Paper finds a decrease of IR radiation from greenhouse gases over past 14 years, contradicts expected increase – cloudiness blamed for difference.
A paper published in the Journal of Climate finds from 800,000 observations a significant decrease in longwave infrared radiation from increasing greenhouse gases over the 14 year period 1996-2010 in the US Great Plains. CO2 levels increased ~7% over this period and according to AGW theory, downwelling IR should have instead increased over this period.
According to the authors,
“The AERI data record demonstrates that the downwelling infrared radiance is decreasing over this 14-yr period in the winter, summer, and autumn seasons but it is increasing in the spring; these trends are statistically significant and are primarily due to long-term change in the cloudiness above the site.”
The findings contradict the main tenet of AGW theory which states increasing greenhouse gases including the primary greenhouse gas water vapor and clouds will cause an increase of downwelling longwave infrared “back-radiation.”
The paper also finds a negative trend in precipitable water vapor, as do other global datasets, again the opposite of predictions of AGW theory that warming allegedly from CO2 will increase precipitable water vapor in the atmosphere to allegedly amplify warming by 3-5 times. Is the unexpected decrease in water vapor the cause of the decrease in downwelling IR?
Global datasets also show an increase of outgoing longwave IR radiation to space from greenhouse gases over the past 62 years, again in contradiction to the predictions of AGW theory.
Gero, P. Jonathan, David D. Turner, 2011: Long-Term Trends in Downwelling Spectral Infrared Radiance over the U.S. Southern Great Plains. J. Climate, 24, 4831–4843.
doi: http://dx.doi.org/10.1175/2011JCLI4210.1
Long-Term Trends in Downwelling Spectral Infrared Radiance over the U.S. Southern Great Plains
P. Jonathan Gero
Space Science and Engineering Center, University of Wisconsin—Madison, Madison, Wisconsin
David D. Turner
NOAA/National Severe Storms Laboratory, Norman, Oklahoma, and Department of Atmospheric and Oceanic Sciences, University of Wisconsin—Madison, Madison, Wisconsin
Abstract
A trend analysis was applied to a 14-yr time series of downwelling spectral infrared radiance observations from the Atmospheric Emitted Radiance Interferometer (AERI) located at the Atmospheric Radiation Measurement Program (ARM) site in the U.S. Southern Great Plains. The highly accurate calibration of the AERI instrument, performed every 10 min, ensures that any statistically significant trend in the observed data over this time can be attributed to changes in the atmospheric properties and composition, and not to changes in the sensitivity or responsivity of the instrument. The measured infrared spectra, numbering more than 800 000, were classified as clear-sky, thin cloud, and thick cloud scenes using a neural network method. The AERI data record demonstrates that the downwelling infrared radiance is decreasing over this 14-yr period in the winter, summer, and autumn seasons but it is increasing in the spring; these trends are statistically significant and are primarily due to long-term change in the cloudiness above the site. The AERI data also show many statistically significant trends on annual, seasonal, and diurnal time scales, with different trend signatures identified in the separate scene classifications. Given the decadal time span of the dataset, effects from natural variability should be considered in drawing broader conclusions. Nevertheless, this dataset has high value owing to the ability to infer possible mechanisms for any trends from the observations themselves and to test the performance of climate models.
via the Hockeyschtick with thanks
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Claude Harvey says:
August 5, 2014 at 5:55 pm
The execrable GCMs still don’t factor in clouds. They dare not.
This is some interesting news!
Nick and Mosher, time will prove the point. CO2 is an after-affect of oceanic/atmospheric teleconnections that have warmed and greened the Earth since the Little Ice Age. The anthropogenic CO2 portion is too small to consider as part of the trend. Solar variation is too small to consider as part of the trend. The real money is on what the Walker Cells are doing around the equatorial band and Bob Tisdale’s work on discharge/recharge events. My gut tells me that because of less than clear sky conditions due to clouds around the globe along the equatorial band means that we are slowly running out of gas, which explains the pause. But if we begin to sink no need to panic. This is a normal up and down thing in this present interglacial. It is okay for you two to let out your CO2 laden breath. The pause as well as any downward trend is just temporary. We will eventually be back to pleasant warmth. Barring a huge equatorial volcanic explosion we will only be a bit cooler and dryer is all.
Nick Stokes says:
August 5, 2014 at 5:54 pm
Sorry, Nick, but when the next US administration joins Canada and Australia in jumping off the global warming band wagon, your gravy train will have been derailed, to mix vehicular metaphors.
Might even happen in 2015 instead of 2017, when GOP regains solid majority in the Senate. The murderous, impoverishing chicanery and conspiracy can’t end soon enough.
Pamela Gray says:
August 5, 2014 at 5:58 pm
Sum of all solar variations is more than sufficient to explain observations, although there are probably other modulating factors at work, too. Indeed, climate at all time frames correlates well with solar and other celestial factors.
doesn’t it stand to reason that if GHGs reflect IR towards the planet, that they also reflect incoming IR back into space?
Nick Stokes says:
August 5, 2014 at 5:54 pm
And Oklahoma is what % of the lower 48? What % of the Earth landmass. What % of the Earth’s surface? What are the odds that the result is just “random variation” of the models?
Steve Mosher says : “One site.”
Nick Stokes claims “Main tenet not affected,”
Quite a site, I’d say, and I wonder which tenet Stokes is referring to.
800,000 observations over a 14 year period.
And not man-made data.
Of course, the fact that this site’s behavior closely replicates the global behavior lends authority to the study’s findings.
Bombshell-ish enough, for most, but not those suddenly skeptical.
Marcos says:
August 5, 2014 at 6:05 pm
GHGs absorb photons of specific energies. The mix of IR photons streaming in from the Sun is different from that radiated from Earth’s surface.
Pamela Gray says:
August 5, 2014 at 5:58 pm
Affect of low and high latitude volcanic eruptions of similar magnitude is different. Prompt effect (one to two years) of big tropical eruptions might be cooling, but longer term is warming. Of course consensus “science” attributes this observation to injection of CO2, but there are better explanations. High latitude eruptions tend not to affect the opposite hemisphere, so are more regional in effect.
M Simon says: August 5, 2014 at 6:09 pm
“And Oklahoma is what % of the lower 48? What % of the Earth landmass. What % of the Earth’s surface?”
That was Mosh’s question.
“What are the odds that the result is just “random variation” of the models?”
What’s your point here? A paper was published three years ago, said to be a bombshell contradicting main tenets of AGW theory. But the paper said that the IR went down because the clouds and humidity went down, quite in line with AGW theory. And in fact, models predict a reduction in precipitation for that region. So where is the contradiction?
For the life of me I can’t see how this would be a bombshell. There is nothing strange about this study. As always, WV and clouds make all the difference.
ONE site has been monitored. In North-Central Oklahoma. And the paper states the following about the trends:
““The seasonal all-sky radiance shows statistically significant decreasing trends in the winter, summer, and autumn, with values greater than 1% yr^-1 in the winter and autumn, and a trend of increasing downwelling radiance in the spring. These trends in all-sky radiance are primarily caused by changes in the fraction of scene types (i.e., cloudiness) over the SGP site. Overall, there are more clear-sky scenes and fewer thick cloud scenes in the winter, summer, and autumn, thus leading to a negative all-sky radiance trend, whereas the opposite is true in the spring. Furthermore, clear-sky radiance is decreasing in all four seasons, which we hypothesize is due to a decrease in the precipitable water vapor in all seasons. Thick cloud radiance is decreasing in autumn and winter. Thin cloud radiance is increasing in spring and decreasing in winter.”
Less clouds and WV in the atmosphere above the study site. Accordingly, less estimated DWLWIR. Go figure!
I’ve referenced this paper a few times in the past (more often on alarmist sites). I’ve always thought it kind of funny that it was completely ignored. What I find most interesting is this work was never replicated all over the world. Seems like an easy approach to verifying the science. It’s almost like the scientists don’t want to take a chance on the data coming back with the wrong answer.
philjourdan says:
August 5, 2014 at 5:29 pm
INteresting! This one CAME from WordPress, not WUWT (I get notifications).
Same here. I got a WordPress notification. In addition on other sites I’m now a spammer.
Come on Nick, how many times have we been told that the models can’t make regional projections with any accuracy? The models depend on the positive feed back chain that CO2 warms the planet, increases water evaporation, which in turn warms the planet more because H2O is also a “greenhouse” gas. The models also assume that clouds, on balance, also warm the planet, so more water vapor creating more clouds increases the feedback even more (the “Venus” scenario). This paper suggests that these positive feedbacks may not exist, and may even be negative (which is believable to me since systems that are dominated by positive feedback tend to not be wildly unstable, unlike our long term climate). Is this a mortal blow to the AGW conjecture? No, but it does increase the doubt factor considerably. At least for people that are looking at it objectively.
Nick Stokes says:
August 5, 2014 at 6:18 pm
It is ludicrous to refer to AGW as a “theory”. Gravitation is a theory. Evolution is a theory. The atomic theory of matter and germ theory of disease are, well, theories. AGW is an hypothesis shown laughably false over and over again since first being pawned off on a world soon to be suffering from its baleful effects.
According to the greenhouse gas theory, your tomatoes would frost on an overcast September night, and would be protected on a clear night by the IR downwelling. We know from experience that this is backwards from the real world. The whole greenhouse gas theory is B.S.
Nick Stokes says:
August 5, 2014 at 5:54 pm
davidmhoffer says: August 5, 2014 at 5:23 pm
“Did any of the climate models predict this particular regional result? Any?”
The paper attributes the reduction primarily to cloud reduction, and the drop in clear-sky radiance to a reduction in humidity. And yes, the AR4 projects reduced precipitation for Oklahoma.
So your claim is that a CAGW “theory” predicts both an increase and a decrease in longwave infrared radiation from increasing greenhouse gases over the 14 year period 1996-2010 in the US Great Plains, given that CO2 levels increased ~7% over this period.
Is that correct Nick?
I have been asking recently if any studies had been done over dry deserts to show that increasing CO2 was increasing the temperature? So far no one has pointed to a study. I wonder why there haven’t been any?
sturgishooper says: August 5, 2014 at 6:23 pm
Nick Stokes says: August 5, 2014 at 6:18 pm
‘It is ludicrous to refer to AGW as a “theory”.’
I’m following the head post:
“The findings contradict the main tenet of AGW theory which states… “
sturgishooper says, August 5, 2014 at 6:23 pm @Nick Stokes:
“It is ludicrous to refer to AGW as a “theory”. Gravitation is a theory. Evolution is a theory. The atomic theory of matter and germ theory of disease are, well, theories. AGW is an hypothesis shown laughably false over and over again since first being pawned off on a world soon to be suffering from its baleful effects.”
To be fair, that’s HockeySchtick originally referring to it as “AGW theory”.
I would love to see similar long term studies published in the microwave and millimeter wave bands.
Hey Nick Stokes, Steven Mosher, and the rest, started working on that CO2 causes Ice Ages paper yet??
Tom In Indy says: August 5, 2014 at 6:26 pm
“So your claim is that a CAGW “theory” predicts both an increase and a decrease”
No. Radiative theory says that total downwelling IR is due to the combined effect of the various GHGs. H2O is the most prevalent. In this case, its reduction exceeded the effect of CO2 increase.
Nick Stokes and Mosher. I would really like to hear your rationalization for the emissivity curves that most engineers use for radiative absorption. These are after Leckner who expanded on Hottel’s work. The curves show that for CO2, there is a point where the absorption flattens out (there is a typo on the label of the Y axis for the CO2 graph). Yes, yes, the curves are never perfectly flat. That doesn’t mean that they are not, nearly perfectly flat for all levels of CO2 that will ever be seen on earth. I have had a back and forth with Science of Doom (excellent site and person) about this. His opinion is that something happens at temperatures below 0. The curves for CO2 and H2O are at my (nearly comatose) blog as “Leckner’s Curves”. The curves are from: Bejan, Adrian; Kraus, Allan D. Heat Transfer Handbook. John Wiley & Sons., 2003 Page 618. I’ve used these curves to derive a forcing curve and it is very similar to that from ΔF = α ln (C/Co) where α=5.35 and Co= 278 ppm, as per Myhre, 1998 and others. The difference is that at high levels of CO2, AT HIGHER TEMPERATURES, we do not see an increase in forcing. This will certainly be true at the elevated levels of CO2 present in earth’s atmosphere. If it is temperature, what is the magic temperature, at which the break occurs? Given that the curves go to 0 C, it has to be lower than this and it has to be a substantial break to account for the increased absorption. If it is due to pressure differential, what is the magic pressure differential. Obviously it can’t be temperature differential as there wouldn’t be a transfer of energy without a differential. Don’t pull that “blanket” stuff. That is accounted for in Leckner’s solutions to the RTE’s (and Ramanathan and those who followed him). At higher temperatures (i.e. 2,000 C), there are a lot more lines to solve, so it isn’t that either. For the sky dragons reading this. CO2 IS a greenhouse gas. It reduces radiant energy transfer. Adding more means the planet surface must get to a higher temperature to maintain thermal equilibrium. This is as well established as gravity. We simplify the explanation of this by calling it the greenhouse effect. For those poor, confused souls who read Wikipedia, I have a number of physics texts etc., that refer to heat as energy, not energy transfer.