Oh dear, now we have three peer reviewed papers (Lindzen and Choi, Spencer and Braswell, and now Richard P. Allan) based on observations that show a net negative feedback for clouds, and a strong one at that. What will Trenberth and Dessler do next? Maybe the editor of Meteorological Applications can be persuaded to commit professional suicide and resign? The key paragraph from the new paper:
…the cloud radiative cooling effect through reflection of short wave radiation is found to dominate over the long wave heating effect, resulting in a net cooling of the climate system of −21 Wm−2.
After all the wailing and gnashing of teeth over the Spencer and Braswell paper in Remote Sensing, and the stunt pulled by its former editor who resigned saying the peer review process failed, another paper was published last week in the journal Meteorological Applications that agrees well with Spencer and Braswell.
This new paper by Richard P. Allan of the University of Reading discovers via a combination of satellite observations and models that the cooling effect of clouds far outweighs the long-wave or “greenhouse” warming effect. While Dessler and Trenberth (among others) claim clouds have an overall positive feedback warming effect upon climate due to the long-wave back-radiation, this new paper shows that clouds have a large net cooling effect by blocking incoming solar radiation and increasing radiative cooling outside the tropics. This is key, because since clouds offer a negative feedback as shown by this paper and Spencer and Braswell plus Lindzen and Choi, it throws a huge monkey wrench in climate model machinery that predict catastrophic levels of positive feedback enhanced global warming due to increased CO2.
The cooling effect is found to be -21 Watts per meter squared, more than 17 times the posited warming effect from a doubling of CO2 concentrations which is calculated to be ~ 1.2 Watts per meter squared. This -21 w/m2 figure from Richard P. Allan is in good agreement with Spencer and Braswell.
[While the -21wm2 and ~1.2 W/m2 values are correct, the comparison is wrong, and it is my mistake. The values are Top of Atmosphere and Surface, which aren’t the same. This prompts a new rule for me, I shall not publish any posts after midnight again (other than something scheduled previously during the day), because clearly I was too tired to recognize this mistake. I’ll add that I have emailed Dr. Allan regarding the question of feedback on hisfigure 7, and have not received a response. – Anthony]
Here’s the paper abstract, links to the full paper (which I located on the author’s website) follow.
Combining satellite data and models to estimate cloud radiative effect at the surface and in the atmosphere
Richard P. Allan
Abstract: Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of -21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of -53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-tropical marine stratocumulus regimes. While clouds act to cool the climate system during the daytime, the cloud greenhouse effect heats the climate system at night. The influence of cloud radiative effect on determining cloud feedbacks and changes in the water cycle are discussed.
1. Introduction
Earth’s radiative energy balance (solar radiative energy absorbed and terrestrial radiation emitted to space) determines current patterns of weather and climate, the complexity of which is illuminated by satellite observations of the evolving distribution and diversity of cloud structures. Representing clouds and the physical processes responsible
for their formation and dissipation is vital in numerical weather and climate prediction, yet many approximations must be made in these detailed models of our atmosphere (e.g. Bony et al., 2006; Allan et al., 2007). Observations of cloud characteristics from satellite instruments and in situ or ground-based measurements are crucial for improving understanding of cloud processes and their impact on Earth’s radiative energy balance (Sohn, 1999; Jensen et al., 2008; Su et al., 2010). The energy exchanges associated with cloud formation and precipitation are also a key component of the global water cycle, of importance for climate change (Trenberth, 2011). In this paper, initially presented at a joint meeting of the Royal Meteorological Society and Institute of Physics on Clouds and Earth’s Radiation Balance (Barber, 2011), the utility of combining weather forecast model output with satellite data in estimating the radiative effect of cloud is highlighted. Using a combination of models and satellite data a simple question is addressed: how do clouds influence the radiative energy balance of the atmosphere and the surface.
As an example of the radiative impact of cloud, Figure 1 displays thermal infra-red and visible channel narrow-band images of the European region from the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) on board the Meteosat-9 satellite (Schmetz et al., 2002).
In both images clouds appear bright: this denotes relatively low infra-red emission to space and relatively high reflection of visible sunlight to space. The hot, generally clear regions of northern Africa are also noticeable in both images since they are associated with substantial thermal emission to space (dark regions in the infra-red image) and high surface reflection from the desert surface (bright in the visible image). The brightest clouds in the thermal image correspond with (1) a trailing cold front extending from the coast of Norway, across Scotland and to the west of Ireland, (2) a developing low pressure system to the west of Iceland, and, (3) a low pressure system in the Mediterranean centred on Sardinia.
These are regions of ascending air with relatively high altitude, low temperature cloud tops which depress the thermal emission to space compared with surrounding regions. These features are also present in the visible image. However, many more cloud structures are also present. There is a prevalence of low altitude cloud over the oceans: this cloud contains large amounts of water droplets which are highly reflective (e.g. Stephens et al., 1978). The imagery captures the complex cellular structure of this cloud (e.g. Jensen et al., 2008) over the region surrounding the Canary Islands. These cloud types are thought to contribute strongly toward uncertainty in climate projections (Bony et al., 2006). While these clouds also strongly attenuate infra-red radiation, their impact on the thermal radiation escaping to space is modest since cloud-top temperatures are not dissimilar to the surface at night and so they do not contribute significantly to the strong natural greenhouse effect of the clear-sky atmosphere.
The altitude and optical thickness of cloud determines the overall radiative impact of cloud, a combination of the warming greenhouse effect and the surface-cooling solar
shading effect. Yet, probably an even stronger influence does not relate to the cloud itself. The time of day and time of year dictate the incident solar radiation and, therefore,
modulates the strength of the short wave reflection: clearly at night the solar influence of cloud is absent.
…
7. Conclusions
Exploiting satellite measurements and combining them with NWP models initialized through assimilation of available observations enables the effect of clouds on the Earth’s radiative energy balance at the surface and within the atmosphere to be quantified for the present day climate. Consistent with previous results (Ramanathan et al., 1989; Su et al., 2010), the cloud radiative cooling effect through reflection of short wave radiation is found
to dominate over the long wave heating effect, resulting in a net cooling of the climate system of −21 Wm−2.
The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of −53 Wm−2 for the global multi-annual mean. The magnitude of this effect is strongly modulated by the incoming solar radiation and the dominance of cloud short wave cooling over long wave greenhouse trapping is maximum around local noon (Nowicki and Merchant, 2004) while the cloud long wave heating effect dominates at night.
The long wave greenhouse effect of cloud measured at the top of the atmosphere is manifest primarily as a heating of the atmosphere in the moist tropics, consistent with calculations by Sohn (1999).
Over the marine stratocumulus regions and across higher latitudes the cloud-base emission to the surface becomes substantial and dominates over the reduced outgoing long wave radiation to space resulting in enhanced radiative cooling of the atmosphere and heating of the surface. The cloud radiative influence on the exchange of radiative fluxes between the atmosphere and the surface are intimately linked with the water cycle through radiativeconvective balance. While tropical, high-altitude clouds act to stabilize the atmospheric profile radiatively, clouds over polar regions tend to cool the atmosphere while heating the surface through enhanced atmospheric longwave radiative emission to the surface. In future work it would be informative to categorize these effects by cloud type further (e.g. Futyan et al., 2005) and compare with climate model simulations. These analyses are vital in constraining cloud feedback processes further and in linking to future changes in the water cycle (Stephens, 2005; Bony et al., 2006; John et al., 2009).
A particular challenge is the accurate quantification of surface radiative fluxes due to the sparse ground-based observing network (Roesch et al., 2011) and also monitoring current changes in cloud radiative effect in satellite data, reanalyses and models (Wielicki et al., 2002); combining meteorological reanalyses with satellite data and surface observations provide a vital methodology for meeting these challenges.
Abstract is here: http://onlinelibrary.wiley.com/doi/10.1002/met.285/abstract
Full paper is here: http://www.met.reading.ac.uk/~sgs02rpa/PAPERS/Allan11MA.pdf
UPDATE: Some people in comments including Dr. Roy Spencer, (and as I was writing this, Dr. Richard Allan) suggest that the paper isn’t about feedback (at least in the eyes of IPCC interpretations, but Spencer adds “it could be”). Thus I’ve removed the word from the headline to satisfy such complaints. My view is that clouds are both a feedback and a forcing. Others disagree. That’s an issue that will occupy us all for sometime I’m sure.
Regarding cloud feedbacks, here’s what I noted in the paper in section 6, near the end. Allan is referring to figure 7 which shows (a) net radiation and (b) net cloud radiative forcing:
Substantial negative anomalies in net radiative flux from ERA Interim are apparent in 1998 and 2010, both El Niño years, suggesting that the substantial re-organization of atmospheric and oceanic circulation systems act to remove energy from Earth during these periods.
You can clearly see the famous double peak in the 1998 El Niño, but it is inverted. To me that looks like a thermostat action, and not one with stuck electrical contacts, i.e. a negative feedback. I’ve also updated the text related to the incorrect comparison I made. – Anthony
dp says:
September 20, 2011 at 8:21 am
“In this thread the opacity of the atmosphere to LW has been mentioned, and the role of clouds at trapping nighttime heat has been offered. This has to mean that the altitude of the cloud base comes in to play and so I can ask this question: Because of the atmospheric opacity, at what altitude must a cloud be to stop trapping night time heat? This would be the altitude at which the cloud is invisible to surface LW radiation, and obviously, the reverse would be true – the cloud generated LW radiation is invisible to the surface. If the answer is the altitude does not matter then one has to ask if the atmosphere is actually opaque to LW radiation.”
Extinction altitude for primary CO2 absorption band is about 2000 meters AGL. That’s what I calculated from IR spectrograph looking downward from 20 kilometers above the arctic ocean. In the IR window you see the temperature of the arctic ocean and in the CO2 absorption band you see a temperature that is 20C colder. Using dry adiabatic lapse rate of 1C per 100 meters that works out to a 2000 meter column of air beginning at sea level.
I’ve not seen any mention of vertical distribution in any of this.
Rich says:
September 20, 2011 at 8:48 am
I wish someone who knew what they were talking about would draw a picture. A nice block diagram with the the blocks and energy flows properly labelled would really help.
AMEN!
However, I believe one of the problems that “someone” will encounter is that in most “flow diagrams” the inputs and outputs are the same–i.e., have the same units, such as voltage, or current, or in the case of digital signal processing flow diagrams, numbers. When you try to make a flow diagram whose inputs are in some cases power density (watts per square meter) and in other cases temperature and CO2 levels, the “flow diagram” will likely be complex. In any event, I too would like to see someone attempt to generate a flow diagram of the physical process of energy flow/temperature/CO2 in the earth’s atmosphere.
Reading this thread, two additional comments did, however, come to mind. First, given that “the science is settled”, there seems to be a whole lot of settling still going on. Second, as many other readers have commented, I too am confused by the terms “forcing”, “feedback–both positive and negative”, etc. However, one thing is becoming increasingly clear by the minute: the CERN experiments, the Spencer paper, and now the Allan paper are likely to constitute a “negative feedback” to the CAGW alarmist “feedbag”.
Can someone let me know I have got this right?
1. The IPCC climate models all work on the hypothesis that increased Co2 causes warming which causes more clouds. The IPCC reports conclude that the net effect of a cloud is that they capture the Earth’s heat and warm up the earth. (a bit like a blanket). So in the models the calculated Co2 warming is magnified by a factor of about 4.
2. The Spenser and Braswell paper, and now this new paper by Richard Allen, calculate that more clouds cause more cooling than warming. So when the C02 in the air rises, and the atmosphere warms there will be more clouds formed, but these clouds will start to cool the atmosphere back down again. So the calculated Co2 heating effect is partly cancelled out by some cooling caused by the extra clouds.
The reason I need this confirmation is that I will spread word of this work in the comment sections of blogs. I want my form of words to be accurate. Thanks
The word ‘feedback’ is multiply ambiguous. That is because there are many kinds of feedback systems that work on different principles. I am talking about physical feedback systems, not mathematical representations of feedback systems. There is a way to clarify these matters and it is the way of traditional science.
Instead of talking about feedbacks, present the physical hypotheses which describe the phenomena in question. In the context of the present discussion, the simplest possible hypothesis is that “Increased GHGs cause increased temperatures (warming) and increased temperatures cause increased cloud cover and increased cloud cover causes increased reflection of sunlight and increased reflection of sunlight causes a lowering of Earth’s temperature.” Then we calculate the net change in Earth’s temperature, find that it is a decrease, and make the simple minded assertion that increased GHGs lower Earth’s temperature. We can choose the unpack the latter claim as the generalization.
Notice that the word ‘feedback’ is neither used nor needed.
“NetDr says:
September 20, 2011 at 6:54 am
Negative feedback drives the temperature back to it’s “set point”.
Warming causes cooling and cooling causes warming.”
Since Earth is relatively stable temperature wise, would you say Le Chatelier’s principle applies on a global scale so that whatever changes are made by nature or man, Earth’s climate system will make adjustments to counteract these changes?
All this talk of feedbacks recalls an interesting post by Willis about his idea of a “homeostatic” mechanism in climate regulation. As I read it, Willis is proposing a “governor” mechanism rather than a simple feed back mechanism in climate regulation. In order to function properly, a governor’s response must exceed the perturbation: which differentiates it from a simple feedback mechanism.
http://wattsupwiththat.com/2011/08/14/its-not-about-feedback/
Dire Wolf says(September 20, 2011 at 5:49 am):
You almost nailed it. I imagine that if you replace your “the relative setting determined by weater vapor availability” with Willis Escenbach’s thermometer theory (i.e. tropical cumulus acting as a governor for temperature) you would be pretty close to where things will settle out after the real scientists take over from the ‘true believers’ and ‘want-a-be’ scientists that currently control government funded climate research.
Let’s call it the Svenmark-Eschenbach Theory for a habitable Earth.
All this minutiae and yet the ice continues to melt. Oh and by the way there are quite a few major corporations out there, taking advantage of the situation – Koreans building ships for the NW passage, Exxon Mobile signing arctic ocean drilling pacts with Russia.
This can only happen because there is less ice and what there is, is thinner. Of course I am not sure that’s all bad it’s just that reality is taking over and your blog is pretty much passé. Also, the sooner we all jump on the band wagon the better – imagine beach front property on the Labrador coast!
Roger Pielke Sr. also has a post on the Carnegie paper, very worth reading:
http://pielkeclimatesci.wordpress.com/2011/09/16/new-paper-climate-forcing-and-response-to-idealized-changes-in-surface-by-ban-weiss-et-al-2011/
Its interesting / amusing(?) that the title of this post has now been amended to drop the word “feedback” without any explicit acknowledgment of the error. However the text of the post is (in my opinion) still erroneous and unnecessarily provocative.
REPLY: Read the update, as well as my reply to Spencer and Allan in comments. The issue remains for discussion because (in my opinion) Dr. Allan clearly demonstrates negative cloud feedback in figure 7 in 1998 and 2010 -Anthony
“There is a prevalence of low altitude cloud over the oceans: this cloud contains large amounts of water droplets which are highly reflective (e.g. Stephens et al., 1978). The imagery captures the complex cellular structure of this cloud (e.g. Jensen et al., 2008) over the region surrounding the Canary Islands. These cloud types are thought to contribute strongly toward uncertainty in climate projections (Bony et al., 2006)”
This would be an ideal location to look for a cloud/CR correlation.
In addition to problems with the word ‘feedback’, there is another dispute that has to be uncovered through the fog of talk about feedback. Warmista, especially Trenberth and friends, strive to handle the phenomena of climate science on a “radiation only” model. They are interested in radiation that arrives from the sun, radiation that leaves Earth, and the radiation that is returned to Earth by CO2 in the atmosphere. I do not think that Trenberth can work with a statement such as “Increased cloud cover causes less sunlight to reach Earth and less sunlight reaching Earth causes a lowering of Earth’s temperature.” He will translate it in some fashion that I have not yet decoded. The big point is that if you are conversing with Trenberthians about the claim that increased cloud cover can reduce Earth’s temperature, then be aware that what they understand by that claim is not what you understand.
Bart Verheggen says:
September 20, 2011 at 6:56 am
RockyRoad, JohnB,
“To first approximation, relative humidity stays the same in a warming world (i.e. specific humidity goes up, but just about enough to conserve RH). Since cloud formation depends (a.o.) on relative humidity and not on specific humidity, your argument doesn’t hold.”
Bart,
True, but perhaps a gross oversimplification of atmospheric processes. With warming, convective processes carry air containing more quantities of water vapour to altitudes at which condensation occurs. Perhaps the condensation occurs at a somewhat higher altitude due to the altered lapse rate but I can’t see your reasoning as precluding enhanced cloud formation as a response to atmospheric warming.
Bart Verheggen says:
September 20, 2011 at 6:56 am
TallBloke,
This post is clearly confusing two very different things; how is that changing goalposts?
Bart, the warmists have claimed for years that cloud feedback is positive. They offer no proof which has any credibilty (R^2=0.02 anyone?).
Now you say:
(clouds as feedback) is about how cloud cover and properties might change in response to a warming or cooling of the climate: Will the net cloud radiative effect become more or less negative.
I reply that if it becomes slightly less negative, it’s still very negative, and overwhelms the effect of changes in co2. I invite you to consider why it is that cloud amount reduced according to ISCCP data in the 80s and 90’s. I think it was due to ongoing above average solar activity.
Got any better ideas? Can’t be temperature according to your statement.
http://tallbloke.wordpress.com/2011/09/17/cloud-albedo-what-does-it-respond-to/
Ron Cram says:
September 20, 2011 at 9:48 am
“So what I am missing? Is he not saying clouds cause a change in radiative forcing resulting in significant cooling which completely swamps the warming feedback at night? Is this not in opposition to the IPCC reports which claim a net positive (warming) feedback?”
What’s missing is the difference between land and water. Downwelling longwave has little effect over the ocean. The primary means of heating and cooling over land is radiative – absorption of shortwave by day and emission of longwave day and night. The ocean is different. First of all ocean absorbs nearly 100% of shortwave that hits it and it is absorbed to a depth of 50-100 meters (the mixed layer). Land absorbs about 20% less shortwave because it is higher albedo and it only heats it down to a few centimeters in a single day. Land gives up this heat very quickly at night. There is very little diurnal temperature variation over the ocean because the shortwave radiation is absorbed to great depth and can’t readily escape radiatively because water is essentially a brick wall to longwave infrared. The ocean cools primarily (70%) through evaporation. Because downwelling longwave cannot penetrate water beyond a depth of a few micrometers the primary effect of downwelling longwave radiation from low clouds or CO2 is increased evaporation rate. Clouds and GHGs don’t insulate deep bodies of water like they insulate land surfaces. This IMO is answer Trenberth’s Travesty (the missing heat). He expected to find it in the ocean but it just isn’t there. It’s being rejected by the skin layer of the ocean in latent heat of vaporization and it remains insensible until it rises far enough for adiabatic lapse rate to cool it below the dewpoint. This effectively functions like an express elevator carrying heat from the ocean upward thousands of feet where it is released upon condensation. The atmosphere between the cloud deck and ocean surface now insulates the surface against the downwelling IR from the cloud and makes the path of least resistance for radiation to travel upwards into space.
Every actual observation supports this scenario. Longwave IR just plain cannot heat a body of water because it’s completely absorbed in a skin layer literally just a few microns deep and between warmer water not being able to sink into colder water and viscosity being the dominant force in the skin layer it isn’t mixed downward by mechanical forces (waves) either.
So for 70% of the earth’s surface there is very little effect from greenhouse gases of any sort. Radiative cooling in the oceanic heat budget is a paltry 20% of the total, 10% is conductive, and the lion’s share of 70% is evaporative. Where longwave radiative cooling is a small fraction of cooling it MUST follow that longwave radiative heating is of similarly small influence.
I though that Roy Spencer came up with the thermostat hypothesis…right?
izen said
September 20, 2011 at 8:49 am
“…While this is just a refinement of the total/net effect of clouds in the average climate with no climate change.With the overall effect just -21W/m2, it would require a 10% change in cloud cover – a massive and obvious alteration – to equal the effect of rising CO2.”
This from the Met Office relating to the UK.
“There is quite a strong positive correlation between maximum temperature and sunshine, especially in the spring and autumn, with values of r up to 0.85. Minimum temperature is negatively correlated with sunshine in the winter, and positively correlated in spring and autumn, but with lower values of r than for maximum temperature. There is a strong positive relationship between sunshine and diurnal temperature range.”
There is an interesting composite chart of temp/sun/rain etc immediately above this comment-sorry no table number
http://www.metoffice.gov.uk/climate/uk/about/UK_climate_trends.pdf
The sunshine records are since 1929 so don’t capture the dramatic decrease in sun due to smog/low cloud and the subsequent increase through various clean air acts. One of the London smog’s is caught here in this;picture of Waterloo Bridge London in 1900 by Monet showing chimneys and smog.
http://www.artnet.com/Magazine/features/nkarlins/karlins7-7-04.asp
Artists came here especially to paint these sort of scenes. A French version from the mid 1880’s can be seen here in this famous painting ‘The bathers’ by Georges Seurat-note the chimney factories in the background
http://www.nationalgallery.org.uk/artists/georges-seurat
Generally the oldest instrumental temp data sets were in industrial cities which for at least 100 years had their temperature records skewed by the effects of atmospheric pollution/lack of sunshine.
tonyb
Steven Mosher says:
September 20, 2011 at 9:40 am
“it is also fascinating because of what we dont see. usually you will see a whole crew of commeters pounce on the word “model”. This time they didnt.
They didnt because they thought the paper supported spencer. But it was on an entirely different topic. That misunderstanding kinda silenced the usual “models are bad” crew.”
No, wrong. We refrained from pouncing on the word ‘model’ because what we are seeing is a conflict among modelers. We celebrate the emergence of a tiny bit of a critical voice in Warmista Land. We (OK, I) see this paper as giving rise to a dispute in Warmista Land. If the Veil of Ignorance which forbids criticism of models can be lifted in Warmista Land then that can only be a good thing for genuine science. I want to see models going head-to-head daily until Warmista realize the futility of modeling as a substitute for creating physical theory.
For those arguing “feedback” versus “forcing” I have a simple question:
If cloud FORCING is highly negative, how is it that cloud FEEDBACK is positive?
Can one point to an example where higher temperatures = fewer clouds?
Richard Allan says:
September 20, 2011 at 9:27 am
I was surprised that this paper was mis-interpreted as suggesting negative cloud feedback. This is a basic error by the author of the post that has been highlighted by many contributors including Roy Spencer.
———————–
That is the author of the paper specifically stating, in this thread, that the paper hes been misinterpreted by Anthony and many commenters.
Anthony, maybe you should consider clearing this up as an update to the original post.
REPLY: I did make an update in the post, two hours ago please see it at the end – Anthony
The paper is strongly indicative that clouds have a huge effect on the temperature. Whatever influences cloud formation/deformation is probably the main controller of temperature (climate). If increases in CO2 causes slight warming and the warming leads to fewer clouds then it COULD have a strongly positive feedback (aka CAGW). However, if that is the case then you shouldn’t need any further increase in CO2 to have runaway global warming because as soon as you drove up the temperature just a little with CO2 you have essentially lit the catastrophic climate fuse. The initial warming would have led to fewer clouds which lead to more warming which leads to still fewer clouds which… well you get the picture. Thus I would have to think then that the feedback MUST be negative (which one would expect anyway in a stable system) with temperature so that you don’t get runaway warming. Therefore since temperature does not appear to have a strong influence on cloud formation (witness the low correlation in the Dessler and Spencer papers) that leaves other effects that influence cloud formation. CERN perhaps?? Ocean cycles??
Looking at Fig. 7, provided above by Anthony, you can see what certainly looks like negative feedback in the El Nino years of 1998 and 2010. But 2010 was a far smaller El Nino than in 1998, as I recall, with a strong La Nina right after it, and yet the drop starting in 2009 and continuing through 2011 is larger than in 1998. This is at least, “consistent” with the cosmic ray hypothesis. But not proof by any means. Merely suggestive.
climatereason says:
September 20, 2011 at 10:35 am
…………..
Hi T
One of more accurate rain records, 160 year long, is held by Oxford University; it shows that rainfall pattern repeats about every 40+ years.
http://www.vukcevic.talktalk.net/ORR.htm
“”””” While clouds act to cool the climate system during the daytime, the cloud greenhouse effect heats the climate system at night. “””””
How often do you have to say that it DOES NOT heat up at night; except when the sun shines at night; which only happens if your planet orbits two stars. That doesn’t apply to earth, so Earth COOLS DOWN at night; it does not heat up by the Greenhouse effect or by any other mechanism; it COOLS DOWN at night.
As for the clouds (increase) causing massive cooling by blocking solar spectrum radiation; I’d like just one dollar for every time I have written that here at WUWT. It’s 8th grade high school Science; or maybe 4H Club Science. It doesn’t require any satellites or terraflop computers to see that clouds block sunlight, as well as reflect more of it back into space. That means it doesn’t get to the top 700 metres of the ocean surface to show up on Bob Tisdale’s graphs.
And maybe none of these three peer reviewed papers authors will say it; but I don’t mind saying it. As a consequence of the NEGATIVE cloud feedback, the result of CO2 based greenhouse effects (which I acknowledge), is for all practical purposes, effectively negated.
K Denison
For those arguing “feedback” versus “forcing” I have a simple question:
If cloud FORCING is highly negative, how is it that cloud FEEDBACK is positive?
Can one point to an example where higher temperatures = fewer clouds?
Yes. Eastman 2011, Variations in cloud cover and cloud types over the ocean from surface observations, 1954–2008, http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI3972.1