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There are still a couple of days left to vote on the outcome of the melting season. The poll for NSIDC September average extent or monthly minimum (which is used for the SIPN Sea Ice Outlook) can be found here, and the poll for JAXA sea ice extent daily minimum can be found here.

Jim Hunt

The cyclones you refer to aren't entirely benevolent Neven. Here's my own take on the start of the 2017 Arctic big wave surfing season:

"Facts About the Arctic in August 2017"

If you can believe the models this weekend's storm produced 2.5 meter waves with a period of ~8 seconds heading in the direction of the ice edge on the Pacific side of the basin:

The next pulse of swell in a couple of days is forecast to be both larger and longer period. It will also be aiming in the direction of the Beaufort Sea marginal ice zone, or what's left of it at least. That is not what happened during GAC 2012.

John Christensen

Great update, thanks Neven!

I agree with the conclusions so far, but the deepening of the low this coming week will result in mixing with warmer surface waters, and with the Arctic sun descending we will start seeing more negative impact from the storms.

Too bad we no longer have the compactness ratio: Have you given thought to using arctic-roos area divided by arctic-roos extent to have some indicator on this? Seems very compact this summer..

Jim Hunt

John - Have you seen Wipneus' compactness graphs?


They do indeed show that this year the ice is more compact than several others in recent history. However there was a big reduction yesterday!


Great to have these updates, as the final act is yet to play in this year's volume-vs-compactness (among other measures) drama. The flattening of the two thickness graphs above certainly supports the "dodged a cannonball" narrative. But thickness could drop quite a bit further if the GFS forecast verifies (loosely in agreement with ECMWF at day 4). Circulation patterns will disperse some of the thin ice towards Siberia, while melting of thicker ice on the Atlantic side picks up somewhat.


Nice summary Neven, thanks.

I tend to agree with Jim, and love to speculate that the persistent cyclone is not as sweet with the ice in the month of August as it was in the month of June (2013). And not precisely with the state of this year.
Much of the remaining thin ice is melting out.

However, since, as the edge reaches further North,
- A lot of ice is MYI
- The water is colder
- there was never much insolation
- The ice is thicker and thicker
- It is almost mid-August
then once this storm fades away (one week?), I would not be surprised the melting slowly peters out with a relatively slow end of the season... as cold as this season has been overall. But we'll see.


Excuse me, I should have said *more ice is MYI and *there has been insolation but Albedo in the CAB has been relatively high for much radiation to be absorbed, per the Albedo potential charts of Nico Sun.

John Christensen

Thanks Jim, had not noticed that!

Yes, navegante; surface temps are starting to creep downwards ever so slowly in the high north - will be interesting to see how this next (last?) summer storm plays out.

Wade Smith

[snip, off-topic; N.]

Wade Smith

[snip, off-topic; N.]

Wade Smith

[snip, off-topic; N.]

Wade Smith

[snip, off-topic; N.]

Elisee Reclus

Yo, Wade Smith

Solar flux is always lower in N hemisphere summer compared to winter because the earth is closer to the sun in N winter. The earth's orbit around the sun is an ellipse, not a circle, and the resulting seasonal variation of solar flux at the top of our atmosphere is not trivial.

For example, the Nautical Almanac tells us the solar disc's semidiameter on 21 Dec is 16'.3, compared to 15'.8 on 21 June. Inverse square law does the rest.

Perhaps the anonymous "dataset on Solar Flux" you reference adjusts for this, but since you did not identify it, I could not verify that.

It is very misleading to gauge warming effects and causes solely on insolation because so many other processes are involved, such as albedo, global circulation patterns, and local weather. For the same reason, it is very misleading to look for one-to-one correspondences between any two phenomena, or short-term trends in any one geographical area.

Daniel Bailey

Thank you, Neven, for your vigilant moderation.


Don't mention it, Daniel. And good to see you again.

Daniel Bailey

Thanks, it's good to be here, as always.


According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average.


Despite this on August 1st the ice was nearly 4% thinner than 2012. From now to the end of the melting season an average melt (1.5M km^2 since 2002) will see 2017 close to 2007. A melt close to the trend (1.8M) km^2 will see a result well below 4M km^2 and hence below 2007.

With the very thin ice we started with, and looking at the way 2016 plummeted towards the end of the season, I expect that 2017 will end up with extent midrange between 2012 and 2017.


According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average.

Wow, I'm actually quite surprised by this. As I write in this blog post: "What's interesting is that despite all these weeks of ideal weather for ice retention (at least as far as sea level pressure goes, temperatures haven't been as low as 2013 or 2014)"

It seems I've been wrong about this, and I must admit it was based on my subjective observations (and in my memory 2013 and 2014 were pretty cold). I didn't actually check the numbers.

I'm going to have to start regularly doing that. It's too bad Andrew Slater is no longer around to make those great monthly temperature rankings.

So, despite being as cloudy and cold as 2013/2014, 2017 is still digging low (JAXA shows two century breaks). That's simply amazing.


Neven wrote

It seems I've been wrong about this...

You weren't, not even in the least. As this "NOAA Earth System Research Laboratory" is a just a giocattolo enabling you to alter reality according to your own taste. Remember, as it's name says, it's a laboratory.

Just to remind, end 2013 it was clear about all glaciers in the Northern hemisphere gained some lenght as well as some thickness. And in 2014 there was a general status quo or just a little bit of loss.

Whereas now, in 2017 glaciers are shrinking at record speed. Do have a look at the Rhone Glacier, Trift Glacier, Stubai glacier, Grossglockner, Mer de Glace, Schnalstall ecc... ecc... ecc. An not only in Europe, but all over the Northern hemisphere.

And while I'm intruding, I'll take the liberty to put a bold prediction: this year there will be a straight free corridor from Murmansk to the Bering Strait. With at worst no ice between this corridor an the Russian coasts.

Jim Hunt

DavidR/Neven - However see also my caveats about NCEP/NCAR R1 at:


It will be extremely interesting to see what ERA and MERRA come up with in due course.

Jim Hunt

The effects of the recent cyclone on the sea ice north of the Chukchi and Beaufort Seas is now readily visible:

"Facts About the Arctic in August 2017"

There's another pulse of significant swell due real soon now too. Perhaps Pen Hadow's mission to sail two yachts to the North Pole this summer isn't entirely beyond the bounds of possibility after all?

Jim Hunt

Kris - To be frank I don't think that's a "bold prediction" at all. I think it's a dead certainty, albeit not just yet:


The Northwest Passage is proving to be a bit more stubborn this year however.


I am happy to take a look at any other source of monthly data for specific regions that you can point me to.

At the moment NOAA-ESRL is the best source I know of monthly data that can be selected for a defined area. eg 67n+, 80N+, 30E-60W etc. It provides 70 years of data,

While it doesn't exactly match other estimates, it matches the trends very well. None of the various estimates in the Arctic exactly match each other but they all give a clear message.

Neven, If you want I can send you my spreadsheets after I up date them each month.

Jim Hunt

DavidR - I suspect your most recent comment should have been addressed to me?

If so did you follow my link and click through to WRIT? It:

Allows you to produce plots and timeseries for arbitrary ares of Planet Earth using NCEP/NCAR, ERA Interim, MERRA-2 and numerous other reanalysis products.


Neven, hi,
The sit is not as surprising as it seems. Summers in the Arctic have never been that anomalously warm. At least, not decisively when '07/'12/'13/'14/'16 and '17 are compared (2m temp is just one of the parameters).
Apparently N Hemisphere circulation has shifted into a somewhat protective mode for the high Arctic. And some positive feedbacks (more snow cover, more clouds) may have kicked in.
The reason this year is still near minimum is the ridiculously 'warm' winter season '16-'17.
I'm waiting in awe whether next winter will once more provide proof of a new regime. Analogue to a slogan in a former American election: "It's winter power, stupid..."


Jim, No I was referring to Kris's comment above. I start from the following page from NOAA-ESRL.

It provides the times series for the selected area so it is easy to display trends, rank months etc.

Kris's dismissal of that site without providing a link to one he finds more useful is disappointing.

Wade Smith

Okay, here's a way of thinking about the arctic sea ice area melt. Don't be fooled by the fact this year's melt season is no longer on pace to break the record lows.

For the month of July, based on the long-term linear trend line, it will take 4.14 years (round up to 5 years,) before the July Sea Ice Area Trend is below the July 2011/2012 actual data. Granted, if we have a really strong melt year, an individual year may still beat that record before the trend gets that low. This would mean that by 5 years from now, we will be averaging July Sea Ice Area equal to 2011/2012, and the low years will be significantly lower than the average.

This estimate is made by noting the difference between the trend line vs 2011/2012, and then applying the average trend loss to the difference between the last trend mean and 2011/2012. Which of course produced 4.14 years worth of melt needed for 2011/2012 to become the new "normal", so I rounded up to 5 years in order to not be exaggerating the situation.

Wade Smith

Dr. James Hansen seems convinced that we have not yet passed a permanent tipping point, but if we don't change something soon we may pass such a point.


I found this speech interesting, and may listen to it again.

I'm not sure when the speech was given, but it was published last September.

Wade Smith

In keeping with the above calculation and the assumption of the current rate of net CO2 production continuing, the Arctic will be ice-free, even in the month of July, by 114 years from now, or about the year 2131.

Wade Smith

This year's data point for the July extent ended up being exactly on the trend line, which means this year's extent melt curve is a very good representation of the "new normal/mean".

Rob Dekker

DavidR said :

According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average.

Thanks David, for pointing this out !
As for the where this 'cold' resided during this summer, here is the NOAA spacial plot (May-July, 60-90deg) :

Note that the cold was most intense around the Laptev shoreline, incidentally the same location where the land snow lasted longest, and created that significant land snow anomaly this June :

Rob Dekker

OK, it looks like 'photobucket' wants me to pay $400/year to be able to post images from my photobucket library.
I am not amused, since I've been posting a LOT of such images over years in the ASIB comment sections (including the ones I really care about, like the 1935-2014 thread.
Some $10/year would be OK. But $400 is just ridiculous.
Let me see what I can do with the old images, but for now, here is the NCEP/NCAR spacial image that belongs in my previous comment :

Rob Dekker

Incidentally, in that image, you can also see the 'dipole' that has been dominating the 2017 summer.


Thanks, Rob. I'll be going on a holiday in two weeks, and will hopefully have some time there to do some proper comparisons. I find it fascinating to see how low volume makes conventional wisdom (with regards to the influence of weather conditions on extent decrease) partially moot. I remember noticing it for the first time in 2012.

Rob Dekker
I find it fascinating to see how low volume makes conventional wisdom (with regards to the influence of weather conditions on extent decrease) partially moot. I remember noticing it for the first time in 2012.

Yes. We will probably never know how close to total oblivion we came in 2012, but it may have been pretty darn close.

And now in 2017, with most of the major indicators (land snow cover, ice concentration, and ice 'area') suggesting a 2013/2014 'recovery' year was in the works, while 'extent' is still running close to record low, it is blatantly clear that we have dodged a canon ball as you suggested before.

Wade Smith

This year's September volume minimum will fall almost exactly on the projection of the 20 year trend line. Which means this year is also a very good representation of the "new normal/new mean" in terms of volume.

I doubt we actually beat 2012 for the record lowest September minimum, but we will come very close to it.

Basically it means the planet has worked out the corrections/over-corrections for the fact that 2007 and 2010 melt seasons were "way ahead of schedule" in terms of the average trend.

Others may have noticed that Volume and Extent seem to be converging to zero at inconsistent rates. The Volume trend suggests converging to zero in about 16 years, while the Extent trend suggests converging to zero in around 46 years.

Obviously, in the real world, these two values must converge to zero at the same time. This means over the next few years we should expect some sort of additional dynamic adjustment in the sea ice melt behavior to compensate for this discrepancy.

Wade Smith

On the Regression lines for September Volume melt:

I think the 20 years linear trend is probably the best we have to go by for the present time.

I think the Exponential regression line is over-playing the melt. Even though the Keeling Curve is technically growing slightly exponentially, due to population growth, the Earth is a sphere, so the positive albedo feedback for each further unit of retreat of snow and ice is smaller than for the previous same-sized unit of retreat. This is roughly a hyperbolic effect, like the Gompertz curve.

I believe these two non-linear effects almost cancel one another, presently anyway, which is why the overall trend continues to be mostly linear; in particular after the past 5 years of corrections, counting this one.

So four out of the past five years for extent have fallen almost exactly on the 30 years trend line. Four out of the past seven years for volume have fallen almost exactly on the 20 years trend line. This suggests the linear trend lines are not quite perfect, but "good enough" for now.

There will be some sort of correction in the Sea Ice budget over the next few years which will cause the trend lines from Volume, Extent, and Area to all begin to converge to the same year, instead of being scattered around.

We are also "due" for another big "down year" sometime within the next few years, based on the past behavior of it happening about once every 3 to 5 years.

Wade Smith

Sorry, another thing to point out is the fact the 20 years linear trend for volume converges to zero in 2025, which is still within the 95% confidence interval for the exponential regression trend. This means it probably doesn't even matter which trend line we are using, since they are predicting an outcome which is within one another's margin of error.

Jim Hunt

Here's a Typepad compatible animation from Wipneus, revealing the effect of the two recent cyclones on the Pacific side, plus everything else that’s been going on in the Arctic too:

Click the image to see a much larger (3.3 Mb) version.


[snip, off-topic; N.]


NSIDC tells us: The linear rate of decline for July 2017 was 72,500 square kilometers (28,000 square miles) per year, or 7.4 percent per decade.

I find this fact, that every 30 years the sea ice in July decreases by 20%, alarming.

I think the case for change has been well and truly made and I expect Trump will act to win his second term. He appears to just be seeing how far the markets are prepared to come to the party, giving the captains of industry as much confidence as possible in his country and so winning friends on the economic front, but I suspect he will need the environmnentalists and he will do something to gain them in circa 2 to 3 years.

I'm sure the same case I have outlined above will only strengthen. So if all this happens I think Trump wasn't such a bad choice as he can argue he is the type to simply wait for rock solid numbers to come in: bang, second term! Back to market forces with the newly altered government intervention strategy that provides some solid environmental outcomes to win him the second term.

Hans Gunnstaddar

Several months ago there was a discussion as to what was causing CO2 numbers out of Hawaii to increase to ~3 ppm added per annum vs. the usual 2.2 average. Below is a link with info. answering that question:


"Record rates of atmospheric CO2 accumulation during 2015 and 2016 correspond with large belches of carbon from tropical forests as a result of severe heat.

Elsewhere, this added burst of carbon did not go unnoticed. And measurements from NOAA’s Earth Systems Research Laboratory indicates that rates of atmospheric carbon accumulation sped up as El Nino and global warming based heat baked the tropical lands. During 2015, rates of atmospheric carbon accumulation accelerated to their fastest pace on record — growing at 3.03 parts per million per year. And in 2016, the second fastest rate of atmospheric CO2 accumulation on record was recorded — 2.98 parts per million per year. This compares to an average 2.2 parts per million annual accumulation that’s primarily driven by fossil fuel burning."

Wade Smith

Oh well. This looks bad.

There's still a chance we could see a semi-normal recovery season, I guess, but every evidence is that we are probably about to see a verify of last year's Global Area meltdown instead.


Hans, I checked that Scribbler article and the graph was worth thinking about.

I like this site: http://glaciology.ethz.ch/messnetz/glacierlist.html

This says 90% of the measured glaciers in the swiss alps are in retreat, atleast in reference to 2015. It gives you some numbers on the individual glaciers so I find it a port of call worth looking at.


Perhaps some radical thinking is needed:

"I know the feeling. But it’s not just the car manufacturers; it is the oil industry that makes the fuel, the construction industry that builds the sprawl, the infrastructure industry that builds the bridges and highways. It seems sometimes that the vast majority of the economy is built around the car."

source: https://www.treehugger.com/cars/its-time-free-ourselves-our-thrall-metal-god.html

If you read Nietszches 'Will to Power' he talks a lot about decadence.... it's about time to wake up I think...

Jevons Paradox is the business plan and blood for oil wars are fought to keep it going... Monbiot is saying electric cars aren't a good enough solution but rather the demand for insane independance has to be kept in check but that isn't going to be easy because the industry is about selling you your independance.

Wade Smith


I agree. The U.S. especially, and Western Civilization in general, actually gives individuals and corporations more "rights" than they rationally should have.

The "right" to own a firearm is not rationally "fundamental".
The "right" to burn 1 ton of Coal per person per day is not rationally "fundamental".
Currently, according to James Hansen, people in the Northern U.S. burn more than twice as much carbon fuel per person, per year than do people in the southern U.S. Yet people in the Southern U.S. tend to be the ones most heavily affected by climate disasters. He doesn't have a personal bias here, because he actually lives in the northern U.S. these days. He literally called this "Unconstitutional" in a recent speech; Also pointing out that certain other nations which contribute very little to pollution are going to take it on the chin as bad or worse than any U.S. state. It's hard to imagine a place which is going to be affected more heavily than Louisiana or Florida over the long term, but there actually are entire nations which are going to be affected more heavily than Louisiana or Florida over the long term.

We need something like 10 different Constitutional Amendments to fix the ethical and moral problems in the U.S. today, and we cannot even begin to fix the Global Warming related problems before then, because we can't get enough people to acknowledge that Global Warming exists at all, never mind that at least 1/3rd of it is man made, and the portion which is man-made will overtake one half of the entire effect, if it has not already done so, within the next decade or two. Within the next decade or two, sea level rise will overtake twice as fast as the average of the past 8000 years.

So how are we supposed to stop Pollution before we get people to admit that, "Oh by the way, you actually don't have a 'fundamental God-given right' to live just any lifestyle you choose to live"?

Wade Smith

For "christian" hypocrites, there is no Biblical law giving man a "right" to be a Republican (nor Democrat), and certainly not waste and destroy nature.

In fact, there are Biblical laws and proverbs condemning the waste of animals, for example, and putting moral responsibility for the environment on humans...So then why is it that so many "christians" are science-denying Republicans, who also deny responsibility to the environment, and also deny medical science? Never mind the fact that their Daniel was called a scientist, and their Luke was called a Physician. You'd think that if there were any intellectually honest Republicans, they'd have to stand up and call the others fools, but nobody does that.

By the end of this decade or next, humans will be contributing 50% of the entire sea level rise effect, and by the end of this century, with business as usual, humans will be contributing 90 to 95% of the entire sea level rise effect...if not more than that.


The PIOMAS updates are updates of sorts, but mostly restricted to all things Arctic. Please, don't veer off every which way. At some point I'm just going to block you guys, because snipping becomes too much work (I have a forum to moderate as well).

John Bilsky

"We need something like 10 different Constitutional Amendments to fix the ethical and moral problems in the U.S. ..."

Ummmm Wade? This is WAYYYY off topic and I'm surprised that Neven didn't snip it. But since you pushed a tender button I'll say this: You cannot legislate ethics or morality. Please keep the politics and religious implications somewhere else. These opinions don't belong here IMO. Thanks.

Robert S

Over the next few days it looks likely that a huge plume of wildfire smoke will be pulled out across the ice north of the CAA. It'll be interesting to see if an albedo effect shows up next year as the melt season progresses in that area.


1) Recent trend has been not-so-hot summers with much warmer than average winters. So I suspected that date of Sept. minimum Extent might be getting later. But NSIDC chart does not show that recent minimum dates are earlier than 1981-2010 average. Seems counterintuitve.

2) PIOMAS only updates monthly. Is there a volume estimate that updates daily like the NSIDC Extent graph?

3) The % Sea Ice Conc. image is nice addition to NSIDC. Would be interesting to see August 2012 or even Aug 2016 version to get sense of how much changes in last month of melt season.
2017 extent is currently higher than 2012, but much of it looks like it could go quickly in remaining weeks of melt season. But that's complete guesswork without previous sea ice concentration graphs to compare against.

4) One possible pattern is new record minimum 2 years after big El Nino. That puts the spotlight on 2018. Another soft winter like the last two and that could happen even with another not-so-hot summer in 2018.


typo - should have said "But NSIDC chart shows that recent minimum dates are earlier than 1981-2010 average."

Hans Gunnstaddar

"Would be interesting to see August 2012 or even Aug 2016 version to get sense of how much changes in last month of melt season."

I agree, gkoehler. Looking at current conditions would be much more informative and comparative if there were past year examples for that same date/period of time, in my opinion particularly with ice concentrations.

Comparative views are often done in updates but would be even better if available on a daily basis. I sometimes see something that looks unusual from memory of previous melt seasons but have no way of knowing for certain if it is.

But maybe we just don't know where to seek out that information?


Daily concentration charts are available from NSIDC on their Charctic page by clicking on the desired date in the graph. Hope this helps, Paul


2) PIOMAS only updates monthly. Is there a volume estimate that updates daily like the NSIDC Extent graph?

Not in numbers, but there are two thickness maps on the ASIG (scroll down to the volume category). DMI and ACNFS.

And this melting season PIOMAS is also updated mid-month, after special request. The numbers are posted on the ASIF (not in yet for this mid-August).

But that's complete guesswork without previous sea ice concentration graphs to compare against.

On the ASIG there are also Concentration maps pages that allows you to compare the current Uni Bremen SIC map with those of previous years since 2005. Check it out, as it takes a lot of time to update those pages.

Glenn Doty


As to your first point, regarding counter-intuitive earlier minimum extent... that isn't so counter-intuitive if you think about it mathematically.

The minimum extent has contracted - considerably - compared to the 80's, 90's, and 00's. So you have a smaller radius, closer to 90 degrees north.

When the sun begins to set at the top of the world, the temperature at the pole gets cold again, even as the warmer September waters continue to eat away at the edges of the icepack which are still in the sun.

But as the radius gets smaller, the point at which the sun sets on the edges of the icepack gets earlier, cooling the water attacking the edges of the pack while the center refreezes and begins its slow re-expansion.

As long as the extent continues to contract, you'll see the minimum continue to happen earlier.


So long as humidity and clouds don't trap that heat, in which case minimum could be delayed. 2016 had a quick rebound due to the high latitudes the retreat reached so quickly at the end of August. But October was scarily anomalous.
I am not saying this is going to happen this year. I don't find convincing arguments on why or why not this winter should be as anomalously warm as 2015 or 2016. But if it happens, well, will be scary definitely


Thanks to Hans, Paul, Neven and Glenn for pointers. Even though it looks 2017 will not reach record low for Extent or Volume, the thickness maps indicate that multiyear ice is below any previous year and close to elimination.

RE ice pack radius & latitude. Earlier min date makes sense in that context. That same issue limits carbon capture potential in the warming Arctic land area and punctures assumptions that agriculture can just move north with temperature gradient. Not only are northern soils not as suitable, but even as temperature gradient shifts, the solar radiation intensity for photosynthesis remains the same.

RE cloud cover - does increased area of open water in September create a reinforcing feedback for increased heat retaining clouds in autumn? Is that a possible driver for recent warm winters, or are they just a fluke?

Wade Smith

The Earth is fighting back.

It looks like my "six years, strictly worse," theory is about to get slightly debunked, which is a good thing, as it turns out. Well, it was a slight over-simplification of the data anyway.

Al Rodger

You were asking about comparing "% Sea Ice Conc. image" and that it "Would be interesting to see August 2012 or even Aug 2016 version to get sense of how much changes in last month of melt season.
The NSIDC Arctic Sea Ice News & Analysis page has a SEE ALSO box. The SeaIceIndex option has a CompareAnomalies function on the top bar leading to this page. It does allow concentration maps for different months to be compared with 2017 months (,indeed any complete month). If you run two internet browser windows you can even compare them to the daily map on the NSIDC ASI N&A's home page. Mind, the images are not as whizzy as the Satellite Obs of Arctic Change page, but that page only goes up to 2015.

Wade Smith

The 2010's average has been added to this graphic, even though we obviously don't have a complete 2010's data set.


So far, even with the rebound years, we're still already 950,000km^2 below the previous decade average.

This wasn't there a few days ago, last time I checked this page.

I still think "Area" is the most reliable measure we have for sea ice, because Area is slightly less effected by randomness, such as wind direction, than is Extent.

Still pretty bad outcome, because it looks like the overall pattern is still accelerating, even though some of the individual years for this decade had slowed down.

Wade Smith

Technically, "my 6 years strictly worse," theory isn't yet busted; Global Area is a lot worse than it was 6 years ago.

Daily record low global area just got broken again yesterday, and global extent has been holding daily record lows for quite some time now.

Susan Anderson

Glenn Doty, that insight responds to a puzzle I've had since last year. It completely makes sense that as the ice recedes the shorter days do just that. Thank you.

Jim Hunt, thanks for the Wipneus animation.

I would add my plea (and as an offender myself take note) for cutting back on excessive (and off topic, particularly on politics and human failings) commentary, particularly with regard to politics. The forum is the place for that.

Kevin McKinney

Following on from Glen's comment above, those interested will find a guide to Arctic sunset here:


FWIW, from today (Aug 18), the Pole will get sun for 36 more days; the 'mid-Arctic' will get sun for 4 more days, when it will then set for 26 minutes; and the Arctic Circle will receive 16 hours and 35 minutes of sun. So there you have it.


Thanks Al - Exactly what I was looking for.

Wade Smith

Wipneus should use a 3rd Order Polynomial Regression, not a 2nd Order Regression.

I've identified at least one 3rd order positive feedback mechanism, and I'm pretty sure there should be at least one 3rd order negative feedback mechanism. I don't know whether we yet have enough data points for a 3rd Order Polynomial Regression to be able to develop a higher Correlation Coefficient, but it should at least be viable.

Don't worry, 3rd order effects are very, very small, but they are definitely non-zero.

Jim Hunt

Whatever criterion you choose to use, I think it's now just about safe to say that the Northern Sea Route is "open":


The Northwest Passage isn't quite there yet. IMHO!

Glenn Doty

gkoehler, Susan Anderson;

I'm happy that I could contribute. I've lurked here for years, just attempting to learn. I'm passionate about climate change, but the cryosphere was such an alien world when I first took interest that it was nice to find a forum where people of significant knowledge gathered and discussed this seemingly unknowable world without many trolls or tangents (Neven really has given us all a wonderful resource here)... and I've learned a lot.

It's nice to give back when I can, and while the cryosphere is still more foreign to me than many regions... I spend my days as an engineer, so the geometry stands out for me.

That was a question I could answer.

Kevin McKinney, thanks for the link.

John Christensen

It's PIOMAS time again Neven.. ;-)


Absolutely, John. I didn't quite get it done this evening, but I will publish tomorrow morning.

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