Above: Mt Erebus, Antarctica
picture by Sean Brocklesby
A press release today by the University of Washington makes a claim that Antarctica is warming and has been for the last 50 years:
“The study found that warming in West Antarctica exceeded one-tenth of a degree Celsius per decade for the last 50 years and more than offset the cooling in East Antarctica.”
…
“The researchers devised a statistical technique that uses data from satellites and from Antarctic weather stations to make a new estimate of temperature trends.”
…
“People were calculating with their heads instead of actually doing the math,” Steig said. “What we did is interpolate carefully instead of just using the back of an envelope. While other interpolations had been done previously, no one had really taken advantage of the satellite data, which provide crucial information about spatial patterns of temperature change.”
Satellites calculate the surface temperature by measuring the intensity of infrared light radiated by the snowpack, and they have the advantage of covering the entire continent. However, they have only been in operation for 25 years. On the other hand, a number of Antarctic weather stations have been in place since 1957, the International Geophysical Year, but virtually all of them are within a short distance of the coast and so provide no direct information about conditions in the continent’s interior.
The scientists found temperature measurements from weather stations corresponded closely with satellite data for overlapping time periods. That allowed them to use the satellite data as a guide to deduce temperatures in areas of the continent without weather stations.
…
Co-authors of the paper are David Schneider of the National Center for Atmospheric Research in Boulder, Colo., a former student of Steig’s; Scott Rutherford of Roger Williams University in Bristol, R.I.; Michael Mann of Pennsylvania State University; Josefino Comiso of NASA’s Goddard Space Flight Center in Greenbelt, Md.; and Drew Shindell of NASA’s Goddard Institute for Space Studies in New York City. The work was supported by grants from the National Science Foundation.
Anytime Michael Mann gets involved in a paper and something is “deduced” it makes me wary of the veracity of the methodology. Why? Mann can’t even correct simple faults like latitude-longitude errors in data used in previous papers he’s written.
But that’s not the focus of the moment. In that press release they cite NASA satellite imagery. Let’s take a look at how the imagery has changed in 5 years.
NASA’s viewpoint – 2004
Click for larger image
NASA’s Viewpoint 2007 (added 1/22)
NASA’s viewpoint – 2009
Earth’s viewpoint – map of Antarctic volcanoes
From the UW paper again:
“West Antarctica is a very different place than East Antarctica, and there is a physical barrier, the Transantarctic Mountains, that separates the two,” said Steig, lead author of a paper documenting the warming published in the Jan. 22 edition of Nature.
But no, it just couldn’t possibly have anything at all to do with the fact that the entire western side of the Antarctic continent and peninsula is dotted with volcanoes. Recent discovery of new volcanic activity isn’t mentioned in the paper at all.
From January 2008, the first evidence of a volcanic eruption from beneath Antarctica’s ice sheet has been discovered by members of the British Antarctic Survey.
The volcano on the West Antarctic Ice Sheet began erupting some 2,000 years ago and remains active to this day. Using airborne ice-sounding radar, scientists discovered a layer of ash produced by a ’subglacial’ volcano. It extends across an area larger than Wales. The volcano is located beneath the West Antarctic ice sheet in the Hudson Mountains at latitude 74.6°South, longitude 97°West.
UPDATE 1/22
In response to questions and challenges in comments, I’ve added imagery above and have a desire to further explain why this paper is problematic in my view.
The author of the paper himself (Steig) mentions the subglacial heat source in a response from “tallbloke” in comments. My issue is that they don’t even consider or investigate the possibility. Science is about testing and if possible, excluding all potential candidates that challenge your hypothesis, and given the geographic correlation between their output map and the volcanic map, it seems a reasonable theory to investigate. They didn’t.
But let’s put the volcanoes aside for a moment. Let’s look at the data error band. The UAH trend for Antarctica since 1978 is -0.77 degrees/century.
In a 2007 press release on Antarctica, NASA’s describes their measurement error at 2-3 degrees, making Steig’s conclusion of .25 degrees Celsius over 25 years statistically meaningless.
“Instead, the team checked the satellite records against ground-based weather station data to inter-calibrate them and make the 26-year satellite record. The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius.”
That is from this 2007 NASA press release, third paragraph.
http://earthobservatory.nasa.gov/IOTD/view.php?id=8239
Also in that PR, NASA shows yet another satellite derived depiction which differs from the ones above. I’ve added it.
Saying you have a .25 deviation over 25 years (based on one-tenth of a degree Celsius per decade per Steig) with a previously established measurement uncertainty of 2-3 degrees means that the “deduced” value Steig obtained is not greater than the error bands previously cited on 2007, which would render it statistically meaningless.
In an AP story Kenneth Trenberth has the quote of the day:
http://news.yahoo.com/s/ap/20090121/ap_on_sc/sci_antarctica
“This looks like a pretty good analysis, but I have to say I remain somewhat skeptical,” Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, said in an e-mail. “It is hard to make data where none exist.”
Allan M R MacRae:
Ah…Using whose temperature record do you find no increase since the 1940s?!?
Well, how can I argue with logic like this? I didn’t make any personal attacks. I just noted who appointed Wegman and what the Republican Congressman who headed the House Science Committee thought of Barton’s committee’s whole approach to this matter. It is quite relevant since that committee (specifically, the Republican majority in charge) are who chose Wegman and gave him his narrow charge. By contrast, the National Academy of Sciences is the organization that is chartered to provide advice and information to Congress (and the federal govt in general) on these sorts of matters.
Joel Shore (15:24:41)
Let me accept your words for the moment – perhaps I imputed malice where there was none.
I have little patience with the opinion of the IPCC or other politically motivated parties – I only look at the data.
I also know and respect some of the parties being slagged here, and I find this practise reprehensible – thus I may be overly sensitive.
I use UAH LT back to 1979; earlier I use HadCrut3 ST’s. I use ST data reluctantly, because there is a warming bias, of probably ~0.2C since 1979.
See the first Figure at http://www.iberica2000.org/Es/Articulo.asp?Id=3774
Prof. Wegman
deconstructsanswers his critics: clickAllan M R MacRae:
Okay, but have you been speaking out when people slag Mann and Hansen and Gavin and all of them? I actually spoke out in this thread when the word “incompetent” was used in relation to Spencer and Christy’s satellite analysis because I thought that was too strong a word. But, then there were people like yourself who wanted to deny even the fact that they had made a whole series of errors that, once corrected, significantly altered the results. This is what prompted me to go back and demonstrate exactly how much difference these corrections have made. (And, for that I am grateful to you because before this exercise I never knew how much of the change in the trend over the years was due to the longer data series and how much was due to the changes in the analysis and now I do.)
Well, that seems like an awful lot of cherry-picking, to be quite honest. First, you take the lowest estimate out there among all of the surface temperature and satellite estimates. Then, you use ST data…which would also tend to underestimate of the warming since the land has warmed more than the oceans (as is expected). And, you seem to have married them in some way that gives the satellite data a low bias compared to the ST data (which is what you want because you compare the ST data from the 1940s to the satellite data today). And, finally you seem to take the one data point for 2008 to compare, rather than the general temperatures over the last several years. (In fact, this may not even be the full year data point if it is true that you last updated the page with the May data.)
If this is what you mean by “I only look at the data”, I can see why you have come to the conclusions that you have!!
Joel Shore (09:45:18) :
It depends on what you want to do with your “trend”. I’ll bet you want to extrapolate it to 2100. In that case, statistical significance doesn’t matter. What matters is whether the linear (or any other) relationship continues outside the range of the available data. Of course, there is no evidence either way for that. But there is strong evidence from the temperature record that extrapolating trends within a cycle gives incorrect predictions. From about 1900 (from memory, I don’t have the graph in front of me) to about 1940 there was a linear(ish) trend similat to the 80s & 90s. Extrapolate that to now and you will see that the”prediction” was way too high. Then about 1940 to about 1970 there was a cooling trend, vaguely linear, and if you extrapolate that to now you get a figure that is way too low. Why would this approach, clearly wrong over those periods, now be right?
As suggested by Allen, just look at the data. Clearly there are cycles, we have been in a warming cycle; it looks like that might have ended (as cycles do) and we seem to be entering another cooling cycle. But it’s a bit early to be sure.
Allan M R MacRae (16:56:49) :
My first impression is that you’ve nailed it. My view has always been that the onus is on the warmers and I haven’t been able to see any evidence to support their proposals. This looks like strong evidence that they’re wrong, not just that they haven’t enough to justify being right. No time yet to look in detail, but a few points that you can easily answer I think:
Vostok 800 yrs lag, you 9 months.
I’ve seen calculations suggesting that deltaT is not enough to explain deltaCO2 on the basis of chemical equilibria (don’t recall author, you probably know it) Failure to reach chemical equilibria doesn’t help you case I think. Biological?
Stability of dCO2/dt data. Can you rely on it (couldn’t for global Tavereage, for example)? Any error analysis?
Just some thoughts on the fly.
Joel (20:35:35)
Your malice is showing again – imputing motive such as “cherry-picking” where none exists.
I have always used UAH and Hadley – the reasons why are so old that I no longer remember them. Recently discovered problems with GISS quality control reinforce my decision to use Hadley ST, although both ST’s show a warming bias.
As regards RSS versus UAH LT’s, the differences between them have never amounted to much, and are now becoming insignificant.
You seem to be unaware that the temperature trends we are discussing are really small, typically from 0.003C/year to 0.013C/year. There is no evidence in the data to support alarm.
More on malice: It is not my side of this debate that has attempted to shout down and intimidate discussion – it is yours.
I am aware of serious threats against some of my friends who have spoken out against the myth of catastrophic AGW, and I am appalled by the hysterical, brutish behaviour of many on your side of this debate.
“Even if we took your claim here on the historical record to be true (which I don’t without some real evidence to back it up)”
How about Greenland burials beneath today’s permafrost?
PS: Or medieval and Roman artifacts coming to light in the wake of retreating alpine glaciers?
John M (10:03:30) :
Who said anything about the number of papers? Certainly not me.
The point I was making is that issues of substance readily make it into the scientific literature. If something is worth publishing it can be and usually is (if it’s in the public domain of course). McIntyre seems still to be making copious and continual critiques of Mann et al’s 1998/9 analysis and was doing so through 2005 when he last published on this. However these critiques have been addressed widely in the scientific literature and shown to be either lacking in merit or to be trivial [see foinavon (17:38:38)]. McIntyre hasn’t taken this further in the scientific literature. Nor has he addressed in the scientific literature the increasing number of studies that largely support the original analysis of Mann et al.
So McIntyre has had his chance to present his case. It turns out to be unsubstantial. The generalized attempt to hound Mann [see Joel Shore (07:15:05), for an eye-opening account of this] is shoddy and embarrassing McIntyre has chosen to pursue critiques of Mann on the blogosphere. Fine, but we should be addressing the validated science if we want to understand these issues.
It’s been my observation that these discussions degenerate into factoid swapping and thus noise. A collection of facts does not necessarily result in knowledge and certainly not wisdom. The real discussion should be centered on the policy that will undoubtedly result from the AGW findings. When science leaves the lab and enters into the public domain in the form of shrill and alarmist pronouncements the discussion is no longer scientific, it is political. Policies have both intended and unintended consequences. It’s my opinion that there is a perfect analog for what is happening with the AGW discussion and that is the banning of DDT and the attending death of tens of millions of Africans. Perhaps the discussion should move on to one about the moral argument for justifying mass murder or population control by other means. Please explain the morality that justifies a cabal of developed countries inflicting economic devastation and hardship on developing countries
Allan M R MacRae says:
I stand by my basic point which is that you are cobbling together data sets in various weird ways to arrive at conclusions completely at odds with the peer-reviewed literature. And, before you managed to make a trend in the entire UAH data set largely disappear by taking the trend over segments in a way where the trend lines did not even join correctly.
Really? That is not what the Republican head of the House Science Committee Sherwood Boehlert thought when fellow Republican Barton’s committee hauled Mann et al before it:
( http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000497letter_from_boehlert.html )
davidc says:
No, the projections for climate change are not based on extrapolating the trend to 2100. They are based on an understanding of the physical processes involved in influencing our climate. However, the general trend in the temperature is important for establishing and checking the science.
Roger Knights says:
Again, the North Atlantic is the region that we know had a pronounced MWP. However, the evidence that this happened elsewhere at the same time is not there.
You mean like this paper http://www3.interscience.wiley.com/journal/114125034/abstract?CRETRY=1&SRETRY=0 regarding a pass in the Swiss Alps whose abstract reads:
And, the surprising aspect of this paper is it is from the general region that hads strong evidence of a significant MWP.
foinavon (02:34:34) :
Sorry, I guess I interpreted these statements by you as somehow referring to “the number of papers”. I’m comfortable leaving this to others to judge.
As far as the comments in Joel Shore (07:15:05), if you’re referring to the opinion of some NSF administrator that scientists are entitled to “own” work paid for by the taxpayers, good luck with that one. If you’re referring to “refutations” of McIntyre’s arguments, again, I’m sure McIntyre would be happy to respond to those one-by-one (probably with references to his blog archives). Unlike Real Climate, he doesn’t censor, so give it a try. If you’re more interested in “what’s published” rather than in the actual argument, you can continue to live in your comfortable world.
Look, you can take this or leave it. I’ve had many years in the chemical industry. When I started my career, a typical argument (including by scientists) was “We’re the experts, we know what we’re doing. There are plenty of published papers backing us up. Our critics really don’t have the expertise to judge, etc. etc. etc.)”
Wanna guess how that turned out?
foinavon says: “McIntyre hasn’t… addressed in the scientific literature the increasing number of studies that largely support the original analysis of Mann et al.”
That is changing history. Steve McIntyre forced the UN/IPCC to withdraw its use of Mann’s bogus hockey stick.
It should also be noted that both Profs. Wegman and Lindzen have shown conclusively that there is a relatively small clique of pro-AGW referees and committee members who control the process and decide just who gets published and who doesn’t.
If foinavon really wanted the climate peer review process to function honestly rather than angling for ever more grant money, he would spend his time writing letters to the various journals demanding change. Instead, he spends countless hours here, attempting to change minds. It appears to be a wasted effort.
Hmmmm… there is at least some evidence of the Medieval Warm period in South America:
http://www.co2science.org/subject/m/summaries/mwpsoutham.php
There seems to have been an article on ClimateAudit about Antarctic warming.
It is interesting … the devil is in the details …
Joel Shore (06:48:03) :
Allan M R MacRae says:
Your malice is showing again – imputing motive such as “cherry-picking” where none exists.
I stand by my basic point which is that you are cobbling together data sets in various weird ways to arrive at conclusions completely at odds with the peer-reviewed literature.
***********************
Joel
Your malice makes further discussion a waste of time.
I have not found any of the points that you initiated to be convincing.
I think we have discussed this subject enough – I will not reply to your further comments.
Smokey says:
What? In what universe has the IPCC not used the hockey stick. The difference between the AR4 report and the TAR report is that there are now several other reconstructions that they show along with Mann’s and this allows them to strengthen their conclusion in regards to the late 20th century temperatures likely being the warmest of any half-century time period in the last 1300 years. They do note that some of the other reconstructions show more variability in the pre-20-century than Mann et al.’s but that is mainly because the LIA is colder in some…not because the MWP is significantly warmer.
They haven’t shown any such thing…And, certainly nothing that is any different from many other fields.
And, what is amazing is not that there are great skeptical papers out there circulating that can’t get published but that there are such severely flawed skeptical papers that have gotten published. For example, the Douglass et al. paper had fundamental errors that one would have hoped a referee would have easily caught.
Schwartz’s paper arguing for a low climate sensitivity seemed to get through despite a flaws that have caused even him to now (in replies to comments) raise his estimate for the climate sensitivity by close to 80% over what he originally published. (It is more arguable whether those flaws were blatant enough to be easily caught in the refereeing process, although a good referee might have asked some questions that would have led Schwartz to consider more issues before publishing.)
And, God knows how the Essex and McKitrick paper on global temperature saw the light of day (although I think it was in a fairly obscure journal far from the climate field) … It probably took me less than half an hour to spot the fatal error in their attempt to show that their argument had any relevance whatsoever to actual measuring of the trends in the global temperature anomaly.
davidc (00:16:17) :
Time is limited so I can only provide some more general answers to your questions:
My paper was posted Jan.31/08 with a spreadsheet at
http://icecap.us/index.php/go/joes-blog/carbon_dioxide_in_not_the_primary_cause_of_global_warming_the_future_can_no/
The paper is located at
http://icecap.us/images/uploads/CO2vsTMacRae.pdf
The relevant spreadsheet is
http://icecap.us/images/uploads/CO2vsTMacRaeFig5b.xls
There are many correlations calculated in the spreadsheet.
In my Figure 1 and 2, global dCO2/dt closely coincides with global Lower Tropospheric Temperature LT and Surface Temperature ST. I believe that the temperature and CO2 datasets are collected completely independently, and yet there is this clear correlation.
After publishing this paper, I also demonstrated the same correlation with different datasets – using Mauna Loa CO2 and Hadcrut3 ST going back to 1958. More recently I examined the close correlation of LT measurements taken by satellite and those taken by radiosonde.
Further, I found earlier papers by Kuo (1990) and Keeling (1995) that discussed the delay of CO2 after temperature, although neither appeared to notice the even closer correlation of dCO2/dt with temperature. This correlation is noted in my Figures 3 and 4.
See also Roy Spencer’s (U of Alabama, Huntsville) take on this subject at
http://wattsupwiththat.wordpress.com/2008/01/25/double-whammy-friday-roy-spencer-on-how-oceans-are-driving-co2/
and
http://wattsupwiththat.wordpress.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/
This subject has generated much discussion among serious scientists, and this discussion continues. Almost no one doubts the dCO2/dt versus LT (and ST) correlation. Some go so far as to say that humankind is not even the primary cause of the current increase in atmospheric CO2 – that it is natural. Others rely on a “material balance argument” to refute this claim – I think these would be in the majority. I am an agnostic on this question, to date.
The warmist side also has also noted this ~9 month delay, but try to explain it as a “feedback effect” – this argument seems more consistent with AGW religious dogma than with science (“ASSUMING AGW is true, then it MUST be feedback”). 🙂
It is interesting to note, however, that the natural seasonal variation in atmospheric CO2 ranges up to ~16ppm in the far North, whereas the annual increase in atmospheric CO2 is only ~2ppm. This reality tends to weaken the “material balance argument”. This seasonal ‘sawtooth” of CO2 is primarily driven by the Northern Hemisphere landmass, which is much greater in area than that of the Southern Hemisphere. CO2 falls during the NH summer due primarily to land-based photosynthesis, and rises in the late fall, winter and early spring as biomass degrades.
There is also likely to be significant CO2 solution and exsolution from the oceans.
See the excellent animation at http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/carbonDioxideSequence2002_2008_at15fps.mp4
It is also interesting to note that the detailed signals we derive from the data show that CO2 lags temperature at all time scales, from the 9 month delay for ~ENSO cycles to the 600 year delay inferred in the ice core data for much longer cycles.
Regards, Allan
Smokey (10:19:15) :
I disagree with your point here. I think we should encourage discussion aimed at trying to change opinions. I think foinavon and Joel Shore are doing us a service here. I see it more of problem when climate scientists and their allies view skeptics as too stupid to argue with.
It’s far better for both sides to engage. And I don’t think we should try to chase people away who disagree with us.
That would be how some other blogs operate.
Joel,
[snip] Surely you can discuss these matters a little more rationally. I was under the impression that you were a published scientist. A calm and well considered answer would be much more persuasive to most people than your rants. When you first started posting here you were a lot calmer. Perhaps it’s time for a vacation.
Mike
A link to that latter post is not complete without a link to this: http://tamino.wordpress.com/2009/01/19/a-bag-of-hammers/ The moral of the story is this: If you take some data and manipulate it in some way and get some result and then manipulate it some more and get the same result (i.e., the same slope to 5 significant figures and the same R^2), rather than conclude “Significantly, note that the ratio of C13 variability to CO2 variability is EXACTLY THE SAME as that seen in the trends!” you might want to ask, “Am I really sure this second result is independent of the first?” In fact, a little bit of elementary calculus shows that they are not independent whatsoever. The second result is not at all significant; it is just a necessary consequence of mathematics and means absolutely nothing physically.
By the way, Spencer has written a very recent post again arguing that most of the rise in CO2 might be natural and has received the following reply from Hans Erren, who is an AGW skeptic but one who admits that the claim that the current rise in CO2 has a significant natural component is mistaken: http://www.drroyspencer.com/2009/01/the-origin-of-increasing-atmospheric-co2-a-response-from-ferdinand-engelbeen/
That the relationship between CO2 and temperature goes both ways (i.e., that CO2 tends to cause warming but also that increased temperature tends to lead to outgassing of CO2 from the oceans…and possibly other mechanisms that rise CO2 levels) has been understood for a long time. In fact, since at least the mid-1970s it has been generally accepted that the trigger for the glacial-interglacial transitions were the so-called Milankovitch oscillations in the earth’s orbit…and thus that these oscillations, and presumably the temperature rise that they started, was what triggered the changes in CO2 levels.
However, if you look at the rise in CO2 levels seen during the glacial – interglacial transitions and compare them to the temperature change, they seem to imply a change in CO2 levels by about 100ppm for about a 5deg C global temperature change, or about 20ppm / deg C.
Thus the current temperature change of a little less than 1 C ought to be associated with about 20ppm of CO2 increase. Furthermore, as Allan has noted, there is a time delay that suggests that even this much change in CO2 in response to a change in temperature takes several hundred years to occur. (This is a time constant likely associated with the time it takes for overturning of waters in the oceans.)
There are a variety of time constants associated with the uptake of CO2 (e.g, about half of our emissions have been taken up by the oceans and biosphere almost right away), so it is not surprising that we do see some variation in this uptake with variations in temperature on short timescales too…but these seem to be quite small. Hans gives a reasonable estimate of them.
Mike Bryant says:
Thanks for the advice. Your suggestion might be a good one…I tend to get a little too caught up in these discussions (and a bit frustrated at times) and perhaps should try to disengage a little and also be more careful about my rhetoric.
On the other hand, looking back at the answers that I have given here, I think they are generally quite factually based (not sure which post of mine you were commenting on in particular) and when I critique something I have tried to explain exactly what points I think are problematic (such as some of Allan MacRae’s analyses) or to give specific examples (such as in my response to what Smokey said in regards to peer review).
I’d be curious more specifically what you think has crossed over the line here.