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Arctic sea ice heads for record low
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A downward trend in summer extent actually began after the 50s, during the relative global cooling period pre-70s, and has accelerated in recent decades, as you would expect with the cumulative effect of proportionately more sea surrounding increasingly less ice. This therefore hints that it was something more than anthropogenic forcing that started this trend. I'm saying that if you look closer it is more marked during warm AMO, but also after a warm PDO, which has become more dominant in recent centuries, and around 20% more so in the last 100 years or so (around 57 warm years versus 47 cold). This warmer bias could be the reason for the increasingly downward trend we see in the chart above. You showed the AMO can account for up to 30% of the difference, and I'm just pointing out another pattern in the records that is fairly obvious to anyone looking at it objectively, eyeballing or not.
PDO reconstruction from 990 to present day.
Have you a link for that graph?
The graph itself shows perhaps the idea of the PDO following 30 year oscillations is a little daft! The issue I have with the PDO contributing to warming or cooling, I that the PDO itself is just a change in the distribution of SST anomalies as worked out through principal component analysis, and should not add to or take away from global or Arctic temperatures. ENSO on the other hand is a switch from +ve to -ve SST anomalies and vice verso, and so does influence global temps.
The drop levelling off and slight drop in temps from the 40s to 70s has also been attributed to increased aerosol pollution, and so trend spotting with short time-spans like that is pointless, especially when the mechanism for the PDO/global temperatures link has yet to be properly fleshed out.
Antarctic sea ice is doing very well anyway, currently highest on record for the time of year, and second overall to 2007. Unfortunately, it's not enough to balance the Arctic ice loss.0 -
Have you a link for that graph?
The graph itself shows perhaps the idea of the PDO following 30 year oscillations is a little daft! The issue I have with the PDO contributing to warming or cooling, I that the PDO itself is just a change in the distribution of SST anomalies as worked out through principal component analysis, and should not add to or take away from global or Arctic temperatures. ENSO on the other hand is a switch from +ve to -ve SST anomalies and vice verso, and so does influence global temps.
The drop levelling off and slight drop in temps from the 40s to 70s has also been attributed to increased aerosol pollution, and so trend spotting with short time-spans like that is pointless, especially when the mechanism for the PDO/global temperatures link has yet to be properly fleshed out.
Antarctic sea ice is doing very well anyway, currently highest on record for the time of year, and second overall to 2007. Unfortunately, it's not enough to balance the Arctic ice loss.
The graph is off Wikipedia, based on the following study.
http://www.agu.org/journals/ABS/2005/2005GL022478.shtml
It also cites these in reference to PDO reconstructions for various periods.
http://www.ncdc.noaa.gov/paleo/pubs/biondi2001/biondi2001.html
http://www.agu.org/journals/ABS/2006/2005GL024804.shtml
http://adsabs.harvard.edu/abs/2006IJCli..26.1607D
That graph is not much use on a decadal scale alright, which is why I posted this monthly one in my original post.
I'm not sure why you say the PDO cannot affect the Arctic as it too is an alternating distribution pattern of SST anomalies. It is possible that the strengthening effect of the warm PDO on the Aleutian Low will cause higher Arctic melt in the westerly latitudes, and possibly more meridionality in the pattern upstream over northern Europe and Asia, where we are seeing the greatest retreat. Just because this link has not been "fleshed out" doesn not mean it doesn't exist and should not at least be looked at.0 -
The graph is off Wikipedia, based on the following study.
http://www.agu.org/journals/ABS/2005/2005GL022478.shtml
It also cites these in reference to PDO reconstructions for various periods.
http://www.ncdc.noaa.gov/paleo/pubs/biondi2001/biondi2001.html
http://www.agu.org/journals/ABS/2006/2005GL024804.shtml
http://adsabs.harvard.edu/abs/2006IJCli..26.1607D
That graph is not much use on a decadal scale alright, which is why I posted this monthly one in my original post.
I'm not sure why you say the PDO cannot affect the Arctic as it too is an alternating distribution pattern of SST anomalies. It is possible that the strengthening effect of the warm PDO on the Aleutian Low will cause higher Arctic melt in the westerly latitudes, and possibly more meridionality in the pattern upstream over northern Europe and Asia, where we are seeing the greatest retreat. Just because this link has not been "fleshed out" doesn not mean it doesn't exist and should not at least be looked at.
Cheers.
I agree that all possibilities should be looked into, including the PDO. But so far little research has suggested a strong link with the Arctic ice. It's great to theorise on possible links between the two, but that could really be done with anything. With the atmosphere as complicated a it is, evidence is needed to be actual science.
I'm actually doing a little work on the sea ice/PDO relationship at the moment, so I'll post up some of the results when I've a little more done, but with my masters starting soon, I'm not sure how much time I'll have...
Your second graph doesn't really show a clear +ve or -ve phase before the 30s, so I guess it may be a little hard to tell whether or not we should expect the current -ve phase to continue for much longer anyway.0 -
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I was waiting for the Antartic to show up.
A 10,000 Year Temperature Reconstruction was recently derived from a 1000 Ft Long Ice Core ...364m. It shows that excursions in temperatures, upwards, are not recent. However that was when the real fun started.
An article in Nature, based on the core science remarks of the temp rises in the past 100 years that: "The high rate of warming over the past century is unusual (but not unprecedented) in the context of natural climate variability over the past two millennia."
Indeed, it is a 10,000 year core so why concentrate on the last 2,000 one might ask. ??
However a PR released just before publication stated that the past 100 years were "unprecedented" followed by "very unusual" and now reads as plain old "unusual".
As The Register notes in a long piece on the story (they who watched the PR flip flop in real time and reported on the core itself) about the plaintive permacry of Global Warming.
"What this episode does show is just how blindly and unquestioningly the general scientific and media communities believe in the idea of carbon-driven climate apocalypse: the mindset of the PR staffer who wrote that press release and the various journalists who have uncritically reprocessed it is more reminiscent of religion than of science."
And now, the fat lady herself below and the full nature piece here
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html
From the Nature Piece.Here we show that the Antarctic Peninsula experienced an early-Holocene warm period followed by stable temperatures, from about 9,200 to 2,500 years ago, that were similar to modern-day levels. Our temperature estimates are based on an ice-core record of deuterium variations from James Ross Island, off the northeastern tip of the Antarctic Peninsula. We find that the late-Holocene development of ice shelves near James Ross Island was coincident with pronounced cooling from 2,500 to 600 years ago. This cooling was part of a millennial-scale climate excursion with opposing anomalies on the eastern and western sides of the Antarctic Peninsula. Although warming of the northeastern Antarctic Peninsula began around 600 years ago, the high rate of warming over the past century is unusual (but not unprecedented) in the context of natural climate variability over the past two millennia.
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Sponge Bob wrote: »I was waiting for the Antartic to show up.
A 10,000 Year Temperature Reconstruction was recently derived from a 1000 Ft Long Ice Core ...364m. It shows that excursions in temperatures, upwards, are not recent. However that was when the real fun started.
An article in Nature, based on the core science remarks of the temp rises in the past 100 years that: "The high rate of warming over the past century is unusual (but not unprecedented) in the context of natural climate variability over the past two millennia."
Indeed, it is a 10,000 year core so why concentrate on the last 2,000 one might ask. ??
However a PR released just before publication stated that the past 100 years were "unprecedented" followed by "very unusual" and now reads as plain old "unusual".
As The Register notes in a long piece on the story (they who watched the PR flip flop in real time and reported on the core itself) about the plaintive permacry of Global Warming.
"What this episode does show is just how blindly and unquestioningly the general scientific and media communities believe in the idea of carbon-driven climate apocalypse: the mindset of the PR staffer who wrote that press release and the various journalists who have uncritically reprocessed it is more reminiscent of religion than of science."
And now, the fat lady herself below and the full nature piece here
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html
From the Nature Piece.
I'm afraid I'm a little uncertain as to which parts you're quoting and which parts are your own opinion?
But anywayIndeed, it is a 10,000 year core so why concentrate on the last 2,000 one might ask. ??
A quick read of the abstract from the link provided shows they didn't
"Here we show that the Antarctic Peninsula experienced an early-Holocene warm period followed by stable temperatures, from about 9,200 to 2,500 years ago, that were similar to modern-day levels."
The register itself is spreading the lie. It claims the Antarctic warming is nothing unusual, when the abstract from the study claims the exact opposite (unusual but not unprecedented))!
The the register claims this little nuggetAs is plain from the graphs, it has often been hotter than it is now at Ross Island during the past 10,000 years - today's temperatures are nothing exceptional. The idea that they must result from man-made carbon emissions doesn't, on the face of it, seem that credible.
There is little scientific reasoning in the above quote. Climate changes based on whatever drives it, the current main driver being anthropogenic CO2.
As for who's lying
The Nature Article says warming over the past 2 century is unusual (but not unprecedented)
The British Antarctic Survey Arcticle said it was unprecedented, then unusual
The register claims the warming is nothing unusual
It seems clear to me who's doing the most lying! The BAS updated the article straight after they we're informed of their mistakes (I know who emailed them about it), whereas the Register still have their lies and nonsense in place for over a month.
To be honest, what this demonstrates to me quite clearly is the double standards, hypocrisy and and plain ignorance and idiocy that makes up so much of AGW denial.
But hey, whatever the author needs to generate a some good ol' controversy!0 -
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None of my bits are in quotes MiNdGaM3
there would be no Reg story had the BAS PR Not grossly overegged the significance of the past 100 years .
Antartic Sea Ice (not land ice but sea ice) is at its greatest ever recorded seasonal extent for this day of the cycle today (see yellow line Here from the Uni Of Illnois) not that I'll bother starting a thread on that mkays!!! Most of the other records seem to have been set in recent years. Yes it could have been caused by better satellites but it is a record.
To this
As for who's lying
The Nature Article says warming over the past 2 century is unusual (but not unprecedented)
The British Antarctic Survey Arcticle said it was unprecedented, then unusual
The register claims the warming is nothing unusual
You have a very confused description there.
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html
The NATURE ARTICLE WAS WRITTEN BY BAS SCIENTISTS, to Nature standards obviously. Click on the contributor names in there.
I have no issue whatsoever with the Nature Article.
The Nature article states that temps were stable for 1000s of years, then underwent a "pronounced cooling from 2,500 to 600 years ago" started to stabilise/rise 600 years ago and recovered rapidly in the past 100 years to the level they are at TODAY.
That modern level is the same as it was 2500 years ago and for 1000s of years before that.
The PR was then written by the BAS and put on their website baldly stating something that was NOT IN the Nature Article. They stated the rise in the last 100 years ALONE was "Unprecedented" ...leaving out the qualifier in the Nature article.
When this anomaly was pointed out to the BAS the PR was reworded by the BAS from "Unprecedented" to "Very Unusual" and then a second time to "Unusual"..same as what the Nature article said.
The person who wrote and rewrote the PR on the BAS website is the only person who LIED!
The rewording of the PR (twice) is the story, especially as El Reg caught them and catching PR BS is something it does rather well as a specialty.
The science itself is very interesting of course, not every day we get a 10,000 year Paleoclimatological Record is it???0 -
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Sponge Bob wrote: »None of my bits are in quotes MiNdGaM3
there would be no Reg story had the BAS PR Not grossly overegged the significance of the past 100 years .
Antartic Sea Ice (not land ice but sea ice) is at its greatest ever recorded seasonal extent for this day of the cycle today (see yellow line Here from the Uni Of Illnois) not that I'll bother starting a thread on that mkays!!! Most of the other records seem to have been set in recent years. Yes it could have been caused by better satellites but it is a record.
To this
You have a very confused description there.
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html
The NATURE ARTICLE WAS WRITTEN BY BAS SCIENTISTS, to Nature standards obviously. Click on the contributor names in there.
I have no issue whatsoever with the Nature Article.
The Nature article states that temps were stable for 1000s of years, then underwent a "pronounced cooling from 2,500 to 600 years ago" started to stabilise/rise 600 years ago and recovered rapidly in the past 100 years to the level they are at TODAY.
That modern level is the same as it was 2500 years ago and for 1000s of years before that.
The PR was then written by the BAS and put on their website baldly stating something that was NOT IN the Nature Article. They stated the rise in the last 100 years ALONE was "Unprecedented" ...leaving out the qualifier in the Nature article.
When this anomaly was pointed out to the BAS the PR was reworded by the BAS from "Unprecedented" to "Very Unusual" and then a second time to "Unusual"..same as what the Nature article said.
The person who wrote and rewrote the PR on the BAS website is the only person who LIED!
The rewording of the PR (twice) is the story, especially as El Reg caught them and catching PR BS is something it does rather well as a specialty.
The science itself is very interesting of course, not every day we get a 10,000 year Paleoclimatological Record is it???
I've no issue with the Antarctic record sea ice, this a positive, is a slightly confusing one as nobody seems to have a good grasp on why it's occurring.
The description I gave was quite clear I thought... and accurate?
The BAS article was reporting on the Nature Journal Article, and The Register was reporting on both.
The BAS article initially exaggerated the how unusual recent warming was, but then changed it.
The Register flat out lied about how unusual the recent warming was, but didn't bother to change anything.
The register didn't catch them, a poster on Netweather did! We were discussing the BAS article on the Nature paper the day it came out and spotted the error. He emailed them, and they amended it.
I admit it was a bad move on there part (the BAS article that is), trying to hype up the importance of the work, but I don't see much more to it than that. I imagine they got a little over-excited, twas kind of a big thing!
But the nonsense that The Register tries to link with it, is pure silly. Especially when they say the opposite to what the Nature paper says, then chastise the BAS article for exaggerating!0 -
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Cheers. Do you know if the model results have been confirmed by observations at all?
I've seen a few others, mentioning changes induced by the ozone hole, increasing snowfall, it being a cycle with only particular areas around the continent experiencing gains... and I'm sure a few other reasons!
Perhaps one or many of those explanations are correct
Well the thing is both the Arctic and Antarctic cover a wide area. Our intuitive view of the poles is basically two dead blocks of ice with nothing going on in them when in reality there are a lot of complex processes at play.
The issue is how each responds to warming, and there is no question each is warming. People like to present the Anarctic sea ice chart as if either somehow balances out losses in the Arctic or it refutes the idea the region or the planet are warming.
That paper dealt with the oceans mostly (I don't know what the state of observations are there, the Antarctic is generally poorly understood) but there are plenty of other factors too:
-The Antarctic Circumpolar Current is effected by warming temperatures which increase their speed. This current is what isolates the Antarctic from the warmer southern oceans. Stronger currents, more isolation.
-The Antarctic land ice is losing mass. The charts posted here all concern the sea ice.
http://www.skepticalscience.com/antarctica-gaining-ice-intermediate.htm
Figure 2: Ice mass changes for the Antarctic ice sheet from April 2002 to February 2009. Unfiltered data are blue crosses. Data filtered for the seasonal dependence are red crosses. The best-fitting quadratic trend is shown as the green line (Velicogna 2009).If the Southern Ocean is warming, why is Antarctic sea ice increasing? There are several contributing factors. One is the drop in ozone levels over Antarctica. The hole in the ozone layer above the South Pole has caused cooling in the stratosphere (Gillet 2003). This strengthens the cyclonic winds that circle the Antarctic continent (Thompson 2002). The wind pushes sea ice around, creating areas of open water known as polynyas. More polynyas lead to increased sea ice production (Turner 2009).
Another contributor is changes in ocean circulation. The Southern Ocean consists of a layer of cold water near the surface and a layer of warmer water below. Water from the warmer layer rises up to the surface, melting sea ice. However, as air temperatures warm, the amount of rain and snowfall also increases. This freshens the surface waters, leading to a surface layer less dense than the saltier, warmer water below. The layers become more stratified and mix less. Less heat is transported upwards from the deeper, warmer layer. Hence less sea ice is melted (Zhang 2007).0 -
Well the thing is both the Arctic and Antarctic cover a wide area. Our intuitive view of the poles is basically two dead blocks of ice with nothing going on in them when in reality there are a lot of complex processes at play.
The issue is how each responds to warming, and there is no question each is warming. People like to present the Anarctic sea ice chart as if either somehow balances out losses in the Arctic or it refutes the idea the region or the planet are warming.
That paper dealt with the oceans mostly (I don't know what the state of observations are there, the Antarctic is generally poorly understood) but there are plenty of other factors too:
-The Antarctic Circumpolar Current is effected by warming temperatures which increase their speed. This current is what isolates the Antarctic from the warmer southern oceans. Stronger currents, more isolation.
-The Antarctic land ice is losing mass. The charts posted here all concern the sea ice.
http://www.skepticalscience.com/antarctica-gaining-ice-intermediate.htm
I'm aware of most of that, but thanks anyway!
Whatever the reasons causing the extra ice (though I don't think the upward trend is statistically significant quite yet), we can certainly say it's not from cooling.
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The register didn't catch them, a poster on Netweather did! We were discussing the BAS article on the Nature paper the day it came out and spotted the error. He emailed them, and they amended it.
I admit it was a bad move on there part (the BAS article that is), trying to hype up the importance of the work, but I don't see much more to it than that. I imagine they got a little over-excited, twas kind of a big thing!
But the nonsense that The Register tries to link with it, is pure silly. Especially when they say the opposite to what the Nature paper says, then chastise the BAS article for exaggerating!
Thats for telling us about all this at the time. Nothing like a bit of a paleoclimatic microscandal to whet ones appetite at breakfast.
Needless to say I don't spend my life on denial sites waiting for that lot to go off on one. 0 -
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Sponge Bob wrote: »Thats for telling us about all this at the time. Nothing like a bit of a paleoclimatic microscandal to whet ones appetite at breakfast.
Needless to say I don't spend my life on denial sites waiting for that lot to go off on one.
Suppose everyone likes a little scandal to some degree:pac:Looks like the sea ice has settled to a minimum according to the National snow and ice data centre
http://nsidc.org/arcticseaicenews/2012/09/arctic-sea-ice-extent-settles-at-record-seasonal-minimum/
Although it is preliminary so a change in weather conditions could add a minor extension to the melt period.
They got that announcement out early. Wasn't expecting it until Friday or Monday.
The official minimum is given as the lowest 5 day mean, which this year is 3.4122 million km2. The lowest 1 day extent this year was 3.3686 million km2 though.
I'm sure some controversy could be generated over that, "hiding the decline" isn't it!0 -
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A nice video showing the effects of storms having on the ice melt.
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https://www.youtube.com/watch?v=9Gsr1503TNg
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