then this year’s minimum might not be all that low. As always, I suspect, it will depend on the winds and currents.
@Mike Jonas
I don’t know Mike. It appears 2007 was really a wind-driven event. This year the freeze up was very slow and the thawing in place looks very significant compared to recent years. I watched those thin spots disappear last year and once they start going, they go fast.
We’ve gotten near 100K extent drops the past 3 days now and I don’t know how much was wind-driven, but the ice looks to be in worse (thinner and more distributed) shape for this time of year than any other year I can find on Cryosphere. Plus, the DMI surface temps are running right at the average, instead of below average as in the past decade or so, and temp anomalies are high across most of the Arctic.
I think the in-place melt over the next month is going to be significant. I’m one who thinks all this global warming baloney is just that, baloney (political baloney, mostly), and that the world is probably cooling, but this ice is not in good shape compared to prior years. Not at all. I’m sticking with under 4.5, my guess in all three polls in here.
Oopse, another hockey stick.
http://ocean.dmi.dk/arctic/icecover.uk.php
Like Rosannadanna would say, you should say “never mind”
@ur momisugly vergent.
The “new hockey stick” is clearly due to data loss.
See http://ocean.dmi.dk/arctic/icedrift_anim/index.uk.php. Choose ice concentration for 20110806 and you will understand the nature of DMI’s hockey stick.
DMI (Aug. 7) shows extent has plunged off a cliff and is now well below `07.
http://ocean.dmi.dk/arctic/icecover.uk.php
And Arctic-roos shows area (Aug. 6) rapidly closing in on `07.
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
REPLY: You really should read the front page of WUWT before commenting – Anthony
” but the ice looks to be in worse (thinner and more distributed) shape for this time of year than any other year I can find on Cryosphere. ”
Yup. It looks absolutely horrible compared to other years. It`s going to go very, very fast. I don`t believe in agw either, but nonetheless the Arctic ice cap is in terrible shape.
Why hasn’t the Navy’s Polar Ice Projection issued a new analysis since August 5th?
This appears blank to me – http://www7320.nrlssc.navy.mil/pips2/archive/retrievepic.html?filetype=Thickness&year=2011&month=8&day=6
Do they often get this far behind?
Does no-one want to comment on the current JAXA data?
re NW Passage: check out the St. Roch (wikipedia):
Judging from the current ice coverage images, the NA side of the Arctic Ocean is heavily iced, but the Russian side is wide open. Russians are more trouble and more dangerous than ice flows, I guess!