Julienne Stroeve from NSIDC asked me to post the figure below in reference to the discussion about future ice-free Arctic summers.
Some notes on the graph:
Model fields come from the models used in the IPCC 2007 report, using the observed record of GHGs from 1900 to 2000, and the “business as usual” scenario afterwards. For models with more than one ensemble member, the ensemble members have been averaged for that model. Observations come from a combination of satellite data, aircraft and ship observations.
The graph makes two important points:1) the models are in qualitative agreement with the observations that the September ice cover has been declining from 1953-2010. This is despite the fact that each model would be in their own phase of natural variability and could therefore be showing increases or decreases. This suggests, that in the models, the forcing by GHG contributes to the decline.2) the observations are outpacing the models in terms of the decline in the Arctic summer ice cover.
Thanks Julienne!
Some notes on the graph:
Model fields come from the models used in the IPCC 2007 report, using the observed record of GHGs from 1900 to 2000, and the “business as usual” scenario afterwards. For models with more than one ensemble member, the ensemble members have been averaged for that model. Observations come from a combination of satellite data, aircraft and ship observations.
The graph makes two important points:
1) the models are in qualitative agreement with the observations that the September ice cover has been declining from 1953-2010. This is despite the fact that each model would be in their own phase of natural variability and could therefore be showing increases or decreases. This suggests, that in the models, the forcing by GHG contributes to the decline.
2) the observations are outpacing the models in terms of the decline in the Arctic summer ice cover.
http://nsidc.org/data/docs/noaa/g02176_aari_charts/
Russian Ice data shows sea ice was quite low in the 1930-40s. So how did this happen when CO2 levels were just above 300ppm?
We really only have satellite data since the 1970s. How can climate be estimated over just 40 years isn’t this too short a measurement to estimate climate, the same mistake was made in the 1970s when a sudden cooling (which Phil Jones still cannot explain) caused climatologists to make incorrect predictions that an ice age is coming.
I wonder what the Arctic area looked like when Hannibal took his elephants across the alps in 219BC. The earth is still here today even though the climate changed….
http://jonova.s3.amazonaws.com/graphs/lappi/gisp-last-10000-new.png
The Minoan warming appears to have been even more warmer then today ,with El Nino fluctuating at least 2-3 times stronger at times. Until we can explain the mechanism of this, we could at the time if the CO2 level had risen, simple attributed this warming to CO2/GHG gases forcing as well. But this was obviously not the case. As CO2 was probably not varying that greatly.
http://www.clim-past.net/6/525/2010/cp-6-525-2010.pdf
It appears currently we are more likely reaching the end of the warming phase when it peaks, and it takes some time for the gigatonnes of water to cool at the poles. The 1470 year bond event is due again. So over the next 10-20 years cooling could start to accelerate….
I see. All the models predict a continuing reduction of ice (to varying degrees, depending on the model) over the next century. And because the observations are worse than the models, then it’s a foregone conclusion the the arctic ice will disappear . . .
Are these the same climate models that are ‘CO2 biased’, which predict warming, that hasn’t occured in the last decade or so?
. . and tell me again why is there so much faith in these models . . ?
Let’s just wait a couple of years to see what happens, because of a changing in the PDO, AMO, and solar cycles.
Reasons why the models may or may not capture the rate of decline observed in the data include (1) the models are not sensitive enough to GHG forcing or (2) the models are missing some natural variability or feedbacks that is contributing to the decline.
Some of these models show stronger warming that what is observed, some less. If you look in the temperature versus sea ice change, none of the models get that ratio correctly, even though the two fields are highly correlated in the models (above 0.98). This means that the models exhibit different sensitivities to temperature changes.
Can the AMO account for the model versus observation difference? Looking at the models, we find that the AMO is not accounting for the model’s sensitivity estimate. Instead, the AMO affects ice cover and temperature in a proportion similar to general natural variability and the observed sensitivity. What accounts for the differences in sensitivity between the observations and the models is still uncertain.
Are these the same climate models that are ‘CO2 biased’, which predict warming, that hasn’t occured in the last decade or so?
Why do you say this? First, the trend is up for the last decade, for all four of the major data sets. Second, that isn’t long enough to exclude natural variation anyway.
This also explains the antarctic sea ice increases by GHG’s, I presume. Outpacing the models once again I would guess…
Nice!
“This suggests, that in the models, the forcing by GHG contributes to the decline.”
What forcing?
Decline since 1979, wait ten years (or thiry) and lets see.
Julienne,
Thank you for the graph.
I am an individual interested in this topic, but it is not even remotely my field of expertise. Now I can track future arctic ice growth vs. models easily and conveniently and see if there is
a) some sort of cyclical pattern that the model simply grasped onto and it happened to the declining part of the cycle; or
b) the mode actually models something
Big fun for the future. Too bad I certainly won’t be around in 2050.
Neither will I (unless I am homing in on 100 but that is not in my plans (pension that is….)) unless…. we are both frozen by (solid) CO2 which is pretty cold, as I gather.
Since the observations start in 1950, and well before satellite data, there is still an opportunity for the variation of polar ice to continue to fluctuate cyclically no matter what models and mathematicians say. Curve fitting on data is an interesting aspect of (anthropogenic) science…
models don’t have their own natural variability they are just models and are not real and all assume that ghg are causing global warming but to different degrees.I would say that a lot of natural variability has been missed by these models it is something that has not been studied as Dr Roy Spencer says because everyone is certain that human carbon emissions is to blame for the climate changes we have seen recently.
Picking the first model, CGCM3 (http://www.ec.gc.ca/ccmac-cccma/default.asp?lang=En&n=1299529F-1 and links therein) some of the factors that went into the model include:
– Ground cover type soil/snow/canopy
– albedo effects
– surface exchanges of heat moisture and momentum
– solar radiative heating
– water vapour transport
– cloud cover
CO2 is probably in there as well.
The models only track the result created from chosen parameters. They attempt to fit these SELECTED parameters and their sensitivities to a short period of observation, and the assumption of trace amounts of CO2 as the dominant forcing. They ignore parameters as they choose and are ignorant of others.
With a variety of unknowns, their conclusions are simply an expression of bias. That is, they tell the desired story.
Since GISS’ speculation of a large positive temp anomaly is not confirmed by legitimate temperature readings (such as DMI), why should anyone believe it is accurate?
Summer extent could go lower or higher. I certainly don’t know. But I do know enough to realize that neither does anyone else.
There are clues that the history as shown by these models may be completely erroneous. These come to mind:
http://wattsupwiththat.com/2009/04/09/was-2007-arctic-ice-really-a-historic-minimum/
http://www.youtube.com/watch?v=tokbiZW3gVY
Good Pick on “In search of” .
Puts the lie to the idea that such ideas were isolated.
Here is part 3 of that Youtube series:
http://www.youtube.com/watch?v=nprY2jSI0Ds&feature=related
According to Bastardi, who fared quite well in his estimate of this years minimum, it is not merely the negative AMO, but its coincidence with a negative PDO that led to this situation in the late 70s, and asserts this combination is due to occur again in a few years.
Julienne,
Where is your model for Antarctic Sea Ice. How is that looking?
Thanks,
John
We showed the Antarctic results in the Stroeve et al. (2007) paper as well. The observations show a slight increase in extent whereas the models show increases and decreases (i.e. the modeled Antarctic sea ice extent lack the consistency that we see in the Arctic). Some of the reasons for this appears to depend on how well the models capture the variability in the Antarctic Oscillation Index which appears to be a dominant factor in the observed changes in Antarctic sea ice.
BTW…it’s not my model…I was using the model data archived by CMIP3 (http://www-pcmdi.llnl.gov/ipcc/about_ipcc.php)
cheers!
Thanks Julienne,
So many variables. Is your model part of a larger climate model or does it just model Sea Ice? How does in compare when you look at all ice i.e.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
This looks fairly flat to me?
Joe Bastardi predicts a major rebound of NH sea ice this winter and beyond, based on cold PDO. What do you think of his prediction?
Regards,
John
Thank you for your reply Julienne,
. . and I should offer an apology, as after seeing my post in print, it does now look at bit ‘snarky ( . . it didn’t as I was writing it . . ). But anyway, I do agree with your point 2 the models may be missing something, whatever it may be, and it might be a combination of things. Time will tell (. . . I hope . . )
no worries…
Why does it matter? In the 1930s the ice was going to all melt. Bear Grylls recently was up there and was saying it was all melting, but could only take a zodiac through the inside passage, why didn’t he take a normal boat? But anyway, he found a human skull on one of the islands in the inside passage, so if the ice has always been there how did that person get their from previous expeditions long ago?
Many thanks Julienne please keep the info coming. I can’t comment yet, still gathering and learning.
I should really also thank Steven, but he can only see cold Chelsea blue, no warm Red!
Those 0-0 matches put me to sleep ……..
http://www.zombietime.com/zomblog/?p=873
What about the Ice Age, I’m confused?
http://thegwpf.org/ipcc-news/1670-hal-lewis-my-resignation-from-the-american-physical-society.html
Did anyone read Hal Lewis’s resignation letter?
You can build your models of the reality of the climate test them against previous times and they could still be proved to be wrong in the future.Trying to make sense of what is happening in the arctic by comparing it to computer simulations of the climate is wrong,I think, we just need to make sense of what is happening in the arctic.I will wait and see if the Arctic ice summer minimum continues to recover next year or not ,despite what your models say, some experts predict that it will recover next year from this years low.I know that the arctic may have been ice free in the summer in past times and it may be so again in the near future if your models are right.But the fact is there is still a lot of sea ice left in the arctic at the summer minimum this year there was more than in 2007 and 2008 ,I would only accept that we are going to see an ice free arctic in the summer if the the amount of Ice was decreasing at the minimum this year it did not and until I do see the extent go below 2007 I am not going along with the scenario.
I know that the arctic may have been ice free in the summer in past times and it may be so again in the near future if your models are right
Let’s forget about the models for a minute. What do you think about the bright red line–the observations? Doesn’t it look like something not so good is going on there?
Don, something to consider. 2007 was an anomalous event linked to persistence of a strong Dipole Anomaly circulation pattern (i.e. strong high pressure over the Beaufort Sea, strong low pressure over Siberia). The fact that the last 3 years remain 2 standard deviations below the mean may represent a new state of the sea ice. In terms of total ice melted (i.e. from maximum to minimum), 2010 and 2008 had more total ice area lost than in 2007. So if you compare these last 4 years in that way, 2007 is not anomalous compared to 2008-2010, but these 4 years are anomalous compared to the earlier data.
It is a good question to ask what would it take to remove even more of the ice. Would another summer like 2007 cause the ice cover to drop below 4 million sq-km? Or would we continue to stay between 4 and 5 million sq-km?
Another thing I find very interesting: The fraction of 2 year old ice has basically stayed the same, but the fraction of ice older than 3 years is on a steep decline (steeper than the FYI). What is causing the Arctic to lose it’s oldest ice? And if that oldest ice disappears, is that enough then to allow the ice extents to start to drop below 4 million sq-km.
Models are just one means to try to figure out what may happen in the future. Process studies are another means, and that’s the work I focus on.
How do the models handle clouds?
I’m not up to speed on the latest analysis of the cloud cover in the models on a global scale, but the models are capturing the autumn increases in cloud cover being observed in the Arctic as well as the spring time increases. In the Arctic, clouds are predicted to increase in all seasons, but most strongly in the autumn. This makes some physical sense since more open water in September results in more transfer of latent and sensible heat from the ocean to the atmosphere.
Like the Iceland “Volcano cloud” that was not even there?
Julien Stroeve, thanks for your graph and your comments.
There is no measurable GHG forcing in the Arctic region and if there would be any you wouldn’t be able to make any effect visible. Why? Because much bigger effects and events take place that have a such a radical influence on the ice extent in the Arctic basin that it overshadows all the “little effects”.
For this you only have to look at the time lapse video of the 2007 melt season where you can see how enormous amounts of ice are simply flushed out of the Arctic basin by wind and ocean currents.
We have “reliable” satellite data available since the end of 1978.
Before that time there simply are no complete records.
Therefore I simply don’t buy your claim that the Arctic summer ice extent is in decline since 1953.
The presented declining summer ice extent scenario is simply not going to happen.
The planet is switching into a cooler phase now and when the AMO goes negative and comes into sync with the negative PDO we will see a rise in summer sea ice extent again.
I also think it is irresponsible of you to make public claims announcing an ice free Arctic based on these models.
http://www.abc.net.au/worldtoday/content/2010/s3029916.htm
No heart feelings, just providing my humble opinion.
OK, what about the data since 1978? Does that 32-year trend appear to be normal?
Actually, no, it does not look “normal”.
http://nsidc.org/data/smmr_ssmi_ancillary/regions/arctic.html
Now, I understand, we switched satellites but the data is a shift UPWARDS (1mil km^2) with the new satellite and then the OLD data get biased UP to match the new satellite. Now, that does not change the trends, but now the variation in the new data is twice the variation of the old. What this means is that the new satellite sensitivity is higher than the older (+/- 0.8mil km^2 vs +/- 0.4mil km^2).
For data going back to 1972 another satellite was used (ESMR dataset) the 30 year data can be found here: http://polynya.gsfc.nasa.gov/seaice_datasets.html
Remember that there is A LOT of interpolation for missing data points.
My favorite source is the ROOS. It rather spares me the gloom and doom of models http://arctic-roos.org/observations/satellite-data/sea-ice/total-icearea-from-1978-2007. Yeah, the summer may be ice free in the future, but at 4.703% loss per decade, that is about 90 years.
Now, for the curiosity, on the ROOS, first graph, note the range that the extent (max and min) have been doing for the last 4-5 years. Ice is growing and shrinking with larger strokes! How ROOS does not have the same land masks for sea-ice, I can not say (NASA method does not count “ice” that over-grows the land-masses, so you might miss a glacier coming your way).
Finally, I still find it to be disturbing a new version 2 calibration “process” with AMSR-E was implemented September 2007.
So, I do have a few issues with the data, but it should sort itself out, eventually 😉
I don’t know of any Arctic scientist who believes natural variability is not important in the observed decline. If 43 ensemble members of the CMIP3 archive are averaged together, and assuming this average filters out the internal variability in the models, the mean could give an idea of the contribution of GHGs to the observed change. Doing so suggests 45% of the decline is related to GHGs in the models.
Those of us studying the ice cover spend a lot of time trying to figure out what the natural forcings on the ice cover are. If we believed it was 100% due to GHGs, we might as well quit our jobs since we would already know what is going to happen to the sea ice in the coming decades.
This may seem stupid, and if so I’ll take my lumps.
But to my eye, all the models agree except to extent, or amplitude.
Are there no models that , who knows, possibly working from some other set of parameters would predict a recovery of the ice ?
Perhaps even a growing of it ?
I mean, were the guys in 70’s dumb, or just full of hot (cold) air ?
Jimash,
I think the people in the 70’s were more interested in writing sensationalist stories with catchy headlines. Though, there were those that predicted cooling, just not as many as those that hypothesized warming.
http://www.skepticalscience.com/What-1970s-science-said-about-global-cooling.html
Though, there were those that predicted cooling
Yes, seven of them 🙂
That’s how many papers that predicted cooling were published from 1965 to 1979–about one every other year. (And some of those were for long-term Milankovitch-style cooling that were probably correct.)
This entire “Scientists predicted a new ice age in the 70s!” myth is based on a few media articles, most of which didn’t actually predict anything. The two articles from Time and Newsweek that everyone “remembers” as saying that an ice age was coming, didn’t. They were about observed cooling, not predicted cooling; neither one contained any predictions at all.
Why would any scientist assume the only remaining variable is CO2? This is myopic and prejudicial. We do not understand the mechanism or extent of all natural variability.
Any attempt to isolate remaining change to CO2 is idiotic. Why should we assume, at this admittedly infantile level of understanding, that we can catagorize remaining forcings, and then limit them to only one?
In my business, there are admittely many mistakes. Yet the product we produce cannot fail in (nearly) any circumstance.
The product we produce must perform as expected with extreme consistency. Not so in the world of Climate Science.
Admittedly, earth’s weather and climate system are extremely complex.
But this only strengthens my position. My product can be evaluated within the limits of its expected usage.
The climate has no such known limits.
No one can presume to predict what lies ahead.
True science isn’t about suppositions. It reports what is known, and is content to recognize that which is unknown.
There is no place for ego or political correctness.
Julienne,
Thanks for taking these questions.
Mine has to do with the temperature record of the great white north. When I poke around looking at the temperature record for the last 100 years for Greenland (look at Nuuk), I just don’t see the temperature profile that would support the IPCC model of disappearing summer Arctic Ice. I do see periodic oscillations, but no increase in temperatures.
When you read about the search for the Franklin expedition in the 1840’s and 50’s, you realize that the Arctic ice was at a minimum. ( McClure almost made it through, and if had had GPS and a satellite to guide him, he probably would have.)
There is plenty of anecdotal evidence that the Arctic ice was at a minimum during the MWP. Chinese, Vikings….settlements in Greenland…………
What is occurring now is the reversal of the PDO, which works in concert with the other oscillations. ‘The oceans cooling per Argos and new data from Roger Pielke Sr telling me that there is a lot less heat contained in the oceans than previously thought.
This tells me that rather than a death spiral for Arctic sea ice, a recovery is going to take place over the next 30 years.
I don’t see the IPCC models taking these oscillations into account. By not taking these oscillations into account the IPCC has shown that it is incapable of true scientific debate.
SMS, you raise some good points. It would be great if we had sea ice measurements extending back in time through the MWP. Anecdotal evidence is important and studies that try to document Inuit and Inupiat knowledge of ice conditions, via their hunting patterns, stories, songs, that extend through centuries is important. Work is going into gathering all this information (see http://eloka-arctic.org/about/index.html of an example of one such project).
A sea ice record has been compiled that extends from 1900 to present, but data prior to 1953 are based on more limited input, so at times climatologies are used instead. But if you were to look at the more trusted sea ice record (i.e. 1953 onwards) together with the temperature record for the Arctic you find strong correlation between the two variables.
IPCC models do take into account variability such as the AMO (i.e. http://www.clivar.org/organization/decadal/rsmas_decadal/rsmas_posters.php#danabasoglu) or the PDO (http://eros.eas.gatech.edu/web_db_papers/edl_pdfs/Furtado_IPCC_2009.pdf) some with better success than others. But to be honest, I’m not a modeler so I haven’t looked into detail at all those studies, my focus was looking into how well the models simulate the sea ice changes.
It will indeed be interesting to see if the forecasts for more ice in the next 30 years pans out with the AMO and PDO phases predicting colder conditions. It’s important to remember though, when an index, such as the AO can explain 30% of the sea ice cover variability for example, 70% is being explained by other factors (this past winter was a perfect example of that). Same is true of AMO or PDO indicies.
bbttxu says:
October 8, 2010 at 11:54 pm
Jimash,
I think the people in the 70?s were more interested in writing sensationalist stories with catchy headlines. Though, there were those that predicted cooling, just not as many as those that hypothesized warming.
——–
That is a biased judgement, especially considering the catchy sensationalism of todays doomy global warming headlines.
http://www.sipa.columbia.edu/academics/directory/jdh1-fac.html
This guy was in the “in search of” video.
He does not strike me as a limelight seeker. Just the opposite.
First, a heart felt “Thank You” to Julienne Stroeve for her contributions to this blog.
She is a major positive force, factual and explicit about her views and the basis for them. Many of the other participants in the AGW controversy could and should emulate her approach, the entire field and the global community would benefit.
The basis for the “ice free summer” projection is the declining trend in the various models as well as in the observations for the past half century, after a half century of stability. Given the existence of well over a century of arctic exploration, plus records going back much longer, particularly on the Russian side, it must be possible to put together some backcast of the actual ice status, enough at least to either confirm or refute the minimum ices flat status from 1900 to the start of the observations in the 1950s. If there were large prior fluctuations, the models need more work and their projections are suspect. If there were none, the models become more credible.
Julienne,
Thanks for the long and detailed reply.
I believe that what you have written suggests a set of error bars for the Arctic ice extent in the future that are significant and well beyond the predictive powers of the modelers.
Cheers,
SMS
I guess I would like to know how many other reconstructions of the sea ice minimum there are. I understand this chart is based on the Stroeve 2007 paper which is based on the Meier 2007 paper which is based on the HadISST dataset. The Chapman and Walsh dataset is not much different.
But there is anecdotal evidence of more cyclical sea ice extents like declining sea ice in the 1930s extending to the mid-1940s. We have the Chylek 2009 paper which links the Arctic temperature anomalies with the AMO (which just happens to have the right cyclical nature – except it would have expect an increasing sea ice trend from the mid-1940s to the early 1970s versus the mostly flat trend in the chart above.
Are we really sure this is the Arctic sea ice pattern? Are there other datasets that provide a different trendline (Miles, Johannessen and Furevik presentations are more in line with the AMO cyclicality).
BillIllis,
(Miles, Johannessen and Furevik presentations are more in line with the AMO cyclicality).
Do you have links to these?
The decline in the graph began around 1976/77. 1976/77 is very significant because “The Great Pacific Climate Shift” happened then. Most global warming believers, for example Tamino, won’t attribute warming to that. Instead co2 is to blame.
These climate models (I take it) assume warming is going to continue in the same manner it has since 1976/77. But indicators show that will not happen.
“Chris de Freitas Ph.D., El Nino, La Nina, and the 1976 Great Pacific Climate Shift”
http://www.youtube.com/watch?v=rnlC4NMLr8E
“Don Easterbrook, PDO warm, PDO cool, the 1977 climate shift”
http://www.youtube.com/watch?v=IR_dawnR7_M
Cooling until 2030:
http://www.youtube.com/watch?v=VakA4-qAuWE
“global warming stopped and a cooling is beginning” – “enjoy global warming while it lasts”
http://wattsupwiththat.com/2009/09/10/svensmark-global-warming-stopped-and-a-cooling-is-beginning-enjoy-global-warming-while-it-lasts/
Peer reviewed work showing unreliability of climate models:
……Model results and observed temperature trends are in disagreement in most of the tropical troposphere, being separated by more than twice the uncertainty of the model mean……
International Journal of Climatology of the Royal Meteorological Society [DOI: 10.1002/joc.1651]
http://www.scribd.com/doc/904914/A-comparison-of-tropical-temperature-trends-with-model-predictions
Peer reviewed:
…..The results show that models perform poorly, even at a climatic (30-year) scale. Thus local model projections cannot be credible, whereas a common argument that models can perform better at larger spatial scales is unsupported…..
http://www.scribd.com/doc/4364173/On-the-credibility-of-climate-predictions
Roy Spencer showing negative feedback from H2O. This finding is part of what is not incorporated into IPCC climate models. This work shows why IPCC models are poor and unreliable. Their climate models are dominated by positive feedback.
part 1
http://www.youtube.com/watch?v=xos49g1sdzo
negative feedback
part 2
http://www.youtube.com/watch?v=LpFk0zTW-ik
Reginald Newell, worked at MIT, NASA, and IAMAP
http://www.youtube.com/watch?v=ofFShSlv8eA
Freeman Dyson on climate models used in global warming
http://www.youtube.com/watch?v=gC3X-FmPuVg
Most of the last 10,000 years has been warmer than now. The earth only recently has emerged from The Little Ice Age and it really isn’t that warm now, comparatively speaking.
http://www.youtube.com/watch?v=wo3ovdBt7wY
Approximate beginning point of above graph—looks to coincide with the 1976 Great Pacific Climate Shift
http://img824.imageshack.us/img824/1641/arcticdecline.png
The correlation between the GCMs and the red line of observations looks impressive indeed. Just to confirm – were all of these ensemble models completed before 1953? If so, then this looks like accurate and skillful prediction.
If they were written or adjusted more recently, the cynical among us might suspect model tweaking to fit observations – the simplest thing to do with a multifactorial simulation.
With 2 years of La Nina and cooling SSTs ahead, it will be interesting to see how robust this fall in ice extent is – whether extent loss continues none-the-less. (Or not.)
were all of these ensemble models completed before 1953?
Good one!