I thought I would post this video illustrating the first time that a change in CO2 forcing has been observed from the ground. The paper is an Observational determination of surface radiative forcing by CO2 from 2000 to 2010 by Feldman et al. (2015). I had a quick read and as I understand it, they observed from two different sites and measured the downwelling spectrum in the infrared band. They then had to use radiative transfer models to try and remove things like seasonal variations so as to extract the change in forcing due to changing atmospheric CO2 concentrations. They detect a trend of 0.2 ± 0.06 Wm-2 per decade.
Something to bear in mind, though, that this is not the first time that the radiative influence of increased atmospheric CO2 has been detected. Harries et al. (2001) measured – from space – a change in the outgoing spectrum. This is the first time that it’s been detected on the surface.
...and Then There's Physics 
I won’t believe it until some of the nuttier blogs deny it. /s
This is an incredibly useful study. Scientifically a bit of a “well duh” but it answers those “no evidence that CO2 causes warming….” memes.
Personally I use this one when challenged on that
http://onlinelibrary.wiley.com/doi/10.1029/2009JD011800/abstract
As I said at Hotwhopper (but apparently did not go through moderation yet), somebody at Berkeley needs to be fired. They write CO2 with a *superscript* 2! Grrrrr….
I noticed that this skeptic blogger and tweeter Blair King does the same thing using a superscript of 2, as in CO^2. And he claims to be a professional chemist !
I am sure the Berkeley video went to some graphics department.
“Both series showed the same trend: atmospheric CO2 emitted an increasing amount of infrared energy, to the tune of 0.2 Watts per square meter per decade.”
Kind of as expected, but worth remembering IPCC models reduced net rad into the surface ( the maps at the bottom ) Presumably due to shortwave attenuation:
Reality?
jsam,
Watts has a semi-supportive article about this study. First comment on the thread: rising CO2 is attributed to human activity with no proof of cause. It goes downhill from there, to wit, they’re once again tripping over the role of water vapor — how can CO2 be the driver when wv accounts for the higher percentage of instantaneous forcing. Noting that CERES EBAF shows a slight decline in upwelling LW from the surface over the same period. Etc. Active thread … I don’t think Watts’ readers appreciate it when he gets too close to discussing real science properly.
Michael 2: I suspect that the instruments used in conducting this research are a tad more sophisticated than your hand-held radiation meter. 🙂
Brandon: I suspect that this research is causing great consternation within all of Deniersville, not just in WUWT’s block. It’s just another nail in the climate denier’s coffin in my opinion.
@jsam
Why the /sarc? Of course they’ll deny the validity of this result.
semyorka,
Interesting paper, thanks. The difference seems to be that that paper is measuring the change in total downwelling longwavelength radiation, rather than simply the CO2 forcing. They get 2.2Wm-2 per decade, which – I must admit – seems quite high (I feel like I’m missing something obvious here).
Marco: Thanks for pointing out the glitch re “CO2” in the Berkeley Lab’s news release. I have prepared a reprint of it for posting on SkS and have converted the subscripts to superscripts.
semyorka
Yes, interesting paper.
The scatter plots in Fig 6 are particularly interesting. Not just Temp vs radiation, but the water vapour – clear trend in total water vapour and no trend in Relative Humidity.
Water Vapour feedback anyone? And the lack of trend for RH is a pretty solid support for the fixed RH assumption dating all the way back to Manabe & Wetherald in 1967.
John Hartz: NOOOOOOOO!O!O!O!O!O!O!
The subscript is right, the superscript in the video is wrong.
Tongue in cheek a bit, but isn’t a Nobel Prize for an Atmospheric Physicist overdue? The chemists were honoured for the Ozone Hole discovery (Crutzen, Molina, Rowland), time for the Nobel Academy to step up and acknowledge that elucidating the effects of CO2 on earth’s climate was a key 20th century discovery, possibly even more important than splitting the atom. Who should share it? Manabe & Wetherald? Veerabhadran Ramanathan? James Hansen?
It will be interesting to see how the deniers cope with this result. Prepare for an attempted sidetrack with a distraction or two.
So for a doubling of CO2 we get between 3-3.8 W.m-2, according to the scale, which is 1 degree of warming?
==> “Brandon: I suspect that this research is causing great consternation within all of Deniersville, not just in WUWT’s block. It’s just another nail in the climate denier’s coffin in my opinion.”
==> “It will be interesting to see how the deniers cope with this result. Prepare for an attempted sidetrack with a distraction or two.”
What world are y’all living in? This will cause nary a hitch in their giddyup.
ATTP: Grist for a future post…
The Year the Dam of Denial Breaks by Paul Gilding, Post Carbon Institute, Feb 25, 2015
“It will be interesting to see how the deniers cope with this result. Prepare for an attempted sidetrack with a distraction or two.”
😀 I’m always happy to help!
Firstly, the two sites show the same trend in forcing but the opposite trend in temperature! The southern plains got hotter, while Alaska got colder over the period. Yes, I know that will be explained in the hand-wave of “natural variation”, “other factors”, and “regional climate”. I haven’t got access to Nature so have onle seen the abstract and PR blurb, but it doesn’t sound like they mentioned that.
Secondly it’s clear sky *only* not all-sky. It therefore does not answer the question of what happens in the real world.
But, on that point, thankfully we have another paper by one of the same authors, using the same site, same equipment and same (full) data, and same period.
http://journals.ametsoc.org/doi/pdf/10.1175/2011JCLI4210.1
The abstract reads (in part):
“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 statisticallysignificant trend in the observeddata 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”
(I bolded the bit about clouds just for BBD…!)
Note that the all-sky data is down, as interestingly is the clear-sky. Note also that the water vapour trend is down.
So why are the two papers so different in their conclusions? To agree with model output…?
Tangential question.. thinking of (CO)^2, why doesn’t it react to form O=C=C=O.. suspect it’s because the oxygen is very electronegative and weakens the double bond to the point where the free CO species is favored. Hmmm..
Less tangential: Bear in mind that creationists have managed to assimilate the evolution of cockroaches that can digest DDT whilst still claiming that ‘macro evolution doesn’t happen’. And they can look at Venus and still claim that CO2-based warming is limited by negative feedbacks..
Andrew, many have asked themselves that question. Dicarbon dioxide (or ethenedioxide) can exist in theory, but as you note, the double bond is pretty difficult to maintain due to the oxygen electronegativity. Add vibrational motions and it falls apart..
David Blake.
You may have answered your own question there. They were measuring forcing at the surface, not temperature. So your point about temperature is irrelevant.
David Blake.
It appears the two papers were different in their conclusions as the studies measured different things. I do not find that a surprising result as it is know clouds can create both positive and negative forcings.
I am not sure what you are implying with your last sentence, unless it was a cover-up by the scientists or something like that:
“So why are the two papers so different in their conclusions? To agree with model output…?”
@David Blake,
CO2 is well mixed enough that a forcing trend due to increasing amounts, even though measured a very few ground sites, is likely highly representative of global trends.
Clouds and H2O can NOT be considered as being well mixed. A trend at the ARM SGP site for forcings associated with Cloud and H2O trends can not be considered to be widely representative.
The two studies do not contradict each other in the slightest.
@harryt,
Thanks for that. As I said I don’t have access to Nature (£), so I can’t confirm if they did, or didn’t mention temperature – let’s assume not. The temperature is a minor point.
Secondly, what do you make of the other paper (here) which seems to give the opposite result to this one? It’s not apples to apples, sure, as one is calculating for CO2 alone, and then only in clear-sky, while the other is all IR,. In the ’11 paper (same place, same data, same instruments) the IR has declined – even looking just at the clear-sky part, while in the ’15 paper it rose! (See fig 7 in the ’11 paper: clear-sky in blue has a negative trend for all seasons and wavelengths…)
I may be missing something so I hope some of the very knowledgable commentators here could tell me: i) why there is this difference between the two papers?, ii) why, when there is nearly 20 years worth of data available (the instrument was installed 1995), did they just pick a period of 10 years?, iii) why the more recent paper (’15) didn’t mention the falling cloud, and seeming lack of water vapour feedback (water vapour fell in the ’11 paper)?
The ’11 paper seems to me to show what actually happened at that site, while the more recent seems to ignore the “real world” and just measure the forcing from CO2. Surely the former is more important?
As ever with climate science – one question raises others..!
as harrytwinotter, points out, they are measuring different things. In this paper, the authors have isolated the CO2 forcing, whereas in the Gero And Turner paper, they’ve measured the total. If you are interested in the total, all-sky makes sense. If you are interested in isolating the CO2 contribution, clear-sky would seem like the appropriate approach.
Also, in the paper here, they’re trying to measure the CO2 forcing only, which requires – as you say – isolating CO2, but also requires removing the Planck response. In the paper that semyorka links to, it’s the increase in downwelling long-wavelength flux at the surface, so it not includes all the different forcings and feebacks, but also includes the Planck response due to the warmer atmosphere. So – unless I’ve got that wrong – two very different things.
Blake, what’s up with the falling cloud?
Where was this falling cloud observed?
David Blake
I hesitate to piss on your parade, but a corner of the Great Plains cannot be used as a proxy for global cloud cover trends.
@ aTTP, Curious, David Donovan,
Thanks for your comments. The interesting thing for me on comparing these two papers is how little the ’15 paper actually tells us. It gives some nice figures for CO2 forcing. It’s good to know that CO2 went up ~20ppm and the forcing by ~0.25W/m^2. But we knew that already didn’t we?
On the otherhand the ’11 paper shows we can’t turn any of that into useful information about what will actually happen given that CO2 forcing! It’s clear that the hydrological cycle and clouds are the dominating factor. And how that will respond to a small CO2 forcing is still ultimately unknown.
The bit that is the most difficult to model also happens to be the most important bit.
David,
Not via direct observations from the surface, which is what makes this an interesting paper.
@ WHT,
Afternoon,
“Blake, what’s up with the falling cloud?”
Indeed. What is up with it? Just to get you up to speed on the ongoing ding-dong: my longstanding position is that falling cloud globally has contributed to global warming. I usually quote the ISCCP data to show it. Then BBD cites studies that say the data is unreliable, then I cite studies showing they are. It’s all good clean family fun.
Moving on… The ’11 paper has a few interesting quotes about clouds in their study:
“This decrease in downwelling radiance is largely governed by the decrease in the amount of time when thick clouds are overhead”
… and very interestingly:
“The most distinct result from these plots is that clear-sky scenes are getting colder (i.e., less downwelling radiance) for all seasons and spectral regions (Fig. 7)”
Clear-sky scenes are the ones that the ’15 paper looked at. The ones with increasing CO2 forcing – yet (apperently) they are getting colder. Can anyone tell me what’s going on there?
David Blake.
We know what happens when the CO2 forcing going up – the average global temperature goes up.
It springs to mind that David is David.
David Blake
First, you don’t (or you don’t understand what you are referencing); second, you don’t seem to understand the way clouds affect climate. They have two sides. Top reflects SW up and out. Bottom traps LW. The effects nearly cancel. So if global cloud cover were to reduce slightly, more SW would reach the surface during the day and more LW would leave during the night.
Then there’s the minor matter of CO2 forcing and modern warming. If most warming over the last several decades is mainly down to changes in cloud cover, then the implication is that the climate sensitivity to CO2 is extremely low. This can be discounted because of paleoclimate behavior.
There’s so much woodworm in your hobby horse that if you ride it any further it will simply fall to bits.
It is a pity the paper is paywalled, the CO2 forcing is 10% of the trend so I am more interested in the 90%.
I followed one of the references and the overall trend in downwelling longwave radiation is around 2 W/m2 per decade – that is quite a chunky amount. I assume it is the total from increases in air temperature, CO2 and water vapour.
harry,
Yes, that is – I think – right.
Oops – forgot one more point:
If such a trend did exist – and there’s no good evidence that it does – then it would be reasonable to argue that it is a positive feedback to CO2 forcing.
I really don’t want to restart the whole “it’s clouds” discussion, so will just post this link that examples not only the way in which clouds influence the radiative balance, but also says
i.e., probably a relatively small positive feedback.
Trend in net surface LW forcing? Surely it can’t be that high? I have had a brief look but can’t find a ref.
BBD,
It’s from this comment. It’s not an increase in forcing, it’s the increase in longwavelength flux at the surface over – I think – land. It’s also over the period 1973 – 2010, so is a total increase of around 8Wm-2 which seems high, but the increase in land surface temperatures over the same period is about 1K, which would increase the outgoing surface flux by about 5.5Wm-2. I might write a quick post about this, as I think it’s an interesting observation.
Thank you ATTP. I’m sorry – as you can see I haven’t followed this thread properly. Migrating from old to new PC. Done now, mercifully.
@ aTTP & BBD,
I won’t press the point – I know patience is running thin on the issue. One more post on clouds as there’s a number of points which are being missed.
Firstly clouds in general. Ignoring if they are actually a feedback or not (leaving aside the ISCCP data) the ERBE data says:
“The latest results from ERBE indicate that in the global mean, clouds reduce the radiative heating of the planet. ”
So more clouds = cooler. Less clouds = hotter, on a global average. Check all the figures therein.
Secondly feedbacks. The IPCC say:
“Conclusion on cloud feedbacks:
Despite some advances in the understanding of the physical processes that control the cloud response to climate change and in the evaluation of some components of cloud feedbacks in current models, it is not yet possible to assess which of the model estimates of cloud feedback is the most reliable”
One model showed a negative feedback, and one a positive. So if clouds are acting as a CO2 feedback (which I don’t hold with), we really don’t know in what direction the sign is…
Thirdly, BBD’s simplified model and aTTP link all ignore the big kahuna of heat sinks: The oceans. SW penetrates to metres depth. LW only to microns. So less cloud (more SW into the oceans) results in higher SSTs which feed to higher atmospheric temperatures.
So again (as it’s worth repeating) “The latest results from ERBE indicate that in the global mean, clouds reduce the radiative heating of the planet. “
Seriously, why are you intent on using this form of english? I have noticed this is quite common among skeptics, that they prefer to use the singular form “cloud” instead of the preferred plural “clouds”.
It is actually quite jarring and is a dog-whistle similar to the old Limbaugh tactic of using “Democrat party” instead of “Democratic party”.
I have a theory of how this happens. Skeptics tend to read what other skeptics write at the expense of real science, and thus adopt the mannerisms of those they read, not knowing there is a preferred verbiage..
@ BBD,
“Migrating from old to new PC. Done now, mercifully.”
I was recently gifted some old windows PCs. I can heartily recommend wiping Windows and installing LXLE (a Linux distro). They now run really well, fast and responsive, with only 500mb ram and a Pentium M.
David,
They really can’t be a forcing, by definition!
If you read the ERBE site it says,
Yes, but this is relative to there being no clouds at all. What we’re interested in here is what happens if we warm through a change in CO2 forcing which then produces a change in cloud cover. If the overall effect of clouds is in the range suggested above, the effect of a small change in cloud cover as we warm is almost certainly small.
However, let’s not start this whole discussion again as there is no way that a blog discussion is going to overturn our current understanding of this topic.
@ WHT,
“Seriously, why are you intent on using this form of english? ”
‘Cos that wuz how I wuz taut it in skool. Innit.
@aTTP,
OK! One last one!
i) Clouds obviously don’t respond to CO2 *alone*, but to the suggested warming and humidifying of the air, plus a nucleation factor. If any of those factors changes independantly more than CO2 we cannot say that CO2 is the “cause” of that change.
ii) The earth had clouds before the industrial revolution, which varied with (presumably) humidity and nucleation. They will cary on varying with humidity and nucleation.
iii) I find it hard to accept that “-13 to -21 Wm-2” for clouds means “the effect of a small change in cloud cover as we warm is almost certainly small” when the all the man-made CO2 forcing is a fraction of that figure!
It just so happened that Eli was discussing spectroradiometry yesterday with someone who does it. The point came up that clear sky measurements are a lot more reliable than when clouds are present. So yeah, you could include cloudy sky measurements, just you would get a lot bigger error bars.
DB,
FFS, it’s not magic! Clouds respond to changes in temperature etc, hence a feedback, not a forcing.
Yes, no one is suggesting otherwise. However, none of the changes in the last thousand years has produced a period of warming as large or as fast as the warming over the last 120 years.
WTF are you talking about? The cloud radiative forcing is the total radiative effect of clouds compared to a world without any clouds. Right? The variations in cloud cover that we’d expect today is almost certainly much smaller than the difference between a world without clouds and what we have – on average – today. Consider the planet without and clouds and without any atmosphere. Now start adding an atmosphere. The total greenhouse effect is about 150Wm-2. The contribution due to CO2 is about 30Wm-2. The rest is due to water vapour and coulds, with clouds producing something like -13Wm-2 to -21Wm-2 (and that’s relative to a world without clouds, so isn’t even necessarily representative of the cloud feedback due to greenhouse warming).
Now add perturbations on top of that. If we perturb the CO2 forcing by a small amount relative to the total CO2 forcing in the greenhouse effect, the cloud feedback has to be a lot smaller than the total cloud radiative effect.
Seriously, this is not complicated. If you can’t work this out, I’m wasting my time and I’ll simply delete any more comments of yours about this. I’m not going to have another one of your “it’s clouds” gish-gallops.
Dung at Bishop Hill recently asked for one piece of evidence which validated AGW. If I still posted there, this paper would be my choice.
ATTP
You are starting to sound like me 😉
TFIF and you can have a glass of wine / raw potato spirit to take the edge off.
@WebHubbleTelescope
“and thus adopt the mannerisms ”
I have noticed bizarre truncation of words and abbreviations, most especially temperature is shorted to temps.
They also tend to be fond of random Capitalization in the middle of phrases.
ATTP: Perhaps David Blake has his head in the clouds. 🙂
Actually, the effect of using the singular cloud instead of the plural clouds is jarring because subliminally your mind tries to associate that form with something more familiar. In my case, I know that it is associating it with “cloud” the discussion, as in making it more murky. And of course this is exactly what the pseudo-skeptics attempt to do, in terms of planting seeds of doubt. Using the word cloud by itself serves a useful purpose to the Luntz-trained pseudo-skeptic crowd.
The worst case ever in that regard is the McKitrick and Essex attempt to call the global temperature record as T-Rex in their “Taken By Storm” book. This has implications for what Curry later pursued with her “Uncertainty Monster” tactics. Make something scary or unknown and that plays into the FUD.
[Mod : Sorry, provide some evidence. Statements aren’t good enough!]
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[Mod : Seriously, I’m not interested. A single paper about one region of the globe does not even come close to providing evidence for your position.]
aTTP:
!!!
It’s the SAME AUTHOR as the paper your article is about, using the SAME DATA from the SAME INSTRUMENTS!!!
As they say WUWT? 😀
David,
I don’t care. Providing a link to a single paper without much of a comment and the paper being about one region of the globe doesn’t suddenly validate your thesis. You still haven’t acknowledged that you don’t seem to understand the cloud radiative effect and one of the previous times you referred to a paper, you had completely misunderstood it. I don’t have time to go through all this again. You’re free to believe whatever you want. I don’t have to let you post it here!
David Blake on cloud forcing v. cloud feedback: the forcing is the *static* net effect of clouds, while the feedback is the *change* in effect that results from a change in something else, like surface temperature. Your reasoning in effect assumes that d(f(T))/dT = c*f(T) for the (very complicated and not completely known) function f that governs how clouds respond to temperature changes. That assumption lacks foundation, and is, of course, false of almost every conceivable function f.
Also, if you’re going to have another run at the Iris Hypothesis, you’ve got to do better than its other proponents at explaining ice-age cycles.
@aTTP:
“Providing a link to a single paper without much of a comment and the paper being about one region of the globe doesn’t suddenly validate your thesis. ”
You may want to read you own article 🙂
I am off to smoke my pipe!
David,
Enjoy.
entropicman,
It still wouldn’t help. Although, interestingly enough, Andrew Montford has just deleted 10 comments on a single post after I had asked why noone was willing to challenge something that was clearly nonsense, and Nic Lewis had – it appears – agreed.
There was a commenter named Jim Cripwell at CE who always said direct physical evidence was needed to verify AGW. Apparently if the measurement didn’t involve a ruler, it wasn’t good enough. Mosher would go on endlessly with him.
Question.
So this study is measuring the DIRECT effect of all the extra CO2 molecules in the atmosphere? This is not measuring changes from feedbacks, wv, clouds etc?
HR,
Yes, and it’s also trying to determine the forcing, which means how the increased CO2 would influence the outgoing top-of-the-atmosphere flux in the absence of a temperature response. So, the analysis is removing all the other feedbacks (wv, clouds, etc) and the Planck response (which is also, technically, a feedback).
John Hartz says: (February 26, 2015 at 4:02 pm) “Michael 2: I suspect that the instruments used in conducting this research are a tad more sophisticated than your hand-held radiation meter.”
Probably. I am dismayed by your lack of enthusiasm for citizen science.
When the science-is-settled-but-not-really comes looking for money, my hand-held radiation meter persuades me more effectively than your photo of what seems to be a multi-million dollar thingy out in a really nasty place, the output of which is washed through many layers of executive bureaucracy.
I have absolutely no idea how to sort out who is telling the truth; I do not have your faith in photographs of metal things in frozen places. I could develop that faith but first I have to confirm that the emperor actually has clothes (metaphor, just in case it isn’t obvious).
That is where the $60 remote reading infrared thermometer comes into the picture. Joe Q. Public can personally validate that there is actually such a thing as “infrared” energy, what passes it, what creates it, what blocks it.
He also can discover its limitations, learn about important concepts such as “emissivity” — different materials at the same temperature do not read the same on the remote reading thermometer. This knowledge influences understanding of the energy budget of Earth; it is not a “blackbody” with emissivity of 1; although the oceans are pretty close to it.
I calibrate mine with a water-ice bath and it’s up to a degree (F) off. But that’s okay, I am not studying tiny variations; I am learning important, basic principles; it is fun and it is a thing almost anyone can do. I am fascinated by the fact that glass is clear at visible wavelengths but perfectly “black” to infrared.
Joshua says: “This will cause nary a hitch in their giddyup.”
Agreed. Hardly any denier denies the actual physics of carbon dioxide (*), so far as I know anyway. My own bubble might be as narrowly defined as yours.
* In this case, carbon dioxide itself is not being measured, but radiation emitted by CO2 and other emitter elements and compounds.
Michael 2
“When the science-is-settled-but-not-really comes looking for money…”
I think you ideological bias is showing.
harrytwinotter says “I think you ideological bias is showing.”
It’s pretty subtle. You are the first to notice it. 😉
On other news, I presume your name implies an affection for the Twin Otter aircraft. I’ve never been in one but it has an excellent reputation.
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