If you agree with the no-feedback response of 1 K, is one conclusion inescapable?
That conclusion being that the climate sensitivity for 2xCO2 is between 2 and 4.5 K? Or at the very least that feedbacks will provide a net amplifying effect?
Lindzen and Spencer's hypothesis sounds great, but an insensitive climate system is *not* compatible with past climatic fluctuations -- the transitions to and from glacial periods, for instance.
Portland,
Newer studies suggest that Lindzen and Choi 2009 made some serious errors
http://www.cgd.ucar.edu/cas/Staff/Fasullo/refs/Trenberth2010etalGRL.pdf
And I have no idea why denialists continue to bring the 'lag' up -- it was discovered by climate scientists, and it's integrated into climate sensitivity estimates.
You also bring up Chilingar et al., which is perhaps the *worst* paper on the GHE I've ever seen. They make error that freshman atmos students could pick up.
The fact is that an insensitive climate system cannot explain the transitions to or from glacial periods.
"IPCC Climate Models failed to predict no warming for the first decade of this century."
1) This is not true. Individual model runs predict periods of flat temps lasting a decade or more.
2) I don't think the last ten years have been flat. I explain why in my answer here
http://answers.yahoo.com/question/index;_ylt=Akai9lMHhbmJL2LbjBha5VPty6IX;_ylv=3?qid=20100423130055AA4F9fB&show=7#profile-info-4ec5baf736e5e1b4200f6e39ea8eda12aa
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"In other words you are assuming two steps forward two steps back is the only type of negative feedback that can exist. Whereas a two steps forward one step back system can also exist."
That's not at all what I'm assuming, Eric. What you and Lindzen are hoping for is 1 step (forcing from CO2 alone) + 4 steps (positive feedbacks) - 4 steps (negative feedbacks). In reality, to be able to explain past climatic fluctuations, it has to be more like 1 step + 4 steps - 2 steps, i.e. a net amplifying effect, not a net dampening or net neutral effect.
Perhaps in the longer term (several thousand years), as CO2 levels are drawn down due to carbon burial by the biosphere, the climate will take a few more steps back, but on the scale of decades to centuries, feedbacks will act to amplify the forcing from CO2.
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Eric
"Are you saying that the Iris Effect relies on a positive and then a negative feedback? "
.....No. With the initial warming from CO2, there will be positive feedbacks (water vapor, surface albedo, methane release, etc). Lindzen thinks clouds will completely (and more) counter those positive feedbacks.
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Portland,
"Looking at the extremes of 2 sigma to say there is a small chance that your CO2 sensitivity theory might be true despite the data is not very convincing."
--That's not what I'm saying. Short term 'pauses' in rising temperatures do not invalidate "CO2 sensitivity theory' anyway, BUT we can't even say that the temperatures have paused with any confidence. And I'm not sure what you're talking about with regards to the links. Trenberth et al. (linked above) show that Lindzen09's calculations were completely wrong.
"I would enjoy your critique of the paper, but you seem to prefer an Ad Hominem attack against the author rather than a valid critique."
--Saying a paper is incredibly bad (and it is) isn't an 'ad hominem' attack against the author.
Your discussion of models in nonsense.
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Portland,
"Our best our best data (first link under sources) indicate they have."
Eyeballing the graph and saying that temperatures have flattened is not analysis. In the link I give I above I explain why, statistically speaking, that we cannot say with any level of confidence that trends have flattened or even slowed.
"No, they do not. What they do is say:"
Did you even read the paper? If you'd actually read it, you'd see that they do say that LC09 contains *serious* flaws. They sum up their results in the conclusion:
"As shown here, the approach taken by LC09 is flawed, and the results are seriously in error."
After corrections to Lindzens methodology, they arrive at a sensitivity within the IPCC range.
"Is an attack on the author."
No. It's an attack on their paper. It's not an ad hominem if they actually make errors that a freshman atmos student would make. I won't go through a whole rebuttal here, but beyond the strange assumptions and some of the equations...
CONTINUED
I'll pose a simple question: The rate of convection is in part determined by the surface temps; what determines the surface temps? (Hint: Not incoming SW alone). Many of their equations are fundamentally wrong as well. I could go into more detail if need be.
"Allow me to relieve you of that myth:"
--Yeah, I don't think seasonal forecasts are very good, either, but that's a different creature altogether.
Let's just get this over with. Chilingar's equation (3) does not apply to Earthly conditions (i.e. with gravity), thus the rest of their paper is null.
QED
"The point that I wanted you to notice is the increased role that vertical convection may have as a negative feedback mechanism as the earth warms. "
This isn't what Chilingar shows. Through some strange computations Chilingar derives the 'Adiabatic Theory of the GreenHouse Effect'. From there they assume that the only temperature change due to increased CO2 is from the pressure change due to increased CO2, which would obviously be negligible, but that's an idiotic calculation.
Their 'adiabatic theory' is also wrong, as I've explained.
And increased convection isn't some 'saving grace' -- it's known and accounted for in things like the lapse rate feedback, which is included in sensitivity estimates.
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"Agreed, you really do need fancy analysis to explain away what is obvious. Still, if you want to go there, check out the BBC link in Edit2."
Not that fancy. All trend estimates contain error, and serially correlated data increases that uncertainty. I've read Phil Jones interview, and it seems all denialists don't understand what it means.
"Then, there is the expectation that forecasts for periods long enough to be called climate would be better."
--Yes. Individual model runs differ greatly in the short term, but longer run's are nearly identical. Multidecadal climate does not exhibit sensitivity to initial conditions.
"Except for the fact that the earth did not go off into the stable warmer equilibrium anytime in the last 300 million years. "
The climate system is essentially run by negative feedbacks -- in the long term (geologically speaking). Net negative feedbacks on the scale of several thousand years CANNOT explain things like the PETM event, glacial periods, D-O events, etc.
In a few thousand years, long after we've weaned ourselves off hydrocarbon fuels, a largescale drawdown of atmospheric CO2 will take place through biological processes, our orbit will become increasingly elliptical, and the planet will ultimately cool. BUT, until then, the planet will warm, and positive feedbacks will dominate.