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2015 Arctic Sea Ice Thread

The main factor is sea ice volume ... then, when there's much less ice, the wind becomes important.

By May 31st, there still were 600 cubic kilometres ice in excess to last years' volume the same date, and 3,000 cubic kilometres more than 2012's. The exceeding volume is not made mainly of ice that is melting now but ice that is multi-year and in the core patch, so, beyond the "variability ... blah, blah" bit, whatever speed the melting process has compared to recent years', it's going to slow down a little in the end.

Aiming at 5 million square kilometres, as I said recently.

About the (almost)Arctic sea ice "freeness", the fact that ice-free waters during Summer make easier for new ice to be created during Winter proves to be an inconvenient feedback for those prone to hop in any truck who takes them to Doomland.

An (almost) sea ice free Arctic requires relatively warm Winters -and that's a matter for greenhouse gases, which build up slowly in the atmosphere- and a steady pace in the multi-year ice melting that encompasses several years in a row.
 
CoolSceptic said:
Yes - internal climate variability absolutely dominates fluctuations in Arctic sea ice extent, in the form of winds and ocean currents; and these are internal parts of the complex, coupled, non-linear climate system and are sensitive to initial conditions, so not deterministically predictable.

But I have a particular interest in the 2015 sea ice level. Back in 2008, I cautioned people here not to read too much into the low level of arctic sea ice in 2007, noting one year was unlikely to be statistically significant on its own, and that rather more data was going to be required; and that understanding the significance of fluctuations required accounting for the long term persistence in the climate system, something which is difficult to do.

Nobody was willing to take me up on the offer of doing a calculation of the significance of the change; I think people realised that 2007 alone would not be significant; but CapelDodger told me it would become significant, and in determining that significance I should assume that in 2015 the Arctic summer would be ice-free. (link) CapelDodger was so sure of himself in this that he told me I could just do the maths right there and then.

I responded by telling him I would rather wait until 2015 for this "ice-free" Arctic summer. Just a few more months to wait for the answer now. Funnily enough, nobody back then was willing to offer the good advice you've given here - that things other than temperature are important in determining what the sea ice extent might be, essentially the point I was making at the time. Given the vitriol that was aimed at me around that time by various people, it is quite satisfying to see that my perspective seems to stand the test of time.
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2015 was the near margin of the range for "ice-free," if I recall correctly it was a fairly unlikely target, but at the time we were running quite ahead of schedule for a lot of related marker events. highest probability was somewhere between 2025-2035 for the first "ice-free" arctic summer but the odds of it not occurring until 2050 was about the same as it happening by 2015. If I were a betting man (and I generally am) I would still take the nearer end of that range rather than the further end. That said, it will be a while yet before the "ice-free" state occurs, yet alone becomes an annual norm.
 
Capeldodger from the link above
Assume an ice-free Arctic in, say, 2015 and you can do the math right now. No need to wait. Do let us know how that works out.
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So do the math instead of weaseling out. At least the US Navy is....

An ongoing US Department of Energy-backed research project led by a US Navy scientist predicts that the Arctic could lose its summer sea ice cover as early as 2016 - 84 years ahead of conventional model projections.

The project, based out of the US Naval Postgraduate School's Department of Oceanography, uses complex modelling techniques that make its projections more accurate than others.

A paper by principal investigator Professor Wieslaw Maslowski in the Annual Review of Earth and Planetary Sciences sets out some of the findings so far of the research project:

"Given the estimated trend and the volume estimate for October–November of 2007 at less than 9,000 km3, one can project that at this rate it would take only 9 more years or until 2016 ± 3 years to reach a nearly ice-free Arctic Ocean in summer. Regardless of high uncertainty associated with such an estimate, it does provide a lower bound of the time range for projections of seasonal sea ice cover."
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http://www.theguardian.com/environment/earth-insight/2013/dec/09/us-navy-arctic-sea-ice-2016-melt

Perhaps you should take it up with them

as for this

CoolSkeptic
Yes - internal climate variability absolutely dominates fluctuations in Arctic sea ice extent, in the form of winds and ocean currents; and these are internal parts of the complex, coupled, non-linear climate system and are sensitive to initial conditions, so not deterministically predictable.
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The usual bafflegab insinuating it's all natural cycles without influence from anthro sources of CO2 ...nothing new there.

Polar amplification reality AND modelling says you are wrong. You would have us think that say the ongoing loss of multi-year ice shelves and the reduction in multi-year ice volume have no influence....that it "starts fresh" each year. Complete nonsense.

http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2071.html

or if you are a Look instead of Life kinda guy

https://www.youtube.com/watch?v=p-qdbICw2f8

Good FEEM lecture...
 
CoolSceptic said:
Nobody was willing to take me up on the offer of doing a calculation of the significance of the change; I think people realised that 2007 alone would not be significant; but CapelDodger told me it would become significant, and in determining that significance I should assume that in 2015 the Arctic summer would be ice-free. (link) CapelDodger was so sure of himself in this that he told me I could just do the maths right there and then.
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If you're going to calculate the significance of an ice-free summer in 2015 then you will start by assuming an ice-free summer in 2015. That's what you're calculating the significance of. It's not remotely similar to an assumption that this summer would be ice-free. Have you been hovering for seven years over this waiting to pounce? Can the world really harbour such a sad dipstick?
 
CapelDodger said:
If you're going to calculate the significance of an ice-free summer in 2015 then you will start by assuming an ice-free summer in 2015.
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We calculate significance on real data for a reason. The calculation above is meaningless and worthless. It is like calculating the "significance" of homeopathy by assuming everyone who uses it was cured. What do we learn? Absolutely nothing.

It's also somewhat problematic and shows neither macdoc or CapelDodger really understand what goes into significance testing. When performing significance tests, estimates of various statistical parameters are made from the data set. Creating artificial series and estimating such parameters requires more things to be defined than a single data point. Even then the answer you get out is just the product of the fabrication you put in.

As I explained to you in the thread containing the quoted post, calculating the significance of everything that happens in your overactive imagination is an exercise in futility. I would rather wait to see what the ACTUAL sea ice area/extent would be in 2015. Which is exactly what I said in 2008, and which is exactly what this thread is about.

Anyway, teaching science to people who aren't interested in learning is not my favourite pastime. So I'll drop out here and let you lot ponder over whether in an alternative universe, where the arctic sea ice extent was zero in 2015 and where homeopathy cured everything, life was significantly different (geddit?), and I'll wait for the actual 2015 arctic sea ice data to come rolling in.
 
Growth in Antarctic sea ice extent has leveled off, increasing by just 250,000 square kilometers (96,500 square miles) between August 1 and August 17. This slow rate of growth has brought this year’s sea ice extent to below the 1981 to 2010 average for the first time in nearly four years.

http://nsidc.org/arcticseaicenews/
 
Growth in Antarctic sea ice extent has leveled off, increasing by just 250,000 square kilometers (96,500 square miles) between August 1 and August 17. This slow rate of growth has brought this year’s sea ice extent to below the 1981 to 2010 average for the first time in nearly four years.
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Denier references to Antarctic sea-ice are also at a four-year low for the time of year. In fact I don't recall seeing any yet.
 
That really is off topic for here but would support its own thread as what is going on down there is very interesting and long term rather dire.

Latest I read was the larger extent is trapping warm water underneath and accelerating the loss of the old ledges.
The freezing extent being created by a combination of fresh water sitting on top and freezing faster and a tightening and increasing antipode polar vortex keeping cold air in place

I imagine there may be limits to that process which may have been reached this year.
 
CapelDodger said:
Denier references to Antarctic sea-ice are also at a four-year low for the time of year. In fact I don't recall seeing any yet.
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ROFLMAO - good luck with that theory. Of course, those of us who correctly recognise that recent variations in Arctic and Antarctic sea ice are driven by unpredictable wind and ocean currents that are sensitive to initial conditions and not predictable, are not surprised at all that fluctuations may go down as well as up. It's natures way.

More entertaining: *if* natural variability causes the Antarctic sea ice to fall will be seeing alarmists who have been insisting for the last few years that Antarctica was "special", and didn't count, suddenly claim it does count after all and switch to promoting it as more proof of global warming. A bit like the horoscope writer that suddenly switches to claim their prediction of the future is whatever happened to turn out.

On a more scientific note, does anyone know why EUMETSAT currently appears to shows a discrepancy with regard to sea ice in comparison to the GCOM-W AMSR2 and DMSP SSM/I instruments?
 
CoolSceptic said:
...More entertaining: *if* natural variability causes the Antarctic sea ice to fall will be seeing alarmists who have been insisting for the last few years that Antarctica was "special", and didn't count, suddenly claim it does count after all and switch to promoting it as more proof of global warming. A bit like the horoscope writer that suddenly switches to claim their prediction of the future is whatever happened to turn out...
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Sounds like a bold and unsupported assertion that is more common to low information "skeptics" than actual climate science. Perhaps you should start a conspiracy thread so we can examine your divinations in more detail in a relevant thread.
 
sphenisc said:
Growth in Antarctic sea ice extent has leveled off, increasing by just 250,000 square kilometers (96,500 square miles) between August 1 and August 17. This slow rate of growth has brought this year’s sea ice extent to below the 1981 to 2010 average for the first time in nearly four years.

http://nsidc.org/arcticseaicenews/
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Correction to what you have said here. The graph in the link says that this year's sea ice extent is now 2 standard deviations below 1980-2010 average sea ice extent.
 
rjh01 said:
Correction to what you have said here. The graph in the link says that this year's sea ice extent is now 2 standard deviations below 1980-2010 average sea ice extent.
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The graph is of Arctic sea-ice, sphenisc's text was on Antarctic sea-ice. Confusion was likely to ensue.
 
CoolSceptic said:
ROFLMAO - good luck with that theory.
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There's no theory involved, just an observation - that denier references to Antarctic sea-ice, recently very common at this time of year, are absent this year.

Of course, those of us who correctly recognise that recent variations in Arctic and Antarctic sea ice are driven by unpredictable wind and ocean currents that are sensitive to initial conditions and not predictable, are not surprised at all that fluctuations may go down as well as up. It's natures way.
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That's why the trend is important.

More entertaining: *if* natural variability causes the Antarctic sea ice to fall will be seeing alarmists who have been insisting for the last few years that Antarctica was "special", and didn't count, suddenly claim it does count after all and switch to promoting it as more proof of global warming.
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The Antarctic certainly is special - ask anyone who's been there. The causes of expanding Antarctic sea-ice in recent years are the subject of research and theorising. As to claiming it didn't count - count as what? Not as something more than natural variation - you yourself say it doesn't count as that. So what do they say it doesn't count as?

My theory is that you're making it up. Disprove it if you can.

A bit like the horoscope writer that suddenly switches to claim their prediction of the future is whatever happened to turn out.
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If you see that happen do point it out. When people celebrate what they believe other people will do it demonstrates how little they've actually got to celebrate.

What has actually been entertaining, of course, is watching actual deniers actually claiming that expanding Antarctic sea-ice actually proves that AGW isn't actually happening, then watching them actually go silent when it stops for a winter. (The latter behaviour was, of course, predictable and predicted; I'm just pointing out that it's happened.)
 
It's being incredibly melty at the moment with some mega day losses on both JAXA and NSIDC.
 
We're on the edge of the end of season.

Ice volume reaching its minimum (probably in 7-9 days):

August 26: 6,234 km3
August 27: 6,127
August 28: 6,047
August 29: 6,014
August 30: 6,005
August 31: 5,975 (1200 less than 2014's, 400 more than 2013's, and >2000 more than 2012's)

more than I expected (I said 5200)

Sea ice extent: 4.609 million square kilometres -MASIE- (forget Bremen and JAXA for comparisons with 2007 as they changed the algorithm in the meantime)

We're almost there (I said 4.3 to 4.9, NSDIC's)
 
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