From the press package:
The findings confirm that carbon dioxide is the most potent greenhouse “control knob”
This seems like a last ditch effort (in the face of falling public opinion) from Gavin Schmidt et al. to make CO2 more important than water vapor in regulating the temperature of the planet.
Via emailed press package, embargoed until 2PM EST 10/14/2010:
Of all the greenhouse gases in the atmosphere, carbon dioxide exerts the most control on Earth’s climate, researchers report. Although carbon dioxide’s greenhouse effect has been known for more than 100 years, its primary role in climate warming is still not universally acknowledged.
For example, water vapor is a powerful greenhouse gas and is more abundant in the atmosphere than carbon dioxide. But, it condenses and precipitates from the atmosphere and thus plays a different role than carbon dioxide and other, noncondensing greenhouse gases, such as ozone, methane and chlorofluorocarbons. Andrew Lacis and colleagues conducted a set of idealized climate model experiments in which various greenhouse gases were added to or subtracted from the atmosphere, in order to illustrate their roles in controlling the temperature of the air.
The findings confirm that carbon dioxide is the most potent greenhouse “control knob” and that its abundance determines how much water vapor the atmosphere contains. Without carbon dioxide, the Earth would plunge into a frozen state, the researchers report, though they caution that increasing levels of this atmospheric gas are also worrisome. “This makes the reduction and control of atmospheric CO2 a serious and pressing issue, worthy of real-time attention,” they write.
[Seems a bit out of balance though.]
- Fig. 1. Attribution of the contributions of individual atmospheric components to the total terrestrial greenhouse effect, separated into feedback and forcing categories. Horizontal dotted and dashed lines depict the fractional response for single-addition and single-subtraction of individual gases to an empty or full-component reference atmosphere, respectively. Horizontal solid black lines are the scaled averages of the dashedand dotted-line fractional response results. The sum of the fractional responses adds up to the total greenhouse effect. The reference atmosphere is for conditions in 1980.
Article #14: “Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature,” by A.A. Lacis; G.A. Schmidt; D. Rind; R.A. Ruedy at NASA Goddard Institute for Space Studies in New York, NY.
Contact: Andrew A. Lacis at alacis@giss.nasa.gov (email).
Here’s the paper: lacis101015 (PDF)
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DR. Spencer,
And then they completely ignore the influence of the biosphere. This is nothing, it is worthless excercise in varying model parameters without any link to actual processess in the wild. If you remove CO2 from the atmosphere, plants will shut down photosynthesis. Below 180 ppm, no net photosynthesis will exist. Animals will die, the entire ecosystem, except for the hot vent related organisms, will stop. We are with current CO2 levels, in the low range of what plants need to thrive. And since plants form the basis for any other form of life on this planet………
If a knob wants control, does that make him a control knob?
Without carbon dioxide, the Earth would plunge into a frozen state.
And all plants would be dead. Which just might leave a mark.
Just sayin.
To Roy Spencer and Andy Lacis, re above: If we differentiate Stefan-Boltzmann, and invert dF/dT, we get dT = dF/4 x sigma x T^3. Using 3.7 W/m^2 as the forcing, sigma = 5.67, and T = 255, the temperature change calculates out to 0.98 deg C. This would be the change at the hypothetical “radiating level” with a temperature of 255 K, but an unchanged lapse rate would then require the surface temperature change to be the same. The cited change at the surface is 1.2 C, which suggests that earlier assumptions of an unchanged lapse rate for “no feedback” calculations were not followed exactly in the current estimates. That may make sense (for example, invasion of stratospheric coolness into the upper troposphere could elevate the lapse rate vis-a-vis the rate that prevailed before a CO2 doubling), but in any case, it seems to me that some deviation from either the ordinarily accepted forcings or the unchanged lapse rate assumption woud be needed to arrive at 1.2 C. Is there some other explanation?
So about this knob idea. Let me clarify my understanding.
Without knobs, the temperature would be freezing.
Is there a general consensus that the temperature of the atmosphere is determined by the knobs?
If you turn the knobs clockwise, does it get hotter?
Which came first, heavy breathing, or knob twisting?
Are there greater and lesser knobs?
How many people would vote for removing knobs?
If the knobs are too big, should they be taxed?
And the most important one, is there a difference between natural knobs and manmade knobs?
A Lacis says:
October 14, 2010 at 3:27 pm
“It is discouraging that most of the commentators here appear to be lacking enough of a basic physics background to comment intelligently on the global warming problem. The world that we live in operates according to the laws of physics, you know. You will do better in understanding global warming if you pay attention to the physics involved.
===================
My nomination for quote of the weak. ;)”
I second!
Bait in the water! Bait in the water! Frenzy! Frenzy!
RE: Patrik’s vacuum chamber (at 1:00 and 1:05)
Have you asked the question you intended to?
Temperature is usually thought of as a measure of the average energy of motion of particles of matter. What is in your chamber?
A Lacis
Hey A, there are plenty of us on this board with advanced science and engineering degrees and more importantly the ability to reason. I have a PhD in chemistry, how about you?
Anyway, real physics experimentation involves more than dry labbing it! Proving a model with a model involves a little circular reasoning, don’t you think?
Roy Spencer says:
October 14, 2010 at 4:54 pm
John Christy and I looked through this paper, and agreed that it seems to *imply* that we should worry about global warming from more CO2 because the climate change from a 100% *removal* of CO2 from the atmosphere has 8 times the effect as a 100% *addition* of CO2 to the atmosphere.
If that line of reasoning doesn’t make any sense to you…..then join the club.>>
Ah, but it DOES make sense. The paper wasn’t written for you, or for anyone with any background in science for that matter. It was written for the press, public and politicians who do not understand what “logarithmic” means. Claiming that the effects of CO2 are so large that removal of the trace amounts currently in the atmosphere would cause an ice age gives the impression that a small amount more would have as big an effect, but doesn’t actually say so. It is perception management, not science.
That said, I think the knob analogy should be endorsed rather than ridiculed. Why? Because it is the perfect opportunity to provide a simple explanation that almost anyone can understand and exposes to them how they have been deliberately misled. It goes like this:
Yup, CO2 is exaclty like a control knob. Its not one of those digital control knobs though that is calibrated to specific values at specific settings. There’s no microprocessor in the climate system checking the settings. It is more like a water tap in your shower. Turn it all the way off, and no water flows (ice age). Turn it “on” a quarter turn, and you get water, lots of it. Turn it on a half turn, and the flow rate goes up perhaps 20%. By the time you get to a full turn, almost no increase happens, and the next few complete turns that open the valve as far as it will go make even less difference. That’s what “logarithmic” means, that’s why turning it down from 1/4 on causes a huge difference (ice age) but turning it up from 1/4 on is close to meaningless.
Not to mention that using an “ideal model” which ignores so many variables is like me telling my wife that flushing the toilet won’t have any effect on the temperature of her shower. Good way for me to get a smack with a wooden stick. With a knob on the end. I’d complain to the police but she would just claim that the knob on the end of the stick was me, and show them a computer simulation of a stick hitting a knob with my name on the knob which would be proof of her theory. After the police left she would hit me on the knob with her stick with a knob and tell me that if I ever flush the toilet while she is in the shower again, she’ll cut my knob right off. I’m rambling here…oh yeah, overdue for my medication. Its in the bathroom cabinet, the one with the white knob… gotta go pull that knob.
Some posters have lamented that most of the others are not addressing the main point of the Gavin paper; rather they are making jokes, knob jokes no less, and otherwise engaging in ad-mominem attacks. It would be helpful if someone with skill in the craft would post a link to a definitive analysis showing why Gavin’s model is wrong.
Just stop right there. Can’t perform experiments with models.
I think they were just trying to settle the age-old question of how much of the 33K greenhouse effect can we attribute to CO2, H2O, and other GHGs etc.
We can probably just quote these numbers from now on (previously there has been lots of varying numbers used).
But we should also keep in mind that global warming theory assumes that CO2/GHGs also controls virtually all of the H2O and clouds as well.
Without CO2/GHGs, there is only about 10% of water vapour left. You can see this in the idea put forward by the authors that if we removed all of the CO2, then the Earth would be frozen. Frozen with hardly any water vapour that is.
So we can quote that water vapour is 75% of the greenhouse effect, but we should understand that the 3.0C per doubling of CO2 proposition is based on a theoritical framework where that 75% is (90%) controlled by the CO2/GHG levels.
I would also comment that the study did not take into account the short-wave solar irradiance absorption of the same gases. Clouds, for example, are 25% of the greenhouse effect, but the amount of sunlight they reflect actually reduces the total energy/temperature at the Earth’s surface. The negative is bigger than the positive. (Next study should be to start netting all these impacts out so we have a better understanding of each individual gas).
That and we really need to nail down how water vapour actually changes (in reality, not in a climate model) to changes in temperature and changes in CO2/GHG levels.
” Andrew Lacis and colleagues conducted a set of idealized climate model experiments…”
That’s the take-away phrase. And, to my ignorant mind, with only 18 years of formal education, that phrase translates into this: “We took on of our beloved computer climate models, finagled the constants which we use in place of the subroutine(s) dealing with the highly complex relationship of water vapor to temperature, the water cycle generally, and everything else which we do not presently have anything resembling a scientific thought about, and produced these computer runs, which we are treating as if they were data from the real world.”
Did I miss something?
At the risk of violating WUWT’s commenting rules, the only “knobs” in this business are the ones in Washington who want to get their hands more fully around our necks, so they can squeeze more tightly. My apologies if that’s a violation.
So, in a nut shell, “Andrew Lacis and colleagues conducted a set of idealized climate model experiments” and discovered…knobs. These men have to get out more.
OXYMORON = “idealized climate model experiments”. This encapsulates one of the major problems with this field. Analyses after analyses with unvalidated models, unconstrained by empirical evidence (except when it’s convenient).
Roy Spencer says:
October 14, 2010 at 4:54 pm
Dr. Spencer. I have a policy, after the great Marx [Groucho] that I would not care to belong to any club that would have me.
Having said that I have to admit that you and Dr. Christie do have a most cogent point. With which I largely agree.
I am not joining your club mind, I prefer to remain baffled, bemused and bewildered all on my lonesome.
Kindest Regards
I learned a new term today. But I was talking about temperature knobs, not my momma’s knobs. However, I also wasn’t raised by my momma. My grandma raised me. She was in silent movies, and she had bodacious …um …er …temperature control devices.
Johannes Rexx says:
October 14, 2010 at 6:39 pm
Huh? They illustrate their “model” with a freakin’ cartoon, and we are supposed to respond to this as if it is data? It’s just Lysenkoism posturing as science beneath a garb of gobble-de-gook and made up jargon.
Science=hypothesis===EXPERIMENT==refinement===new hypothesis===repeat as necessary. Models are just hypotheses that remain as such until tested by experimentation. An untested hypothesis remains an untested hypothesis. Anyone can come up with them, and that ain’t science.
New Climate Fight, Same as the Old One?
ANDREW C. REVKIN
http://nyti.ms/chr08F
“The decade-long effort to pass comprehensive climate legislation framed around a declining cap and trading for carbon dioxide emissions died an ignominious death.”
Congratulation to all who opposed this policy, as it was not based on the observed data.
http://bit.ly/cuMYIz
The purpose of the climate legislation was to reduce global warming by reducing human emission of CO2. However, the data clearly shows there is NO relationship between human emission of CO2 and global warming.
Here is the observed global mean temperature trend for 90-years from 1910 to 2000:
http://bit.ly/bylFMq
1) Global warming rate of 0.15 deg C per decade from 1910 to 1940, which gives a global warming of 0.45 deg C during the previous 30-years warming phase.
2) Global warming rate of 0.16 deg C per decade from 1970 to 2000, which gives a global warming of 0.48 deg C during the recent 30-years warming phase.
3) Slight global cooling from 1940 to 1970.
As a result, the effect of 60 years of human emission of CO2 between the two warming phases on the global warming rate is nil.
Also, the effect of 30 years of human emission of CO2 during the global cooling phase from 1940 to 1970 is obviously nil.
The data above describes the global mean temperature trend for 90 years until year 2000.
What is the global mean temperature trend since 2000?
4) Since year 2000, the global mean temperature anomaly trend is nearly flat at 0.4 deg C as shown in the following plot:
http://bit.ly/aDni90
In conclusion, man-made global warming is not supported by the observed data.
According to the data, according to the apolitical science, the effect of human emission of CO2 on global mean temperature is NIL.
The biggest scare of our lifetime is coming to an end soon. Congratulation to all!
Girma Orssengo, PhD
Johannes Rexx says:
October 14, 2010 at 6:39 pm
“It would be helpful if someone with skill in the craft would post a link to a definitive analysis showing why Gavin’s model is wrong.”
There is no need to show why a non-starter is a non-starter. After all, it is a non-starter.
So if the knob is our center of attention now, we need to focus on knob controls and reductions. And is it just me, or are we about ready to change yet again from the passe terms of “global warming”, “climate change”, and “climate interruption”, to…wait for it…
“Manmade …” …okay…I can’t say it. And I’m quite sure I would be snipped if I did.
Johannes Rexx says:
October 14, 2010 at 6:39 pm
It would be helpful if someone with skill in the craft would post a link to a definitive analysis showing why Gavin’s model is wrong.
Not claiming any “skill”, but if “wrong” means contradicted by real data, then – unless Gavin’s model is inconsistent with the other GCM’s – perhaps because real data does not indicate the presence of a Tropical Tropospheric Hot Spot, the “fingerprint” of CO2 AGW?
JPeden, if they are just now discovering the knobs, it is no wonder they haven’t found the elusive Tropical Tropospheric Hot Spot.
Actually I have to take issue with Roy Spencer and those agreeing with him. Reducing CO2 100% is certainly going to cause more cooling than doubling it will increase heating. This is because there are indeed certain frequencies where CO2 absorbs and H2O doesn’t. At the present CO2 levels, these bands are mostly saturated.* So if you remove all CO2 these bands will be open and radiation will be able to escape, while doubling CO2 will cause much less increase in absorption.
* Some caveats should be observed such as widening of bands from pressure in the lower atmosphere and in general from the relative velocity of the molecules in the atmosphere. Also at many frequencies H2O will absorb to some extend so it isn’t an all or nothing effect. And there will also be more of an effect once we’re above the clouds and there isn’t much H2O interfering with the CO2.