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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Climate science needs to get back to basics — observe the real world, make an hypothesis, test, revise and repeat. Take the emphasis away from computer models and go back to working in the physical world.
Roger, I agree about the rants, but the topic of political decisions that are being made entirely on the premise of anthropogenic CO2 climate warming must be included in the discussions here.
Would that a more scientific discussion be its main form. Instead of rants, how about advanced level debate around the topic of political science? Rants just don’t do it for me, but nonetheless, the topic must be included.
Your RSS feed is fixed … Thanks.
It would appear that the last refuge of the UN IPCC is to use the ruse of correlation to show causation. That and very careful weasel wording — Most people will not understand the lies that can be told using that method.
One fact is the upper atmosphere CO2 measurements destroy the models credibility.
We must always remember that that CO2 tale is impossible:
Air can not hold enough heat as water.
Air volumetric heat capacity: 0.001297 J cm-3 K-1
Water volumetric heat capacity: 4.186 J cm-3 K-1
Once again, what a WUWT contribuitor said here a few days ago:
Green house gases are gases in a greenhouse
RW (06:12:35) If not, what exactly is your problem with the term ‘consistent with’?
How about that it is a meaningless term, that amounts to ‘might be correlated with, but no causal attribution can be made’. They don’t use ‘proof’ because they have none. Their use of language exposes their tenuous grasp of climate.
Just as an aside RC has declined my attempt to post up this video. http://cdsweb.cern.ch/record/1181073/ or the pdf http://indico.cern.ch/getFile.py/access?resId=0&materialId=slides&confId=52576
Interesting stuff.
There is one item, mentioned in Bob Tisdale first post that I think needs clarifying.
As RC states, the FINGERPRINT is made up of at least 3 components. The first 2 are the Hot Spot and the increase in the altitude of the Tropopause. Both of these items are common to most warming as they are mostly very basic physics of more heat causing more rising and expanding gasses especially in the tropics.
The third part of the FINGERPRINT is the decrease in Stratospheric Temperatures. This is specifically caused by the increase in GHG’s. With more GHG’s in the Stratosphere to radiate away the heat, it cools due to the inability of the system to move the extra heat across the tropopause from the Hot Spot area into the Strat.
WITH this third item we complete a real fingerprint. As the Stratospheric temps appear to have been flat for about 15 years with no measurable Hot Spot or increase in the Tropopause height, we also have the confirmation of no AGW!!!!!
The RC claim is that we have all these items but our measurements are so poor that they do not show up.
As the Hot Spot should be warming at a rate FASTER than the surface, possibly as much as 3x, according to the models, and the surface has alledgedly warmed about .5c in the last 30 years, I find their claims to be specious.
If the actual warming was on the order of .2c then I might believe it. Of course, then we would STILL NOT HAVE A PROBLEM!!!!
HAHAHAHAHAHAHAHAHAHAHAHAHA
OT
Anthony, I tried to e-mail a couple of new updated pics from the Yosemite station, but the e-amil came back undelivered. Will get the pics posted at Surface…..org later today. BTW, nothing has changed for the better. In fact, it looks worse than before.
Mike
Maybe this is the hot spot they are looking for:
http://www.breitbart.tv/mystery-halo-over-moscow-spooks-residents/
What is the thought process that more warming over land than ocean is a fingerprint of AGW? Less humidity over land?
Could more warming over land than ocean also be a fingerprint of UHI and land use trends?
Scientists Rebut Claim That Man Causes Climate Change
http://www.cnsnews.com/news/article/55278
It is claimed by the IPCC that there are ‘fingerprints’ associated with global warming
Absolutely. This is irrefutable. Considering from where the IPCC pulls its supporting “scientific” evidence, it is absolutely no surprise that there are lots of smelly brown fingerprints associated with Global Warming. There are many brown noses in public funded climate research institutions too…
tarpon (07:15:48) :
It would appear that the last refuge of the UN IPCC is to use the ruse of correlation to show causation
UN IPCC it is just one version, the other version is from UN’s FAO:
http://www.giurfa.com/fao_temps.jpg
Which relates temperatures with LOD (Length of the day and fish catches.
http://www.fao.org/docrep/005/y2787e/Y2787E04.HTM
Ray (08:50:21) :
Maybe this is the hot spot they are looking for:
http://www.breitbart.tv/mystery-halo-over-moscow-spooks-residents/
Anthony posted something like that a while ago
http://wattsupwiththat.com/2009/08/27/when-airplanes-attack/
“a hole punch cloud”
“This relatively rare occurenvce is the result of an aircraft flying through a layer of high clouds that have precisely the right temperatre and moisture. As the jet aircraft flies through the layer it contributes just enough additonal moisture and exhaust particles for the ice crystals in the cloud to grow large enough to fall out as ”fall streaks”. This happens in a circular pattern around the path of the jet with a hole in the cloud layer being the result.”
Moderators, stay the course, please. The two parts of the parcel should not be exclusive. There are reasons the IPCC came into existence and formulated/advanced the AGW theory and they are not scientific, or so most here believe.
anna v (09:46:26) :
Forget about jets, it is an electrical phenomena. The fourth state of matter: plasma.
@Roy Spencer…
Thanks a lot for this article which Phil. had been needing urgently for update his physics. I would like to bring the attention of bloggers on the next assertions from your article:
“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.”
As I have said in other threads at WUWT, most AGWer authors praise the accuracy of their models after some A Posteriori “adjustments” to their models. Mostly, they fail in their predictions, like this one on the heat spots and fingerprints.
There is another good example when they refer to the effects of the warming of the troposphere on the middle and upper troposphere and in the stratosphere. I remember they were saying some years ago that the fingerprint of the anthropogenic global warming will be the warming of the middle and upper troposphere, which never in the last 20 years happened.
You say at the end of your very explicit article:
“…rather than to that exceedingly scarce atmospheric constituent that is necessary for life of Earth – carbon dioxide.”
This assertion is absolutely true. Carbon dioxide is essential for life on Earth. Photosynthetic plants and phytoplankton depend absolutely on the current (and higher than current) concentrations of carbon dioxide, as in the atmosphere as in the oceans.
Now this party of green activists pretends to eliminate the food for plants from the world’s atmosphere.
On the other hand, the carbon dioxide at its current concentration wields a very low pressure in the atmosphere, which makes it to be a very inefficient greenhouse gas. For the absorptivity-emissivity (erroneously or purposely handled by AGWers) of around 0.3, the carbon dioxide would have to be at a concentration of 100%, at a uniform temperature, and with a partial pressure of 1 atmosphere. This is not the case in nature. The carbon dioxide barely reaches a 0.038% of the atmosphere, which means a Pp of 0.00038 atm, so it is impossible that this gas, at its current concentration in the atmosphere, could have a high thermal (or spectral, or monochromatic) absorbency-emittancy capacity higher than 0.001.
Congratulations for your article, Roy…
🙂
tallbloke (03:33:50) :
Are you talking about logic, or the complexity of climate?
Yes I was talking about climate, but I take your point, and yes the logic isn’t rocket science.
For those who haven’t seen this entry (or same elsewhere), now Department of Energy’s Oak Ridge National Laboratory and the National Center for Atmospheric Research have published in the current issue of Biogeosciences, “Key new ingredient in climate model refines global predictions”. Link at Brightsurf.Com for press release: http://www.brightsurf.com/news/headlines/49366/Key_new_ingredient_in_climate_model_refines_global_predictions.html
Pamela Gray (07:09:17) :
Politicians have been given what amounts to matches to play with, in AGW.
The danger is not at all unlike the A-bomb. The scientists who gave it to them realized too late what they had unleashed.
Until the day that it goes too far, it’s not too late to stop the opening of the AGW Pandorra’s Box that cannot be closed.
Not all Politicians are so uninformed as to be naieve of the contents of the Climate Change box. The bad part is that those that see the danger of opening it are in the minority.
Sceptics welcome BBC report on ‘global cooling’
http://www.telegraph.co.uk/earth/environment/globalwarming/6300329/Sceptics-welcome-BBC-report-on-global-cooling.html
Pascvaks (10:23:07) : Utterly non-sense. Read and study Nasif Nahle’s pages at:
http://www.biocab.org
Pascvaks (10:23:07) :
For those who haven’t seen this entry (or same elsewhere), now Department of Energy’s Oak Ridge National Laboratory and the National Center for Atmospheric Research have published in the current issue of Biogeosciences, “Key new ingredient in climate model refines global predictions”. Link at Brightsurf.Com for press release: http://www.brightsurf.com/news/headlines/49366/Key_new_ingredient_in_climate_model_refines_global_predictions.html
Models, simulations. They think their models are more real than reality…
Here comes the flood of global cooling stories I’ve been eagerly anticipating for a while now. The TV news stories should be starting soon.
http://news.google.com/news/story?hl=en&source=hp&q=global+cooling+news&um=1&ie=UTF-8&ncl=dwtY-1a6KginQoM&ei=OWrTSvL5O8Kktgf_x5TvAw&sa=X&oi=news_result&ct=more-results&resnum=4&ved=0CBIQqgIwAw
Was snowing at 4AM when the cats got me up. Still snowing but now tapering to flurries. Snowed Saturday but only stuck on the grass as now. Damned warmening, where are ye?