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.”
The report does say that these temperature trends are an”estimate”. That gives a distinct possibility that they could be wrong, by a long way! I am always bothered by new “techniques” that produce the desired results, April is coming, the new UK financial year looming, cuts in public funds are inevitable I suppose.
Any guess given on why Antarctica is such a good Christian? ( the left hand does not know what the right hand is doing).
Let me see if I have this straight…
They didn’t just use their heads, they calculated it using deduction.
And people call the skeptics “anti-science” !!!!!
By the time this is shot down they will have the headlines they wanted. Bit like “the hottest October ever”. Matty, Perth, Western Australia
And all this contrasts with an above average Antarctic seaice for the last couple of years!!!
Unfortunately the satellite data only covers the recent warming period. Many trends during a warming period (like the PDO for example) are radically different than trends during a cooling mode. In my part of the US it actually gets warmer (relative to the rest of the country) during a cooling PDO. Using warming mode data to work out cooling mode data is probably about as stupid as using arctic ice extents to predict antarctic ice extents. On the surface it sounds like it would work but we know from experience that it can often give radically different (and wrong) results.
“statistical technique”, “estimate”, “guide to deduce”! No mention of what the uncertainty is in the one-tenth of a degree or how much the cooling was in the East Antarctic. It doesn’t sound like real science, more like an attempt to find some way of plugging another hole in the sinking of the ship SSAGW. The press release does not give any confidence that the paper has any worth.
“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.”
Wow, scary hot! One tenth of a degree per decade. How can they ‘measure’ to this degree of accuracy I have to wonder, especially with interpolation, albeit “careful interpolation”. So its gone from really really really cold to only really really really cold (same number of reallys there due to the uncertainty bands!).
per the following map , http://earthobservatory.nasa.gov/IOTD/view.php?id=8239 and eyeballing an average temperature change works out to
25years x 0.05deg/year = +1.25deg over 20 years
using the 2004 map above, and eyeballing an average temperature change works out to
25 years x -.1 = -2.5deg over 20 years
Thats a poorly estimated on my part, whopping difference of 4 degrees. I wonder how the difference came about?
But wait… they added a disclaimer on latest data: “The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius.”
So it looks to me like they decided to change thier color scheme to suit good buisness practices, in hopes of getting some funding for more reaserch.
I’d like to see how the following graph looks now, after “correction”
http://icecap.us/images/uploads/ANTARCTIC_SP.jpg
Scientists involved in this field have to toe the line for the sake of their careers. An article in the http://www.cato.org web site (Vol.15, No.2, Spring 1992) notes that one scientist lost funding from the National Science Foundation (who also funded the study above) because of:
*quote*
“…data analyses that were failing to show net warming over the past century. Reviewers suggested that his results were dangerous to humanity.”
*end quote*
I am trying to get my head around the methodology used, they say this is not back of the envelope guestimation but end up saying that in effect their work is nothing more than calculation by guess work?
Interpolation is a grand word for it but a simpler explanation may be that they have been trying every which way to get the figures to fit a desired outcome and this ‘interpolation of data’ is just another complicated way of smashing that square peg into that obstinate round hole.
The ommision of volcanic activity in the western quarter must at least raise the spectre of selective and biased procedures.
The BBC have been flogging the story to death which also leads me to believe that something fishy is going on.
I’ll have to read their paper before giving serious comment, but, before I read it, my guess is that the inconvenient trend over the past three decades or so in Antarctica (which is the opposite of the trend observed elsewhere, perhaps due to cloudiness-albedo issues, or perhaps due to the fact that it’s the only terrestrial area on Earth without urban heat island issues) gave them cause to go out and prove that the continent was actually warming. The period with the highest and most rapidly rising CO2 concentrations was showing some cooling, so it made sense to go back and find a cold starting point. Then they could turn around and say that the long-term trend is upward. This, of course, is true, but belittles the fact that this has not been the case since the 1970’s. Next, they will tell us that the reason for the increase in sea ice in the area around the Antarctic is because of the added melting caused by warming and increased precipitation, and the resultant increase in freshwater, which is more stable and has a higher melting point. Never mind the more likely possibility that it has something to do with the slight cooling during the past three decades (though I’ll bet this is conveniently no longer apparent in their paper). Anyway, enough with my diatribe. I’ll pick it up on the weekend and actually read it before I comment further. Maybe they’ll convince me.
I suppose with the arctic sea ice ignoring Al Gore’s prediction that it will vanish within 5 years, they had to divert attention somewhere else. The other side of the globe seems to be far enough away…
George Smith of this parish spoke directly with Steig on this and posted on another thread, but I can’t find the post now. I hope he reposts it here. – Anthony, please badger wordpress for a better author search facility!
Climate Audit is also covering this one…http://www.climateaudit.org/?p=4914#comments
I posted the comment below earlier today, as it’s station related I thought it might interest some readers here. I posted a brief version of this on Real Climate but it appears to be one of those questions that some prefer not asked.
The following are the station history comments for Butler Island AWS WMO ID 89266 from the University of Wisconson Antarctic Automated weather stations project. I assume this is GISS station ID Butler Island 700892660009. The temperature graph from GISS is available through- http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=700892660009&data_set=0&num_neighbors=1
The supplementary data of Steig et al 2009(www.nature.com/nature/journal/v457/n7228/extref/nature07669-s1.pdf) indicate a warming trend of 0.45 C/decade for Butler Island – the highest of any site reported. I thought it would be interesting to see what the station history revealed-(from http://amrc.ssec.wisc.edu/aws/butlerismain.html). Note that Butler Island sits on the east side of the Antarctic Peninsula. Google earth shows a featureless rounded island surrounded by sea ice.
Station history
1983: This unit was deployed by the BAS but upon installation at Butler Island the unit did not operate. The unit was removed leaving the tower and other equipment in place on Butler Island and will be returned to Wisconsin for repairs.
1986: AWS 8902 was tested and found to be functioning well. This unit was deployed 1 March 1986. The old station was located and found to be almost totally buried. The solar panel, aerovanes, and top tower section were returned to Rothera.
1986-87; 01 Mar 86. On 01 Oct 86 wind direction failed for unknown reasons. On 19 Jul 87 station stopped transmitting for unknown reasons.
1990: Wind speed and direction were intermittent after 2 May.
1991: Pressure gauge ceased functioning 8 Dec.
1992: Performance: 100%
1993: Performance: Station not functioning after 3 November.
1994: Performance: Station off until 15 February, and again 18 March-5 April. Wind system intermittent July, October-December.
1997: Performance:Aerovane replaced 11 February. Pressure had to be corrected due to a failure of the precision time-based correction to the system clock. Aerovane “frozen” most of the time in May and August through November.
1998: Performance:Aerovane not functioning from 10 September to 27 October. Pressure continues to need correction due to the failure of the precisiontime-based correctin to the system clock.
1999: Performance:Aerovane intermittently “frozen” in July. Pressure continues to need correction due to the failure of the precision time-based correction to the system clock.
2000: Performance:Aerovane not functioning from mid-June through December. Pressure continues to need correction due to the failure of the precision time-based correction to the system clock.
2001: the following work was done “Moved Solar panel and electronic boxes up so all above 120cm allowing accumulation for the next year.”(amrc.ssec.wisc.edu/aws/butlerismain.html).
2003 Visited on 22/12/03 The mast was not raised but the old solar panel and charging box were removed. The new solar panel was mounted on the mast. The new battery box was placed at the bottom of the mast in a hole that just buried it on the western side of the mast. A flag was placed on top of the box so it could easily be located. The wind vane was replaced with a repaired one. New cables were connected and the AWS started up without any trouble.
The GISS graph shows a break between 2003 and two new data points for 2007, 2008(?). There is data available for station 892660 for the intervening period but not shown on GISS (eg http://www.tutiempo.net/en/Climate/BUTLER_ISLAND/01-2005/892660.htm) for some reason.
Given the station history I am surprised that Steig et al 2009 manage to define a trend at all let alone a rising one of 0.45degrees C/decade. If it were me I would have left this station out of the analysis altogether as it appears far to unreliable. I wonder how many other stations are similarly affected? Did reviewers bother to examine station records at all?
Note also there is a change in station altitude of about 100 m but I am unable to work out when this occurred.
From NASA: Satellites Confirm Half-Century of West Antarctic Warming — global-warming hype of the day?
Update: I contacted the ‘Today’ program on radio 4 which just ran the story with a praisee of George’s comments. They emailed me straight back and asked George to contact them direct. http://news.bbc.co.uk/today/hi/contact_today/default.stm
I hope George sees this and sends them the post he made.
One of the main arguments in this thread is one ad hominem against one of the authors of the paper in Nature ( “Anytime Michael Mann gets involved …” ). This sounds poor.
The other argument is, volcanoes. I’m missing the quantification of this point – how can spots of volcanism be relevant for the warming of one half of the continent?
Somehow, not much justice is done to the paper. It corroborates results of several other papers and it uses widely applied methods. Using satellite data to fill gaps in coverage is used in many fields including weather forecast, and the verification proves that it works.
With this work we now have a broader picture of global warming in work in general, the dynamics of the lower stratosphere and the ozone layer influencing continental Antarctica and even cooling it in the last two or three decades, and regional winds and sea ice influencing the pattern of temperature change over the continent. It gives us hints, where coupled models need improvement, because we understand better, why they fail in some points. This is, how science works.
@ur momisugly Mike (23:57:08) :
Hype of the day?
To identify causes of the warming, the team turned to Drew Shindell of NASA’s Goddard Institute for Space Studies in New York, who has used computer models to identify mechanisms driving Antarctica’s enigmatic temperature trends.
Some bloke at GISS who has used computer models to identify
AGW is a ship called Titanic in 1912 ignoring the warnings of pack-ice and icebergs.
So they have combined satellite data with conventional weather station data to show the Antarctic is warming.
Does this mean that the satellite data is now considered to be a valid measurement of global temperature trends or is it only valid in Antartica?
As a side issue read Richard North’s posts on carbon permits at http://eureferendum.blogspot.com/
A Study in Useless says that a side effect of the recession is that the steel and cement industries in the EU now have a surplus of permits. They are trying to sell them to raise funds that they can’t get from their normal channels in the crippled banking system. Reuters reckons they could raise 1 billion Euros.
It will also depress the price still further, possibly as low as $5 a ton….bet Al Gore is crying into his Cheerios as he watches his carbon based investments tank. (Do they release CO2 into the atmosphere too as they evaporate?)
“Look behind You” says our government (UK) has committed to selling 25 million permits this year. Hardly worth the effort to raise just £125m. Mind you anything is something as they try to “save the planet”.
Belated congratulations to you Anthony. We’ve been away so only found out the good news today. Well deserved and hopefully you’re picking up a few more visitors from the UK now.
Almost exactly a year ago on 22/01/08 there was an article “Suprise! There’s an active volcano under Antarctic ice”, And the same pictures were used, perhaps on 22/01/09 there might be an article about one of those volcanoes blasting a hole in the ice sheet!
*22/01/10 not 09
I cant wait to see Steve McIntyre’s take on this paper
Wathever the conclusion, this article invents a new kind of modelling, the retro-modelling, which gives them a very large road in order to re-write history …