By Roy W. Spencer, Ph. D., October 11th, 2009
It is claimed by the IPCC that there are ‘fingerprints’ associated with global warming which can be tied to humanity’s greenhouse gas emissions, as if the signatures were somehow unique like real fingerprints.
But I have never been convinced that there is ANY fingerprint of anthropogenic warming. And the reason is that any sufficiently strong radiative warming influence – for instance, a small (even unmeasurable) decrease in cloud cover letting in slightly more sunlight starting back in the late 1970’s or 1980’s– would have had the same effect.
The intent of the following figure from Chapter 9 in the latest (AR4) version IPCC report is to convince the reader that greenhouse gas emissions have been tested against all other sources of warming, and that GHGs are the only agent that can cause substantial warming. (The snarky reference to “proof” is my addition.)
But all the figure demonstrates is that the warming influence of GHGs is stronger than that from a couple of other known external forcing mechanisms, specifically a very small increase in the sun’s output, and a change in ozone. It says absolutely nothing about the possibility that warming might have been simply part of a natural, internal fluctuation (cycle, if you wish) in the climate system.
For instance, the famous “hot spot” seen in the figure has become a hot topic in recent years since at least two satellite temperature datasets (including our UAH dataset), and most radiosonde data analyses suggest the tropical hotspot does not exist. Some have claimed that this somehow invalidates the hypothesis that anthropogenic greenhouse gas emissions are responsible for global warming.
But the hotspot is not a unique signature of manmade greenhouse gases. It simply reflects anomalous heating of the troposphere — no matter what its source. Anomalous heating gets spread throughout the depth of the troposphere by convection, and greater temperature rise in the upper troposphere than in the lower troposphere is because of latent heat release (rainfall formation) there.
For instance, a natural decrease in cloud cover would have had the same effect. It would lead to increased solar warming of the ocean, followed by warming and humidifying of the global atmosphere and an acceleration of the hydrologic cycle.
Thus, while possibly significant from the standpoint of indicating problems with feedbacks in climate models, the lack of a hotspot no more disproves manmade global warming than the existence of the hotspot would have proved manmade global warming. At most, it would be evidence that the warming influence of increasing GHGs in the models has been exaggerated, probably due to exaggerated positive feedback from water vapor.
The same is true of the supposed fingerprint of greater warming over land than over the ocean, of which there is some observational evidence. But this would also be caused by a slight decrease in cloud cover…even if that decrease only occurred over the ocean (Compo, G.P., and P. D. Sardeshmukh, 2009).
What you find in the AR4 report is artfully constructed prose about how patterns of warming are “consistent with” that expected from manmade greenhouse gases. But “consistent with” is not “proof of”.
The AR4 authors are careful to refer to “natural external factors” that have been ruled out as potential causes, like those seen in the above figure. I can only assume this is was deliberate attempt to cover themselves just in case most warming eventually gets traced to natural internal changes in the climate system, rather than to that exceedingly scarce atmospheric constituent that is necessary for life of Earth – carbon dioxide.
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“The AR4 authors are careful to refer to “natural external factors” that have been ruled out as potential causes, like those seen in the above figure”.
“I can only assume this is was deliberate attempt to cover themselves just in case most warming eventually gets traced to natural internal changes in the climate system, rather than to that exceedingly scarce atmospheric constituent that is necessary for life of Earth – carbon dioxide.”
The voice of truth!
Also….they finally mention “Natural External Factors”.
With many more pressing scientific issues vexing our species and our planet…how much more scientific energy will be wasted on the AGW scare??
Chris
Norfolk, VA, USA
“With many more pressing scientific issues vexing our species and our planet…how much more scientific energy will be wasted on the AGW scare??”
Enough “scientific” energy so that government gets an ability to tax and control…or is that destroy?
I can see your point about the presence or absence of the hotspot not implicating AGM, but I thought that the tropical hotspot conjecture had been disproved by thousands of radiosonde balloons.
When AGW science denies and ignores all these possibles…….amazing!
And here’s yet another! How can the models be anything but wrong.
http://www.eurekalert.org/pub_releases/2009-10/drnl-kni100909.php
As you mention, the Models do not work correctly. If the models are wrong, it matters not whether there is a Hot Spot.
It DOES matter what would cause PROBLEMS in the climate system. If corrected, the models might be able to show this. Until then, all the spending and reorganisations of society are contraindicated as we DO NOTKNOW HOW THINGS HAPPEN AND THEREFOR WE DO NOT KNOW HOW TO CORRECTLY IMPLEMENT SOLUTIONS!!
Actions we take could, instead of improving the situation, actually exacerbate it through our ignorance.
Thank you for sticking with your excellent work and also taking the time to clarify issues for us .
OT: The BBC has it’s problems for sure, and one of those problems has been its uncritical acceptance of Man-made global warming, but perhaps the harsh light of reality is starting to get through:
http://news.bbc.co.uk/2/hi/science/nature/8299079.stm
BBC — Friday, 9 October 2009 — What happened to global warming?
“This headline may come as a bit of a surprise, so too might that fact that the warmest year recorded globally was not in 2008 or 2007, but in 1998.”
Old news to readers, here, but apparently not to the BBC.
Continuing…
“But it is true. For the last 11 years we have not observed any increase in global temperatures.
And our climate models did not forecast it, even though man-made carbon dioxide, the gas thought to be responsible for warming our planet, has continued to rise.
So what on Earth is going on?”
For all the faults of the BBC, it is a major news outlet in England and gets play all over the world.
Perhaps, this winter, should the solar minimum continue, will be AGW’s waterloo.
Another passage from the BBC’s story:
“But one solar scientist Piers Corbyn from Weatheraction, a company specialising in long range weather forecasting, disagrees.
He claims that solar charged particles [ electrons and ions] impact us far more than is currently accepted, so much so he says that they are almost entirely responsible for what happens to global temperatures.
He is so excited by what he has discovered that he plans to tell the international scientific community at a conference in London at the end of the month.
If proved correct, this could revolutionise the whole subject.”
Yes, an electromagnetic hypothesis warms the cockles of my heart!
Could someone lead me please to a baloon data that falsifies the formation of tropical stratosphere hot spot ?
It seems that the “hot spot” and any other change in the atmosphere might be caused by any one or combination of factors. Thus, there is nothing that will refute the AGW argument and as long as it is not refuted it keeps rolling along. Perhaps a prolonged cold spell will divert most of the responsible people to direct their attention to solving serious problems but, in most cases, they will still want to throw money at these problems and, at the moment, they see only one source for that, namely, anything that can be linked to carbon dioxide. Eventually the workings of the atmosphere and oceans will be better understood but that won’t make much difference as socialist elites will have established the procedures they hope will restructure the world to their own liking well before a grand theory of climate change is written.
May I ask someone another favor.
My source of the UAH satellite data is limited to low- and mid-troposphere data on the Junkscience site.
Where should I go to watch similar data for troposphere/stratosphere interfacial region (TTS) and for mid-stratosphere (TLS) ?
tokyoboy (22:11:36) :
May I ask someone another favor.
My source of the UAH satellite data is limited to low- and mid-troposphere data on the Junkscience site.
Where should I go to watch similar data for troposphere/stratosphere interfacial region (TTS) and for mid-stratosphere (TLS) ?
http://discover.itsc.uah.edu/amsutemps/amsutemps.html
Friday, October 9, 2009 BBC News: What happened to global warming?
BBC News climate correspondent, Paul Hudson, declares “For the last 11 years we have not observed any increase in global temperatures. And our climate models did not forecast it, even though man-made carbon dioxide, the gas thought to be responsible for warming our planet, has continued to rise.”
More at http://news.bbc.co.uk/2/hi/science/nature/8299079.stm
I keep being surprised by the amount of fuzzy thinking that enters CO2 culprit climate discussions .
In my scientific books, whether it is mathematics or entomology, proof requires conditions called necessary and sufficient.
According to the authors of the IPCC reports, the hot spot is a necessary condition coming out of the model runs that give all the dire predictions that are stampeding politicians to destroy the western economies.
A necessary condition not being there means throw the runs in the wastebasket and start again. Nothing less.
They have not done even that, i.e. given us runs that show no hotspots and at the same time give dire predictions for the next 100 years.
GIGO.
If there were in the data a hotspot, I would agree with the author that it would not be enough/sufficient to demonstrate its origin: it would have been another confirmation/fit to the data showing consistency/sufficiency but not necessity.
We need to demonize CO2 and destroy the economy of the world because the models predict such disastrous consequences that billions of people will die by the end of the century if we don’t. They’re right of course, at least 8 to 10 billion people will die by 2100, if we don’t stop using fossil fuels immediately. Of course, 8 to 10 billion people will die by 2100 no matter what we do and judging by the resounding success of all the green initiatives of the past 40 yrs, DDT ban, biofuels etc., if we follow their demands, the number of dead will be far larger than if we do absolutely nothing. The fact that most everything the models have predicted to be increasing rapidly is occurring slower than predicted, except for everything that’s happening far faster than expected. But, if you put it all together, couldn’t we all just agree that when it comes to predicting the climate, the models just plain suck!
Roy,
A query: You say: Anomalous heating gets spread throughout the depth of the troposphere by convection, and greater temperature rise in the upper troposphere than in the lower troposphere is because of latent heat release (rainfall formation) there.
By upper troposphere are we referring to above 200hPa. I would maintain that the greater temperature rise there (by up to two or three times the surface temperature increase, as surface temperature increases) is due to the presence of ozone rather than precipitation. The capacity for precipitation above 200hPa is very much limited by low specific humidity. Would you not agree?
John F. Hultquist (22:07:40)
A prolonged cooling appears to be what we are going to experience. While this will not convince alarmists, as the goal posts will simply be moved, it may change the thinking of billions of others. The political machinations and scientific malfeasance of AGW supporters only have the ability to affect human beliefs, they cannot affect nature. Just as King Canute could not stop the tide, AGW promoters cannot stop natural global cooling. It is disappointing that the AGW hoax will be stopped by nature rather than good science, but I am thankful that skeptics have managed to at least delay the AGW train long enough for cooling to begin. I’m guessing there may not be too may outdoor photo opportunities with Al or the Teleprompter Reader in Chief at Copenhagen this December.
tokyoboy (22:02:31) :
Could someone lead me please to a baloon data that falsifies the formation of tropical stratosphere hot spot ?
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf
there is a plot a the end with the measured spot, which is not there .
Now “falsifies” needs the ability to use elementary logic as far hypothesis testing and results go, as I stated in my post above.
anna v (22:49:44) :
fuzzy myself 🙂
If there were in the data a hotspot, I would agree with the author that it would not be enough/sufficient to demonstrate its origin: it would have been another confirmation/fit to the data showing consistency/sufficiency but not necessity.
“constistency/sufficiency” should of course be only “consistency” . No slash. Sufficiency would mean it were sufficient to prove CO2 the culprit, which is not possible with so many “forcings” entering in the problem.
With real “fingerprints” you can demonstrate the ability to identify a person by their fingerprint with a blind study involving a sufficient number of people. Absent the initial demonstration that fingerprints are in fact an effective means of uniquely identifying people, the word “fingerprint” wouldn’t have the meaning we attribute to it today.
How can you show that AGW has a “fingerprint” that can distinguish the warming attributable to greenhouse gasses from other causes of warming if you have no means of removing the AGW influence (of whatever magnitude) from the climate system. I can see how it is reasonable to speculate as to what characteristics AGW might show over time, but there is no actual means to verify that the speculative “fingerprint” is in fact useful to distinguish warming from CO2 over warming from other causes.
I agree that there would be almost certainly many other mechanisms that would lead to the same fingerprint. But is this question relevant at all if this fingerprint is actually found not to exist according to the observations? In my opinion, it does exclude the greenhouse effect as the “predominant” driver – and it does exclude all other mechanisms with the same fingerprint, too.
Consistency is not enough as a proof but inconsistency is enough for a negative proof, isn’t it? By Bayesian inference, consistency may be a more or less strong circumstantial evidence that a hypothesis is correct – except that the consistency doesn’t seem to exist here so the question how strong evidence it would be seems immaterial.
Cheers
LM
Rooftop demo at Parliament
http://news.bbc.co.uk/1/hi/uk_politics/8301640.stm
Anna V, good solid logic and analysis. I too am always astonished at the basic scientific illiteracy displayed by pro AGW climate
soothsayers‘scientists’.Mind you, a good many on all sides of the debate are guilty. Why isn’t propositional logic taught alongside basic maths at school? It ain’t rocket science.
What small cloud changes? How about the large observed cloud decrease of 4% that explains 90% of the warming that occurred since 1980.
Just compare the Troposphere cross section to the cloud changes cross section and you get a match!
Luboš Motl (00:16:16) :
Consistency is not enough as a proof but inconsistency is enough for a negative proof, isn’t it? By Bayesian inference, consistency may be a more or less strong circumstantial evidence that a hypothesis is correct – except that the consistency doesn’t seem to exist here so the question how strong evidence it would be seems immaterial.
The logical upshot of this is that either:
1) The warming just wasn’t strong enough to produce a hotspot, and therefore the theory which predicts it is wrong.
2) The measurement of the temperature increase is in error.
3) The warming didn’t take place in the troposphere, but somewhere else.
I suspect a combination of the three.
Observations:
We know the atmosphere can’t heat the ocean to any great extent.
We know the sun can.
We know the ocean can heat the atmosphere – but no hotspot is seen.
We know temperature has risen but not fast enough to create a detectable hotspot.
We know high latitude temperature in the N.H. rose more than at the equator.
We know the steric sea level and surface to thermocline temperature gradient indicates that heat mixes down to at least 1000m in the ocean readily. (Tell Ray Pierre-Humbug to stitch that one Roy!)
Deductive propositions:
The heat coming out of the tropical ocean is diffused by wind and absorbed at relatively low levels.
Heat is diffused throughout the oceans more readily than our understanding of currents indicates.
Inductive proposition:
It’s time to bin AGW theory and start developing a coherent solar-oceanic theory.
I happen to have one half baked already. 🙂
This one is difficult to summarize. Is this how it works?
1) GHG warming, including positive feedback amplification of intial warming from any cause, implies the existence of a hot spot.
2) The hot spot would exist if there is GHG positive feedback, regardless of what the stimulus is that is being amplified.
3) It would exist if the stimulus is increased heating due to cloud albedo changes, and it would also exist were it due to increasing CO2.
4) Its existence therefore would not prove the existence of man-made CO2 induced GHG warming. Its existence would however prove the existence of water vapor positive feedback amplification of any warming of any kind.
5) The evidence is mixed, but tends to show that there either is no hot spot or it is not as large as the models predict, which suggests that there is either no positive feedback from a water vapor GHG effect, or a lot smaller one than the models assume.
______________________________________
By the way, these rants people are indulging in about socialism, world government, plans to wreck the economy, they add nothing whatever to our understanding of climate and the evidence. That sort of idiocy belongs on Real Climate and Tamino – its the same thing, just turned 180 degrees, and equally stupid.
It must be quite probable (moderators please note) that these are in fact trolls. I have long suspected that the most plausible explanation for some of the wilder and more frenzied postings on Tamino and RC is that those who appear the most fanatical proponents of AGW are in fact trolls seeking to undermine it.
So, moderators, why not follow Steve M’s example, and just snip all this irrelevant silliness? You’ll improve the quality of discussion and raise the credibility of the site, and avoid being taken in by trolls.
kuhnkat (21:36:06) :
Actions we take could, instead of improving the situation, actually exacerbate it through our ignorance.
That is a huge problem with AGW. They are transfixed on taking drastic (and probably irreversible) actions against something that might be, not knowing what the consequences are due to the inability to understand how it works.
And even if it were true, not knowing how much correction to apply and what to apply makes the chances of getting it right slim indeed.
Uncertainty of lagtimes translates to a high chance of overdoing it.
How can the Earth be warmed if it is cooled too much? No exit strategy.
Sucking vast quantities of carbon out of the atmosphere and sucessfully sequestering it sound dangerous, and it likely is. Agriculture could teeter or simply fail, propelling stronger nations to attack thier neighbors in a desperate struggle for dwindling resources.
It can be done from a single nation, and doing so may hit the panic button of other nations and ignite open warfare.
Next up are the economic weakenings as the energy tax saps all recovery efforts, which are puny to begin with. Faltering nations are the playground of every anarchist.
All that risk for so poor of a calculation.
Reads like a Sci-Fi thriller with a very bad ending.