When faced with enemy graphs, remember that if extent is dropping then clearly we are looking at the wrong metric. Perhaps we should look at volume instead, unless that is dropping too, in which case we should look at area. If all that fails take a look at extent again because it might have gone up again in the meantime. If not then we should look to regional ice trends or if push comes to shove abandon the arctic entirely and talk about Antarctica instead. This is not cherrypicking because we know there is a recovery it is only a matter of finding a metric that shows it.
- Log in to post comments
More like this
Its hardly an original question. And the answer (we don't know) isn't original either. In case you were wondering, this is Overland and Wang, GRL 2013, doi: 10.1002/grl.50316 (PDF courtesy of V). Different but not entirely different to A sea ice free summer Arctic within 30 years?, also in GRL; or…
For the last 25 years or so there has been a decrease in the amount of ice that remains on the surface of the Arctic Ocean every summer. This is a trend that can be attributed to global warming, which in turn, can be attributed to the steady release of previously fossilized Carbon to the atmosphere…
The troops are getting restive. What wil happen to this year's sea ice? Rumours abound. Let's look at some pictures.
Probably the least interesting is this one from NSIDC. But it looks exciting, doesn't it. Woo-hoo, look, the sea ice now is lower than it was in 2007, that means it will be at…
Time for another look at sea ice. Here is the familiar IARC-JAXA plot:
And we see: well, it is looking low, and has been consistently all winter. Not record-breakingly, like it was last December, but even so. Interesting.
This year, I'm not planning to run a book, unless anyone offers to make a…
This blog you pull from must be satirical... right? Please say it is?
Noboby can be that stupid unless it's intentional.
If it's not a blog satirizing the denial movement, then the commentors are simply awesome.
Wow, confirmation bias as strategy.
I marvel at the sophistry where every breath is yoked to serve the desired end. To the point that every fiber of reality itself is assumed to be a available for reinterpretation until it serves the cause.
I like this bit:
"Neither is ice unfamiliar with human tragedy. In 1912 a rogue iceberg in the mid Atlantic was ultimately responsible for the suffering of audiences around the world to one of the worst movies ever made. No one in their right mind should care ice disappears."
The comments are as much value as the post. Look out for P. O. E. Slaw!
"Category: humour ⢠other blogs"
I think we get it, Byron. But thanks.
"every fiber of reality itself is assumed to be a available for reinterpretation until it serves the cause."
Somehow this has a familiar ring. Have I seen this happen somewhere before?
"Nobody can be that stupid unless it's intentional."
Boy oh boy, have you got some reading ahead of you. Just don't equip yourself with hot drinks, splattering the delicate electronic equipment doesn't do it any good.
Adelady,
Covering said equipment in glad wrap works a treat.
What is the best method for measuring sea ice?
I enjoyed the picture with the caption "An ice beast posturing in a typically threatening manner."
This method was published as "The Data Enrichment Method" in the Journal of Irreproducible Results some years back.
Probably not the right thread for this but as we all know GISS is now saying 2010 is the hottest year on record. Part of this record breaking year is the temps in the Arctic (above 80N lat). Giss claims the Arctic is up to 4C hotter than usual.
Is the ice melting faster because the temps are so high?
A closer look at the DMI we see that during June the temps were normal and now in July the temps are slightly below normal.
How can this be? How can we have two independant measuring sources give us such a big change in results? The answer lies in how the results have been created. The DMI actually measure the temp in the Arctic whilst GISS who have no thermometers in the Arctic so they extrapolate there results from stations over 250 kilometers away.
This raises two questions, 1 if the temp is not rising in the Arctic then what is causing the sea ice to trend down and second (a little off topic) how will this 4C error in GISS temp effect the overall global temp?
crakar, what's warming and melting the ice?
I follow Arctic Sea Ice blog - as well as the cryosphere today pretty pictures. (Pretty alarming sometimes.) Someone mentioned on Arctic SI the other day that the issue at that moment was melting from underneath the ice by warm water entering on one of the major currents. If you look at DMI-COI it gives you more pretty pictures of the water temperatures.
Apparently the issue at this time of the year is cloud cover and humidity having varying effects in different parts of the Arctic. Changes day to day. But if you do the Cryosphere 30 day animation you can see the ice spreading and compacting on different days - but decreasing all the time.
Thanks Adelady,
I have asked these types of questions before but i generally dont get an answer.
Obviously the trend began heading down before this year so if what started the decline stops it will take a few years for the ice to recover (assuming it does).
So if we assume GISS is incorrect due to extrapolation and DMI is a more accurate result then the air temp cannot be increasing to cause the ice to melt. I do not believe temp rise to be the culprit here but am willing to be corrected if wrong.
You mention ocean temp as a possible cause, maybe you are right if the oceans warm (via mans CO2) then this could cause some ice loss but what about currents? Currents could bring in warmer water and accelerate the melt, is this due to mans CO2 or natural cycles?.
Currents can also push ice away or closer together confusing us as to what the real state of the ice pack is. Then of course we only have 30 years of data to look at.
I am not saying that AGW is not to blame, what i am saying is that there appears to be many factors whether it be actual ice levels or how/how long we have been measuring.
I think it is too simplistic to state "AGW did it", regardless the fact remains the ice is trending down so i suppose it is easier to simply blame it all on Agw.
Sorry Crakar, but the DMI interpolates Arctic temperatures too. Temperatures have been well above average for most of the year, but dropped below the long term mean in June.
Meanwhile the satellites are showing very warm anomalies in the sea surface temperatures:
http://ocean.dmi.dk/satellite/index.uk.php
It would help to know the area of the interpolation, both in absolute terms and as a percentage of the total area defined as the Arctic in these data. Anyone got these figures to hand?
I think it is too simplistic to state "AGW did it"
--Crakar
That's a fair point in its own right but you have to consider it in the context of everything else we know. At some point we have to admit that the best and overwhelming evidence out there is that human carbon emissions are impacting the planet. ("Climate disruption" as Adelady might say.) You can't just play the humility-of-science card every time as an argument for inaction.
Skip,
I was watching the TV news last night with my son and they were talking about the 10 signs of AGW and how all 10 signs where pointing to AGW being real etc the reporter than ended his report by saying on a brighter note Antarctic sea ice is at an all time high.
My son responded by saying "that does not make any sense".
see: http://www.adelaidenow.com.au/news/world/more-data-points-to-undeniable…
But what else does not make sense?
The report states 3 of the 10 Indicators are declining and they are snow cover, glaciers and sea ice.
See: http://icecap.us/images/uploads/Winter_Snow_NH.JPG
3 out of the top 4 years of Nth Hemisphere snow cover have occurred in the last decade.
Antarctic sea ice is at record levels and world sea ice is unchanged after 30 years.
Do you know how many glaciers there are Skip? thousands and how many have been closely studied? A handful that is all and most of the big ones are not melting so "poof" there goes a 3rd sign.
Yes the temps have risen but they did from 1860 to 1880 and from 1910 to 1940 and from 1970 to 2000. Do you know what they all have in common Skip? They all have the same rate of warming, thats right each period warmed at the same rate. The warming from the first two periods is basically unexplainable and yet for the last warming period we are 90% (or is it 95% now) sure it is mans fault.
In response to my statement "I think it is too simplistic to state "AGW did it"
You said
"That's a fair point in its own right but you have to consider it in the context of everything else we know" Good idea lets do that. Problem is when you cut through written for the media bullshit we find we dont know a whole lot.
"the reporter than ended his report by saying on a brighter note Antarctic sea ice is at an all time high. My son responded by saying "that does not make any sense". - Crakar.
I don't know how old your son is Crakar, but maybe we can excuse his ignorance, however how difficult would it have been for that reporter to have actually investigated the topic?.
The trend in Antarctic sea ice is certainly not new, and although it seems counter-intuitive, the asymmetry in sea ice was predicted in some climate models a few decades ago. Maybe if the two poles were similar in geography we might expect similar trends.
@dappledwater
Please could you (or anyone) point me to the whereabouts of these "few decades old" climate models. I should like to check them for the accuracy of their other predictions.
"Please could you (or anyone) point me to the whereabouts of these "few decades old" climate models." - Jack Savage.
Manabe et al 1992.
"Transient Responses of a Coupled OceanâAtmosphere Model to Gradual Changes of Atmospheric CO2. Part I. Annual Mean Response"
&
"Transient Responses of a Coupled Ocean-Atmosphere Model to Gradual Changes of Atmospheric CO2. Part II: Seasonal Response"
I actually saw the NOAA report of which you speak, Crakar, and alerted Coby via email.
I have not read it yet and thus am entitled to no comment.
(See how that works?)
@dappledwater
The articles you mention seem to me to be saying that asymmetry would be caused by the shutting down of thermohaline circulation (have I got that right?) but latest NASA research seems to show that this is not taking place.
http://www.nasa.gov/topics/earth/features/atlantic20100325.html
Actually, I would find it surprising (only intuitively!) if the ice in the Artic and the Antarctic ever increased or decreased in lockstep and I would have thought all combinations were possible. I would suggest that these few decades old papers have managed to predict the present (possibly transient) ice trends at each pole purely by accident.
What does anyone else think?
I would think enough was known a couple of decades ago to make more than a random guess.
The reasons are important ones and not subtle! There is a great deal more land in the NH than the SH, the arctic ice cap is morstly sea ice whereas the antarctic is mostly land ice and the southern ocean has a giant circumpolar current inhibiting heat transfer from the tropics to the antarctic. Thus arctic response to warming is expected to be larger and faster. Also as the antarctic temperatures are well below freezing, slow warming would be expected to lead to more snowfall and thus accumulated ice mass.
"The articles you mention seem to me to be saying that asymmetry would be caused by the shutting down of thermohaline circulation (have I got that right?)" - Jack Savage
No. Around Antarctica the increased water supply (precipitation) from warming leads to a reduction in sea surface salinity and a decrease in convective overturning between the surface and deep ocean (stratification). This leads to slight cooling at the surface and increased sea ice production.
The simulations indicated the increase sea ice production would occur mainly in the Ross and Weddell Seas. And this has been observed:
http://www.agu.org/journals/ABS/2008/2007JC004564.shtml
Note though, that the actual sea ice trends in Antarctica are regional in nature, increasing in some areas whilst decreasing in others (West Antarctica), but overall a positive trend in sea ice production thus far. Not that GCM's are perfect of course, but they certainly have demonstrated some predictive skill.
And we haven't even touched on the ozone hole, and it's effect on the Southern Annular Mode (circumpolar winds).
@dappledwater. This is the abstract of the paper you sent me to, is it not? This is all about thermohaline current. If you have sent me to the wrong article please say so. Apologies for the effects cutting and pasting has on the setting out of the abstract.
ABSTRACT
The influence of differing rates of increase of the atmospheric CO2 concentration on the climatic response is investigated using a coupled oceanâatmosphere model. Five transient integrations are performed each using a
different constant exponential rate of CO2 increase ranging from 4% yr21 to 0.25% yr21. By the time of CO2
doubling, the surface air temperature response in all the transient integrations is locally more than 50% and
globally more than 35% of the equilibrium response. The landâsea contrast in the warming, which is evident
in the equilibrium results, is larger in all the transient experiments. The landâsea difference in the response
increases with the rate of increase in atmospheric CO2 concentration. The thermohaline circulation (THC) weakens
in response to increasing atmospheric CO2 concentration in all the transient integrations, confirming earlier
work. The results also indicate that the slower the rate of increase, the larger the weakening of the THC by the
time of doubling. Two of the transient experiments are continued beyond the time of CO2 doubling with the
CO2 concentration maintained at that level. The amount of weakening of the THC after the CO2 stops increasing
is smaller in the experiment with the slower rate of CO2 increase, indicating that the coupled system has more
time to adjust to the forcing when the rate of CO2 increase is slower. After a period of slow overturning, the
THC gradually recovers and eventually regains the intensity found in the control integration, so that the equilibrium
THC is very similar in the control and doubled CO2 integrations. Considering only the sea level changes
due to the thermal expansion of seawater, the integration with the slowest rate of increase in CO2 concentration
(i.e., 0.25% yr21) has the largest globally averaged sea level rise by the time of CO2 doubling (about 42 cm).
However, only a relatively small fraction of the equilibrium sea level rise of 1.9 m is realized by the time of doubling in all the transient integrations. This implies that sea level continues to rise long after the CO2
concentration stops increasing, as the warm anomaly penetrates deeper into the ocean.
Jack:
You have to read more than the abstract to know everything that's in the paper. Dappledwater's description is correct.
I've written about this previously, at WUWT trumpets result supporting climate modelling.
Jack Savage, you'll have to read both papers, not the abstracts. You can access them here:
http://journals.ametsoc.org/doi/abs/10.1175/1520-0442(1992)005%3C0105:T…
Note also the other papers highlighted by Rob Grumbine at his website.
DW
Post 13, I will see your DMI link and raise you with another one.
http://ocean.dmi.dk/arctic/meant80n.uk.php
This link gives you the temps since 1958 i think, all of which show no trend in air temp during the summer melt season, this would suggest AGW is not melting the ice by warming the air.
It must be melting it another way.
DW,
post 17.
My son is 15 and he has a skeptical view on things but dont blame me, when he was 6 he questioned his religious teacher about biblical accuracy saying the dinosaurs were here long before man (teacher and catholic school was not impressed).
Skip, 20
No comment is fine Skip.
Crakar, that's the graph I commented on at #13, above the long term average for much of the year, then dropping below in June. And yes, the water is warming in the Arctic, hence the rapid thinning of the sea ice.
Not sure i follow are you saying the air temp has not changed as per the link in 27 but the water is warming and this is what is causing the sea ice extent to decline?
Crakar, if you define "not changed" as different to the long term average, then yes it has "not changed". I wouldn't though.
As far as the thinning of the ice is concerned, well yes, it's the warming water that is thinning the ice from below, how would you expect the air temperatures to melt the ice which is under water?.
Have a look at those satellite sea surface temps at the DMI I linked to earlier, plug in the sea surface temp anomalies and the Arctic Ocean, you'll see much of the Arctic ocean and surrounding waters are 1 - 5 degrees C above the long term average.
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolum…
But even that, doesn't give us an accurate picture of what's going on with the sea ice. It might look okay on satellite pictures, however recent expeditions to the Arctic reveal the sea ice, is structurally very weak, icebreakers are able to plough through it without losing speed. I watched a video about it a month or two back, I'll see if I can track it down.
http://video.hint.no/mmt201v10/osc/?vid=55
Barber's talk starts about 12 mins in, and the interesting stuff about 18 mins in.
One other thing Crakar, whether we see a record Arctic Sea Ice "extent" minimum this year or not, will depend on the weather. We have however already seen a record minimum in the sea ice "volume" (link at #30)
DW,
You said, "Crakar, if you define "not changed" as different to the long term average, then yes it has "not changed". I wouldn't though."
For the life of me i cannot see any change to the long term average. It appears to me that the air temps in the Arctic have not changed since 1958 despite what GISS claim, can you show me how the temps have increased?
Assuming the air temps have not changed then what is causing the sea ice decline?
You say it is water temp but your link only goes back 30 days so does not tell us the past 30 years worth of temp. Does anyone have the water temps going back to 1958?
If we accept the water temps have risen which in turn is causing the sea ice decline then what is causing the water temp to rise?
Can AGW warm the ocean without warming the air?
Have the currents changed bringing warmer than normal water into the region?
How did AGW warm this water somewhere else and then change the currents to bring it to the Arctic?
I am not disputing what you say DW i just want a credible explanation as to how AGW is doing this.
Cheers
crakar
"....For the life of me i cannot see any change to the long term average. It appears to me that the air temps in the Arctic have not changed since 1958 despite what GISS claim, can you show me how the temps have increased?...."
I am not sure where you get the information about air temperatures in the Arctic not changing. The link from post #27 is just a daily snapshot taken over a few months, and does not show long term trends. You may wish to look at a longer term study of temperatures, such as here:
http://www.lanl.gov/source/orgs/ees/ees14/pdfs/09Chlylek.pdf
To quote from the paper:
".....The rate of increase of the mean annual global land
surface air temperature (Table 1) was about 0.11 K/decade
from 1910â1940 and 0.19 K/decade from 1970â2008. The
cooling rate from 1940 to 1970 was â0.04 K/decade...."
NOAA has this to say:
"....The annual mean Arctic temperature for the year 2008 was the fourth warmest year for land areas since 1990 (Figure A1). This continued the 21st century positive Arctic-wide surface air temperature (SAT) anomalies of greater than 1.0° C, relative to the 1961-1990 reference period. The mean annual temperature for 2008 was cooler than 2007, coinciding with cooler global and Pacific temperatures (Hansen, 2009). The outlook is for increased temperatures, because there are currently (October 2009) El Nino conditions which are expected to continue through winter 2009-2010...."
(source: http://www.arctic.noaa.gov/reportcard/atmosphere.html)
I think that's pretty clear.
Mandas,
Maybe you can explain further what the DMI data is showing us as i do not understand what you are saying.
In regards to your first paper, your quote is in regards to global temps, here is the quote you should have used.
"The rate of mean annual low Arctic air temperature
increase from 1910â1940 was 0.59 K/decade compared to
0.38 K/decade from 1970â2008. The decreasing trend from
1940â1970 was 0.36 K/decade (Table 1)."
A few points, firstly i will chalk up your quote as a mistake on your behalf and not an attempt to pull the wool over my eyes (get ready for Skip and his sheep jokes).
Secondly it would appear that the warming rate from 1910 to 1940 was much larger than 1970 to 2008 even though man made CO2 would have absolutely no affect way back then, not to mention the 30 years of cooling after that, thirdly we keep seeing these same periods of time popping up dont we.
Also "The high Arctic (70â90!N) warmed at the rate of
0.55K/decade from 1970â2008 and at 0.76K/decade from 1940â1970 [IPCC, 2007; Chylek and Lesins, 2008; Shindell
and Faluvegi, 2009] and the warming since 1970s."
So once again we have more warming from a period of less CO2 and less warming from a period of more CO2. The scientists involved saw this and declared the AMO is the major driver of Arctic temps not AGW.
I did not bother looking at the second citation as i saw the name "Hansen", i do not see how GISS can say what the temps are in the Arctic when they do not have a thermometer within 1000 kilometers of the place.
Out of interest here is another quote from the first cite.
"Finally a recent attribution study
[Gillett et al., 2008] showed that the climate models reproduced
well the observed Arctic warming since about 1970.
However, they could not reproduce the large warming during
the early part of the 20th century and the strong Arctic cooling
during 1940 â1970 [e.g.,Parker et al., 1994]."
So the models cannot reproduce the warming and cooling of the Arctic pre 1970's which strongly suggests we do not fully understand the warming of today
crakar
I apologise, I did provide the incorrect quote from the paper.
I also accept your mea culpa regarding the lack of warming in the Arctic. You now seem to accept that it is occuring, based on our discussion (and I am not suggesting what is causing it - just that it is happening).
crakar,
Sorry - I forgot to address your point about warming in the first half of the twentieth century as opposed to now. But then, we have had this discussion so many times I am not sure why you are bringing it up again.
Noone has ever claimed CO2 is the only driver of climate - and we all know the sun is important. And we all know that an increase in TSI was the main driver of the earlier warming, but since the TSI has been flat to decreasing recently, CO2 has been the main driver. I am not going to provide links, because there are so many of them, and my most recent post is still awaiting moderation because it had too many links in it. Go to Google Scholar (not 'normal' Google) and type in 'solar irradiance climate' or something similar. That way you can choose the papers you want (but do limit your search to recent papers, say after 2000 - science research 101!)
No need to apologies Mandas i realised it was a simple error, It would appear that the Arctic has warmed the same way as the rest of the planet has warmed from 1910-40, cooled from 40 to 70 and then warmed again.
I would ask 3 questions.
Q1, Has Arctic sea ice declined?
A, Yes, some talk of recovery but i feel we need to see a few years above say 2000 levels (?) before we can call it that.
Q2, Is this part of a long term cycle?
A, We dont know as we only have 30 years of data, we do have anecdotal evidence which may suggest it was both higher and lower in the past but essentially we have no idea.
Q3, What is causing the decline now?
A, I dont know, it could be a combination of ocean currents, ocean temp rises (caused by what), air temps (caused by what), solar, aerosols and who knows what else.
The problem here is that if you stray from the common theme of "AGW did it" you get shot down pretty quick, dont get me wrong i am not complaining its just par for the course and besides it can be a little fun some times.
Although at times it can get a bit nasty which is not very enjoyable (i am as much to blame here as anyone else).
I would suggest we would both agree to the answers of Q1 and Q2, that leaves the answer to Q3 for debate, you up for it?
Cheers
Crakar
Read your last post after posting mine
"For the life of me i cannot see any change to the long term average." - Crakar
Crakar, I'll assume your'e not taking the piss (dangerous I know). Look at the graph:
http://ocean.dmi.dk/arctic/meant80n.uk.php
It's a plot of the average daily temperatures for each day of the year, hence the bell- shaped curve. The green line is the average daily temp for the period 1958 to 2002. The red line is the daily plotted temperature in any given year, and the blue line indicates 0 degrees celcius.
If you click on the values for 2010, you'll see for the early part of the year, the red line (2010) was well above the average for a large portion, and as the Northern Hemisphere summer approaches the trend dips slightly below the average.
Now click on the years in the box on the left of the graph, and it will plot that years data. If you look at 2007, the record summer sea ice extent minima, you'll see that the trend approaching summer is very similar to 2010. Intuitively you might expect to see the daily value climb much higher in summer, but what is happening is that all that extra heat is going into melting the ice, that's why you don't see much annual variation as the temperatures near the melting point - click back through the years to see for yourself. Clearly that is going to change at some point in the future, given current trends, sooner or later a lot of that energy is going to end up in the air, rather than go into melting the ice.
Anyway, hope that helps. That graph is a bit misleading for us laymen, but they're Danish, what do you expect?.
Oh, and watch that video, very interesting.
"Q1, Has Arctic sea ice declined?" - Crakar
Yes.
"Q2, Is this part of a long term cycle?" - Crakar
No, not unless dinosaurs and other prehistoric creatures, have created industrial civilizations at regular intervals - pumped massive amounts of CO2 into the atmosphere by burning fossil fuels - magically replaced said fossil fuels, and then left no trace in the paleo record.
"Q3, What is causing the decline now?" - Crakar.
Anthropogenic Global Warming. Climate trains the boxer, and weather throws the punches (nice quote I've seen floating about the blogosphere).
No Crakar I will eschew sheep jokes for the moment and simply lurk/learn.
P.S. Baaaaa
DW,
If i understand your post (40) you are saying that over the past 52 years the temp during the summer has not changed (when compared to the green line), however in reality the air temp has in fact risen but we do not see it because it is melting the ice so it does not appear in the temp record.
We will not see the summer temp rise (against the green line) until all the ice is melted, when all the ice is melted then the temp will have nowhere to go except into the temp record.
If this is what you are saying then sorry but i must disagree. I will apply logic to this and see where we end up.
If i have a thermometer that measures the air temp at or near the surface then i would expect it to measure the air temp at or near the surface.
If the air temp increases (over a period of time) then i would expect my thermometer to measure the increase in air temp.
If the air temp increases (over a period of time) then this increase could aid in the melting of the ice, however i would expect my thermometer would still measure the increase in the air temp.
Can you explain to me how the air temp can increase and thus melt the ice without my thermometer detect any increase in said temp?
"DW, if i understand your post (40) you are saying that over the past 52 years the temp during the summer has not changed (when compared to the green line), however in reality the air temp has in fact risen but we do not see it because it is melting the ice so it does not appear in the temp record." - Crakar
Close, but not the full picture. Flick back through the annual data at the DMI. What do you notice at the height of summer in the 1960's?. The summer season warmer than now for many of those years?. Why do you think that is, given that there has been a dramatic decline in the Arctic sea ice?
Now look at the months, outside of summer, a great deal of inter annual variability, but back in the 1960's much of the time the temperatures are well below the long term average. Compare those to the recent decades. Notice how it's now much warmer than the long term average outside of the summer in more recent years?. What effect do you think that might having of the Arctic ice?.
Here's a hint:
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolum…
Remember too that that is only one data set. Other's such as NASA GISTEMP show the greater cool season warming, but a little bit more summer warming than DMI.
How does NASA GISTEMP come to such a conclusion when they do not actually measure the temp inside the Arctic circle?
"How does NASA GISTEMP come to such a conclusion when they do not actually measure the temp inside the Arctic circle?" - Crakar.
Really?, I've counted 31 inside the Arctic circle. Maybe you mean the North Pole?.