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Kevin McKinney

Thanks, Neven--I was waiting for the PIOMAS number. Now I think we are ready to really summarize all of this.

L. Hamilton

Sorry, the 10/3/2011 date on my 2012 graph implies clairvoyance (or re-using last year's do-file). At Photobucket I've replaced it with a more plausible 10/2/2012.

Wipneus


PIOMAS update:
Latest value : 2012-9-30 3.578
Minimum value: 2012-9-18 3.263


I have updated my graphics at ArctischePinguin for the September data:

Monthly data Colors where changed for better visibility (I hope).
Daily data
Daily data with a "prediction" based on exponential trend
Daily Anomalies

Since the yearly minimum is known, the following graphics where updated:
September minimum with several "fits"
Exponential still has a slight advantage over alternatives. Note that the linear trend calculated for
the last 15 years now crosses zero in 2019. An "alarmist's" exponential fit is not required to predict zero ice vefore the end of the decade.
September exponential fit with confidence intervals
September linear fit
September gompertz fit

Old versions of these graphs are still available for a while under "./archive/Saved PIOMAS 2011 graphs/".

Oh, there is also:
a video of the ice thickness 1978-2011 based on PIOMAS gridded data.

LRC

@Neven: "There are two lines of evidence for this"
Think we could also add the continuing observations of scientist on the field that what they are seeing are not isolated just to their current locations. I would also add myself that a high percentage of that thickness is rotten ice.
Side note: which would have higher insulating values trapping in heat, rotten ice with a thin layer of FYI or solid 2nd yr ice?

Wipneus

The scientists at the PSC say this about the September update:

Monthly averaged ice volume for September 2012 was 3,400 km3. This value is 72% lower than the mean over this period, 80% lower than the maximum in 1979, and 2.0 standard deviations below the 1979-2011 trend. September ice volume was about 800 km3 less than the prior minimum on September 10 2011 though this difference is within the estimated uncertainty of PIOMAS. In contrast to the dramatic reduction in ice extent, the 2011 to 2012 change in volume was in line with volume losses that occurred in previous years, with 2007 and 2010 losses being substantial greater.

http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

Frankd 1977

The number I've been reading from multiple sources (mostly linked though this blog) is that the arctic has been loosing 900 km3 per year according to Godiva 2. If that continues from the September 2012 volume of 3400 km3; it means a completely ice free arctic ocean in the (early) summer of 2016.

I didn't want to believe the sea ice decline was exponential back in 2010, but I guess I'm left with no choice at this point!

Neven

Thanks, Wipneus. I've added your graph as ell.

Wipneus

One more tidbit:

September 1979 minimum: 16855 km3
September 2012 minimum: 3263 km3

That is less than 19.4% left. Over 80% of the summer ice volume is gone.

In a more or less exponential (doubling time of decline 7.8 year) way.

GeoffBeacon

Yesterday's NSIDC press release says

Climate models have suggested that the Arctic could lose almost all of its summer ice cover by 2100, but in recent years, ice extent has declined faster than the models predicted. Serreze said, “The big summer ice loss in 2011 set us up for another big melt year in 2012. We may be looking at an Arctic Ocean essentially free of summer ice only a few decades from now.”

Comments?

Freewayblogger.blogspot.com

I've managed to reach a lot of people using this method:

http://www.freewayblogger.com/wakeupandsmellthepermafrost.htm

enough, in fact, so that when you type "wake up and" into google, "Smell the permafrost" is the first suggestion... at least out here on the west coast.

Anybody got any slogan ideas about the Albedo Effect?

Chris Alemany

Just a thought in relation to the talking points (i know i know)... are these graphs available for the Southern Hemisphere?


...... perhaps I can stare at them for awhile and convince myself it'll all be alright.....

Cheers.
Chris

Account Deleted

Geoff it depends on what they mean by essentially free of summer ice. Some people seem to be suggesting that 1 million Km^2 is ice-free essentially ice free. Which I think is just giving ammuntion to the fruitcakes. When the first headline comes out in the next few years - saying the arctic is ice free using that definition - the Goddards and others will quickly blog that the ice scientists are making it up and the satelite still shows plenty of ice.

Account Deleted

Like they will probably take these two figures:
2011: 1.25
2012: 1.27

And say: look the ice is thicker in 2012, so we are in a recovery.

Ggelsrinc

Freewayblogger.

Reflect on not having sea ice, because the sunlight won't.

Thereoncewasawindmill.wordpress.com

Nice work Wipneus.

Here's an interesting exercise: Using the uncertainty intervals, you can calculate the probablility of seeing a new record for any year in the future.

By eye, for 2013 the probability of seeing a new PIOMAS record is approximately:
Exponential: 90%
Gompertz: 55%
Linear: <1%

For 2014 it is approximately:
Exponential: 98%
Gompertz: 80%
Linear: <1%

Al Rodger

The PIOMAS anomaly graphed year-on-year 2007-2012 through the end of the melt with timing of minimum shown. 2012 was the latest minimum since 2008, changing the trend toward earlier minimums.
Graph here (usually 2 clicks to 'download your attachment').

GeoffBeacon

Colin

So you think the Julia Slingo and Tim Lenton were probably right in the Parliamentary session I mention in Climate officials and climate provisionals... and that Peter Wadhams and John Nissen were wrong.

That would surprise me. It's not the impression I got from reading this blog over the summer. This is an important question and has consequences for me because I have been using this to confront politicians for the past few days.

How does your answer fit with the web page I am using to contact Connie the Environment Commissioner http://bkuk.com/eu . I've got a few more MEPs to promise to pursue this. Am I out on a limb? I can cope with any embarrassment but it wastes my time to follow up false stories.

Seke Rob

A few notes to the below 2 updated charts, one likened to DNA, but it's in regression:

1) 2012 was not a record melt in cubics. That continues to stand with 2010, but it's truly statistical (values on the drop-down bars.
2) The data was revised back to day 15 2012, so you know if any plotter merely appended the additional day lines.
3) Someone asked to extend the projection... well, not to the full zero, but 2017 it could be touching, if it continues like this. But, I think there will always be a 50-100 cubic km left or whatever that calves off the glaciers. Don't know how PIOMAS treats this. [This calving is helping the Antarctic to keep the extent up, maintains the denialiati's illusion].
4) 2nd chart, simple extrapolation, the new record low thickness [YTD] is computed as 1.46 meters remaining for the CT area. We now know that really melt on submerged ice above the xxx thickness long as there's not or has been substantial air temps of below -11C. (See waynedavidson poats)

Thereoncewasawindmill.wordpress.com

GeoffBeacon: You may want to read the comments on this post:
http://neven1.typepad.com/blog/2012/09/arctic-ice-melt-20-years-of-co2-emissions.html#more
and also this from Tamino:
http://tamino.wordpress.com/2012/10/01/sea-ice-insolation/

While many here, including myself, think that the Arctic will be largely ice free in summer by 2020 as a result of AGW, that does not necessarily mean we accept Wadhams or the Arctic Methane group's reasoning. I for one am very dubious of a number of their claims - they are one of the few scientific groups to whom I would attach 'alarmist' as a perjorative.

Seke Rob

A fresh Arctic sea ice records summary [didn't see any blog posts or news for Arctic-Roos, IMS or DMI to say what the final minimum was]

NLPatents

Vis-a-vis the exponential curve for volume, 2012 was almost a bit of a "recovery" year. When you look at last winter especially. I think we are at the point where annual variation will have a hard time overcoming the climate forcing and there will be records to the volume melt until its gone - absent some time of miraculous or catestrophic intervention.

Seke Rob

Re Thereoncewasawindmill.wordpress.com | October 03, 2012 at 13:49

Whether 2013-2015-2017-2020 where polar bears wont be leaving land at all, it's freakin' alarming without Wadham's input on methane. He's got the ear though.

GeoffBeacon

Thereoncewasawindmill

Thanks

There are more contentious aspects of the Arctic Methane Group's predictions but on the issue of Arctic sea ice collapse, Peter Wadhams has been out there in submarines under the ice for years watching it disappear and few seem to have heeded his reports.

He seems to have had a better handle on the sea ice losses than the conventional climate scientists - particularly the climate modelers. If I remember correctly he said to me "When it's a conflict between the real world and their models, the modelers believe their models."

The failings of CMIP4 & CMIP5 models have been discussed here (missing feedbacks etc) .... and theirs are the results that tend to get into the policy making chain but we can see they lag well behind the real world.

If we see that outliers such as Peter Wadhams have made better predictions than the mainstream, "more official" scientists, it raises important questions.

I was in the same meeting as a member of UK Parliament's Environmental Audit Committee yesterday. Posting here is part of my research before asking him to call for a further statement from Slingo and Lenton after this summer's events.

I need to do more research (which includes polling people of good judgment) before I do.

Guidance welcome.

Lennartvdl

Geoff,

Wadhams and Maslowski are supported I think by scientists like Jim Hansen in arguing that the/most sea ice models (amongst others) are not good enough yet to be trusted too much, to put it mildly. But Hansen also argues that many scientists suffer from a certain reticence and fear of being outcast as too 'alarmist'. Erring on the cautious side could in this case however be more risky than erring on the supposedly 'alarmist' side. So I think you have a strong case towards the politicians and the more people (and scientists) tell them so the better.

Lennartvdl

Even an average linear decrease of 400 km3/yr from now on would bring us below 1000 km3 in 6 years and to practically zero by 2020. Over the past 25 years the linear decrease seems to have been about 500 km3/yr on average. Over the past 10 years it seems to have been about 800 km3/yr. If that speed continues it would be about 4 years until the Arctic is ice free for the first time, and 3 yrs for the first time below 1000 km3. It seems Wadhams and Maslowski have a good chance of being right on the spot with their 2015/2016 projections.

Donald

Here is what I just posted to my FB page --

Question: when will this series hit zero?
1979: 16855
...
2005: 9159
2006: 8993
2007: 6458
2008: 7072
2009: 6893
2010: 4428
2011: 4017
2012: 3263

The numbers are the volume of Arctic sea ice remaining in September of the indicated year, measured in cubic km. This loss of sea ice has profound implications for our climate.

source: University of Washington Polar Science Center

Chuck Yokota

The link to Tamino's article in Thereoncewasawindmill's post makes me wish for a graph combining the insolation information with the sea ice coverage data, showing the energy absorbed by the Arctic Ocean through the year. I imagine the limits would be a bell-shaped curve representing a completely ice-free ocean centered on the summer solstice, and a much shorter but similar curve representing complete ice cover. The curve for the year's data would be a curve in between, skewed toward later in the summer due to the timing of the melt. Does such a graphical representation exist?

Jim_pettit

I've updated my PIOMAS volume charts, as well. No surprises: things are, as we all know, getting ugly. Or uglier...

The polar ("Death Spiral") graph shows just how close ice volume is getting to becoming non-existent in summer (click for larger image):

PIOMAS

This chart clearly shows that, in terms of percentage, the total volume lost this year was the greatest on record at 85.12% (click for larger image):

PIOMAS

And this chart shows how quickly the lines denoting maximum volume and volume lost are converging (click for larger image):

PIOMAS

Jim Williams

GeoffBeacon, the global models seem to be doing rather well on millennial timescales, and to be basically meaningless on decade timescales. If you want to know what the sea ice is going to do by 2300 study the models. If you want to know what the sea ice is going to do in the next 20 years you are better off listening to the statisticians than the modelers.

Andrew Dodds

Just from the numbers, it seems that if we have a big YOY decline, it reduces the final volume by about 2500km3 (2006-07, 2009-10).

If that happened now, we'd be down to a few hundred km3 left.. and at 1m think, you need 1000 km3 to get 1 million km2 Area.

So... given a big melt year, volume-wise, then we would be within touching distance of seasonally ice-free from next year onwards, unless there is a very large and surprising jump..

Nightvid Cole

So... given a big melt year, volume-wise, then we would be within touching distance of seasonally ice-free from next year onwards, unless there is a very large and surprising jump..

Keep in mind that as surface area decreases, more thickness has to be lost to get the same volume drop, so it becomes harder. Another way of looking at the same thing is that areas that melt out earlier in the summer (e.g. by mid-July) cannot contribute to the volume loss through the remainder of the season.

Of course, if large areas in the CAB do open up by mid-July the ice albedo feedback will kick in like crazy, but if it doesn't happen until mid-August, much less so. Time will tell...

Tommi Kyntola

Could someone explain the rationale behind the gompertz curve? Why would the last remaining blobs of ice have trouble melting? With all the major feedbacks being positive I cannot see but acceleration in the melt right down to the zero area/extent point.

idunno

Hi all,

Looking at this graph:

https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd4-1.png

...posted by Wipneus, above, it would seem that this year has not seen a volume minimum that is especially or unusually low, compared to the exponential trend. This is about what was expected.

Average weather, (new) normal volume loss...

Yet every measure of area and extent has plummeted.

Protege Cuajimalpa

Answering Geoff comment, I will say that Serreze and in general the NSIDC and the IPCC, are very wrong if they keep looking at SIE instead of Sea Ice Volume. They are also wrong thinking that Sea Ice will last until 2030 or 2040, because they are measuring only extend. Even NSIDC area numbers are increasing faster that NSIDC extend, so area will be a better base to start. It is important to highlight that no model is working correctly with extend, like NSIDC recently mention at the end of their August analysis:

http://nsidc.org/arcticseaicenews/2012/08/

Even if you ask Excel to establish the equation, you will find that there is little correlation in any SIE option. It is like trying to know the size of an elephant by measuring the gross of his nails. They are related, but not necessary correlated. It is important that 15% of ice cannot be 100% of ice, so it is better any model using area, but again, the important measure is volume, even if it is hard to get.

On the other hand, it is very important the September exponential fit with confidence intervals that made Wipneus:

https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd6.png

But I want to ask Wipneus to add the equation and the R2. I made it in excel and I found:
Y = 0.0134x2 + 53.247x – 52786
R2=0.9231

Looking at the R2, I will challenge anyone, if their model on extend can give the same confidence that we have with PIOMAS numbers, even if volume is hard to get.
On the other hand, PIOMAS on their last comment, they said:

“Monthly averaged ice volume for September 2012 was 3,400 km3. This value is 72% lower than the mean over this period, 80% lower than the maximum in 1979, and 2.0 standard deviations below the 1979-2011 trend. September ice volume was about 800 km3 less than the prior minimum on September 10 2011 though this difference is within the estimated uncertainty of PIOMAS.”

Even that the comment is honest, I don’t like what an ordinary reader could think when they read that 800 km3 is an estimated uncertainty of PIOMAS. It seems that their numbers can be very wrong. What it really means this uncertainty, is that a free ice Arctic could be 2018 or even 2020, instead of 2016. So given the fact that their numbers are correlated and they are taking into account volume (not just extend), it is important to make public that PIOMAS is the best model that humanity has. It also put us in great warning, because collapse is going to be faster that almost everybody anticipated it. From my point of view, we don’t need more models, what we need is to react to what AGW means.

Wipneus

Hi idunno,

I had been thinking the same things. Also whether there may be a negative correlation with the "exceptional" volume and area/extent:

Suppose the extent would NOT have plummeted,
more ice would have been spread over a larger area. It would have covered areas with warmer sea water and more volume would have melted. I think I see something similar in the last melting weeks in 2007.

Just thinking out loud.

idunno

Hi Geoff,

I'm not sure that any individual here has the right to set themselves up as a referee of the Slingo vs Wadhams discussion.

I think you do best, as you have done, to refer you interlocutor to discussions here and, even more so, to the actual data and information on the "Daily Graphs" link, above.

Then its a question of how you interpret the data. On volume, Slingo appears to see this:

https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd7.png

Whereas Wadhams sees this:

https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd6.png

I personally agree with Wadhams' view on this point. (Having said this, I also think that, when it comes to geo-engineering etc, somebody at AMEG watched too much "Thunderbirds" as a kid.)

Finally, if you are engaging with the UK EAC, then the aspect of their report that I found most depressing was that it seemed to conclude that it was all a subject that needed to be addressed in multilateral discussions with the Arctic Council and EU, etc. I saw nothing suggesting that the UK could achieve anything within the actual fiefdom of the UK Parliament. This despite the fact that of the two oil companies currently moving polewards, one (Cairn) is Edinburgh based and the other (Shell) is Anglo-Dutch.

I may be very wrong about this, but it seems to me that this does place both Cairn and Shell within the jurisdiction of Westminster.

Protege Cuajimalpa

When I said "Even NSIDC area numbers are increasing faster that NSIDC extend...", I should said "decreasing faster..."

Bob Wallace

Gompertz curve thinking.

I suspect a lot of it has been based on the belief that there would be large hunks of thick ice pressed up against the north side of Greenland and the Canadian Archipelago.

If you look at the sea ice thickness images posted here -

https://sites.google.com/site/apocalypse4realseaice2012/home/sea-ice-concentration-and-thickness-comparison

- you can see that the very old, thick ice is largely gone and there is no protection for what is left. It's now mobile enough that it's getting flushed out through the Fram Straight and down into the CA where it melts.

I'm guessing that by this time next year there will be no, or almost no, "red" left. The ice is going to be so thin and so mobile that it's more likely we'll see an accelerated melt rather than a slowing melt rate as we approach zero ice.

Bosbas

Protege - thanks for explaining that sentence "September ice volume was about 800 km3 less than the prior minimum on September 10 2011 though this difference is within the estimated uncertainty of PIOMAS." I have always been in doubt about what "this difference" would refer to. Could you suggest a better way to put it?

Wipneus

But I want to ask Wipneus to add the equation and the R2.

Protege, you will find these in the graph https://sites.google.com/site/arctischepinguin/home/piomas/piomas-trnd1.png

Protege Cuajimalpa

Bosbas:

If PIOMAS September 2012 uncertainty is 1,000 km3, I would like them to put their uncertainty as:

Monthly averaged ice volume for September 2012 was 3,400 km3 (+/- 1,000 km3). This value is 72% (+/- 8%) lower than the mean over this period and 2.0 standard deviations below the 1979-2011 trend. Regarding 1979, this value is 80% (+/- 6%) lower than the maximum in 1979.

In this way, we will know that in the best of the cases, we have lost almost 3/4 of sea ice volume against the 1979 volume or 2/3 of the 1979-2011 average. That contrast with the 49% loss of Sea Ice Extend that NSIDC reports over the average 1979-2000 (will be less SIE lost, if they report against the 1979-2011 average).

But best of all, then we will know the range and we can be confident that where PIOMAS stands for. As they write their September post, I could understand (maybe because English is not my native language) that there is a Sea Ice Volume decrease of 800 km3 against 2011, but because they are uncertain, maybe this melt did not happen at all.

Protege Cuajimalpa

Thanks for the answer, Wipneus. I want to ask you what will be your favorite forecast. For the comments that I have read in general, I thought that almost everybody agrees that we will be near ice free by 2016.

Chris Biscan

AMSU Channel 5 temps have ran into fisrt place by about .12-.13C right now over 2010.

Wild, so we are basically at record warmth globally attm.

Al Rodger

Bosbas,
The usual definitive thesis for the accuracy of PIOMAS is Uncertainty in modeled Arctic sea ice volume. Schweiger et al. (2011) here linked as a 5 Mb PDF. (Normally it is linked to behind a paywall.) It is still not the easiest of reads.
There are two difficulties with making PIOMAS accurate. The first is deriving a figure via the model from point thickness measurements. The second is deriving the change in thickness/volume with time. This second difficulty is (as I remembrer it) the big one. It is also the one that will become a lot less difficult when the likes of CryoSat2 start to provide thickness data. So far prelimenary results appear encouraging for an accurate PIOMAS.
Other accuracy figures that sometimes appear are the internal accuracy of the PIOMAS model, but these are (as I understand it) independent of the other (external) accuracy assessments.

Account Deleted

Geoff,

No I don't think the Slingo will be right, I suspect we will continue to see ice-loss out-performing the predictions.
However, I think they have to be cautious with how they are defining "essentially Ice-free". What seems to happen is the details/definition/science get lost in the headlines (the recent: Only a 100 Cod left is a good example of this), and it then give the denialist more "failed" predictions to make noise about.

Djprice537

it seems to me that this does place both Cairn and Shell within the jurisdiction of Westminster.

How is drilling in the arctic at all relevant to global warming? There are far bigger battles to be fought.

I am also amused by articles that attempt to suggest that we need to be cautious about developing the resources of the newly open arctic ocean so as to protect the ecosystem. We are wreaking havoc on that ecosystem right now! In 20 years nobody is going to be discussing damaging the fragile arctic ecosysytem. We will be far more concerned about the devastating effect on food production that drastic climate change has wrought.

Bob Wallace

"Keep in mind that as surface area decreases, more thickness has to be lost to get the same volume drop, so it becomes harder."

As surface area decreases there is more opportunity for thicker ice to be flushed out the Central Basin.

During the melt season thinner ice tends to push down against the remaining thick ice and prevent its escape through the Fram. If that thinner ice melts earlier it frees up the exit route, no need to melt the thick stuff in place when you can ship it to the Atlantic.

Brian Wind

Hi Folks
I'm an amateur naturalist and environmentalist reading this blog for about a year. First time posting here.Thank you for consistant and trust-worthy science.
What we are seeing here is: No arctic ice by 2015. We all see this. But by 2015, what will the Greenland ice be doing? Antarctic ice? Both melting much faster than expected, much faster than we want to admit. How about the possibility of massive methane release? How about severe weather and drought? And ultimatly agriculture... We cannot grow food with spiking temperatures and irratic weather, and global population will be hitting 8 billion people. Basic ecology and natural history suggest we are about to lose about 7 billion people within 20-30 years. I have young adult kids and I bet you do too. People around me think I am a nut if I discuss these things, so I rarely do, but I am sure we all see... We are looking at the beginning of a huge planetary catastrophe.

Twemoran

Brian

You are an optimist.

Seriously I share your concerns. There may well be reasonable solutions to some of the issues you raised, but at this late date no one in power seems willing to acknowledge that problems exist.

Terry

Terry

Lennartvdl

On modelling ice volume (and sea level) further into the future see this new article by Goelzer et al:
http://iopscience.iop.org/1748-9326/7/4/045401/article

As compared to this recent one by Meehl et al:
http://www.nature.com/nclimate/journal/v2/n8/fig_tab/nclimate1529_F3.html

Goelzer et al project until the year 3000; Meehl et al until 2300.

The first expect less than 2 meters of SLR at most by 2300 and about 1 meter/century by the end of the millennium.

The second seem to think almost 3 meters is likely under BAU by 2300, but don't exclude a risk of up to 12 meters and about 5-6 meters/century by then.

How seriously should we take this risk? And how serious should we take Goelzer et al?

Rob Dekker

GeoffBeacon,
I think you nailed the problem right on the head.
Reality seems to be outpacing our ability to model it, and Wadhams and Maslowski's projections turned out to be much more accurate than CMIP3, CMIP4 or even CMIP5 models.

I posted this issue at William Connolley's site, with a summary of the difference between models and reality in the Arctic :
http://scienceblogs.com/stoat/2012/09/18/wadhams-on-seaice-again/
Please note that William is a scientist and climate modeler, and that I have deep respect for how he has stood up for climate science in the face of intense scrutiny by climate change deniers and self-proclaimed "skeptics".

He mentioned that he is "going to duck out of that for now" since "there is more to look at" but also that "I'll return to it".

I'm really looking forward to his response on the discrepancy between models and reality in the Arctic, but allow me to make a note that may be relevant to the issue of extrapolation beyond scientific models.

The core problem that we are facing in my opinion, is that models are the best we have.
We, as an intelligent species, make future projections based on models. If it turns out that our models overestimate
(or in the Arctic case) underestimate reality, then we have nothing left over for future projection, except for wild speculation and prejudice (which is what science is supposed to eliminate in the first place) or figure out why our models are off.

In that sense, Wadhams extrapolations based on past trends may be right, but we would need to leave science behind to accept them. And that is simply not an acceptable argument to base any policy decisions on.
So, unless we want to throw overboard the very basis of science and reason that made us an intelligent species in the first place, I think we have no other choice but to figure out why our models seem to underestimate Arctic sea ice decline (and underestimate snow cover anomaly).

Beyond that (fixing our models and getting them rightly), we would be giving in to unscientific speculation, which would immediately invite unscientific speculation towards the other side, a side that is much more biased and much better funded than Wadhams and Maslowski combined.

Andrew Dodds

Lennartvdl..

I come to this from the viewpoint of a geologist, with a fair bit of experience of computer modellng.

Basically, from what we can see in the record, anything up to 10m/century, with spikes of 2m/decade are possible. However, this is within the context og the glacial/interglacial cycle - the current warming seems to be faster.

Modelling ice loss - sea or land - is a very fraught problem. You have an in-situ forcing, changes in external heat transport, albedo changes, induced weather changes, and in the case of land ice, changes in the physical properties of the ice sheet.

Thus far, where modelers have tried to simplify these features (because you have to to get anywhere at all..) it seems that this results in models that underestimate ice loss. This is reasonable, if there are parts of the system you can't model yet, you have to be conservative or your models can end up looking silly.

Anyway.. from past evidence, I would not be particularly surprised to see 3m or more of sea level rise by 2100, at least no more surprised than rolling a 6 with a die..

Lennartvdl

Andrew,

Seems fair in general. However, that 10 m/century is new to me. You have sources?

As far as I know, about 4-5 m/century during Meltwater Pulse 1A seems to have been the maximum speed in the past. But I'm just a layman, so may have missed something.

Lennart

Lennartvdl

Rob,

I think models are the best we have, if they have a minimum match with reality. We still have to judge that quality by some form of expert judgment or common sense, which still seems something better than wild speculation. Science also implies recognizing the limits of our knowledge, so the risk of putting too much trust in not yet fully enough developed models needs to be compensated by let's call it expert judgement. To me that's what Wadhams and Maslowski seem to provide, apparently to the annoyance of some of their colleagues?

idunno

Hi Rob Dekker,

"In that sense, Wadhams extrapolations based on past trends may be right, but we would need to leave science behind to accept them."

You've lost me. In what sense can you claim that taking observations of real world data, and then extrapolating predictions based on that data, is not science?

Also, both Wadhams and Maslowski are not marginal, underfunded figures. Both seem able to draw on the resources of their respective national Navies.

Conrad Schmidt

Protege:
I think you mean "sea ice extent" (extent is a noun) not "sea ice extend" (extend is a verb).

Yuha
"Keep in mind that as surface area decreases, more thickness has to be lost to get the same volume drop, so it becomes harder."

I've been thinking about this too and came up with this equation:


dV = E x dT

where

  • dV = volume loss rate, the (average) annual loss of ice volume from September to September.
  • E = sea ice extent in September.
  • dT = thickness loss rate, the (average) annual loss of ice thickness from September to September.

For example the equation for 80s is:


75 km3/a = 7.5M km2 x 10 mm/a

and for the decade 2002-2012:

750 km3/a = 5M km2 x 150 mm/a

(These are rough numbers obtained by eyeballing some graphs.)

The rationale for the equation is that any additional heat input (such as absorbed insolation) to the September extend area is almost completely spent on melting ice that would otherwise survive through the melt season. Additional heat input elsewhere ends up warming the ocean waters instead.

Up to now, the equation has been dominated by the dramatic increase in the thickness loss rate, which can be explained by two factors. First, when you start low, near zero, as in the 80s, a small increase in the average temperature can cause a large relative growth of the melt rate. Second, feedback effects like meltpond albedo effect and loss of multi-year ice have caused further acceleration. I'm not expecting this to continue, however. The thickness loss rate is already so high that any further growth is likely to be relatively small. In contrast, the reduction of ice extent is becoming more and more significant in the relative sense. This could mean a sigmoidal tail to the curves.

The real world is not that simple of course. There are effects like ice export through Fram strait and storm damage to the thinning ice that do not fit in the equation. Also plain natural variation can muddle the picture. 2007 and 2010 saw the ice volume drop by 2500 km3 from the previous year. A similar drop next year would leave less than 1000 km3 of ice. Thus, while there may be theoretical reasons to expect a sigmoidal tail, the ice might not survive long enough for us to see it through the noise.

Kevin McKinney

Goelzer et al. is not paywalled, which is nice! It seems reasonable enough to my amateur eye, if far from conclusive, and is conservative in some ways--CO2 is simply imposed according to emissions scenarios, and ice dynamics are not modeled in detail.

The authors describe the model used as of 'medium complexity', and investigated 4 emissions scenarios. The climate sensitivity of their model was low, (1.6 C) but this was compensated by higher polar amplification than most. They acknowledge considerable uncertainty.

Even so, it's not as 'comforting' to me as Lennartvdl perhaps took it to be. The sea level rise by 3000 varied from 1.1 meters to 6.8 meters--that last presumably involves loss of most of the GrIS, and the authors say that SRL was still increasing at the end of the simulation. And note that the whole point of the lowest simulation was to give a sense of what we are committed to already: that forcing was based on stabilization at 2000's CO2 levels, which we are already well past.

Wipneus
Thanks for the answer, Wipneus. I want to ask you what will be your favorite forecast.

Protege, I have some trouble answering this accurately. As a scientist (not in this area) I am used to look at all the available information and as such I don't have "favorites".

On the other hand an exponential function fits the spectacular decline of 80% from the original ice volume nicely. The question whether the remaining 20% will disappear the same way is not far fetched and I am interested in finding the answer.

Therefore I prefer to use the exponential to judge whether and when the "negative feed backs" will kick in. It is clear that if they don't do that sufficiently, ice will be "mostly gone" at some time before the end of this decade.

Lennartvdl

Kevin,

Goelzer et al would only be relatively comforting compared to for example Meehl et al. What I appreciate about Meehl's figure 3 is that they show explicitly a risk of much higher sea level than the models. But how well-founded is the estimation of that risk?

Goelzer et al do acknowledge uncertainty, but don't give an estimation of the potential magnitude of that uncertainty, perhaps because they consider that impossible. Still, indeed, that may give the larger public a false sense of relative comfort as far as the potential risk of SLR is concerned.

Lennart

Protege Cuajimalpa

Rob Dekker:
You are right that models are very important. I am just very concern that there has not been a clear UN agreement in actions against Anthropogenic Global Warming. I know that deniers have taken advantage with false models and prolonged too much the discussion on the reality of climate change. I also know that true scientist have underestimated the real pace in which climate change is happening. So I feel that we are facing several points of not return and it is extremely important to acknowledge the importance of climate change and put the needed resources on the possible solutions.

Best Regards,

Juan C. Garcia

Protege Cuajimalpa

Conrad Schmidt:
Thank you for your correction on “extent” vs “extend”. I haven’t practice my English in more or less 15 years, but I am looking to have it back.

Djprice537

Beyond that (fixing our models and getting them rightly), we would be giving in to unscientific speculation...

How is making direct observation of losses, far in excess of the models, speculation? It is called sampling and in this case we are sampling on a more or less continuous basis. In manufacturing (have had a 30 year career) periodic sampling is appropriate when a process is in control. Continuous sampling is advised when a process is drifting out of control. I would suggest that what we are seeing in the Arctic is a process that is drifting wildly out of control, not speculation but reality.

Nightvid Cole

Yuha,

Because extent is not constant, your equation needs to use the proper product rule:

dV = E dT + T dE

where T is defined to include the leads since we are using extent rather than area.

Djprice537

In complex processes (Surface mount soldering of BGA's and fine pitch devices would be an example in manufacturing) engineering models work great when a process is in control. This is not because the model has accurately quantified the impact and cross correlations of all inputs. This becomes evident when a change occurs. All models fail when rapid change occurs.

I am not a climate scientist but I would argue that climate is far more complex than surface mount soldering. Our models will never catch up to reality. When they seem to, some unanticipated change will throw them off again. We are now, I believe, firmly entrenched in a rapidly changing dynamic and we have, unfortunately, become spectators.

In a now famous interview of Karl Rove by Ron Suskind......

in the summer of 2002, after I had written an article in Esquire that the White House didn’t like about Bush’s former communications director, Karen Hughes, I had a meeting with a senior adviser to Bush. He expressed the White House’s displeasure, and then he told me something that at the time I didn’t fully comprehend –but which I now believe gets to the very heart of the Bush presidency.

"The aide said that guys like me were ‘in what we call the reality-based community,’ which he defined as people who ‘believe that solutions emerge from your judicious study of discernible reality.’ I nodded and murmured something about enlightenment principles and empiricism. He cut me off. ‘That’s not the way the world really works anymore,’ he continued. ‘We’re an empire now, and when we act, we create our own reality. And while you’re studying that reality – judiciously, as you will – we’ll act again, creating other new realities, which you can study too, and that’s how things will sort out. We’re history’s actors . . . and you, all of you, will be left to just study what we do.’"

In this case, a dynamic Artic is "history's actor" and we are left to study what it will do.

Espen

Antarctica:

I need some figures about the sea ice volume in Antarctica, but I dont know were to find them.
They will much needed in some arguments I have locally with some semi-denialists, they only have some few straws left like: Ice extend Antarctica , coldest ever measured this "summer" Antarctica, and Hubbard Glacier Alaska.

Devi869

When you cannot trust the models then you have to study paleoclimatology. Holocene Thermal Maximum conditions ~8000 years ago had led to summer ice far less than 2m km2 extent(possibly half than this). Temperatures over the arctic are reaching the HTM levels. So 2 sq km will be reachead very soon.

Andrew Dodds

Lennart -

http://www.nature.com/scitable/knowledge/library/ice-sheets-and-sea-level-in-earth-24148940

Gives a recent overview. Actually I think my 10m may have been slightly OTT, 3 is indeed closer.

Although, of course, the rate of change of temperature/forcing never approached the levels we are seeing now.

Lennartvdl

Andrew,

Nice overview, thanks. On Meltwater Pulse 1A there seems to exist some debate as to the probable sources and speed, with most estimates ranging from 3-5 m/century, but maybe even up to 10 m/century, if this Wikipedia entry is correct:
http://en.wikipedia.org/wiki/Meltwater_pulse_1A

Maybe that's where your 10 m/century came from?

Also see for example:
http://www.nature.com/nature/journal/v483/n7391/full/483549a.html

The dating here seems to be extremely exact (duration of the pulse of 340 years). Don't know how reliable that is.

idunno

Apparently, there are some new models being used for IPCC5, which do a better job:

http://www.climatecentral.org/news/scientists-refine-their-understanding-in-wake-of-sea-ice-record-15068

(The article, from the excellent Andrew Freeman also has some very interesting stuff on snow and melt-ponds.)

Looking at the final graph in the post above, PIOMAS thickness, it seems that thickness has been hovering just above 1 metre for the last 3 years.

I suspect that it cannot fall much below this. At a certain level of thin-ness, which I would guesstimate to be around 30-50cm, I think that the ice becomes so vulnerable to even average sea conditions, that it will be pulverised by wave action and disappear very rapidly.

Donald

[I]Continuous sampling is advised when a process is drifting out of control. I would suggest that what we are seeing in the Arctic is a process that is drifting wildly out of control, not speculation but reality.[/I]

From a mathematics point of view, the problem is that the feedbacks have kicked in. The models probably are roughly correct, but the rate of change has been understated, due to transient things like storms speeding up the disintegration of the ice and mixing of the water layers. Or like broken ice moving south through the Framm straight.

One way to explain the problem is to identify what negative feedbacks will eventually come into play to restrain the warming trend. My fear is that quite a bit of warming would need to occur before this happens.

Lennartvdl

The complete Nature-article on MWP 1A is here and explains the uncertainty margins:
http://sciences.blogs.liberation.fr/files/deschamps12nature-1.pdf

An earlier one gave a range of 290-500 years for a pulse of 14-24 meters:
http://oceanography.dal.ca/publications/files/Kienast_et_al._2003_Geol.pdf

It seems the uncertainty is gradually narrowing down, even if there's still quite some debate on the sources/causes.

Jim Williams

Donald: "From a mathematics point of view, the problem is that the feedbacks have kicked in. The models probably are roughly correct, but the rate of change has been understated, due to transient things like storms speeding up the disintegration of the ice and mixing of the water layers. Or like broken ice moving south through the Framm straight."

Maybe another way to put this is weather is what happens in 10-20 years and climate is what happens in 100-200 years.

It's not that the climate models are somehow wrong, but it is that we are asking them to forecast the weather.

Espen

Kimmirut first snow: http://www.kimmirutweather.com/

A few days ago it was + 6 C

Donald

Jim, The issue is one of feedbacks piling on feedbacks, which is what led Wipneus to recognize that an exponential equation best matches the data.

Here, the presence of storms, with 20 foot swells breaking up thin ice, is a predictable consequence of the newly opened water. The timing of this occurrence for 2012 probably was not predictable, so you are right in applying the term "weather" to the event, but such storms now are likely to occur fairly frequently and thus have become part of the Arctic "climate".

Jim Williams

I'd agree Donald, except that the climate can only be determined after the fact. Once we have determined the climate for 2012 some hundred years from now I'm sure the increased severity of storms will be a factor.

Conrad Schmidt

Protege:
You're welcome, but never mind the English, work on growing
a chin:-)

RunInCircles

I was reviewing the data from the Navy thickness charts and although there is less ice left at the end of this season versus 2010 the remaining ice is thicker than the ice in the same locations were in 2010.
So we lost more extent but the thickness of the very center of the ice pack increased. Can anybody verify that PIOMAS shows the same behavior?

Daniel Bailey

Just wanted to share some SkS author community thoughts on Goelzer et al 2012:

1. The authors hinge their best-case projection from the perspective of the year 2000, with CO2 concentrations at what appears to be ~360ppm and following a predicted trend that's clearly not going to happen; by the year 2012 where we sit the concentration is already off-scale for the "preferred model version," meaning the "preferred model version" has no demonstrated connection to reality, is in fact demonstrated to be wrong from inception. Plainly stated, the IPCC concentration scenario employed by the authors in the "preferred model version" was wrong and is useless for these purposes.

2. Here's a major problem with the paper - the Antarctic barely responds in the modelling, whereas in the real world Antarctica has shown very dynamic behaviour in every interglacial. The West Antarctic Ice Sheet has essentially disintegrated during interglacials, making it the largest contributor to sea level rise during previous interglacials.

3. But the biggest problem in the paper is this:

"Uncertainties of the ice sheet projections also arise from poorly constrained physics in prescribing ice-sheet mass balance, basal sliding conditions, and the effects of oceanic erosion of ice shelves and calving fronts. Such limitations are thought to be less crucial for the Greenland ice sheet than for the Antarctic ice sheet, but were not investigated further with the current model setup."

The dominant mechanism for mass-loss in marine-terminating outlet glaciers, calving at the terminal front, was not investigated for the WAIS. Thus, any attempt to use this paper to prosecute a claim of "It won't be that bad" is simply appalling.

The study is an interesting proof-of-concept modeling exercise, but little more.

Ethan O'Connor

I've added the 2012 September minimum point to Stroeve's PIOMAS vs. CMIP5 graph:

This illustration doesn't appear in the published paper ("Trends in Arctic sea ice extent from CMIP5, CMIP3 and observations, Stroeve et al 2012), but is from a presentation retrieved from http://www.cesm.ucar.edu/working_groups/Polar/presentations/2012/stroeve.pdf

Yuha

Nightvid Cole,

Because extent is not constant, your equation needs to use the proper product rule:

dV = E dT + T dE

You are rigth. My equation was badly formulated. What I meant was

dV = E cH

where H is the average net heat flux per square kilometer and c is some constant (with appropriate units). I used dT as a proxy for cH but that is not correct as you point out.

The rest of my argument still holds. H is not growing very fast anymore while E is starting to fall rapidly leading to slower ice loss. In theory.

Chris Biscan

http://www.drroyspencer.com/2012/10/uah-global-temperature-update-for-september-2012-deg-c/#comment-61877

I am Chris there.


I think it's a conspiracy. I think they have worked on a way to use the noise to slightly alter there data set. They said the warming is the same just the recent extra record warmth is spurious.

Yet there is literally ZERO EVIDENCE of it being spurious.

http://i174.photobucket.com/albums/w109/frivolousz21/compday-195.gif?t=1349393271

NCEP has spurious warming to it appears.


I think climate crook Christy and Dr. Roy have no room left to hold their personal position. And when you believe a lie you will go to the end of the Earth to protect if your self identity is tied to it, and there's is, there entire life's work is tied to this lie.

And there own data set is vehemently disproving it.

While all other evidence supports there data set.

Now they claim up to 0.2C of spurious warming?

I guess the record level energy imbalance globally was changed by David Copperfield.

Unlike Sea Ice there is very few people who can contest what they are doing.

I am so discouraged by this, If I am insane or that bias then I guess I am wrong.

But I can't even find one piece of evidence I am wrong.

On Americanwx of course no one says a word except to act like I am nuts.

Please check this out and give me some feedback.

Chris Biscan

http://i174.photobucket.com/albums/w109/frivolousz21/compday-198.gif?t=1349396311

check that out.

We will get more images like that with more and more red showing up.

Aaron Lewis

Geoff Beacon,
A key problem is that the climate system has very recently moved away from being in near equilibrium, with enough negative feedback processes that weather and climate tended to revert to the mean. In the past, how ever bad the weather got, we could ALWAYS trust it to go back to normal. That is no longer true.

With global warming, some of the negative feedback processes have been overwhelmed, and the system no longer reverts to the mean. We can trust the system to get warmer and warmer, and behave in ways that we have never experienced before. This it the behavior of a non-linear feedback system that is out of control.

The experts on non-linear feedback systems were Jay Forester and Ed Deming. It is worth going back and reading their (popular) books. (e.g., Limits to Growth and The New Economics ) They both point out that people, even highly trained scientists in other fields, do not understand the likely behavior of out of control, non-linear systems. They both validated this view by having people try to predict the behavior of various kinds of non-linear systems.

If students of Forester and Deming had been involved in the development of our climate models, our climate models would be very different.

Climate scientists are no more likely to correctly predict the behavior of an out of control climate system, than Forester's and Deming's students were likely to predict the behavior of an out of control industrial process.

Climate scientists think of the current sea ice as being like the sea ice of 6 years ago. The do not see it as thinner, and thereby having much less mechanical strength. They do not think of it as being warmer, and thereby having much less mechanical strength. They do think of how it has been "worked" and cracked over the last few years. These factors all combine to make it much more likely that the sea ice will break up into small pieces with huge surface area that will allow the Arctic sea ice to melt rapidly next summer. Add in the flows of latent heat into the Arctic since 2007, and the substantial loss of sea ice next melt season is reasonable rather than alarmist.

If you have any policy responsibility, read Ed Deming and Jay Forester.

Kevin O'Neill

Chris Biscan - Looking at the data Dr. Spencer posted, it's pretty obvious that the Aqua AMSU channel 5 shouldn't be used any longer. There's nearly 5 degrees of noise.

Now, as to whether this has biased recent readings and whether that bias is in a positive or negative direction - he is the project team leader and should know the preliminary results of their analysis.

Remember, if UAH departs dramatically from the other temperature measures - he'll be called on the carpet for it. I'm sure he doesn't want to be caught making another major mistake (like he did with the orbital decay error).

Fairfax Climate Watch

Espen, Antarctica has about 30 million cubic km of ice volume.

I suggest searching on noaa.gov for more details, or possibly nasa.gov, or maybe even usgs.gov

all those sites, while somewhat clunky, have some very useful data.

Neven

Very interesting, Chris Biscan. This comment made me laugh. Christy and Spencer constantly change stuff when the temps go up. They started doing that in 2010.

I'm sure we haven't heard the last of this.

BTW, how about this NCEP global temperature map?

Protege Cuajimalpa

Wipneus and Al Rodger:

I am still looking to understand PIOMAS uncertainty.
When I see the popular PIOMAS graph, I visually see +/- 0.8 [10^3 km3]. Regarding the “Uncertainty in modeled Arctic sea ice volume” that Al Rodger highlight, PIOMAS said on lines 29-31:
“yields a conservative estimate for October Arctic ice volume uncertainty of +/-1.35x10^3 km3 and an uncertainty of the ice volume trend over the 1979-2010 period of +/-1.0x10^3 km3/decade.”
On the other hand, at the Wipneus graph we have a 2.5 [10^3 km3] and it is the complex procedure to calculate the uncertainty that Al Rodger comment us.
Is there a simple way to know the PIOMAS September’s uncertainties or at least, for the 2012 value? Or we have an uncertainty in PIOMAS uncertainty?

Thank you for your answers…

Popular PIOMAS graph, with +/- 0.8 [10^3 km3]:
http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.png?%3C?php%20echo%20time%28%29%20?

PIOMAS Uncertainty in modeled Arctic sea ice volume (pdf):
http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/pubs/IceVolume-2011-06-02-accepted-with-figures.pdf

Wipneus graph:
http://neven1.typepad.com/.a/6a0133f03a1e37970b017d3c780730970c-pi

LRC

Daniel Bailey | October 04, 2012 at 22:21:
I to find it interesting that whenever there is talk about SLR in the next 100-1000 years GIS is the main topic. Yet anything I have read about scientists studying the WAIS the never talk about more ice it is all about how bad things are getting and that they are getting worse. What they also are talking about is heat getting to the ice sheets there through the back door of low warm ocean currents getting under that ice. very similar to what has caused the problems in the Arctic.
So if those currents can cause conditions so that vast amounts of ice can be broken away and exported. My thinking also is that it would not just stick with the WAIS but start spreading out in both directions I would think in a more exponential rate rather then a linear.
And has been noted many times the speed of a glacier seems to depend a lot upon what damage is happening at the tongue end of it.

Andy Lee Robinson

I have a new PIOMAS animation cooking as we speak.
Hopefully be ready tomorrow.
Pity can't update youtube videos with new content - perhaps in future YT videos could have a dynamic option for trusted users? - don't really want to clutter my channel with 12 almost identical videos a year, so perhaps best to do it yearly.
I can host avi/mp4 on my own servers for intermediate files instead.

http://www.youtube.com/watch?v=EnCy-R7mLHI is already well referenced, and brilliantly illustrates what's going on without data for the rest of this year. I don't think adding another video for every month is really worth it, unless....

Rob Dekker

Djprice537

How is making direct observation of losses, far in excess of the models, speculation?

You are right, it's not, Many scientists are involved in gathering observations, both present, and past (paleo-climate) reconstructions. And to gather these observations in an objective way, science and the scientific method are crucial.

But when we make future projections, we need a model. And of course, models are based on the laws of physics.
Climate is long-term weather, and weather is chaotic. So, when the best models underestimate reality (in the Arctic in this case) the problem is that we don't know if this is because we underestimated the chaos of weather in the long term (called "climate variability") or if we underestimated the response to some variable (such as GHG emissions).

And if models can't tell us the difference, which basis do we have to decide that it is one or the other ?

Wipneus
Is there a simple way to know the PIOMAS September’s uncertainties or at least, for the 2012 value? Or we have an uncertainty in PIOMAS uncertainty?

Thank you for your answers…

Protege, when I followed my class in "measurements in physics" decades ago, I was told that there are always uncertainties, especially in uncertainties :).

Now the best estimate on uncertainties we have on PIOMAS are those reported by their creators, about 1350 km3 in the absolute value. Year to year is probably applicable to the 700 km3 figure.

The confidence band that I draw in the figures must also include modeling uncertainties. That is you can draw several exponential functions that approximate the real data but differ in the expected value of say 2012.

This modeling uncertainty is about 1500 km3 (for 2012, based on data 1979-2011).
The final figure is a combination of the two sources of error and is plotted in the graph.

I hope this helps.



Rob Dekker

Juan Garcia

So I feel that we are facing several points of not return and it is extremely important to acknowledge the importance of climate change and put the needed resources on the possible solutions.

I don't disagree with you, but I think that the rest of the world wants to see evidence that we have reached "several points of no return" and a comprehensive analysis of how many resources should be allocated to exactly which "possible solutions".

james cobban

Brian Wind | October 04, 2012 at 07:14

"What we are seeing here is: No arctic ice by 2015. We all see this. But by 2015, what will the Greenland ice be doing? Antarctic ice? Both melting much faster than expected, much faster than we want to admit. How about the possibility of massive methane release? How about severe weather and drought? And ultimatly agriculture... We cannot grow food with spiking temperatures and irratic weather,
and global population will be hitting 8 billion people. Basic ecology and natural history suggest we are about to lose about 7 billion people within 20-30 years. I have young adult kids and I bet you do too. People around me think I am a nut if I discuss these things, so I rarely do, but I am sure we all see... We are looking at the beginning of a huge planetary catastrophe."

Brian, I share your forebodings. The fairly near-term future may turn out to be somewhat apocalyptic. Too many separate strands are tending in the same (negative) direction to allow one to reasonably expect a salutary outcome. Climate change, peak oil, suicidally psychopathic corporations and governments, mystifyingly bizarre US Republicans, etc., etc. As they said in No Country for Old Men, 'its not the one thing, its the dismal tide'.

As has been discussed on this blog, a main source of distress is likely to be food shortages due to widespread drought. I am beginning to learn how to grow my own food in case I am still around when things start to really change. I have just run across what seems to be a very informative site run by Jules Dervaes at

http://www.urbanhomestead.org/

He and his three young adult children produce about 6000 pounds (about 2700kg)of produce each year on their 1/10th acre city property. Watch this 15 minute youtube video, and perhaps you will feel as eager as I do to start digging in the dirt!

http://www.youtube.com/watch?v=7IbODJiEM5A&feature=related

Rob Dekker

Wipneus,
Thank you for keeping track of the exceptional decline of PIOMAS volume data. The graphs you compiled are compelling and convincing of imminent decline of Arctic sea ice.
The exponential fit that seems to match PIOMAS data is troublesome however :
If I recall the course in "control systems" at TU Delft correctly (it's been a while, so don't kill me on this) then only an unstable system would cause an time-exponential derivation from the mean (like a ball on a saddle will roll off) and make it collapse or expand to extreme extent.

I have often made the case that exponential extrapolation does not have any basis in physics (since it implies an inherently instable system) but that a 2nd, 3rd or even 4th order polynomial decline is possible IF and only IF the Arctic is more sensitive to external forcing (such as GHG concentration changes) than our models suggest.

What is your take on this issue ?

Kris

Neven asked:

BTW, how about this NCEP global temperature map?

Well, it's a bit frightening, isn't it?

One thing to pay attention to is Antarctica.
Apparently the overall extreme anomalous high temperature has lead to a record SIE.

Looks at first sight rather a contradictio in terminis. On the other hand it's just as could have been expected. The warmer Antartica's temperatures, all the more quickly glaciers will glide into the ocean, with as a result a more extensive SIE.

By the way, and unbelievable as it is, it has been raining at 01:53 in the middle of the night at Barrow.

Jim Williams

Neven: "BTW, how about this NCEP global temperature map?"

I think the interesting thing about surface temps lately is what is going on between Cape Hatteras and the southern tip of Greenland, though it's the SST anomalies which really show it off.

Jim Williams

http://www.osdpd.noaa.gov/data/sst/anomaly/2012/anomnight.10.4.2012.gif

The red outline about Labrador keeps getting bigger and redder.

Espen

Jim,

I may be the Gulf Stream changing direction?

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