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.”
Let me add one other observation. If the east side is cooling and west side is warming exactly how does that fit the current models? How do the models explain the eastern cooling.
In my mind this simply strengthens the arguments that climate is regional and without regionalizing the models there is little hope of getting anything close to reality.
“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 …” )”
Is it an attack on Mann or a comment on the poor quality of his science? I believe you’ll find it to be the latter and not the former. Criticizing Mann’s work is not an ad hominem argument.
Could the picture showing the Antarctic Volcanoes be made expandable by “Click for Larger Image” ???
Flanagan (07:24:18)…
…Appears to be deliberately misrepresenting the situation, by stating that petition signers are “paid” a $144 “reward” for signing.
Event sponsors offer a 20% discount only to legitimate, degree-holding scientists, if they wish to add their names to the OISM petition [and only those with degrees in the hard sciences qualify; no English Lit majors, no Sociologists, etc.].
There are always some people who have not heard about the OISM petition, and this is a way to make them aware. It is no less legitimate than a newspaper coupon that gives a discount at the door.
Since many universities and professional organizations pay entry fees for events such as this, those attending may not receive any compensation from the discount.
And regarding that silly Guardian link, the names of signers are verified prior to being added to the list. From the OISM website:
But rather than shout and point at something, anything, in order to distract from the issue, it’s best to keep focused on exactly what the petition says, since it has been signed by over 31,000 U.S. scientists:
If anyone disagrees with that statement, I would like to hear credible reasons, backed up by facts, showing that it is not accurate.
Flanagan:
You raise doubts about your ability to analyze if you think that a $144 discount on a conference registration fee will persuade a scientist to sign a petition in which he doesn’t believe.
Mark P
“The alarmists really are getting desperate now.”
This is what makes them so dangerous. They’ve become Orwellian, and that tells me they won’t stop at nothing. I see our inconvenient sceptic blogs getting shut down soon. And good bye Talk Radio. You’ll see.
Get ready to be a dissident on the run. I’m glad I live only 6 hours away from the Czech Republic. It might be the only country left that will offer climate asylum! It’s getting serious.
Let’s me see now. Words like “devised a statistical technique”, deduce and intropolate vs calculating in their heads and back of an envelop. Michael Mann is a coauthor. I don’t know if I want to waste my time reading the whole report.
Has an experienced PhD statistician examined their “statistical technique”?
From Nature:
A new reconstruction of Antarctic surface temperature trends for 1957–2006, reported this week by Steig et al., suggests that overall the continent is warming by about 0.1 °C per decade.
The work ends in 2006. sure.
reconstruction,reconstrutcion,reconstruction….
suggests, suggests, suggests, suggests….
Sorry.
With the benefit of the doubt, the work must be repeated. (2007 and 2008)????
Dr Leif, 0.01 ° C / year.( days … weeks .. months .. years … century millennium …) a small question;
is compatible with a range of 1W/m ^ 2?..(TSI)
Leif, independent of your wife. I love your comments.
Just as I predicted a few day ago, this La Nina now appears to be fizzling away.
http://www.osdpd.noaa.gov/PSB/EPS/SST/climo&hot.html
Overall, now that Obama is Prez,
expect a blizzard of global warming reports to come out.
This will give him the momentum needed to ram
climate policy down our throats.
The big blizzard is coming!
Gripegut (07:15:06) :
The temperature data is from the USGS Advanced Very High Resolution Radiometer:
http://edc.usgs.gov/guides/avhrr.html
which has pole to pole coverage and measures the temperature of radiating surfaces
It’s the satellite tropospheric temperature data that is somewhat dodgy at high latitudes since the microwave sounding units (MSU) seem to pick up spurious non-temperature-related artefacts from seasonal sea ice cycles (and also from high altitude snow covered mountains, as it happens):
http://www.agu.org/journals/gl/gl0320/2003GL017938
So, for example, the RSS tropospheric temperature analysis omits tropospheric temperature data from regions more southerly than 70′ latitude.
Joerg Zimmermann: Thanks for the suggestion about reading the paper, but I understand the basis. My comments, the two before yours and the one after, were provided to illustrate longer-term datasets and to show the inconsistencies between the study and those records. My third comment also asked two very basic questions.
Did the researchers account for the apparent changes in variability due to volcanic activity?
And how did the researchers account for the apparent ENSO-induced step changes?
The step changes are visible in Cell b of Stieg et al (2009) Figure 2. You just have to look beyond that pesty trend line. I try not to use trend lines for just that reason. They alter the appearance of the graph. (But sometimes I get carried away and throw them on, usually because I want to influence the viewer’s perception of the data.)
I’ve posted the above questions on the Nature website, but they have not been moderated yet.
Regards.
“a good Christian? ( the left hand does not know what the right hand is doing).”
Anna, I’m crushed!
What does my nature have to do with my belief system?
“Most ground-based temperature measurements from Antarctica began in 1957, and the data is largely from coastal areas. Gauging the vast interior by satellite didn’t begin until 1979. Steig’s team used mathematical models to establish the relationship between the ground and satellite measurements between 1979 and 2006 and then used the correlation they found to calculate temperatures for the interior going back to 1957.”
This makes sense if the statistical weather patterms — that is, climate pattern — does not change between the coast and the interior. Then the correlations between the coast and interior can, with some plausibility, be assumed to be constant. However, the correlations were from data taken during decades of a slight warming trend (1979-2000) and then used to estimate data in the interior during decades of a slight cooling trend (1957-1979). This sounds like it may be the hockey stick all over again. You should use correlations established for one climate-change pattern to estimate temperatures during an era of the opposite climate-change pattern only if you’re desperate for some sort of approximate result — or tryiing to baffle people with “science”.
Zeke and others
The author of the paper himself mentions the subglacial heat source in a response from “tallbloke” above. 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, NASA’s data describes their measurement error at 2-3 degrees, making Steig’s conclusion statistically meaningless.
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.
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 certainly does not seem like they “crossed their Ts and dotted their Is” on the analysis this time around.
Congratulations are in order for Anthony. This IS the best science blog in my humble opinion for topic quality and the astute postings by those who contribute to the discussion. Thank you again for an enlightening and entertaining site.
Steig et al appears to be another “hockey stick” paper. Just cherry pick the timeframe, use incomplete data, average the incomplete data, interpolate the results, and by using “new” mathematical techniques get the desired result.
Flanagan (07:24:18) :
Yes it’s pretty dreary (a gift of $144 if registrants to the Heartland Institue pretend Climate “Science” meeting sign some petition devised years ago by a tobacco company propagandist nearly 10 years ago). I wonder who might consider that one can assess science by petition!
The list of cosponsers (click on the poster with the gallery of rogues on the Intro page of the meeting site) gives a pretty good indication of the purpose of this sort of “meeting”..
http://www.heartland.org/events/NewYork09/newyork09.html
It should be fun!
I saw a report on BBC teletext early this morning and thought here we go again.
Interestingly it has now been removed, presumably because the likes of Anthony, Steve Mcintyre et al are already on the case.
Alex Jones on Info Wars.com has a piece today about a leading AGW site in big trouble as they know the mantra is falling apart.
He also reckoned that President Obama did’nt mention AGW either…I was out all day Tue so cannot verify this.
Despite what Gavin has claimed, the SH in general and the Antartic in general have posed serious problems for the Alarmists. It just hasn’t cooperated with thier model projection and theories. What the MWP was to the paleos, the Antartic is to the Alarmists. Something had to be done.
Flanagan (07:24:18) :
Yes it’s pretty dreary (a gift of $144 if registrants to the Heartland Institue pretend Climate “Science” meeting sign some petition devised by a tobacco company propagandist nearly 10 years ago). I wonder who they consider might be taken in by that!?
The list of cosponsers (click on the poster with the gallery of rogues on the Intro page of the meeting site) gives a pretty good indication of the purpose of this sort of “meeting” and perhaps helps to understand the dubious thinking that considers that dodgy petitions have anything to do with science…
http://www.heartland.org/events/NewYork09/newyork09.html
It should be a blast!
So in the 1940s the warming was due to warming in the tropical Pacific, but now warming is due to global warming. And the cooling since 1998 is not relevant because 1998 was an El Nino year, and that exceptionally large warming of the tropical Pacific doesn’t count. So there hasn’t, yet there has been, tropical Pacific warming.
And from various comments, it sounds as if the history might have been:
1. Warm west Antarctica circa 1940.
2. Cooler west Antarctica 50 years ago.
3. Warmer west Antarctica until 20 years ago.
4. Cooler west Antarctica in last two decades (yet still warmer than 50 years ago).
I haven’t dug through the various sources above, but if this is the situation, then this latest paper cherry-picked the cool period 50 years ago as the starting point and found that the region warmed since then…without highlighting the variations.
Several questions: If the warming in the west exceeds the cooling in the east, shouldn’t there be less ice overall? How can Antarctica have more ice?
How do they measure temps? What equipment? surfacestations project has shown some big problems with measurements in this country. Do we believe that everything at the south pole is pristine and properly working?
0.1 degree C per decade? In industry, we wanted better measurement accuracy in our equipment than the thing we needed to measure. 10x was the goal. How in the (blank) can they measure 0.1 degree with equipment that is lucky to measure 1 degree with any confidence?
Anthony,
The link to the NASA article is from 2007, discusses a different study, and is rather vague if that 2-3 degree uncertainty range reflects the temperature of any given location or of the aggregate trend (given its magnitude, I suspect the former). I strongly doubt the aggregate uncertainty range of the 1950s-present trend is anywhere near the magnitude of 2-3 degrees, both because the time period in question is longer and the methodologies have been improved in the interim (hence the new paper).
That said, I’m still waiting for a friend to send me the full text of the paper (as I can’t get through the paywall at work), so I’ll have to withhold some judgment until I have a chance to get into the nitty gritty. However, Eric Stieg seems like an amiable enough chap, and I’m sure if you email him with your questions about both vulcanism and uncertainty ranges, he could give a far better answer than I could.
james griffin,
President Obama did’nt mention AGW probably because it was quite cold out there and thus avoided committing his first blooper.
I’m looking forward to what Mr McIntyre will uncover in this latest hockey stick, let’s-rewrite history report.
1. I appreciate the unconventional thought that many of you including the author of this blog are contributing to the world.
2. I am led to believe that many of the readers of this blog probably did not consider the possibility that Steig already took the volcanic information into account before drawing his conclusions about the data.
3. As a scientists I typically despise a) the content of most “mass” press releases concerning the topics I study b) the fact that unless a scientific topic arouses controversy it tends to be dismissed by the public and c) that the press (including bloggers) seems to believe that all scientific ideas (evolution, global climate change, space exploration) are equally controversial.