More Interesting Global Warming Research
By ehosterman Posted in Archived — Comments (19) / Email this page » / Leave a comment »
Credit to "Planet Gore" blog in National Review on-line fro uncovering this study by Stephen Schwartz of Brookhaven National Lab. http://www.ecd.bnl.gov/steve/pubs/HeatCapacity.pdf
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The study is based on statistical analysis of actual temperature data, not computer climate models. In short, the study finds the climate forcing function for CO2 to be much lower than the IPCC study and the time constant for climate change in response to CO2 changes to be on the order of 5-7 years.
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Net result, effects of CO2 on climate are much less severe and shorter acting. Haven't completed reading and digesting the paper, just putting it out there for comment.
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Let the games begin.
Somehow, in the AGW universe, future predictions from computer models that can't predict current conditions from past data (all knowns) are more reliable than studies performed on actual data
95% of all statistics are worthless.
Data, Statistics, reading tea leaves, bones, etc are not relevant.
What is relevant is consensus.
When the consensus changes, the weather will change along with it.
is not what I would call this. It's a signal, or frequency response, analysis. Coupled global climate models will do the same thing, using much more complex (and realistic) ocean transport models. Because of the complexity, it is a very good thing if someone tries to strip it down to the basics, and see what the response to the observed signal is, and what we can learn from it. It is a reality check, not a replacement. And I think this is what SS has done.
Frequency response analysis is what you do when you hit a bell with a hammer, and fourier analyse the sound. The trouble here is that the Earth hasn't been hit with a hammer, just some small taps from volcanoes etc, and AGW, which in signal terms is more like being hit with a gust of wind. It's hard to sort the frequency response from the noise.
The main thing SS has found which disagrees with the GCM conclusions is that the time constant to equilibrium is much less (5 yr). That doesn't affect how the climate system will respond to what it will probably get - sustained added radiation. It does affect how it would respond to a sudden cessation of carbon burning.
FWIW, my theory of the discrepancy is this. SS infers a high figure for added radiation load in C20(1.9 W/m2), and a low figure for how long heating would go on if we suddenly stopped. I think this results from his implied assumption of rapid mixing in the ocean. That means that it absorbed more heat to get to where it is (the 1.9), but is closer to equilibrium than GCM models predict (hence the low 5yr)
As I understand it we are 100% sure that there is global warming. However there is much debate over how much of that warming is man-made.
Let's say for a moment that we were 100% sure all of the global warming was coming from humans. How would you feel about paying $.50 more per gallon of gas as an economic incentive to not drive as much?
of the tax in reducing climate change. My view of the demand for gasoline is that a $0.50 tax will not reduce demand at all. Additionally, even if it did reduce demand marginally, the reduction would have negligible effect on affecting climate change (even if we accepted that all climate change was manmade). Based on those assumptions, I would not support an increase in the gasoline tax. It's that old cost - benefit tradeoff.
to mix ethanol with gas? Paying more than a $1. more for a gallon of milk cause of higher dairy cow feeding costs. Tortillas not dirt cheap anymore.
Yet the brown haze over India and China as a result of dung and wood burning raises temperatures significantly there akin to the urban island affect. Going to coal, oil and gas would clean up this part of the world.
If the Crichton analogy holds true, then about 1/4 in is carbon dioxide. 80 yards is nitrogen out of a football field analogy. Do these global warming types ever take into consideration basic elementary school science that plants convert co2 back into oxygen?
No, I pay entirely too much under the current rate of gas taxation.
...a long habit of not thinking a thing wrong, gives it a superficial appearance of being right...
---Thomas Paine---
Question: Why do you think that your tax will work? Gasoline is usually considered a rather inelastic product.
...a long habit of not thinking a thing wrong, gives it a superficial appearance of being right...
---Thomas Paine---
"True Believers" in AGW shouldn't mind paying higher taxes.
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"Enlightened statesmen will not always be at the helm." -- James Madison
As you say, it's long, takes a while to absorb, and it is 9 am where I am. Still, I read some different messages in it from what NRO's Joel Schwartz deduced.
It's not a statistical analysis, it's a time series (signal) analysis. Although it is suggested that it is quite different to the climate model approach, there are implied spatial models. Essentially he simplifies these so that he can get more out of the signal analysis. That a reasonable trade-off to try, but you need to be aware that it is happening. He is assigning an effective specific heat to the ocean (and to the atmosphere, continents etc), and treating it as in effect, a well-mixed block with heat transfer coefficients. That is where his time constants come from.
In fact, heat transfer in air/ocean is more diffusive, and a simple time constant (or heat transfer coefficient) doesn't really apply. I found that the most doubtful part.
There is actually quite a lot of agreement with GCM-based AGW. The figure that stood out to me was his estimate of GHG radiative forcing of 2.2 W/m2, with an estimate of 1.9 as the 20C average. That is in close agreement with the IPCC figure (2.5). His chief point of disagreement is the short time constant of about 5 yr. But I think the coupled air/ocean climate models take a lot more of the diffusive complexities into account.
I'm still reading, and I agree with EH that this is an excellent paper to discuss. It's no anti-AGW screed, though, and I'll leave for the moment with his final sentence:
The estimated increase in GMST by well mixed greenhouse gases from
preindustrial times to the present, 0.7 ± 0.3 K; the upper end of this range approaches the threshold for "dangerous anthropogenic interference with the climate system," which is considered to be in the range 1 to 2 K
sensitivity to the climate forcing functions leading to much lower estimated temperature increases for a doubling of CO2, as well his much lower time constant.
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I would tend to agree that this is not a statistical analysis, as I first stated. At the time I had only read the abstract and badly misinterpreted his analytical methods. While he does treat this as a signal analysis, I would characterize in more like a time dependant series of one dimensional heat transfer analyses.
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When you discuss heat transfer within the ocean and atmosphere as "diffusive", you refer to convection, I would tend to agree, although in the short run, the ocean temperatures would be subject to signifcant stratification. I believe this would tend to support the short time constant as the portions of the ocean in direct contact with the atmosphere would tend to remain closer to the temperature of the air , than if the whole mass were well mixed.
His low estimate of the time constant leads to the lower sensitivity, calculated as (time constant)/(heat capacity). I would worry about this - as I mentioned above, he's deducing the time constant from the response of a GMST signal with small identifiable forcing, so lots of noise. But another worry is that he detrended the GMST signal, and without detrending, the time constant was about three times longer, which puts the sensitivity right in the IPCC range. He discusses this at the top of p14, acknowledges the issue, but decides to proceed with the detrended data, basically because he finds inconsistencies if he doesn't. As he points out, detrending is a high-pass filter which amplifies the short-term response, biasing towards a short time constant. I think his inconsistencies without detrending are real, result from low resolution of the longer term processes, and detrending just throws out the poorly resolved longterm effects leaving the better resolved short-term effects, and so, presto, a short time constant.
In the "diffusive" issue, yes, I mean that the sum of convection, turbulent diffusion etc, leads to a diffusion-like dependence on sqrt(time) rather than on time, which is why the time "constant" may be rather variable. He actually discusses the stratification question in some detail when talking about evaluating the ocean heat content.
Hot winters are cool. Pave the world. Birds are stupid. Bees aren't important. If we run out , we can buy some from China on credit.
Liberalis Trivialis Absurdum.
Best characterized by its extreme need to trivialize the concerns of people that it disagrees with. Also well known for shouting down opponents and attending Howard Dean rallies.
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-Thomas Paine: The American Crisis, No. 4, 1777
teeth one finds over 100 miles inland in NC, SC and GA.
case closed
Sun, sans man, warns earth 1 million times more than all the SUVs man can produce.
I probably understate the case for the Sun.
Mike Gamecock DeVine @ The Charlotte Observer
www.race42008.com
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www.theminorityreportblog.com
"One man with courage makes a majority" - Andrew Jackson
being invalid.
Of course seeing as we don't yet understand the system that argument falls flat.
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"Those who expect to reap the blessings of freedom must, like men, undergo the fatigue of supporting it."
-Thomas Paine: The American Crisis, No. 4, 1777