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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NASA:
The above article says
There is a striking relationship between how well my models of pigs simulate muscle development in key areas and how much wing-development they show in response to increasing pig swill. Given how fundamental these processes are to flight and overall porcine behaviour, my findings indicate that porcine elevation is likely to be on the high side of current projections.
NASA, can I have some funding, please?
Richard
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.
@levelgaze et al
Dr. Trenberth is a Nobel Laureate (shared) with IPCC 2007. He is listed in more Who’s Who’s than I can count and has “many appearances on national and local television programs and news.” Did you know that one of his papers has been cited 766 times?!
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.
My first thoughts were when I read this article was this was just one of Trenberth’s attempt to take over Mann’s place as the most deluded and derided ‘climate scientist’ on the planet.
I read the article again, the first thing that struck me was the title: “A Less Cloudy Future: The Role of Subtropical Subsidence in Climate Sensitivity.”
The second thing was: “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.”
So, on the one hand we have a hypothesis which states increasing temperatures mean less clouds, but this ignores the self-evident reality of: increasing temperatures obviously mean more evaporation and therefore higher humidity and therefore more clouds.
Next we see a statement that effectively says: “clouds get in the way of us producing the results we want from climate models, so let’s use something else.”
So Trenberth’s paper argues that a warmer, more humid future will have less clouds and that clouds should be ignored as they cannot be measured. All perfectly good stuff if you are a ‘climate scientist’.
The problem is, of course, that increasing cloud cover is now known to create a negative feedback on temperature, as more of the sun’s energy is reflected back into space than trapped under the new clouds.
I really need to get on the Climate Change gravy train, before it all goes horribly sour. It really is amazing how much you can con out of gullible governments by proposing ‘research’ with a scary title and a pre-determined conclusion.
Ummm…. I think he’s gone Hansen.
Oh my!
All I can stammer out is; has any of these team members done any REAL work this past decade? Anything that will make anyone, beside the eco-wackos, proud? How does a team climate member look anyone in the eye and says “I did a good days work today.”?
This flim flam attempt at the climate shell game is sad and shameful. The only thing more shameful is how the IPCC teams of ‘experts’ and their groupie media will lap this up and proclaim disasters for all.
Reply to DHG:
….according to respect for a Mr. Trenberth from New Zealand…..
This Mr Trenberth gained a reputation [not to be questioned] by propagating
climate alarmism……and the uninformed public invited him to receive their
wanted goosebumps….. this is nothing more than pseudo”science”….
I recommend you read our paper hhht://www.knowledgeminer.eu/eoo_paper.html
where you get the full proof that temps will NOT rise any further….
Mr. Trenberth’s “work” is based on omitting the 5 major MACRO-climate drivers
of the past 20,000 years and singling out the CO2, which is nothing more than
a MICRO-driver….thus unable to predict the present flat temp plateau of the
21st Cty……JS Everybody who claims Merits for his alarmism will have to do
penents in 20 years…..the global warming has stopped for good…see lit quoted…
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.
One thing that really stands out about Trenberth, Mann and all the other nut job Alarmists when you read their CVs is their monumental egos. I wonder if they are trying to compensate for something…
Peter Miller says:
November 8, 2012 at 11:05 pm
‘Climate science’ Commandments 3 and 4:
“Thou shallt make your scary predictions so far into the future that no adult alive today will live to see if those predictions are true.”
“Thou shallt only use computer models which imperfectly match reality and are pre-programmed to produce a doomsday result.”
May i add the following:
Commandment 3.5
“Thou shallt make clear the models can’t be validated against current data for at least 15 years hence at all times so that the actual real data can never be used to refute scary predictions.”
Commandment 3.6
“Thou shalt ignore current data regardless and keep predictions of temperature at 3C or above in 2100 constant regardless of how low or unchanging or slow changing temperatures actually are so no articles may ever be written to say we are backtracking on our predictions.”
Commandment 3.7
“Thou shalt say the situation is worse than we thought at every opportunity regardless of the actual data. In general one shall ignore any current data that doesn’t conform to the models regardless of how long the data is different or how far off from model output. One shall continue to say the models are good and getting better regardless of actual conformance to reality.”
Commandment 3.8
“If current temperatures do not rise sufficiently to keep our graphs looking scary enough we shall adjust the pairwise adjustment algorithm to push down historical temperatures so our overall goal of maintaining the 3C in 2100 prediction is viable. Remember nobody remembers the past so keep changing the past and nobody will notice.”
Commandment 3.9
“Thou shalt never show the error bars in the models predictions since those error bars would make our predictions anywhere between +20 and -10C and people will laugh at us so just keep saying the models are good and getting better regardless of the truth.”
Not to mention his prompting the resignation of editor Wagner over the paper by Spencer.
Reminds me of the missing hot spot . Since the temperature did not rise as predicted, someone tried to substituted wind speed for for temperature. I don’t think that shaky evidence panned out either.
Fasullo in Italian actually means phoney or dud.
Seems like a fasullo paper about fasullo model effects with fasullo T results by the fasullo bros.
Projecting future is uncertain; the past is the best guide we can have.
Jim Bouldin, University of California:
Extrapolation into the future, based on past trends, is in fact highly reliable if you have strong reason to believe that the underlying physical drivers of the system under study are not going to change.
Here is an extrapolation into the future based on the 3 CET constituent harmonic components + the existing linear trend:
http://www.vukcevic.talktalk.net/CET-NV.htm
As it happens the multi-decadal trends closely follow the geological non-climatic based records (North Atlantic Precursor) confirming the primacy of the natural variability.
Very unusual, but on the RC blog Gavin Schmidt didn’t censor the above.
Recent years’ extreme weather events have tempted the alarmists to go out on a limb again, as they did after 1998’s temperature ramp up and 2006’s Katrina. I think The Pranksters on Olympus are setting them up for a fall.
Quite illogical. I’m sure there’s a fallacy for it (must ask Lord Monckton).
They say that the models which most accurately predict observed relative humidity must be the ones that can most accurately predict future warming. Oh, and these particular models also trend to the highest warming predictions.
But what about models that most accurately predict albedo, or cloud cover, or sea surface temperature, or any other metric you care to name? Doesn’t it also follow (by the same reasoning) that a model that most accurately predicted one of those outcomes, must also be more accurate in predicting future temperature rises?
But leaving aside the logic of it, surely a lower humidity presupposes less warming, not more? So I am intrigued as to how a model with less humidity generating capability would come up with greater temperature senstivity. Maybe they generate less cloud cover as a result (just guessing here), and less cloud cover trumps the lower humidity. Of course, they can’t test for this, because as the authors admit, cloud cover cannot be accurately measured by today’s satellites. Which is a shame, because if they could be measured, and the models turn out to have significantly under estimated cloud cover, then they would be wrong, wouldn’t they?
“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.
And yet he doesn’t say what this “striking relationship” is and what defines these areas as “key.” 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, both of which we inevitably choose to attribute to rising CO2. We decided to call these areas Key Areas because it makes it sound more impressive.”
Or does someone have an alternative translation?
So we have a few models that accurately simulate the lack of Tropical troposphere Hotspot and the lack of water vapour feedback. What about actually simulating the climate? Why is there such a spread about something very basic like relative humidity in the climate models. This is a fundamental aspect of the climate. There shouldn’t be so many inaccurate models off by so much on this important feature.
And then, UKMO HadGEM1 appears to be the most accurate in simulating one aspect of the climate – low relative humidity at 300 Mb (previously thought of the tropical hotspot). This model also has a high climate sensitivity.
But how accurately does HadGEM1 actually simulate the climate.
It is one of the worst models there is. It is off by almost twice as much as the other climate models right now. Shown here from 1980 to 2030 versus the average IPCC climate model forecasts over time and the actual temperature observations.
http://s7.postimage.org/3tnmjti7f/Had_GEM1_IPCC_Vs_Obs_1980_2030.png
So very, very poor form from Dr. Trenberth in this paper. Trying to scare people into believing again rather than stating the factual information. The headline should be:
– “The Most Inaccurate High Sensitivity Climate Models Accidently Forecast Low Relative Humidity in the Tropical Hotspot Accurately – None of the Other Models Do However”.
DGH says:
November 9, 2012 at 3:13 am
@levelgaze et al
Dr. Trenberth is a Nobel Laureate (shared) with IPCC 2007. He is listed in more Who’s Who’s than I can count and has “many appearances on national and local television programs and news.” Did you know that one of his papers has been cited 766 times?!
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.
To quote FOIA 2011:
“Over 2.5 billion people live on less than $2 a day.”
“Every day nearly 16.000 children die from hunger and related causes.”
“One dollar can save a life” — the opposite must also be true.
“Poverty is a death sentence.”
“Nations must invest $37 trillion in energy technologies by 2030 to stabilize
greenhouse gas emissions at sustainable levels.”
You can also find the stats at http://www.bread.org/hunger/global/
and other websites from the UN.
So the recipient of your respect – playing with models that are consistently falsified by reality – has succeeded with others in persuading politicians, the media and the general public that it is more important to the tune of $37 trillion in energy technologies by 2030 to stabilize the output of a gas that INCREASES crop yield and resistance to heat and drought stress. Yet while you read this post around 12 more children have died that could have been saved if that money had been spent elsewhere; and you want respect to be given to these climate ‘scientists”?
These climate ‘scientists’ are useful idiots for those politicians who wish to raise taxes and obtain power and who have zero concern for humanity.
Fingunt simul creduntque – Tacitus
It’s hard to get rid of conmen like Mann and Trenberth when the whole US government machinery and financial sector is behind them. The banks and hedge funds can’t wait for the US to get into carbon trading and Obama is praying the carbon taxes raised will help chip away at the $16 trillion debt he’s got the US into. The whole game is stacked against honest people opposing the scammers like Mann and Trenberth. Dark times, bro, dark times.
@Stephen Fisher Wilde
You have made a convincing explanation of what they are attempting and why it is wrong. Thank you. Can you provide links to where I can learn more about the concepts you raise?
I am particularly interested in why temperature is a poor proxy for changes in heat content, due to the differing heat capacities of wet and dry air.
It would be excruciatingly painful watching this self-styled “Emperor” still trying to pretend that he has new clothes ….. if I felt sorry for him.
But I don’t.
I love how it says “financed by NASA”. And who finances NASA? The tax payer. How much did this “study” cost?
Somewhat related, but I am regularly checking the (subtropical) Brisbane, Australia rain radar for its potential impact on the cricket match between South Africa and Australia. The circle of no rain over Brisbane itself, while there is rain surrounding Brisbane, is striking.
Urban aerosols at work.
@Stephen Fisher Wilde
My last comment may be cryptic. I have read comments to the effect that averaging temperature changes from parcels of air with varying humidities tells us nothing about changes in heat content because of water’s heat capacity. 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