A closer look at the NASA paper referred to by the AOL article.
Without the sustaining support by the non-condensing greenhouse gases, Earth’s greenhouse effect collapsed as water vapor quickly precipitated from the atmosphere, plunging the model Earth into an icebound state
carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth’s greenhouse effect.
water vapor, although contributing 50 percent of the total greenhouse warming, acts as a feedback process, and as such, cannot by itself uphold the Earth’s greenhouse effect.
Apparently the authors believe that CO2 is a good thing. Nevertheless, this study looks flawed. It doesn’t represent an actual planet Earth.
- 1. CO2 is emitted from volcanoes. It would be impossible to have a CO2 free atmosphere on Earth. In fact, CO2 concentrations were much higher in the past.
- 2. The vast majority of the CO2 caused greenhouse effect occurs from the first few ppm. The effect tails off logarithmically after that. Given 1 and 2, the whole premise of this paper is fatally flawed. It represents a hypothetical situation which could never occur, and is backwards from the evolutionary history of the planet.
- 3. Next problem is that radiative transfer models show that the loss of all CO2 in the tropics causes less than 2% reduction in downwelling longwave radiation at the surface. It doesn’t seem credible that this causes the equator to freeze up.
- 4. The authors claim that all clouds disappear. Did they forget that this also means a lot more more SW radiation reaching the surface? Imagine a body of water in the tropics being warmed by directly overhead sunshine 12 hours a day. Is this water not going to warm, evaporate, and return water vapour to the atmosphere, thus massively increasing the greenhouse effect and warming higher latitudes?
- 5. The claim that water vapour is only responsible for 50% of greenhouse warming is absurd. The number is much higher, particularly when considering that clouds are made of water vapour.
This study is a marketing exercise, not a scientific one. It represents an impossible hypothetical situation, the claims are incorrect, and it tells us nothing about the effect of increases beyond 390 ppm.
Flawed? NASA? Come on, James Hansen works there.
Back of the envelope calculations indicate that water vapor is the dominant greenhouse gas, with CO2 playing a bit part.
SOTA climate models in the early 1960’s (e.g. Manabe and Strickler) concluded that water vapor is the dominant greenhouse gas, with CO2 playing a bit part.
Earth’s past climate includes times with low temperatures and very high CO2 levels, demonstrating that CO2 plays a bit part.
This new climate model indicates the opposite.
Conclusion- this nonsensical result demonstrates fundamental problems with the new climate model’s implicit and explicit assumptions on water vapor feedback and clouds.
Good, then you agree with NASA. The NASA paper explicitly states that water vapor and clouds together provide 75% of the total greenhouse effect, and CO2 only 20%.
No, it doesn’t. As I said, NASA agrees with you that water vapor is the major greenhouse gas. There is nothing in the study that says otherwise.
The point of the study is that CO2 and the other long-lived greenhouse gases control the level of water vapor in the atmosphere, which means that they control the total greenhouse effect even though water vapor is a much larger percentage of the overall effect.
It appears that this paper is nothing new after all. The GISS models assume a strong positive water vapor/cloud feedback to enhance the CO2-only forcing delta. The positive feedback must also be at work as CO2 levels drop, greatly enhancing the temperature drop due to the reduced CO2 forcing alone. The same hypothesis (incorrect in my opinion) results in equally exaggerated results, whether CO2 goes up or down.
The conclusion that zero GHG concentrations causes an iceball Earth requires that the tropics are covered with ice. As long as any small region around the equator has open water, there will be sufficient water vapor to generate a strong greenhouse effect.
The paper is a simple regurgitation of the status quo with no new physics, insights, measurements or mechanisms.
How do you figure that? This small amount of water, even if it’s not frozen, would be very cold, as would be the atmosphere above it. Since evaporation is dependent on temperature (and pressure, not relevant here), the evaporation rate would be quite low. How would this low evaporation rate put enough water vapor in the atmosphere to produce “a strong greenhouse effect” for the entire globe?
Steve, I don’t understand the point of this. It’s a theoretical exercise. Nobody suggested that this would or could ever actually happen.
Straw man. Of course they do. I don’t know of anyone who ever said otherwise. It’s excess CO2 that’s the problem. Water is a good thing. Overhydration can be fatal.
No. Clouds are not made of water vapor, which is an invisible gas. Clouds are made of condensed water vapor–water droplets. NASA considers them separately:
I don’t know whether you just don’t read carefully enough or you’re being intentionally misleading, but you’re certainly wrong.
http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
That’s rich , D M. If that isn’t an ad hominem attack – – – those who don’t agree with your opinion are unskilled, reach erroneous conclusion, and are incompetent of seeing that . . .
( sarc: . . . any I won’t even THINK about giving consideration that it better applies to those supporting AGW . . . ! )
Glad to see others are aware of Dr. Spencer’s reply . . thanks Mike for posting the link – I had neglected to . . .
So you think clouds will form without any water vapour in the air? Interesting theory.
The fact that the NASA article contradicts itself and is misleading – as evidenced by the AOL article – does not trouble you?
Given your spam, I am going to change my posting policy especially for you.
Unless you directly address the points of my articles, you are limited to one post per thread.
So which of the five points I made do you disagree with, and why?
No, that’s not what I said, is it? I said that clouds are made of condensed water vapor. I pointed out that you misrepresented what NASA said, which you unequivocally did.
You said that NASA’s claim of water vapor = 50% is ridiculous because water vapor is much more if you include clouds. Well, that is precisely what NASA said: water vapor + clouds = 75%.
Show me the difference between these two statements:
NASA: Water vapor + clouds = 75%
Steve: Water vapor including clouds = much more than 50%.
You can’t have clouds without water vapour. If there is no water vapour there are no clouds.
If I said the cake is made of flour, would you disagree because a cake is not the same as a bag of flour?
You can’t have clouds without water vapour. If there is no water vapour there are no clouds.
Are you being intentionally obtuse? I’ve said twice that clouds are made of condensed water vapor. How many more times do you want me to say it?
Your analogy is fatally flawed. A cake is not simply flour in a different form. Clouds consist of liquid water. Water vapor is water in its gaseous state. Clouds are not made of water vapor, which is an invisible gas.
Look, this is majestically simple.
NASA said that water vapor is 50% of the greenhouse effect, and water vapor plus clouds is 75%.
You said that NASA is “absurd” because water vapor, including clouds, is more than 50%.
That is exactly what NASA said: water vapor + clouds is 75%.
So, please explain to this cretin exactly what NASA said there that was wrong.
First the numbers are much too low
Second, the article is blatantly and intentionally misleading about the importance of CO2 relative to H2O – as evidenced by the AOL article.
Sorry, blaming NASA for the AOL reporter’s screwup is just ridiculous. If he can’t understand what it said, he has no business writing science stuff. That’s not NASA’s fault.
the article is blatantly and intentionally misleading about the importance of CO2 relative to H2O – as evidenced by the AOL article.
Well, I understood it, and I ain’t either a scientist or a science reporter.
It is, however, gratifying to see that you now admit that the AOL article was wrong, since yesterday you insisted that “The AOL reporter was absolutely correct.”
ChrisD says:
October 16, 2010 at 7:43 pm
and I ain’t either a scientist
OMG, we couldn’t tell. Thanks for saying that.
;o)
Thanks for the ad hom. I assume it will get deleted.
The AOL reporter took away from the press release exactly what they wanted him too. The whole study and press release was AGW marketing. It had nothing to do with science.
Do you believe that the tropical oceans would freeze without CO2? That is a fundamental requirement of their claim.
It sound ludicrous to me.
The AOL reporter took away from the press release exactly what they wanted him too. The whole study and press release was AGW marketing. It had nothing to do with science.
That is unadulterated malarkey. You are blandly making assertions with no evidence and no basis in fact.
Do you believe that the tropical oceans would freeze without CO2? That is a fundamental requirement of their claim. It sounds ludicrous to me.
It’s not fundamental to their claim in any way, shape, or form, and I already answered this question anyway. Scroll down.
And, sorry, but “it sounds ludicrous to me” is not science. Lots of things turn out to be true that sound ludicrous at first. If you don’t think this is right, come up with a real argument that explains how the atmosphere would remain warm enough–indefinitely–to support evaporation without CO2 and the other forcing GHGs.
As I said on the other thread, “radiative forcing” refers to a CHANGE in the greenhouse effect, not its magnitude. Saying 80% of the radiative forcing is due to CO2 is just saying that 80% of the CHANGE in the greenhouse effect is dure to a CHANGE in CO2. It is not saying that 80% of the greenhouse effect itself is due to CO2. If you are going to criticise scientific papers, you do need to take the trouble to find out what basic terms, such as “radiative forcing” actually mean, e.g. by looking them up in the glossary of the IPCC WG1 report, or perhaps reading a textbook or two.
This study is nonsense. But feel free to keep repeating yourself over and over again.
Is it ever possible for you to actually address any of the points in the article? You seem to be completely incapable of staying on topic.
A companion study led by GISS co-author Gavin Schmidt
Ahhhhhhhhhh…. now I get it.
This paper could be RealClimate’s way to give a lame response to Roy Spencer’s work on negative feedback. They will probably use this paper in reply every time Roy Spencer’s work is used to show strong negative feedback from H2O when CO2 increases send more energy down to the surface.
RealClimate has a stream of lame responses for the Hockey Stick. Now they’ve started a stream of lame responses to strong negative feedback from H2O.
carbon dioxide accounts for about 20 percent of the greenhouse effect, water vapor and clouds together account for 75 percent, and minor gases and aerosols make up the remaining five percent. However, it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth’s greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth’s greenhouse effect.
Ok folks! Which shell is the pea under?!
The article does suggest that without co2 there would be no greenhouse effect.It seems to me that co2 is viewed as the boss molecule ,it has little effect on its own,but without co2 none of the other molecules would know where they were supposed to be or what state they should be in. The water molecule is too dumb to change into water vapour without the help of co2.
You have got it almost exactly. Well done.
So you believe that the equatorial oceans would be frozen with no CO2?
The point, Steve, is that Don understood the underlying thesis of the NASA paper, and it appears that you did not.
But, in answer to your off-topic question (there’s no mention of “equatorial oceans” in the NASA post):
I haven’t seen the actual paper, so I can only extrapolate from what the post says and what I already know. Suppose we somehow remove all of the forcing greenhouse gases. The temperature declines sufficiently that water vapor starts precipitating out. This feeds back into the cooling effect, and the whole system quickly collapses–essentially all of the water vapor is gone. Now you have essentially no greenhouse effect at all.
Some fairly straighforward physics has shown that with no atmospheric forcing–i.e., on a planet with the same albedo but no atmospheric absorption–the global average temperature would be about 33C cooler than Earth. That would put Earth’s global average temp at around -18C (-0.4F).
But that’s a global average. Whether the equatorial oceans would be cold enough to freeze, I have no idea.
The entire point of the NASA claim is that the Earth freezes over and there is no water vapour in the atmosphere. In order for that theory to work, the tropical oceans have to freeze over.
No, that is not “the entire point.” The entire point is that CO2 and the other forcing GHGs control the water vapor content and therefore the greenhouse effect. Whether or not the equatorial ocenas would freeze is quite beside the point. The point is that CO2 is the man behind the curtain.
ChrisD says:
October 16, 2010 at 7:46 pm
The point is that CO2 is the man behind the curtain.
You mean that the Wizard of Oz was faked by the man behind the curtain just like co2 is faked to be controlling climate.
Well done.
ChrisD
spiteful, arent we.
Not really. I just notice hypocrisy when I see it.
ChrisD says:
October 16, 2010 at 7:36 pm
the underlying thesis of the NASA paper
What are the other works that confirm this finding you claim?
ChrisD says:
October 16, 2010 at 7:36 pm
I haven’t seen the actual paper, so I can only extrapolate from what the post says and what I already know.
You haven’t seen the paper but you claim that what someone said about it is right. Are you going to criticize yourself for doing that? Or, are you going to be a hypocrite and exempt yourself from critique?
ChrisD says:
October 16, 2010 at 7:36 pm
Suppose we somehow remove all of the forcing greenhouse gases. The temperature declines sufficiently that water vapor starts precipitating out. This feeds back into the cooling effect, and the whole system quickly collapses–essentially all of the water vapor is gone. Now you have essentially no greenhouse effect at all.
Would you write a paper on that and submit it for peer review to see if it will get published?
There’s nothing radically new about this idea, Amino. It’s been understood for quite a long time.
See, for example:
http://maths.ucd.ie/met/msc/ClimSyn/heldsode00.pdf
http://www.pnas.org/content/104/39/15248.full.pdf
You haven’t seen the paper but you claim that what someone said about it is right.
No, I assume that what NASA said about its own paper is right.
Would you write a paper on that and submit it for peer review to see if it will get published?
I don’t need to, Amino. It’s already been done. This is exactly what the NASA post we are talking about says. Didn’t you read it?
If C02 has been rising these last ten years and the global temperature has been static then the radiative forcing of this control knob must be 0%.
The issue isn’t what does CO2 do for the entire greenhouse effect, the issue is “what does the CHANGE in CO2 do to temperatures as the CO2 level increases?”
So far, there is no correlation of temperature to CO2 in the real world, other than ‘tweaking’ of the models for aerosols that were supposed to cause the 1940s-1970s (or there about) cooling.
Also, the model, in removing all the CO2 and showing the great cooling (regardless of whether one believe the model or not) isn’t an issue, because of absorption of OLR being logarithmic. A CO2 increase of 350 ppm to 400 ppm has much less effect than, say, from 50 ppm to 100 ppm.
I would sure like to see the authors of this paper have a debate with, oh maybe, Dr. Spencer and Dr. Lindzen. Ya think that may if we ask them all, they would agree to a debate of this paper?
Ya think that may if we ask them all, they would agree to a debate of this paper?
No, nor should they. Scientific debates occur in peer-reviewed journals, not on a stage, with an audience. If Lindzen and/or Spencer think this is wrong, they get to write a paper explaining why, and get it published.
Chris D,
. . I should have put a ‘smiley’ face after my question, instead of started it with ‘Ya’ rather than ‘ Do you’; maybe then it would have been better understood as rhetorical and asked in a bit of fun . . ..
But as a reply anyway, I think there could be different venues for scientific debate. Peer reviewed journals are one, a ‘live’ discussion/debate forum is another. Though, I suspect Gavin wouldn’t agree even if someone were to ask (for those who aren’t familiar as to why, see here http://www.npr.org/templates/story/story.php?storyId=9082151)
And Dr. Roy Spencer HAS commented on this paper. The issue isn’t the paper being ‘wrong’, just what it is trying to portray. And Dr. Spencer’s had comment on trying to get a paper that DOESN’T support AGW at the end of his article.
I am sure none of this will change your mind. FYI until the 2007 IPCC report, I used to think that man was causing the significant part of global warming. That is, until I started looking more into it myself, on both sides of the argument. I suggest anyone who isn’t sure do the same.
I’ll be producing empirical evidence that this theory is wrong later this evening.
Dr. Roy Spencer has added his view.
http://www.drroyspencer.com/2010/10/does-co2-drive-the-earths-climate-system-comments-on-the-latest-nasa-giss-paper/
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