Pekka
Yes. The authors are very careful not to describe the observed change in cloud cover as a “feedback”.
Nowhere in the paper is there a mention of a “mechanism”, which caused this change in cloud cover and reflectivity.
It could just as well have been a separate “forcing” (e.g. Roy Spencer).
Hasn’t the “Chief” also discussed the role of clouds as a separate “forcing”?
Max
Max said:
“That a reduction on cloud cover over this period resulted in 2.3 Wm-2 added warming of the Earth’s surface…This seems to reopen the question raised by Roy Spencer of clouds as a significant climate forcing.”
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Not unless the paper is claiming that the change in cloudiness represents and external forcing on the climate (versus a response to some external forcing). And you also forgot to mention (but the paper did not) that the reduction in cloudiness also also more LW from the surface to escape back to space. No assumptions can be made about the net effect of this reduction in cloudiness on either near surface tropospheric temperatures or net gains to the Earth’s overall energy system. If the reduction is cloudiness is causing the Earth system to retain more energy, then we have might have a positive feedback with clouds to an external forcing, and Hansen’s warnings should be listened to.
True…the ‘hockey stick’ isn’t about the future its an admission by Michael Mann:
The suspicion is in the air nowadays that the superiority of one of our formulas to another may not consist so much in its literal ‘objectivity,’ as in subjective qualities like its usefulness, its ‘elegance,’ or its congruity with our residual beliefs . (William James)
The “Chief” is part of a group of Australian pranksters trying to mock any attempt at rational scientific discussion.
Skeptical
Don’t pontificate too much about “paid advertisements” and “lack of morals and honor”: one could argue that the whole AR4 report of IPCC was nothing more than just that (and AR5 will be more of the same).
An “advertisement” for the IPCC CAGW message, “paid” for by the politicians of this world with funding from the taxpayers.
Right?
Max
Tony B. “thought you might be interested in this 1939 article concening a 16 year cycle.”
Thanks for the link, but I’d rather not get distracted into other discussions for the moment. It looks like Vaughan is slowing starting to realise how realistic his millikelvin claims are so some progess is being made and I’d like to concentrate on the subject of this thread until we get some conclusions on the value of his presentation.
Do you have a machine with Excel on it?
“so the fact that it agrees with Usoskin 2005 is nothing unusual.”
So when the Usoskin 2005 abstract says:
The long-term trends in solar data and in northern hemisphere temperatures have a correlation coefficient of about 0.7-0.8 at a 94% – 98% confidence level.
You are saying this is meaningless?
lolwot
Read the studies I cited. They all come to basically the same conclusion, as I stated, namely that around half of the past warming can be attributed to the unusually high level of 20th century solar activity.
Max
Max said:
“It could just as well have been a separate “forcing” (e.g. Roy Spencer)”
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Clouds are not going to be external forcings to the climate system. Roy Spencer was wrong then and would be wrong now if he implies this Clouds respond to and provide feedbacks (positive or negative) to external forcings. The only issue with clouds and AGW is whether or not they will provide net negative or positive feedbacks to increases in GHG’s concentrations. The mere observation of a reduction in SW reflective cloudiness & aerosols over a several decades does not answer this question. If it turns out that a reduction in cloudiness adds more net energy to the Earth system (that is, more SW energy comes in than LW energy is let out), then we might indeed have a positive feedback from clouds responding to the external forcing of rapidly increasing GHG concentrations, and Jim Hansen’s warnings should be listened to with utmost attention.
.
Everything, nominally, is related to the Sun.
Yes, Spencer is a fan of the idea that forcing can’t be separated into internal and external components, and that clouds have some spontaneous way of changing the forcing by themselves. This was the crux of the argument with Dessler when the connection of cloud feedback to ENSO, implied by Spencer’s logic that clouds could force ENSO. The argument stopped at that point.
JIm,
I noticed that the SAW had a period equal to the number of years in the data but it didn’t even come to my mind that this would be anything else that accidental. Whether the value is really fitted or only selected as it leads to roughly the right period and happens to agree with the number of years in data the period represents one free fitted parameter for me to be counted with the same weight as other free parameters.
How many effective degrees of freedom are used in selecting the sawtooth as starting point is more difficult to tell.
Jim D. said:
“Yes, Spencer is a fan of the idea that forcing can’t be separated into internal and external components.”
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Interesting notion if that is indeed what he believes.
Jim Cripwell
Yes. I agree with you that trying to convince lolwot that IPCC may have overstated confidence in AGW in AR4, and may be doing the same in AR5, is a basic waste of time, as he already has his mind made up that this cannot be the case.
I was simply trying to open his mind to something outside his belief system.
But, as you say, this might be an impossible task.
Max
That’s a bit questionable because there’s very little contribution by any climate scientist to this thread. Leif Svalsgaard might be one exception and I may have mistaken on someone but otherwise the contributions are by people whose background is in other fields (other sciences for some and non-scientific activities for others).
There is a lot of curve fits and models and most were created with instrumented data of the past 130 years. Curve fits made during a warming period between the little ice age and now. If the data for the past ten thousand years was curve fit, it would show a warm max about now with a cool period to follow.
You find the same thing in any prisons and communist countries — lots of smart secular socialists who know they’re smarter than everyone else look upon the rest of us like their prey.
manacker
This all does not change the fact that it has not warmed globally over the past 12 to 15 years despite unabated emissions of human GHGs.
You cannot say this. Some records show warming. Your absolutism is at variance with the evidence. It is not a fact and some records show warming. Things that follow logically from this:
- You will have to stop making factually inaccurate claims.
- You will have to acknowledge that nobody ever said natural variability would stop because of AGW.
- You will have to acknowledge that this means monotonic warming is nothing more than a contrarian strawman.
- You will have to acknowledge that the recent slow-down in warming is consistent with natural variability.
- You will have to acknowledge that it in no way ‘falsifies’ AGW.
- You will have to acknowledge that making such a claim – implicitly or explicitly – is simply denialist rhetoric, not scientific analysis.
- You will have to acknowledge that you have been using this denialist rhetoric incessantly in comments here.
