Scientists resolve long-standing puzzle in climate science

October 10, 2008
Climate visualizations 1919 - 2099. Image: LLNL

(PhysOrg.com) -- A team led by Livermore scientists has helped reconcile the differences between simulated and observed temperature trends in the tropics.

Using state-of-the-art observational datasets and results from computer model simulations archived at Lawrence Livermore National Laboratory, LLNL researchers and colleagues from 11 other scientific institutions have refuted a recent claim that simulated temperature trends in the tropics are fundamentally inconsistent with observations. This claim was based on the application of a flawed statistical test and the use of older observational datasets.

Climate model experiments invariably predict that human-caused greenhouse gas increases should lead to more warming in the tropical troposphere (the lowest layer of the atmosphere) than at the tropical land and ocean surface. This predicted “amplification” behavior is in accord with basic theoretical expectations.

Until several years ago, however, most satellite and weather balloon records suggested that the tropical troposphere had warmed substantially less than the surface.

For nearly a decade, this apparent discrepancy between simulations and reality was a major conundrum for climate scientists. The discrepancy was at odds with the overwhelming body of other scientific evidence pointing toward a “discernible human influence” on global climate.

A paper published online last year in the International Journal of Climatology claimed to show definitively that “models and observations disagree to a statistically significant extent” in terms of their tropical temperature trends. This claim formed the starting point for an investigation by a large team of climate modelers and observational data specialists, which was led by LLNL’s Benjamin Santer.

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.

Other researchers in this international consortium were Karl Taylor, Peter Gleckler and Stephen Klein (all at Livermore); Peter Thorne at the United Kingdom Meteorological Office Hadley Centre; Leo Haimberger at the University of Vienna; Tom Wigley and Doug Nychka at the National Center for Atmospheric Research; John Lanzante at the National Oceanic and Atmospheric Administration (NOAA)/Geophysical Fluid Dynamics Laboratory; Susan Solomon at the NOAA/Earth System Research Laboratory; Melissa Free at the NOAA/Air Resources Laboratory; Phil Jones at the University of East Anglia; Tom Karl at the NOAA/National Climatic Data Center; Carl Mears and Frank Wentz at Remote Sensing Systems; Gavin Schmidt at the NASA/Goddard Institute for Space Studies; and Steve Sherwood at Yale University.

Provided by Livermore National Laboratory

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31 comments

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Rick69
2.5 / 5 (24) Oct 10, 2008
"reconciling modeled and observed temperatures" as in possibly "fudging" the numbers?
SteveS
3.3 / 5 (24) Oct 10, 2008
Dear Rick69 and Modenmystic

I'm sorry but I had to rate your comments as poor, immediately negative and pejorative comments are not a very effective way of starting a useful debate.

My understanding of the article is that a large number of scientists have tried to understand why the climate models have not agreed with observed data. Until it can be shown that their work is in some way flawed surely we should respect their integrity, otherwise we are just shouting down anybody with whom we disagree.
Modernmystic
2.6 / 5 (19) Oct 10, 2008
Dear Rick69 and Modenmystic

I'm sorry but I had to rate your comments as poor, immediately negative and pejorative comments are not a very effective way of starting a useful debate.

My understanding of the article is that a large number of scientists have tried to understand why the climate models have not agreed with observed data. Until it can be shown that their work is in some way flawed surely we should respect their integrity, otherwise we are just shouting down anybody with whom we disagree.


Uh so what? Rate away, it's a free country.
cougar1701
2.8 / 5 (10) Oct 10, 2008
"historical observing strategies, which were geared toward weather forecasting rather than climate monitoring."
I don't get this. If I take a temperature and a weatherperson at the same time and place we should get the same result. Based on the quote we should not as one is trained and the other is not.
CWFlink
3.9 / 5 (14) Oct 10, 2008
The problem I have with manmade global warming is simple... most of the advocates and enemies of the theory have political or financial bias, coupled with a remarkably narrow perspective on geologic history and the adaptability of humanity. Heck, where I live was under 500 feet of water just 10,000 years ago!

Until the prejudices are removed from the analysis, and "hype" toned down, I remain a sceptic.

Anyway... we're in for total financial collapse and world wide starvation long before mankind can pollute itself out of existence. ...my "hype".
deatopmg
3.3 / 5 (12) Oct 10, 2008
I will remain suspect of human made global warming for one main reason and a lot of little ones. The main reason is that the IR absorption bands are already ~95% saturated at ~300 ppm CO2. Insignificant amounts of ADDITIONAL IR energy can be absorbed by increasing the concentration of CO2. That being the case, the ADDITIONAL absorbed energy due to the actual percentage increase in CO2 is tiny in comparison with the total amount of energy needed to explain the "observed" warming. [Even though the past few years appear to been have cooling.]

So, where is the warming coming from if it's not CO2??
gmurphy
2.7 / 5 (14) Oct 10, 2008
ok, deep breath, cougar1701, I believe that modern climate monitoring requires every imaginable aspect of the climate to be monitored (solar variance, cloud cover, wind rain etc). Old observational records are more restricted in their observations. CWFlink, the climate has and always will change. We have constructed reasonably accurate records of climate change over hundreds of thousands of years. The heating of the planet since we started pumping c02 into the atmosphere is anomalous. Nothing like the scale of the temperature increases we observe on a global scale have never happened before (locally it has happened though). Velanarris, climate data is variable, not arbitrary. This variability has been steadily decreased as our methods have improved. Its insulting to the quality of work done on this subject to call it "arbitrary". If you have proof of this, please, by all means, provide it. Finally, deatopmg, c02 absorption bands are not saturated. Even if they were, it wouldn't matter in the lower atmosphere, as the absorption band is overlapped by water vapour. However, in the upper atmosphere there is very little water vapour. All the extra CO2 we've pumped into the air has the most effect in the upper atmosphere. That's because it heats up the air enough for water vapour to get hold, which increases the absorption spectrum causing a feedback effect which propagates up the atmosphere. Finally, the last few years seem to be cooling because of the "la nina" cycle (associated with cooling). Also, the sun is going through one of the deepest solar minimums observed in 50 years which also causes cooling. Really, by historical records we should be a lot cooler.
NotParker
3.4 / 5 (13) Oct 10, 2008
Land based global temperatures are contaminated by UHI. The great lie of the AGW fanatics is that UHI is negligible. In fact tests in places like Arizona and Singapore show it to be as high as 4C.
MikeB
3.4 / 5 (11) Oct 10, 2008
"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.

"We've gone a long way"? In other words they have not reconciled it.

"Problem area of the tropics"?
No problem unless you trust Atari climate models.

Their own words show that the study is lacking.
ErickS
1.7 / 5 (6) Oct 11, 2008
Concerning saturation of IR bands:

- What about Venus?
- What about the IR bands that are absorbed by water vapour but not carbon dioxide?
gmurphy
2.1 / 5 (11) Oct 11, 2008
Velanarris, your co2 data is incorrect. You got those figures off an anti-global warming website (big surprise there). The paper that supposedly derives these results is not published, check on google scholar. This is a science website. Try to be scientific. If you want to talk to other obstinately obtuse idiots who agree with your flawed data, by all means do, but do not inflict it on those who respect the integrity of scientific insight.
gmurphy
2.3 / 5 (12) Oct 11, 2008
Velanarris, the reason the author of the website you've provided hasn't successfully published that paper is because the arguments he uses are flawed. If he had a valid paper, he would have published it. He doesn't, so he uses the web, like every other nut. Face it man, you're a fanatic grasping at straws.
gmurphy
2.8 / 5 (9) Oct 11, 2008
he's not dead, hug heinz is an anti-global warming fanatic and has published results from 2006. The paper on that website is from 1998. This is one of his papers http://www.ingent...art00006 Open the door Velanarris, let reality back in.
gmurphy
2.1 / 5 (11) Oct 11, 2008
I didn't say he wasn't a published scientist, I said the paper you sourced your co2 absorption data from wasn't published. Your move idiot.
gmurphy
2.4 / 5 (11) Oct 11, 2008
Velanarris, you stated this : "CO2 in the upper atmosphere does not have a positive feedback mechanism as you're describing". Here is a paper proving you wrong both an empirical observations and theoretical predictions, I can't get the link to work so look for "The Role of Water Vapor Feedback in Unperturbed Climate Variability and Global Warming" on google.
barakn
2.8 / 5 (12) Oct 11, 2008
I see that deatompg and velanarris are once again spreading the same lie that CO2 infrared absorption is saturated or close to it at current concentrations. Velanarris's assertions are especially egregious, stating the absorption is 100% saturated within 10 meters. It is not. Look at this graph of absorption by various atmospheric components (keeping in mind the scale is transmittance, so the dips are absorbances):
http://earthobser...tion.gif
Note in particular that between 10 and 14 microns there is a great deal of under-saturated absorption peaks that don't coincide with peaks from other atmopsheric components. Also note that this is absorption by the entire thickness of the atmosphere, not just 10 m of it.
gmurphy
2 / 5 (12) Oct 11, 2008
Velanarris, your missing the point, its a feedback mechanism. As soon as warming gets a hold in the lower atmosphere it propagates upwards. Here's another CO2 absorption spectrum graph: http://home.casem...5124.gif Your facts are obsolete Velanarris
jburchel
4.4 / 5 (8) Oct 12, 2008
It is easy to defend a theory for which any event is automatically considered evidence. Anybody heard of Karl Popper? Global Warming is not a scientific theory. It is pseudo-scientific, like Marxism or Freudianism. It makes no falsifiable claims, and all incoming information can be used to make the argument in favor. What a crying shame so many so-called scientists are on this bandwagon. The love of money (NOTE: NOT MONEY ITSELF) has corrupted science. Where are we heading? Will science just be abandoned?
gmurphy
2.2 / 5 (12) Oct 12, 2008
Velanarris, your assertion that the model is obsolete is based on an unpublished paper, which I've already pointed out. It says a lot that you still fall back onto unpublished unverified papers when I can simply go directly to google scholar for my sources. Finally, this image http://home.casem...gifshows that a doubling of co2 will increase the IR absorption. Your total commitment to spreading misinformation about this subject is staggering. For example, you immediately stated the author of your "paper" was dead when I pointed out that he didn't publish it. Your exact words were "Died before he finished it". Now, when this was pointed out, you claimed you misread. Nowhere on that page does it suggest the author has died. I think your full of shit, I have a phd in evolutionary algorithms, I'm a fully qualified scientist and frankly I'm wasting my time on a lost cause like you.
yor_on
2.2 / 5 (10) Oct 12, 2008
Kind of strange with all those seeing the scientific community as lier's and cheats?

Wanna hear something sad.
while some(?) pays good money on debunking your future.
The carboncycle don't give a sh**.

It takes fity years at least for our manmade CO2 to finish its cycle in the atmosphere into the so called heatsinks (primarilly the oceans).

Those oceans are now getting both acidic (unable to sustain life as we know it) by the C02 and unable to take up more CO2.

I saw that one of the ideas behind the so called 'clean coal' project was to use

" Ocean storage, a technology still in its early stages, involves injecting liquid CO2 into waters 500 to 3,000 meters deep, where it dissolves under pressure. However, this method would slightly decrease pH and potentially harm marine habitats. All forms of CO2 storage require careful preparation and monitoring to avoid creating environmental problems that outweigh the benefits of CO2 containment. "

Now, this is f*ng Brilliant isn't it:)

And that carboncycle means that if we stopped all man made CO2 today (Cars coal plants etc etc) we would still have to look at a rising CO2 level for at least fifty years before any 'dip' would show itself.

So?
MikeB
3.7 / 5 (6) Oct 12, 2008
"we would still have to look at a rising CO2 level for at least fifty years before any 'dip' would show itself. So?"

I think the 'dip' just showed itself.
gmurphy
1.1 / 5 (10) Oct 13, 2008
Velanarris, the data wasn't bad, there was uncertainty in it which conflicted with the models. This uncertainty has now been removed and the conclusions are still the same. Do you understand that?. You stated CO2 was too heavy to cause a feedback loop. You are incorrect. This article states quite clearly that the models and observations show more heating as you go up the atmosphere. This is written in the article. Read it. I know you seem to have some difficulty coping with multiple frames of reference but I'm sure you could give it a try. Your argument about the semantics of upper vs lower is pedantic and the last refuge of a beaten man. I admit should have specified more clearly that the feedback effect exerts itself more as you go up the atmosphere but I had not anticipated your literal and simple mind. The very fact that you argue about this shows that you don't have any actual facts to use to defend yourself. Not that you had any facts to begin with. What strikes me is that your convinced that I'm a victim of propaganda. You seem to think that this all a great conspiracy. Such mental behaviour is typical of people who don't have much control over their lives. http://www.physor...136.html Maybe you should get some help. Better yet, try publishing an article in a climate journal or conference. Let us know how you do. Of course if they don't publish your work, you can always fall back onto the conspiracy hypothesis. Do let us know...
CaptSpaulding
5 / 5 (7) Oct 13, 2008
http://www.nature...8a0.html

According to this, CO2 enters altitudes over 20km by tropical upwelling, not diffusion. However it does follow the same basic trend as ground level in overall increase. There is a very clear decrease in CO2 in the upper atmosphere relative to other gasous species.

Just figured since everyone seems to be insulting each other repeatedly, I would throw in my own 5 minutes of research. Oh, and I figure a nature article on direct sampling of atmosphere percentages gets to qualify as a worthwhile source for everybody.

I personally don't know how much of warming is human or not. I know it is happening, but I also know that correlation IS NOT causation. Every high school chemistry/physics student is taught that. As always, the earth most DEFINITELY goes through abrupt warming and cooling cycles: http://en.wikiped...ture.png

If you notice, we are at the end of an ice age, which means it is warmer than it used to be and historically we still haven't hit our peak. We might be screwed regardless. Alternatively we should refocus our efforts on ending deforestation and, if for no other reason than it seems to just make good sense, continue to explore more efficient/clean/safe power production.

Oh, feel free to call me a tard, idiot, etc. because frankly I don't care. It is clearly an argumentum ad hominem, making the entire argument look weak.
gmurphy
1 / 5 (8) Oct 13, 2008
Velanarris, this is from the article : "Santers international team found that there is no fundamental discrepancy between modelled and observed trends in tropical temperatures." Nothing was tampered with. Furthermore you use simple models in your tampering argument while arguing against simplicity in models when they're used in global warming predictions.

Furthermore, the article that Spaulding links to states that the variance in CO2 levels is 1% from the tropopause to the mid-stratosphere (given that we're currently at 380ppm). This is hardly a decrease.

You also say you have a wealth of existing data. That sounds a bit weak as you have previously used data from an unpublished source. Where is this data?, inquiring minds would like to know.

I don't understand your reference to green guilt?

Last but not least, your assertion that you're "too busy" to write a published paper which disproves the global warming "conspiracy" is a joke. I mean, c'mon, at this stage I expected better. Maybe you could use the "wealth of data" you've got squirrelled away to back it up.
gmurphy
1 / 5 (8) Oct 13, 2008
Velanarris, they didn't re-estimate the data. They calculated it correctly for the first time. Your insinuating that they have manipulated the data to fit the model. Do you know how insane that sounds?, you don't have a shred of proof for this statement. Either provide evidence or admit you're wrong.

The fact that you say that whether data is published or unpublished has zero bearing on scientific fact shows you are not a scientist. Data only has value once it has passed a rigorous peer reviewed process. Everything else is speculation. You don't seem to appreciate the importance of this fact. Now, maybe you have data which has been scientifically generated but if you can't get it published its pretty clear that it's flawed in some fundamental way.

Why don't you write the article so then?, try and get your theories published. Its clear from this exchange you believe that the data from this article has been tampered with. Why don't you start there?
mikiwud
5 / 5 (4) Oct 13, 2008
The "models" show a hotspot in the tropical mid troposphere compared to the tropical lower troposphere according to the IPCC.
If you look at http://www.junkscience.com it shows the new graphs from this study and this hotspot is still not there.Its there in the write up but not in the data.
gmurphy
1 / 5 (5) Oct 14, 2008
Velanarris, the fact is you have criticised a scientific paper in an unscientific manner. Therefore your criticism has no virtue from a scientific perspective. Lets leave it at that.
gmurphy
1 / 5 (5) Oct 14, 2008
that is the reality. Where is this data you speak of?, why do you rely on on unpublished data?, why do you deliberately spread misinformation?, I am not going to let this rest, you can't answer my criticisms so you deflect the issue.
gmurphy
1.7 / 5 (6) Oct 14, 2008
Velanarris, you say you don't have time to write a paper, yet you found time to over the last few days to form counter-arguments to my arguments. Evidently you have plenty of time. I assert that the reason you haven't published is because you can't. Prove me wrong, that's all I'm asking, Come back when you've got your published article. Then I will accept your validated scientific criticism of the article we're commenting on.
gmurphy
1 / 5 (4) Oct 14, 2008
Velanarris, I've learned a lot from the exchange. I entered into this thinking you could be reasoned with. Now, I realise my mistake. You cling to global warming scepticism when the entire scientific community agrees that the world is warming and it is due to CO2 pollution by human beings. This should have warned me of the fallacy of arguing with you.

This is the best you will ever do, spreading misinformation doggedly on the internet. You will never rise above this.

I will close with a quote from Max Planck : "truth never wins -- its opponents just go extinct."
GrayMouser
5 / 5 (3) Oct 16, 2008
...I have a phd in evolutionary algorithms, I'm a fully qualified scientist...


EA as in artificial intelligence? In that case you no more qualified than I am. Outside of computer science you are not expert in the subject matter.

On the subject of computers and software engineering I am qualified to comment and, given the state of the art in programming (especially by people that are not CS techies) I would say that the models being used are questionable.

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