2010-08-31 14:16:29Basic Rebuttal 47:There is no tropospheric hot spot - Updated
Jim Meador

jimm58@gmail...
67.101.213.181

{Please scroll down to the latest and greatest...} 

There's no tropospheric hot spot

What the science says...

New analysis shows much better agreement between computer models and measurements. 

Computerized climate models have predicted that as the surface warms in the tropics (within 20 degrees north and south of the equator) there will be even greater warming in the tropical atmosphere. Moisture in the warm tropical air rising up from the ground carries “extra” heat into the higher layers, which increases or “amplifies” the surface warming.

This warming of the air above the tropics (at altitudes of 5-15 kilometers or 16,000 to 50,000 feet) has been labeled by skeptics as the “Tropospheric Hot Spot”, and they have seized on early measurements to claim that it is missing, and thus there can’t be any warming caused by humans.

The troposphere is the low part of the atmosphere, extending from the surface up to around 16 km. (It’s not as thick at the poles.) Temperature in the troposphere is measured by both weather balloons and satellites, but the satellite record goes back only to 1979.

The IPCC report in 2007 mentioned that measured temperature trends in the troposphere were uncertain, with weaker warming that had been expected in the “hot spot” layers. However, the temperature observations from the various sources did not agree with each other, reflecting the difficulty of measuring accurately at these altitudes.

Since 2007 additional analyses of the data was done with improved techniques, and a new method was developed to assess temperature trends. (Allen and Sherwood 2008) The new estimates show greater warming in the “hot spot”, bringing them into closer agreement with the models (Thorne 2008). Furthermore, other measurements show that the troposphere has become thicker in the tropics, which is a sign of warming.

The latest published research (Santer et. al., 2008) showed that the earlier studies made an error in their analysis, and Santer used an improved method to account for year-to-year variations in the measurements. He also made use of new measurement databases that corrected for biases in the measurements. Santer’s team found no major difference between the models and observed trends in tropical temperatures. 

 


 

 

2010-09-02 07:18:16Key element of rebuttal?---Not really...it's out of date.
Jim Meador

jimm58@gmail...
67.101.213.215

 
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm  
 
I thought this was recent but it is actually several years old, and not very useful for the rebuttal.
 
2010-09-02 13:55:49Another rebuttal source
Jim Meador

jimm58@gmail...
67.101.209.184

http://climatechangepsychology.blogspot.com/2008/10/benjamin-santer-et-al-warming-in.html

In marked contrast to the earlier claim, Santer’s international team found that there is no fundamental discrepancy between modeled and observed trends in tropical temperatures.

“We’ve gone a long way toward reconciling modeled and observed temperature trends in the problem area of the tropics,” said Santer, the lead author of a paper now appearing online in the International Journal of Climatology.

There are two reasons for this reconciliation.

First, the analysis that reported disagreement between models and observations had applied an inappropriate statistical test, which did not account for the statistical uncertainty in observed warming trends. This uncertainty arises because the human-caused component of recent temperature changes is not perfectly known in any individual observed time series – it must be estimated from data that are influenced by both human effects and the “noise” of natural climate variability. Examples of such “noise” include large El Niño and La Niña events, which have pronounced effects on the year-to-year variability of tropical temperatures.

The Livermore-led consortium applied this inappropriate test to randomly generated data. The test revealed a strong bias in the method toward “detecting” differences that were not real.

The consortium modified the test to correctly account for uncertainty in estimating temperature trends from noisy observational data. With this modified test, there were no longer pervasive, statistically significant differences between simulated and observed tropical temperature trends.

The second reason for the reconciliation of models and observations was the availability of new and improved observational datasets, both for surface and tropospheric temperatures. The developers of these datasets used different procedures to identify and adjust for biases (such as those caused by changes over time in the instruments and platforms used to measure temperature).

Access to multiple, independently produced datasets provided the LLNL-led consortium with a valuable perspective on the inherent uncertainty in observations. Many of the recently developed observational datasets showed larger warming aloft than at the surface, and were more consistent with climate model results.

Even with improved datasets, there are still important uncertainties in observational estimates of recent tropospheric temperature trends that may never be fully resolved, and are partly a consequence of historical observing strategies, which were geared toward weather forecasting rather than climate monitoring.

“We should apply what we learned in this study toward improving existing climate monitoring systems, so that future model evaluation studies are less sensitive to observational ambiguity,” Santer said. 

 

2010-09-02 19:55:18Language way too sophisticated
nealjking

nealjking@gmail...
91.33.99.186
I guess you have quoted the article, but for a basic-level rebuttal it needs a lot of work.
2010-09-03 01:18:29Any particular language you object to?
Jim Meador

jimm58@gmail...
67.101.209.184

Hi Neal,

I agree it is kind of an arcane subject, and does not lend itself well to simple language. It would be helpful to me if you could point out particular sentences that you feel need more attention, and of course any suggestsion for better language are welcomed!

-Jim 

 

2010-09-03 02:37:06
Nicholas Berini

nberini@gmail...
24.189.119.236

Jim - I put a few of your paragraphs together below because I felt the beginning could have been a little stronger though I hardly wrote a new word.  Feel free to incorporate if you like.

 ________

The skeptic argument "There is no Topospheric Hot Spot" claims that climate models are unreliable becuase although the models predicted increased warming over the tropics, early data analysis did not support these predictions.  

The troposphere is the lowest part of the atmosphere, extending from the surface up to around 16km, and the "tropospheric hot spot" refers to a particularly hot troposphere over the tropics.  Computerized climate models have predicted that as the surface warms in the tropics (within 20 degrees north and south of the equator) there will be even greater warming in the tropical atmosphere. Moisture in the warm tropical air rising up from the ground carries “extra” heat into the higher layers, which increases or “amplifies” the surface warming.

At the time of the last IPCC assessment report, this was still an issue of some uncertainty for climate scientists and skeptics alike.  The IPCC report in 2007 mentioned that measured temperature trends in the troposphere were uncertain, with weaker warming that had been expected in the “hot spot” layers. However, the temperature observations from the various sources did not agree with each other, reflecting the difficulty of measuring accurately at these altitudes.

However, great improvements have been made in this area since 2007.  Additional analyses of the data was done with improved techniques, and a new method was developed to assess temperature trends. (Allen and Sherwood 2008) The new estimates show greater warming in the “hot spot”, bringing them into closer agreement with the models (Thorne 2008). Furthermore, other measurements show that the troposphere has become thicker in the tropics, which is a sign of warming. *(source/link here?)*

The latest published research (Santer et. al., 2008) showed that the earlier studies made an error in their analysis, and Santer used an improved method to account for year-to-year variations in the measurements. He also made use of new measurement databases that corrected for biases in the measurements. Santer’s team found no major difference between the models and observed trends in tropical temperatures.

*(maybe a quick concluding paragraph/sentence?)* 

------------------------ 

Finally check this out: (sciencespeak.com/MissingSignature.pdf)  for a recent and continued claim the the lack of tropospheric hot spot makes all of the IPCC claims false.  This piece has the whole denier meme - little ice age, that scientists and carbon traders benefit from the $ (no mention of oil companies) etc - but might inspire a nice little conclusion linking to the "its not happening" and "its not us" pages.

 

In any case it seems all the right information is here and Im ready to ok it. 

 

2010-09-03 05:32:57Language
nealjking

nealjking@gmail...
91.33.99.186

Jim,

The issue is not sophistication of the concepts but sophistication of the language. To put it simply: You're writing at grade-level 16+, whereas to be readable by the "typical" individual, it should be at about grade-level 8.

I can't give you a suggestion about specific language: I would just have to rewrite the whole article.

As the great experimental nuclear physicist Ernest Rutherford once said, "If you can't explain what you're doing to a barmaid, you don't understand it."

 

 

2010-09-04 01:03:26
doug_bostrom

dbostrom@clearwire...
184.77.83.151

What -was- Rutherford doing to the barmaid, anyway? 

Neal, I'm not sure there's any way to avoid using multi-syllable words such as "troposphere" when discussing this. As well, it's simply not an easy topic because of the spatial visualization required to understand the problem. 

Jim's original treatment includes the important matter of the altitude of the "hotspot"; it's not the warming of the entire troposphere within the tropics that was supposed to have been the issue but instead the "missing" heat in a particular zone of altitude within the troposphere, in the tropics.  If Jim incorporates Nicholas' suggestions Jim should definitely make sure this latitude-limited inversion concept is carried across. The first version successfully did that though it might be made even more explicit.

Frankly I think the first explanation works well. A graphic to cement the altitude matter would be great.  

2010-09-04 03:55:54Simple hot spot rebuttal
Jim Meador

jimm58@gmail...
67.101.147.179

Doug...LOL!!! 

I think this rebuttal should target this version of the skeptic argument...

http://www.sciencespeak.com/SimpleHotspot.pdf  

I am not sure that this one is really aimed at 8th graders, but I will take another crack at simplifying this one.

2010-09-04 07:39:09Latest attempt here
Jim Meador

jimm58@gmail...
67.103.38.254

The skeptic argument "There is no Topospheric Hot Spot" claims that climate change predictions are overstated.  Climate models have predicted increased warming over the tropics, but the data available in 2005 did not support these predictions. Skeptics have seized on this mismatch between predictions and measurements to proclaim that a critical “fingerprint” of global warming is missing.

The troposphere is the lowest part of the atmosphere, extending from the surface up to around 16km. Computerized climate models predicted that as the surface warms in the tropics (within 30 degrees north and south of the equator) there will be even greater warming in the tropical atmosphere, because the moisture in the warm tropical air rising up from the ground carries “extra” heat into the higher layers, which increases or “amplifies” the surface warming.

The diagram below shows the warming predicted by the models in the air above the tropics, and climate skeptics have labeled the red area as the “tropospheric hot spot.”

{hot spot image here} 

In this diagram, left and right show latitude, with the equator in the center. The vertical axis shows the altitude. The red area, with 2°C of predicted warming, shows the  so-called “hot spot”, between 30 degrees north and south of the equator, and between 8 and 12 kilometers above the surface.

At the time of the last IPCC assessment report, in 2007 questions about the “missing” hot spot remained. The report made no secret of this fact noting that measured temperature trends in the troposphere were uncertain, with weaker warming that had been expected. However, the temperature observations from various sources did not even agree with each other, reflecting that there could be problems with the accuracy of the records.

Temperatures are fairly easy to measure on the ground, but measuring air temperature 10 kilometers up in the sky is not as simple.  The earliest records come from radiosonde (weather balloon) measurements, and since 1978 satellites also provide data. 

Skeptics tout the accuracy of the radiosondes, and it is true that any single unit “can reliably detect temperature differences of 0.1°C”.  However, this overlooks that fact that the radiosondes were mainly used to gather day-to-day information for weather predictions. Consistent year-to-year readings were less important. Changes in site location, measurement time, sensor design, and solar shading all contributed to the hundreds of error sources that have been found in the radiosonde data record.

Satellite data has it’s own set of challenges, because of aging of the satellites, small shifts in their orbits over time, and especially because it is difficult to separate the temperature readings of different air layers as the satellite peers down from overhead.

The latest published research (Santer et. al., 2008) uncovered an error in the earlier work, and Santer used an improved method to account for year-to-year variations in the measurements. He also made use of new databases that did a better job of correcting for errors in the measurements. Santer’s team found no major difference between the models and observed trends in tropical temperatures.

When skeptics find a mismatch between predictions and measurements, they seize it as proof that scientists are exaggerating. For open-minded scientists, a mismatch reveals a place where more work is needed to gain improved understanding. The latest work shows that the “fingerprint” of global warming from human CO2 emissions is indeed present in the “tropospheric hot spot”.
2010-09-04 11:49:49
Nicholas Berini

nberini@gmail...
24.189.119.236

Im wondering if the following two paragraphs went over the "basic" level for this one but either way: 

 

Skeptics tout the accuracy of the radiosondes, and it is true that any single unit “can reliably detect temperature differences of 0.1°C”.  However, because the radiosondes were designed to gather day-to-day temperature, year-to-year measurements are not quite as accurate. Changes in site location, measurement time, sensor design, and solar shading all contributed to the hundreds of error sources that have been found in the radiosonde data record.

Satellite data has it’s own set of challenges.  Satellites have to separate temperature readings from a large number of layers as they peer down from overhead.  In addition, satellite data suffers from aging satellites and tiny shifts in a satellite's orbit.

Id also love a mention of the 10 anthropogenic fingerprints in the conclusion.

(already gave the thumb) 

2010-09-04 17:45:37Language is better
nealjking

nealjking@gmail...
84.151.49.66

Jim,

Seems like you've brought it a bit more "down to the ground," which is good.

Couple of points:

- I think there has been a history of corrections applied to radiosonde measurements: There was a decade when they seemed to show a cooling trend, gave great encouragement to the deniers. Then it turned out that either Spencer or Christy's group had screwed up their part of the data reduction; and when it was fixed, the discrepancy went away.

- A fundamental problem seems to be that the radiosondes were never intended for long-term measurements; so a lot of the data have to be worked on from several angles to compensate for various effects (like different sizes of balloons, different colors, etc.)

- I don't have any sources for this right at hand, I just remember reading it when looking at "radiosonde" topics.

 

Another suggestion: Right now, the article doesn't cleanly separate the problems from the resolution. I suggest a clearer separation, by organizing the article into sections with different headings.

2010-09-04 17:48:38Too much detail
gpwayne
Graham Wayne
graham@gpwayne...
81.152.234.172
Sorry Jim, but I don't think this is simple enough. Too much technical detail, not enough broad sweep...
2010-09-05 00:50:04
doug_bostrom

dbostrom@clearwire...
184.77.83.151
My vote was for the first version, at top. In My Grand Opinion Jim is being pushed in the wrong direction here.   Graham, did you look Jim's first take?
2010-09-05 06:22:56Wrong image
Jim Meador

jimm58@gmail...
67.101.213.221

After sleeping on this, I think that including the "hot spot" image is wrong for this rebuttal. Skeptics are sure to have seen it already.

Any suggestions for a good image to include?

 

THis has been a challenging rebuttal to write, but I appreciate the insights provided so far. The subject matter is of a much more technical nature than the others I have worked on.

I do feel like the rebuttal as it stands is on pretty much the same level as the skeptics "simple hot spot" document mentioned above, although I will take another look to see how I can simplify/clarify. 

2010-09-05 18:40:19The first one...
gpwayne
Graham Wayne
graham@gpwayne...
81.152.234.172

Doug - I did indeed feel the first one was more appropriate. Things have got more complex, and broader, but in a way I think makes it less focused and less approachable. There's always this tension between being simple and being simplistic, which tempts us to put in more and more 'bits' to cover all the angles.

Jim - what drove you to 'beef up' the first take? I really thought you'd nailed it rather well, and with commendable economy.

2010-09-07 15:13:54
Jim Meador

jimm58@gmail...
67.103.38.223
This thread summarizes my latest thinking on this rebuttal. I started writing it before I had the complete lay of the land. Given what I know now, I would start over from scratch, focusing on "error bars" or "uncertainty"....but I think the intermediate rebuttal needs to be updated first, so that the basic and intermediate can work together.
2010-09-16 20:08:20
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.198.88

Jim, I prefer the first draft too. Perhaps for a graphic, a simple one of the tropopause height vs latitude, to accompany your explanation?. Something like

And maybe?:

"Computerized climate models have predicted that as the surface warms in the tropics (within 20 degrees north and south of the equator) there will be even greater warming in the tropical atmosphere. Moisture in the warm tropical air rising up from the ground carries “extra” heat into the higher layers, which increases or “amplifies” the surface warming. This amplified trend in the tropical atmosphere is expected regardless of the source of warming, so is not a feature specific to an increase in greenhouse gases"
2010-09-19 16:42:27Up for grabs
Jim Meador

jimm58@gmail...
67.101.212.83

I still believe that the intermediate version of this rebuttal needs to be rewritten.

My first version above is OK, but since I wrote it I learned more about the Santer paper...basically there is no significant difference between models and observations, but both still have a lot of uncertainty. I think the rebuttal needs to focus on the fact that the famous hot spot picture does not show any error bars. Skeptics have seized on the picture as gospel truth, even though it was initally presented as part of a "preliminary" fingerprint analysis. 

I am realizing that I am not going to have time in the near future to rewrite the intermediate or advanced versions of this rebuttal, and I don't feel like the basic ones presented here adequately address the skeptics or capture the science. So I am going to unclaim this rebuttal, and throw it open to someone who may have more time and energy to get it done.

2010-09-19 17:13:43the easiest way to do this
nealjking

nealjking@gmail...
84.151.40.102

Is to start by writing the Advanced exposition, so you can sort out ALL the evidence and reasoning without constraint; and then do the Intermediate and Basic arguments, when you know what you can afford to cut out.

It seems a shame that Jim Meador is getting discouraged on this, because he should really be up on all the evidence by now. However, I respect that everyone has only so much time, and (violin playing in the background...) other priorities than saving the planet... (I'm kidding, Jim, I'm kidding!). 

Seriously, it could be very useful for you to arrange your thoughts and arguments in some kind of structured list, without any attempt to write it up for the readers, but as a guide for someone else who has more time to try to take over the set of write-ups. It could save that individual a lot of time getting re-oriented and finding sources, etc. If there are holes in your discussion, mention that as well. Prepare a hand-over document, just between us chickens. Don't let your valuable effort be wasted.

2010-10-05 07:22:16
doug_bostrom

dbostrom@clearwire...
184.77.83.151

Shame to see all this effort go fallow.

Look, we know this argument in any form will never satisfy skeptics, nothing will. As usual there are perhaps two key metrics for evaluation. Does the first, most simple version at top work well enough to convey the basic facts in an approachable way? Does it mislead? Still MHO, "Yes and No" respectively.

2010-10-05 08:35:22
Riccardo

riccardoreitano@tiscali...
93.147.82.168
I'm with Doug, the first version is better. Maybe it needs some concluding remarks.
2010-11-07 08:07:23Tropospheric warming
jimalakirti

jimalakirti@gmail...
76.113.66.180
I am good with the first version, and vote a green thumb to get it published. (Or is it the second one? -- the other version with a Green Thumb already.)  Sometimes I get confused when rewritten, whole versions are strung out amongst the discussion.  Perhaps the authors ought to clearly mark each new version that is intended to replace an older version with something like "Version 1?, "Version 2", "Version n".  Refinements, if any are necessary, can be made later. 
2010-11-07 08:12:28Tropospheric warming
jimalakirti

jimalakirti@gmail...
76.113.66.180
I am good with the first version, and vote a green thumb to get it published. refinements, if any are necessary, can be made later.
2011-01-23 12:22:03Two things missing from the rebuttal
John Cook

john@skepticalscience...
60.231.100.70

Deepest apologies that I come to this so late. To me, there are two very key points that need to be made when rebutting the tropospheric hot spot argument.

First, a very common misconception is that the hot spot is a unique signature of greenhouse warming. It is not, it is the result of any type of warming. This myth needs to be shot down.

Second, there is a unique signature of greenhouse warming in the atmosphere - it's that the upper atmosphere cools while the lower atmosphere warms.

So any rebuttal should be stronger - it shouldy turn this argument against skeptics. You say there's a missing human signature? The hot spot is unique to greenhouse warming - it's not a "human signature". But there is a human signature and it's being observed and here's a picture...

Here's how I treat the subject in A Scientific Guide to the Skeptics Handbook. If I had my time over, I'd have written it without referring to the 'moist adiabatic lapse rate' - I think it's possible to refer to the physical phenomena without having to use tongue twisting technical terms. Nevertheless, I think it does cover the important points in a relatively simple fashion:

 

2011-01-23 16:56:35comment
Robert Way

robert_way19@hotmail...
142.162.207.106
John, the scale on human fingerprint 1 is a little counter intuitive.
2011-01-23 18:20:51Fingerprint graph
John Cook

john@skepticalscience...
60.231.100.70
I probably wouldn't use that graph anyway - it has copped some criticism as it uses light red colour for the 0 trend, making it look like warming where there is none. In the original paper, it's not such a big deal as the whole point of the graph as to compare it to model predictions which used the same scale. But I wouldn't use it in the basic rebuttal. That's why in the Guide to Skepticism, I use a different graph - contrasting stratospheric trends to tropospheric trends,