From NCAR:
Future warming likely to be on high side of climate projections, analysis finds
November 08, 2012
BOULDER—Climate model projections showing a greater rise in global temperature are likely to prove more accurate than those showing a lesser rise, according to a new analysis by scientists at the National Center for Atmospheric Research (NCAR). The findings, published in this week’s issue of Science, could provide a breakthrough in the longstanding quest to narrow the range of global warming expected in coming decades and beyond.
NCAR scientists John Fasullo and Kevin Trenberth, who co-authored the study, reached their conclusions by analyzing how well sophisticated climate models reproduce observed relative humidity in the tropics and subtropics.
The climate models that most accurately captured these complex moisture processes and associated clouds, which have a major influence on global climate, were also the ones that showed the greatest amounts of warming as society emits more greenhouse gas into the atmosphere.
“There is a striking relationship between how well climate models simulate relative humidity in key areas and how much warming they show in response to increasing carbon dioxide,” Fasullo says. “Given how fundamental these processes are to clouds and the overall global climate, our findings indicate that warming is likely to be on the high side of current projections.”
The research was funded by NASA.
Moisture, clouds, and heat
The world’s major global climate models, numbering more than two dozen, are all based on long-established physical laws known to guide the atmosphere. However, because these relationships are challenging to translate into software, each model differs slightly in its portrayal of global climate. In particular, some processes, such as those associated with clouds, are too small to be represented properly.
The most common benchmark for comparing model projections is equilibrium climate sensitivity (ECS), or the amount of warming that eventually occurs in a model when carbon dioxide is doubled over preindustrial values. At current rates of global emission, that doubling will occur well before 2100.
For more than 30 years, ECS in the leading models has averaged around 5 degrees Fahrenheit (3 degrees Celsius). This provides the best estimate of global temperature increase expected by the late 21st century compared to late 19th century values, assuming that society continues to emit significant amounts of carbon dioxide. However, the ECS within individual models is as low as 3 degrees F and as high as 8 degrees F (, leaving a wide range of uncertainty that has proven difficult to narrow over the past three decades.
The difference is important to reconcile, as a higher temperature rise would produce greater impacts on society in terms of sea level rise, heat waves, droughts, and other threats.
Clouds are one of the main sticking points, say the NCAR authors. Although satellites observe many types of clouds, satellite failure, observing errors, and other inconsistencies make it challenging to build a comprehensive global cloud census that is consistent over many years.
However, satellites perform better in measuring water vapor, and estimates of the global distribution of relative humidity have become more reliable. Relative humidity is also incorporated in climate models to generate and dissipate clouds.
Fasullo and Trenberth checked the distribution of relative humidity in 16 leading climate models to see how accurately they portray the present climate. In particular, they focused on the subtropics, where sinking air from the tropics produce very dry zones where most of the world’s major deserts are located. The researchers drew on observations from two NASA satellite instruments — the Atmospheric Infrared Sounder (AIRS) and Clouds and Earth’s Radiant Energy System (CERES) – and used a NASA data analysis, the Modern-Era Retrospective Analysis for Research and Applications (MERRA).
The seasonal drying in the subtropics and the associated decrease in clouds, especially during May through August, serve as a good analog for patterns projected by climate models.
“The dry subtropics are a critical element in our future climate,” Fasullo says. “If we can better represent these regions in models, we can improve our predictions and provide society with a better sense of the impacts to expect in a warming world.”
Accurate humidity yields higher future temperatures
Estimates based on observations show that the relative humidity in the dry zones averages between about 15 and 25 percent, whereas many of the models depicted humidities of 30 percent or higher for the same period. The models that better capture the actual dryness were among those with the highest ECS, projecting a global temperature rise for doubled carbon dioxide of more than 7 degrees F. The three models with the lowest ECS were also the least accurate in depicting relative humidity in these zones.
“Because we have more reliable observations for humidity than for clouds, we can use the humidity patterns that change seasonally to evaluate climate models,” says Trenberth. “When examining the impact of future increases in heat-trapping gases, we find that the simulations with the best fidelity come from models that produce more warming.”
The authors focused on climate models used for the 2007–08 assessment by the Intergovernmental Panel on Climate Change. The next-generation models being used for the upcoming 2013–14 IPCC assessment were found to behave in a similar fashion, as described in a preliminary analysis by the authors in a supplement to their paper.
“In addition to providing a path forward and focus for improving models, results strongly suggest that the more sensitive models perform better, and indeed the less sensitive models are not adequate in replicating vital aspects of today’s climate,” write the authors in the paper.
About the article
Title: A Less Cloudy Future: The Role of Subtropical Subsidence in Climate Sensitivity
Authors: John Fasullo and Kevin Trenberth
Journal: Science
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Climate model projections showing a greater rise in global temperature are likely to prove more accurate than those showing a lesser rise, according to a new analysis by scientists at the National Center for Atmospheric Research (NCAR)…
NCAR scientists John Fasullo and Kevin Trenberth, who co-authored the study, reached their conclusions by analyzing how well sophisticated climate models reproduce observed relative humidity in the tropics and subtropics.
The climate models that most accurately captured these complex moisture processes and associated clouds, which have a major influence on global climate, were also the ones that showed the greatest amounts of warming as society emits more greenhouse gas into the atmosphere.
Hey dumb@ur momisugly$$, the relevant question is not how much warming the models that reproduce humidity predict – it is how much warming the models that reproduce temperature predict.
FFS, are there any scientists left in this game?
My God! These scientists have discovered that relative humidity declines as temperature rises.
The brilliance of these people is unbelievable, definitely worth a Nobel.
I’m not getting into the nitty grittiy. My biggest objections are just in the visuals: the use of the shading of the right hand side of the graph as “Observations”. Perhaps the Observations are the 0 – 22% relative humidity. Perhaps you can shade the X-Axis in that range. The shading, however implies by design that we have observed high sensitivity values. In truth, the only observations we have can support shading only the lower right portion of the graph, right around the word “observations”.
This chart belongs in an addendum to “How to Lie with Graphs.” Why else should Relative Humidity be a reversed axis? Trenberth cannot have a chart with a negative slope; it gives the wrong subliminal message. So reverse the axis and make it trend to the upper right.
David, UK says:
Maybe it’s all Mumbo Jumbo for “In a minority of geographical areas the models happened to strike it lucky by correctly guessing both humidity and temperature, …”
No!
They look at models that correctly guess humidity, and “find” that those models predict high temperature. There is no correct guess of temperature involved in this exercise.
Von Neumann said “With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.” Give Trenberth a couple of dozen parameters and let him cherry pick one, and he can give an elephant hot flashes.
kwik says:
November 8, 2012 at 10:07 pm
“There is a striking relationship between how well climate models simulate relative humidity in key areas and how much warming they show in response to increasing carbon dioxide,”
Bwahahaha!
________________________
All lower drier air does is allow the media to scream about the ‘record high’ temperatures.
Relative humidity graphs:
graph 1
graph 2 (NOAA)
Monthly variations in Total Global Cloud Cover since July 1983 to September 2011
(This all falsifies the water positive feed back part of the CAGW message)
However as anyone with two braincells to rub together knows less relative humidity means larger temperature swings with a rapid cooling at night. It also means that while the temperature may go up the ENERGY contained in the atmosphere goes down. As one commenter keeps saying the Climastrologists are measuring the wrong parameter.
Sleepalot in a comment shows a comparison of the Brazilian rainforest and the N. African Desert. I elaborate here
…..#2 The effect of the addition of water vapor (~ 4%) is not to raise the temperature but to even the temperature out. The monthly high is 10C lower and the monthly low is ~ 10C higher when the GHG H2O is added to the atmosphere in this example. The average temperature is about 4C lower in Brazil despite the fact that Algeria is further north above the tropic of Cancer. Some of the difference is from the effect of clouds/albedo but the dramatic effect on the temperature extremes is also from the humidity….
The disconnect from reality and the media spin is getting even worse.
My apologies, my mistake, the opening post was indeed credited to NCAR. Please ignore my mistaken previous post at http://wattsupwiththat.com/2012/11/08/trenberth-dials-up-the-warming-predictions/#comment-1141058
Or delete both that post and this correction, if desired.
Ron C. says:
November 9, 2012 at 5:03 am
“That is, the amount of heat used to raise 1C a unit of cold wet air is not the same as to raise 1C a unit of hot dry air. Is this correct? It seems important because of all the fuss made over global mean temperatures”
An insightful observation. If the water droplets have already truly evaporated, then the specific heat (Cp) of dry air or humid air is not much different: – Dry with Cp of 1.006kJ/Kg degK and air with 25% humidity Cp~1.04 kJ/Kg degK. Essentially, ideal gases all have roughly the same heat capacity. However, the evaporated water has has an enthalpy ~2500kJ/Kg heat of evaporation. 25% humidity is 0.02kg of water per kg of air so this water contains 0.02*2500=50kJ of enthalpy (latent heat). If the water is as water droplets as in fog, then yes, you have to input the 2500kJ/kg of water before it can be truly evaporated and before the temp can go up. Also, of course, when the evaporated water condenses into droplets, it releases this 2500kJ/kg. I have no doubt that this process is far and away the most important basis for our climate behaviour.
In the 30 years of building climate models, it appears that no one has explored the what-if scenario of a negligible effect of CO2. The main proponents of CAGW I think are in denial although they, too, have roughly set an ultimatum for their CO2 effect 17 years of no warming? 20 years of no warming? I wish someone outside the Climate Synod would work on such a model (I came 30 years too late to this kind of thing) – say give CO2 a low sensitivity and try to make the bulk of the effect a thermodynamic one using the inputs we have measured: incoming energy from the sun, reflected energy (ice, land,water, clouds, aerosols, volcanics), LW emission out, evaporation, condensation, thermolhaline circulation, add in cosmic rays and solar effects. Run the model and see how it matches reality. Then adjust the less certain components in various ways to get a fit bearing in mind that a “fit” is still only one of more than one possible combination. At least we would be making progress that would not be possible if we doggedly stick to one central component that might not be so important. I say, lets start building models and stop just criticising the lame offerings from the Synod.
KR says:
November 9, 2012 at 7:51 am
The opening post appears to be an uncredited copy of the article in http://phys.org/news/2012-11-future-high-side-climate.html – directly reproducing someone else’s article, in entirety, without attribution, is both a copyright and intellectual property violation.
No, it’s not. It’s from the National Center for Atmospheric Research (see here: https://www2.ucar.edu/atmosnews/news/8264/future-warming-likely-be-high-side-climate-projections-analysis-finds), and was attributed accordingly. This was not “phys.org”‘s article.
LetsBeReasonable says:
November 8, 2012 at 11:30 pm
Michealwiseguy,
We admit there is climate change due to natural causes, especially solar cycles.
I thought this idea had been refuted as the the last three solar cycles spanning the last 33 years or so had not effected earth’s climate as it seemed to go up steadily over that time.
_______________________________
Jury is still out mainly because it is not just solar cycles. There are a lot of factors water in all its forms being a big one.
See my comments with lots of links as usual
here and here
The world’s major global climate models, numbering more than two dozen, are all based on long-established physical laws known to guide the atmosphere.
My understanding is that 1 in 8 models predicted a stall in temperatures of 10 years but none predicted a stall in temperatures of 15 years. Were these past models also “based on long-established physical laws”? If so, perhaps new laws need to be found as the “long-established physical laws” do not seem to be doing the job.
For the followers of Cerase Lombroso’s theory: in Italian Fasullo means “Fake”.
-:)
KR says:
The opening post appears to be an uncredited copy of the article in http://phys.org/news/2012-11-future-high-side-climate.html –
Or, it is “From NCAR”.
Given that both the opening post here as well as the phys.org article that you refer to clearly state exactly that, it would be the conclusion to which most functionally literate people would gravitate.
… directly reproducing someone else’s article, in entirety, without attribution, is both a copyright and intellectual property violation.
Whereas being a babbling idiot who falsely accuses someone of plagarism is just an annoying abuse of ones rights and faculties to speak.
Lucky you, huh?
“The world’s major global climate models, numbering more than two dozen, are all based on long-established physical laws known to guide the atmosphere. ”
They don’t have a clue what guides the atmosphere…!
AngusPangus says:
November 9, 2012 at 12:49 am
Let me see if I’ve got this…..
All that high end warming must be hiding just around the corner, ready to spring out and surprise us very, err, soon, honest, just you wait and see, unless we all sacrifice to Gaia immediately.
I mean, it would be a TRAVESTY if these guys were just making sh*t up to try and flog a bit more life out of their dead hobby horse.
_____________________
When did you say Trenberth is due for retirement?
Hmm, his CV says he was born November 1944. So why hasn’t he been retired yet?
“Science advances one funeral at a time.” ~ Max Planck
Can’t we just make it one retirement at a time and then speed up the process with forced retirements?
“Clouds are one of the main sticking points, say the NCAR authors. Although satellites observe many types of clouds, satellite failure, observing errors, and other inconsistencies make it challenging to build a comprehensive global cloud census that is consistent over many years.”
You bet they are and they show why this nonsense model assumptions are wrong. Satellite failure and observing errors are now the excuse for global cloud levels showing opposite what should have been expected with CO2. The errors are smaller than surface temperature record, but apparently that is good enough and can spread data 1200km too.
Name anything that only one thing can remove all the warming from the post 1970’s. The only thing is cloud albedo and this matches very well and very likely is the reason for the previous warming. CO2 is suppose to increase water vapor not reduce it, so observations are evidence of natural changes nothing to do with CO2. There is no science mechanism why CO2 would reduce water vapor or clouds. Therefore this awful model assumption is based on nothing to do with CO2.
John Marshall says:
November 9, 2012 at 2:42 am
Models again. Garbage in-garbage out. First you have to prove that CO2 actually causes climate change using observation not model output.
KT- I think the missing heat is bound up in latent heat within water vapour. Difficult to find given that loss/gain of latent heat does not alter temperature only state.
_____________________________
And it is REAL difficult to find when the relative humidity and cloud cover are DECREASING and therefore so is that latent heat.
global relative humidity 300 – 700 mb and
Global cloud cover
DGH says:
November 9, 2012 at 3:13 am
…He is a very big deal. Just ask him. http://www.cgd.ucar.edu/cas/Trenberth/trenberth-cv.html
Now how about a little respect.
__________________
Yes and Kenneth Lay was a real big deal having meeting with US presidents and all. didn’t keep him from being convicted in 2006 of fraud and conspiracy in one of the biggest corporate scandals in U.S. history. The charges against Lay, 64, carry a maximum penalty of 45 years in prison for the corporate trial and 120 years in the personal trial. The charges against Skilling, 52, carry a maximum 185 years.
Kenneth Lay had a…Ph.D. in economics at the University of Houston… served as the Energy Deputy Under Secretary for the United States Department of Interior until 1974. Ken Lay died of a heart attack before sentencing. Bio
Having a PhD and becoming known to the media and politicians says nothing about a man’s honesty and integrity. All it says is he is good at kissing the correct rumps and/or he has a lot of $$$.
Someone forgot to apply the warning sticker,”Objects in mirror are closer than they appear”
On the other hand,here’s some numbers,equations,formulas,and diagrams about air:
http://www.engineeringtoolbox.com/air-psychrometrics-properties-t_8.html
Clouds inject more uncertainty in climate models as a recent article by Stevens & Schwartz 2012 explains: beware, a bit of a slog but well worth it:
http://www.mpimet.mpg.de/fileadmin/staff/stevensbjorn/Documents/StevensSchwartz2012.pdf
Last Paragraph of the paper: Major questions persist. These include the
relative contributions of various cloud types to
the overall cloud feedback (19) and the sources
of biases in the vertical RH and cloud distributions,
and these are the focus of ongoing research.
In a broader context, improved representation of
regions of strong subsidence, particularly at low
latitudes, is of fundamental importance. Such an
improvement is essential not only for correctly
simulating climate sensitivity, but also for characterizing
changes in climate extremes and related
impacts. Their scrutiny is therefore likely to
be beneficial in understanding the broad range
of uncertainties that currently exist in our future
climate.
This looks to me like a good paper, but I don’t see how it supports the title. Maybe in subsequent reads that will become clearer.
John Marshall: Models again. Garbage in-garbage out.
One of the goals is to improve the model inputs sufficiently so that the model outputs begin to have demonstrable accuracy and reliability. This is a step toward that goal. Many more such steps will be needed, and the goal will be reached slowly.
Gail,
Looks like global cloud cover decreased until around 2000 and has increased a little since then.
The inflection point is approximately when I first noticed the jets becoming more equatorward / meridional so I suspect a link between global cloudiness and jet stream meridionality.
Dr. Trenberth, do you realize dialing up the warming predictions also dials up the travesty of no statistically significant warming for a given period. With the suggested warming as high has 4C (you did say the higher was more probable) by 2100, would you say its okay for no warming until after, say, 2015? How likely is 0.47 C/decade average thereafter following a run of ~0/decade for 20 years? Your comment in the Climategate emails that it was a travesty there had been no warming for a decade (?) and Dr. Jones comments on none since 1995 is clearly an admission that the models and the thinking are incorrect. This is not a question. Surely, searching among these failed models (temperature predictions) for a fit to something has to be anathema to a logical mind. You could substitute the growth in wine consumption in the United States for CO2 probably and get the same result.
I would also like to say,that the Relative Truth on that study is very low(studying models is not what i call science)or very high(if its true if you say it is or if you keep saying it over and over).I haven’t decided what direction i want the scale to go.Maybe it goes both ways from a center point or maybe thats an artifact of being skeptical?
Thanks for the interesting articles and comments
Bob says:
November 9, 2012 at 4:02 am
Seems simple to me. We know the ideal climate. We know the ideal CO2 level to control the change of the climate, and by implication, control the climate. I don’t know why we are frittering around the edges with stuff like this instead of discussing which widget design is best to regulate CO2 worldwide to that ideal level.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The best level for CO2 is MINIMUM 1000 ppm. Just ask the plants. graph
Most of our food plants and trees are C3 most weeds/grasses are C4. Also higher CO2 levels make (C3) plants more drought tolerant too. (First link I found) however I suggest you read it.
Paper: Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California
And please wake up, The Climastrologists can’t even predict the weather correctly a couple weeks out so how do you think they can actually CONTROL it?
There are some funny entries In this blog today. I have been laughing all morning. Gail is correct. 1000ppm would be good for plants, therefore life in general. Guarentee (hopefully) no ice age, expanding arable and decent land for people to live. Less severe winters, less variable rain. Not a bad world. The opposite direction would be death. At 180ppm almost all plants and soon thereafter almost all animals would die. Brutal cold, extinction much faster and more concentration of man in the few habitable places left. That seems to be the world the agw crowd wants. They are so remorseful of the eroding arctic sea ice. Boo Hoo. Really. There will be plenty of ice to see. Don’t fret. Sure over the next few hundred years we’d have to slowly move a little farther inland and build some structures for the movement of the coastline. Most buildings have to be majorly rebuilt or replaced every 50 years anyway. I’m not saying its perfect but nothing’s perfect. There is no world with no change, no storms. People who think things are getting worse simply have not bothered to read history. Just 110 years ago the average death rate per year was well over 1,000,000 from natural disasters alone. Over the last 100 years the thing we’ve been more effective at doing is cutting the deaths from natural disasters. 95% reduction. Even if NYC was hit with Sandys every year for decades the deaths would be only a fraction of a fraction of a fraction of those that die from eating fried chicken.
Jeff and JJ:
Thankyou for drawing attention to the error by KR.
In common with most regular readers of WUWT, I skip over posts by KR because I don’t want to waste time on them. However, in this case his error is not only blatant but is also offensive to our host. And, importantly, it clearly shows the validity of posts by KR so it needed to be pointed out for the benefit of people who may be tempted to take his posts seriously.
Richard