Bishop Hill Striking back at Svensmark
Oct 7, 2011 Climate: solar Nigel Calder reports on a new paper that purports to rebut Svensmark's cloud hypothesis.
During recent years, so the story goes, the Sun has been weak, cosmic rays have been relatively intense, and yet the expected increase in low clouds has not occurred. On the contrary, we’re told, low cloud cover has remained relatively sparse. That’s according the International Satellite Cloud Climatology Project, ISCCP, which pools data from the satellites of several nations.
However, the ISCCP data are apparently problematic:
The conspicuous downward trend in the ISCCP cloud data is almost certainly unreal. An expert view is that it results from changes in the operational status of the satellites from which the data are pooled.
In other words, the jury is still out.
Calder is very critical of the authors of the new paper - Agee et al - suggesting that they have cherrypicked the ISCCP figures rather than mentioning any of the other data sources, which tell a different story. He calls the paper "shoddy".
Reader Comments (183)
BBD: I am puzzled by the assertion that the missing heat cannot be found so must be in the sea and would genuinely like a scientific lesson on how that could be so. As with an awful lot of climate science (like more precipitation and receding glaciers) it seems to be counter intuitive to me that the heat could get into the oceans and not warm them. You know, the Laws of Thermodynamics and all that. What physical process is making the heat huddle together in the deep cold oceans so we cannot find it? Do you have a paper I can look at explaining this phenomenon? Tx.
BBD - I don't see a big problem here. The increased insolance from just a 1% reduction in average cloud cover over the tropics and mid latitudes is a much greater 'forcing' (for want of a better word) than the IPCC's alleged 2 or 3 W/m2 from anthropogenic CO2. But extra cloud cover in the high latitudes most likely has a net warming effect, as the loss of direct insolance is not such a big deal due to the fact that IR recieved from the low-angled sun is barely and rarely enough to melt butter. (this is also why I don't consider the loss of NP sea ice a big issue - ok there will be some extra net warming in the long days of the summer months from decreased albedo, but less ice also means more heat direct loss from the ocean the following autumn and winter, due to the fact that snow covered ice acts as a very good insulator - this is a significant negative feedback that I have never hear mentioned by the warmists). So reduced cloud cover can have different results at different latitudes, and there are seasonal and diurnal complications. Likewise the consequences may be different over land and ocean. Then there are the long lag times and complications thrown in by ocean circulations and currents, and the not insignificant role played by the hydrological cycle in chaotically distributing all the heat tropical heat around the globe. .
So as Shrub has pointed out, and you know well, trying to establish trends from just 6 years of data (even if it was good quality, which it seems it is not) is hardly reputable. I would suggest that even 30 years isn't nearly long enough. That's why I have a high regard for Tallbloke, Peter Taylor, Bob Tisdale, Stephen Wilde and Vukcevic and others; they are at the very least trying to piece together all the parts of the jigsaw - rather than just jump on the bandwagon and accept the IPCC's simplistic and political rather than scientific 'it's all due to CO2 and we are going to die before teatime" meme. Tallbloke et al may not all be right all or even some of the time, but it would be unrealistic and unreasonable to expect them to be - they are grappling with the many uncertainties and questions over data and sensitivities.
FWIW I think Svensmark and Shaviv's contention that variations in CGR will have an effect on cloud cover looks fundamentally sound, but it will only be a small effect, which may just be discernible over decadal timescales, and more likely centennial. In the meantime there are many other factors which can influence the resultant average global temperature (if that can ever be measured accurately).
As Neil has pointed out, there has not been much of a correlation between CO2 emissions and GAT in the 50s, 60s and 70s. So certainly some double standards there.
As I think I have said before, the lack of correlation in the 40-70s, and the lack of warming in the last 15 years, are the main reasons why don't think increased atmospheric CO2 concentrations have much if anything to do with the slight warming we saw in the late 20th Century. My mind has certainly not been changed after seeing this video, which literally blows the lid off the CO2-AGW thesis. Any thoughts on this? If this video's main contention is correct (and I can't find a fault in it but my faith in human intelligence would be somewhat restored if someone can) it makes the arguments over climate sensitivities and the billions spent on CO2-AGW research look very silly indeed. I fear that too much money has now been spent for the truth to come out.
sorry - got one bracket the wrong way round:
BBD - I don't see a big problem here. The increased insolance from just a 1% reduction in average cloud cover over the tropics and mid latitudes is a much greater 'forcing' (for want of a better word) than the IPCC's alleged 2 or 3 W/m2 from anthropogenic CO2. But extra cloud cover in the high latitudes most likely has a net warming effect, as the loss of direct insolance is not such a big deal due to the fact that IR recieved from the low-angled sun is barely and rarely enough to melt butter. (this is also why I don't consider the loss of NP sea ice a big issue - ok there will be some extra net warming in the long days of the summer months from decreased albedo, but less ice also means more heat direct loss from the ocean the following autumn and winter, due to the fact that snow covered ice acts as a very good insulator - this is a significant negative feedback that I have never hear mentioned by the warmists). So reduced cloud cover can have different results at different latitudes, and there are seasonal and diurnal complications. Likewise the consequences may be different over land and ocean. Then there are the long lag times and complications thrown in by ocean circulations and currents, and the not insignificant role played by the hydrological cycle in chaotically distributing all the heat tropical heat around the globe. see here for a recent discussion of these and other points.
So as Shrub has pointed out, and you know well, trying to establish trends from just 6 years of data (even if it was good quality, which it seems it is not) is hardly reputable. I would suggest that even 30 years isn't nearly long enough. That's why I have a high regard for Tallbloke, Peter Taylor, Bob Tisdale, Stephen Wilde and Vukcevic and others; they are at the very least trying to piece together all the parts of the jigsaw - rather than just jump on the bandwagon and accept the IPCC's simplistic and political rather than scientific 'it's all due to CO2 and we are going to die before teatime" meme. Tallbloke et al may not all be right all or even some of the time, but it would be unrealistic and unreasonable to expect them to be - they are grappling with the many uncertainties and questions over data and sensitivities.
FWIW I think Svensmark and Shaviv's contention that variations in CGR will have an effect on cloud cover looks fundamentally sound, but it will only be a small effect, which may just be discernible over decadal timescales, and more likely centennial. In the meantime there are many other factors which can influence the resultant average global temperature (if that can ever be measured accurately).
As Neil has pointed out, there has not been much of a correlation between CO2 emissions and GAT in the 50s, 60s and 70s. So certainly some double standards there.
As I think I have said before, the lack of correlation in the 40-70s, and the lack of warming in the last 15 years, are the main reasons why don't think increased atmospheric CO2 concentrations have much if anything to do with the slight warming we saw in the late 20th Century. My mind has certainly not been changed after seeing this video, which literally blows the lid off the CO2-AGW thesis. Any thoughts on this? If this video's main contention is correct (and I can't find a fault in it but my faith in human intelligence would be somewhat restored if someone can) it makes the arguments over climate sensitivities and the billions spent on CO2-AGW research look very silly indeed. I fear that too much money has now been spent for the truth to come out.
There it is again, in every comment. Collective refusal to acknowledge the laws of physics that require an increase in RF from an increase in the atmospheric fraction of CO2.
Well done Lapogus for admitting that GCR/cloud effects are too small to force a significant climate response.
Not so well done for failing to spot that Calder's rebuttal of the Agee paper is the same as the one I gave you for Tallbloke's hypothesis. The ISCCP data are misleading and have been misinterpreted.
So to defend Svensmark you have to abandon Tallbloke. But since GCRs don't have significant climate effects, we're back to the dominant forcing of the latter C20th - CO2.
A really unimpressive collection of responses.
Shub
Those six year trends you are so unhappy with are the same used by sceptics to argue for decreased cloud cover and DSW-forced warming of the upper ocean layer. So why is it okay for sceptics and not okay for everyone else?
It is ok for anyone to do "it" as long as "it" is just a tentative or exploratory suggestion. Which is exactly what these papers do. Or, that is how we should take them to be.
It is you who set them up into camps and pit them against each other.
Frosty (and Shub)
If you took the trouble to check, you would know that the ISCCP data set starts in 1983, so cannot tell us anything about the early 1970s.
Here's the ISCCP global mean cloud anomaly.
Where's the increased cloud from the late 1990s? There's a dip and recovery after the 1998 El Nino, that's all.
Now look at the zonal monthly means by latitude. There is a reduction in equatorial cloud cover from the early 1990s.
For a standard view of the tropical data, go here, select variable [VIS-IR Low-Level Cloud Amount (%)] and geographic region [Tropical (LAT:+/- 15)].
Oh dear.
BA
If you actually spend some time at the Blackboard reading what Lucia says, you will discover the following:
- she is fully accepts that AGW is real
- she is fully accepts the physics that make it so
- she believes (but I have not seen her reasons) that climate sensitivity is low
- she is in the process of demonstrating that the multi-model mean referenced in AR4 is currently trending higher than observations
- it is not possible to say whether this will continue
With you, it is very useful to do a frequent "pea in the thimble" raincheck, every now and then?
What exactly are you saying? Could you please repeat it ?
- she is fully accepts that AGW is real = Belief
- she is fully accepts the physics that make it so = Belief
- she BELIEVES (but I have not seen her reasons) that climate sensitivity is low
- she is in the process of demonstrating that the multi-model mean referenced in AR4 is currently trending higher than observations = Entertainment
- it is not possible to say whether this will continue - REALLY?
Andrew
BA
So now you don't rate Lucia so much? It's just that you kept saying 'ask L this' and 'ask L that'.
AGW is a fraud = BELIEF
Shub
No. Read the comments again and stop asking me to do all the work. If you don't understand what is being said, you should refrain from further comment here.
Someone called the Blackboard an echo chamber and I responded that it is a chamber orchestra which can simply outplay any dissonance from 'lukewarming and do something about it'. Key is that lucia herself doesn't know why she believes the sensitivity she does.
=====================
Shub and others
I feel rather guilty about my previous comment.
Let me atone with the 'missing explanation' ;-)
Tallbloke suggests that decreased low cloud cover, especially equatorial cover, explains recent warming. The problem is that both sources he relies on (Palle's earthshine studies and ISCCP) appear to be unreliable.
Calder rightly points to the issues with ISCCP and argues that this vindicates Svensmark.
Assuming Svensmark to be correct, can the GCR/cloud relation explain recent climate variation? The suggestion is that it cannot.
So what remains?
-------------------
Calder explains:
GCR/cloud hypothesis as driver of recent climate change?
- Sloan & Wolfendale (2011) (full); (abstract):
- Pierce & Adams (2009) (full); (abstract):
"AGW is a fraud = BELIEF"
Not at all. No one can produce any evidence that it's true. Therefore, anyone who promotes it as if it were conclusively determined are perpetrating a fraud, by the defintion of the word 'fraud'.
Definition of FRAUD
1a : deceit, trickery; specifically : intentional perversion of truth in order to induce another to part with something of value or to surrender a legal right
Andrew
BA
Okay, you win. They made it all up.
What I would love to know is how they hacked the laws of physics to get around the RF from CO2.
Some boffin once said that you can't fool nature, but doubtless you would have soon put him straight.
"They made it all up."
They and you, BBD.
Andrew
BA
Thank you. I never knew how creative I was. This is a pleasant surprise.
BA
It's nice to chat, but can we talk about this?
Tallbloke suggests that decreased low cloud cover, especially equatorial cover, explains recent warming. The problem is that both sources he relies on (Palle's earthshine studies and ISCCP) appear to be unreliable.
Calder rightly points to the issues with ISCCP and argues that this vindicates Svensmark.
Assuming Svensmark to be correct, can the GCR/cloud relation explain recent climate variation? The suggestion is that it cannot.
So what remains?
BBD,
We aren't going to be able to have a dialogue because you will make your case based upon assumptions that I will reject and upon appeals to authorities that I do not recognize. The only way is to start from no assumptions, like a scientific minded person would. I doubt you have the necessary knowledege to complete such an endeavour.
We can cut to the chase though, and you can tell us whether or not you think AGW has been conclusively determined and how specifically that was done (all the dotted letters), if that's what you believe.
Andrew
BA
We aren't having a dialogue because you refuse to engage in one. See above.
BBD,
You forgot to politely address this part:
"We can cut to the chase though, and you can tell us whether or not you think AGW has been conclusively determined and how specifically that was done (all the dotted letters), if that's what you believe."
Andrew
Moving from the behaviour of CO2 in the laboratory to its behaviour in the fantastically complex heat engine that is the atmosphere and the oceans, not to mention interactions with the biosphere, is a journey fraught with enough Scyllae and Charibdi to founder the most intrepid sailors.
=============
Kim
Message in a bottle was a lot simpler than Wrapped around your finger!
BA
Physics and observations are in fairly close agreement. GAT has risen by 0.6C since 1979. An alternative explanation to increasing RF from CO2 has not emerged. You reject the current understanding of atmospheric physics but do not provide an alternative cause for modern warming.
You say:
Share your hypothesis that counters everything known about the physical properties of CO2 and the energy flows into and out of the climate system.
BBD,
You didn't:
"tell us whether or not you think AGW has been conclusively determined and how specifically that was done"
Andrew
BA
GAT has risen by 0.6C since 1979 and increased RF from CO2 is the only well-supported explanation.
Unless you provide a coherent counter-argument, you insistence on 'proof' is meaningless. You can't just demand, you must also provide.
Or it's just yapping in the dark.
Now, back to the interesting stuff.
Tallbloke suggests that decreased low cloud cover, especially equatorial cover, explains recent warming. The problem is that both sources he relies on (Palle's earthshine studies and ISCCP) appear to be unreliable.
Calder rightly points to the issues with ISCCP and argues that this vindicates Svensmark.
Assuming Svensmark to be correct, can the GCR/cloud relation explain recent climate variation? The suggestion is that it cannot (see Oct 8, 2011 at 9:25 PM).
So what remains?
BBD,
These sources are not 'unreliable'.
Tallbloke is making a claim based on a short term trend. Just like the IPCC does - first third (or so) solar, second third aerosols, third CO2 etc. We are all familiar with that right?
The Svensmark theorem is that of a long term trend. We need long term cloud cover data before we can reject it.
BBD,
You (unpolitely) didn't:
"tell us whether or not you think AGW has been conclusively determined and how specifically that was done"
Andrew
P.S. Mr. Bishop Hill, sir... please wake up the Polite Police for they are apparently sleeping on the job tonite for some reason. I'm wondering where they are. They seemed pretty quick to respond t'other day.
BBD sez, "no sane person wants to be right on global warming", and yet we have so many believers fighting so hard to make sure no one doubts they are right on global warming.
BBD: quoting Willis Eschenbach "On average, the earth at the top of the atmosphere (TOA) receives around 340 watts of solar energy for every square metre of the planet (W/m2).
In round numbers, about 75 W/m2 are reflected back to space by clouds. Now, global cloud cover is on the order of about 70%. This gives us about 1 W/m2 for each 1% change in cloud cover, which is conveniently simple.
However, that’s global cloud cover on average, which means little. In the tropics, mid-day surface insolation averages about a kilowatt per square metre, and the amount reflected by clouds is on the order of 340 W/m2.
This gives us a cloud effect about five times as strong as the global average. In the tropics there is a change of 5 W/m2 in reflected energy for each 1% change in cloud cover. This allows for large swings, as I showed in my paper."
The consensus position (as represented for example by the IPCC Fourth Assessment Report) says that solar radiation may have increased by 0.12 W/m² since 1750, compared to 1.6 W/m² for the net anthropogenic forcing.
Have we got cloud data with high enough resolution, with a long enough record, to discount equatorial cloud changes of less than 1% being responsible for the apparent c.30yr warming period? Personally I think the data is not good enough to refute the null hypothesis. Further I think the issue is often clouded by averaging everything, GAT is a useless metric in this regard, especially as the quantification required is hidden in the error bars, also considering the reverse engineering NASA et al have applied to the record.
Quantifying some relevant uncertainty: Quoting "Climate process & change" By Edward Bryant, Edward Arndt Bryant.
"The Earth has undergone substantial short-term climate change since 1975, so that even if the satellite measurements were accurate, there is a degree of variation or noise in the measurements of albedo, longwave emission and cloud that reduces the accuracy of the plotted values. In addition satellite measurements are subject to error and sampling deficiencies. Both of these problems increase towards the poles. At most, the radiation estimates are accurate to +/- 2%. In addition measurements of the average global longwave emission vary between 229 and 244 W/M2. While this range approximates the value of 239 W/M2 required to balance incoming solar radiation absorbed by the Earth-atmosphere system, the 15 W/M2 uncertainty is substantial, being equivalent to the longwave energy transfer between the Earth's surface and the atmosphere due to either convection or turbulence. These errors must be considered, or at least acknowledged, when modelling radiation transfers in the Earth-atmosphere system."
BA
The problem with your question is that there is no eureka moment with large-scale, slowly emerging phenomena like this. What you get is an accumulation of observations that increasingly appear to confirm the hypothesis.
The 'scientifically-minded' understand this, and draw their conclusions accordingly. Obviously, there's a tactical space for an inappropriately reductive demand for a singular 'proof'. But making this demand shows no understanding of the nature of scientific inquiry into the relationship between CO2 and climate change.
Everything hinges on the difference between evidence and 'proof'. The evidence is of course all around you: GAT, OHC, cryosphere, Keeling curve.
However, your chosen position requires that you ignore it all while loudly and insistently demanding 'proof'. This is illogical but it works as a way of closing down rational debate on your own terms. This is not the same thing as being right. A subtle distinction, I know.
Has it ever occurred to you that I am actually far more courteous and attentive to you than your commentary merits? Because really, it should have.
After all, you clearly read nothing, understand nothing, and contribute nothing except a dogged, monotone contrarianism?
So why do I bother? Well, mainly to try and prevent you from confusing others who read these exchanges.
Shub
Why do you not read my comments? Now I'll have to repeat myself with emphasis:
- On ISCCPCalder explains:
- On Palle's earthshine and ISCCP:
Although Tallbloke neglects to provide a reference for this assertion, it is based on Palle et al. (2004) and Palle et al. (2005).
Palle et al. (2004) has been criticised by Wielicki et al. (2005), Evan et al. (2007) and Loeb et al. (2007).
Palle et al. (2005) is critiqued in Bender (2006).
Tallbloke's hypothesis really rests on Palle's claim that:
But it very much looks as though Palle is mistaken. Which is not good news for Tallbloke.
But Shub hopes we have forgotten all this because we are little silly goldfish. That's why he starts off by saying:
Anyone who has been following this exchange should feel duly intellectually insulted by this tactic.
Oh, and I love the way Shub waits for me to go to bed before posting blatantly misleading stuff like this. Another cheap trick. Keep it up - people will get the picture eventually.
BBD said: "No sane human being wants to be right about AGW."
You may be right, but some people think it "would be nice":
as Phil Jones wrote in Jan 5 2009 (email 1231190304.txt).
Frosty
Again, goldfish syndrome. Again, I'm forced to repeat myself:
Tallbloke suggests that decreased low cloud cover, especially equatorial cover, explains recent warming. The problem is that both sources he relies on (Palle's earthshine studies and ISCCP) appear to be unreliable. [Yes, we agree on that]
Calder rightly points to the issues with ISCCP and argues that this vindicates Svensmark.
Assuming Svensmark to be correct, can the GCR/cloud relation explain recent climate variation? The suggestion is that it cannot. [references upthread]
Your argument is: okay, there's no reliable observational evidence that cloud cover change (equatorial or otherwise) is responsible for recent warming. So I will make an absolutely unsupported claim and expect to be taken seriously.
But you won't be, because you ignore RF from CO2. So, junk analysis.
Quoting Eschenbach is completely beside the point until you address the amazing vanishing CO2 forcing. Or do you not believe in all that sort of thing? By the way, what 'paper' is Eschenbach referring to? In what reviewed journal? Or should he have said 'unpublished essay posted at WUWT'?
No BBD,
I didn't post quick responses simply because we'd end up hogging the thread. Moreover the 'unreliabilty' (that's the word you chose) of a data series is a topic by itself.
[1] To declare data as 'unreliable', we need a baseline or a gold-standard against which the particular set can be compared.
[2] Additionally, we need to be able to pin down a specific artifact/step in the method generating that data, to which we can attribute the 'unreliability' to.
Although, we can see that the ICCSP data is different from the rest of the cloud cover series, we can do neither of the above categorically.
Cloud-cover generating algorithms are multi-step processes common to all methods, and there is no accepted gold-standard, yet. If the ICCSP diverges from the rest of the series long enough (which would be a question of judgement), one can perhaps, finally, keep it aside. Or make corrections. Or, vice-versa.
This is what Calder refers to, as the state of the cloud data being "parlous".
Secondly, and more to your point:
I read the thread again. I cannot understand your central claim. It seems to start in a post to lapogus where you put some text in inverted quotes - that is all I can make out.
Are you saying that, since Calder has called the ICCSP trend "unreal", the 'tallbloke hypothesis', which presumably is stated in this post, refuted, because he uses ICCSP data?
I don't know, man, ... you got to let me (and others) know - I don't know how strong a claim Tallbloke's making.
BBD,
If you can't describe a pathway/process to conclusively determining AGW, just say so and save some server bytes and time.
Andrew
Or try to find a fault in this, because afaik no-one else has been able to so far -
http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html
see also:
http://myweb.cableone.net/carlallen/Site/Greenhouse%20In%20A%20Bottle-Reconsidered.html
Shub - 'Tallbloke's hypothesis' was posted back in June:
http://tallbloke.wordpress.com/2011/06/02/what-caused-global-warming-in-the-late-c20th/
No-one really noticed it at the time. iirc BBD was very dismissive of it then, and said it was just a just a rehash of Peter Taylor's Chill.
BA
Sigh. Repeat:
"The problem with your question is that there is no eureka moment with large-scale, slowly emerging phenomena like this. What you get is an accumulation of observations that increasingly appear to confirm the hypothesis.
The 'scientifically-minded' understand this, and draw their conclusions accordingly. Obviously, there's a tactical space for an inappropriately reductive demand for a singular 'proof'. But making this demand shows no understanding of the nature of scientific inquiry into the relationship between CO2 and climate change.
Everything hinges on the difference between evidence and 'proof'. The evidence is of course all around you: GAT, OHC, cryosphere, Keeling curve.
However, your chosen position requires that you ignore it all while loudly and insistently demanding 'proof'. This is illogical but it works as a way of closing down rational debate on your own terms. This is not the same thing as being right. A subtle distinction, I know. " ... etc etc
You really don't get it do you? Do you never have a sense that since you are clearly confused by the science, you should not be criticising it?
lapogus
I am not going to deal with claims that 'there's no greenhouse effect'. Why? Because if there was no greenhouse effect, it would be too cold and we would not be having this or any conversation. I do not have time, or the inclination, to try and work out where these people are going wrong, because I already know that a major error exists.
There are limits to even my patience, you know.
Shub
The first part of your comment is basically what I said, twisted round to make it look as if you are putting me straight. This is either another of your little tricks, or you still haven't understood (or possibly read) my earlier comments.
Yes. TB bases his hypothesis on both Palle's earthshine studies and ISCCP. Both have been robustly challenged. TB's hypothesis is build on the shakiest of foundations. Also, it ignores the RF from CO2. Something common to all sceptical attempts to explain modern climate behaviour. Something I'm not going to let pass unchallenged any more.
Commenters who deny the radiative physics underpinning the greenhouse effect set themselves outside the framework of rational debate.
If you did not - and do not - understand what I was discussing with Lapogus, why did you insert yourself into the conversation? You have confused the matter. But ah! Of course, how silly of me.
lapogus
As far as I can see, TB's hypothesis is essentially Taylor's, although Taylor invokes ocean oscillations and variation in TSI as well as solar UV and EMF.
From Chill, p 217:
@ BBD - There are limits to even my patience, you know.
But not arrogance.
BBD
I don't have time for your nonsense either: the first part of my post above is the exact opposite of what you said.
If we are to reject or accept a short term cloud cover decrease, we need a gold standard. We don't have one.
This is exactly what Calder says.
There are those who use the purported cloud cover decrease to argue against Svensmark. There are those who use the purported cloud cover decrease to argue for a direct solar heating of the oceans. Who knows?
For a skeptic, people who argue with short term data are a distraction.
In order to reject Svensmark, we need much longer, good data than the Agee et al presentation - I would like you saying anything against that. Just try it.
Tallbloke's hypothesis, if correct, is exactly like the IPCC approach - different reasons for different multi-decadal trends. Big deal. The very fact that such explanations exist, speaks to the fact that multiple influences can have more or less the same magnitude of observed effect on the 'global anomaly' equal to CO2.
Shub
Look carefully at the figure Calder provides from Arndt et al. (2010).
There are two outliers: ISCCP and PATMOS-x. Everything else runs close to the zero anomaly. Arguing for a 'gold standard' etc is a red herring. You argue from the available data, and the data are most consistent on there being only minor variation in cloud cover.
TB is probably wrong. Svensmark is probably right, but as has been shown, GCR/cloud effects are very slight and do not have a significant influence on climate.
First, I'm not 'rejecting Svensmark'. You are muddling again. You seem to have missed this, so I'll repeat:
GCR/cloud hypothesis as driver of recent climate change?
- Sloan & Wolfendale (2011) (full); (abstract):
- Pierce & Adams (2009) (full); (abstract):
Do you see now? GCR/cloud effects may be real, but they have had no significant effect on climate over at least the last century.
And the evidence for climatically significant reductions in low cloud as an explanation for recent warming looks weak.
lapogus
How is it arrogant to say that stuff posted on the internet does not and will not overturn decades of vigilantly scrutinised work on the role of CO2 in atmospheric heating.
Why is it arrogant to pose a demonstration: no greenhouse effect = freezing surface?
Why is it arrogant to refuse to chase down yet another rabbit hole when the conclusion is foregone?
To me, it is arrogant to suggest that this stuff should be taken seriously in the first place. To do so is to dismiss, out of hand, a significant body of work which isn't even controversial except amongst 'sceptics'.
BBD
You are obsessed with 'explaining the 20th century warming'. You believe that others share that obsession. You also believe in an IPCC approach - quantifying 'forcings' and arguing from incredulity. Secondly, you editorialize unnecessarily. 'Arrogant' is what it looks like. For eg, you posted that I wait until you go to sleep. How do I know when you go to sleep?
Thirdly you could use your own words to explain your position. Posting bits and pieces of abstracts or papers is useless and unimpressive.
This is where you and I differ. I prefer not to say anything with short-term data. You believe in shooting one's mouth off, today. Then saying another thing tomorrow etc.
What is "short-term" and what is "long-term" is again a matter of judgement. Half a decade of divergence (as per Agee) is not enough to dismiss Svensmark. For the idiotic consensus on the other hand, apparently, decades of divergence between sets of data (tree rings, satellites) are still ok.
Even if one trusts that the ICCSP is wrong, if one carefully observes the trends during the various overlapping intervals between ICCSP on the one hand and PATMOS on the other, there are periods where the trends match up, even as the absolute values for the cloud cover anomalies dont. PATMOS does show a decline in cloud cover starting from 1994 to 2003, for example. It can be understood that a system would generate 'false' absolute values but capture trends with some accuracy. In other words, consistency in error can be expected, if the ICCSP method generates cloud cover using a method that is reproducibly affected over a period of time.
Of course, your attempts to force commenters here to defend 'tallbloke's hypothesis' just because they are 'sceptics' is weird, and reflects more on your adopting a stupid classification scheme for people, rather than any real scientific argument. If you think Agee et al + Calder's position beats tallbloke - you should be telling that to tallbloke.