The greenhouse effect is real. If there were no greenhouse gases in the atmosphere, earth would be a cold place. Compare Mars versus Venus – Mars has minimal greenhouse gas molecules in its’ atmosphere due to low atmospheric pressure, and is cold. By contrast, Venus has a lot of greenhouse gas molecules in its’ atmosphere, and is very hot. Temperature increases as greenhouse gas concentration increases. These are undisputed facts.
outgoing radiation = incoming radiation – changes in oceanic heat content
The image below from AER Research explains the radiative balance.
http://www.aer.com/scienceResearch/rc/rc.html
About 30% of the incoming shortwave radiation (SW) is reflected by clouds and from the earth’s surface. 20% is absorbed by clouds and re-emitted back into space as longwave (LW) radiation. The other 50% reaches the earth’s surface and warms us. All of that 50% eventually makes it back out into space as LW radiation, through intermediate processes of convection, conduction or radiation. As greenhouse gas concentration increases, the total number of collisions with GHG molecules increases. This makes it more difficult for LW radiation to escape. In order to maintain equilibrium, the temperature has to increase. Higher temperatures mean higher energies, which in turn increase the frequency of emission events. Thus the incoming/outgoing balance is maintained.
Click for larger image
http://www.aer.com/scienceResearch/rc/m-proj/lbl_clrt_mls.html
The important greenhouse gases are: H2O, CO2, O3, N2O, CO and CH4. The reason why the desert can get very cold at night is because of a lack of water vapor. The same is true for Antarctica. The extreme cold in Antarctica is due to high albedo and a lack of water vapor and clouds in the atmosphere, which results in almost all of the incoming radiation returning immediately to space.
An earth with no CO2 would be very cold. The first few tens of PPM produce a strong warming effect, and increases after that are incremental. It is widely agreed that a doubling of CO2 will increase atmospheric temperatures by about 1.2C, before feedbacks. So the debate is not about the greenhouse effect, it is about the feedbacks.
Suppose that the amount of reflected SW from clouds increases from 20% to 21%? That would cause a significant cooling effect. Thus the ability of GCM models to model future temperatures is largely dependent on the ability to model future clouds. Cloud modeling is acknowledged to be currently one of the weakest links in the GCMs. Given the sensitivity to clouds, it is perhaps surprising that some high profile climate scientists are willing to claim that 6C+ temperature rises are established science.
So the bottom line is that the greenhouse effect is real. Increasing CO2 will increase temperatures. If you want to make a knowledgeable argument, learn about the feedbacks. That is where the disagreement lies.
DR says:
I replied in my post of 17:36:27 (26/02/2009).
The GCM predictions and observational data appear to agree well on tropical tropospheric amplification when one looks at fluctuations on timescales of several months to at least a few years. There appears to be some discrepancies between the models and many of the data sets for the multidecadal trends but the data sets have known problems in determining these trends and in fact do not even agree well with each other. Progress has been made on reconciling these discrepancies although the issue cannot as of yet be said to be resolved. This is not surprising as in any scientific field at any given time there are certain puzzles that scientists are working to understand better. If climate science weren’t that way, it would be pretty boring scientifically!
And, finally, while the question of how well the models handle tropospheric amplification is an important one in regards to how faithful the models are in reproducing the earth’s climate system, particularly convective processes in the tropics, any apparent discrepancy between data and models has essentially nothing to say in regards to the mechanism responsible for the observed warming since the prediction of tropospheric amplification appears to a feature of the models that is independent of the mechanism causing the warming.
His [Joe 6-pack’s] motto is family, land and his rifle. Any change to deal with climate change will have to be done with out him.
Halleluja! At last, to be finally left alone – thankyou, thank you, thank you – while Alkataba [pbuh] bravely sallies forth without us alcoholic
whitetrash, “[de]evolving” back to the era of Horse-drawn carriages, and, Yea, beyond that even to The Garden, noblely forsaking his family, land, and rifle to “save the World” and, yes, preventing “the destruction of Creation” by coal carrying railroad cars!Alklataba [pbuh], may your Fairy Tale end as full flowered as it begins! Burp…Ma, git me another one o’ them thar carbonated beverages.
The AGW folks admit to a logarithmic (or something close) relationship between CO2 concentration and the mysterious greenhouse effect. But I cannot, for the life of me, find similar discussions about the relationship between water vapor levels and the mysterious greenhouse effect. Why? Water vapor is present in ppm levels around 25,000; whereas, CO2 is down around 385 ppm. [snip] Come on “climate scientists,” please explain the relationship between the most important “greenhouse gas” and temperature. This should be a priority in research in the new “transparent” administration, no? This whole “climate science” “science” ain’t “science” at all!
Phil,
I don’t think you understood my question. How did the CO2 get excited at 1mb in the first place? What event caused it to get excited?
Re: AJ Abrams (09:56:51) :
You’ve described what I was thinking back when I posted at aurbo (11:42:45) which was Boyles Law:
PV= nRT
Once some sort of radiation balance is acheived, one should be able to discern T from simply knowing P and V. But In the planetary case when dealing with a single phase (gaseous) compound and in the absence of monopolar changes in the atmospheric mass of the compund over time, V should be essentially a constant. at any given altitude. Thus, if V=~ a constant, PV then =~ a constant and T can be obtained by simply knowing P.
Since no part of Mars’ atmoshere reaches 1 atm, and Mercury has no atmosphere, we are left with Venus as the only nearby planet on which to test this idea. Some of the data I’ve seen puts the temeprature at the 50km height, where the pressure is roughly 1 bar, at between 300°-400°K this is warmer than Earth’s ~288°K. However, no error bars are availble for the Venus estimate.
In a gaseous atmosphere, PV determines T. If either P or V can be held constant, then T is determined by the other…P or V.
Joel Shore,
I have read the Schmidt et al 2005 paper thoroughly, so drop the patronizing. Point me to the data and the models that correlate in support their claims. I don’t give a rat’s behind what authors of any paper say; they say a lot of things, and most end up being wrong. I want to see the numbers.
No amount of obfuscation on your part can change the facts. The “hot spot” has been thoroughly discussed over at CA.
http://www.climateaudit.org/?p=4731
The recent Dessler et al 2008 paper on water vapor feedback resides in the same vain. How does such garbage make it past reviewers? It is a polished turd like so many pro-AGW material being pushed through so-called “peer review” in recent years like crap through a goose. It seems to have started with the hockey stick.
I will also point, after failing to show the “hot spot” exists via UAH satellite and balloon data (which do correlate), it shifted to claiming thermal winds finding the non-existent “hot spot” which you say doesn’t matter. A recent submitted paper on the matter in direct conflict with the “high impact” journal ‘Nature’:
http://www.climatesci.org/publications/pdf/R-342.pdf
Herman et al UAH vs RSS
http://www.agu.org/pubs/crossref/2008/2007JD008864.shtml
BTW, you are aware Tamino conceded on this issue after a long UAH bashing thread when Herman and Douglass kindly put him in his place?
What’s next, Hansen’s “smoking gun” is also not a problem? How many mulligans does CO2 AGW get?
http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf
A very simple yes or no answer will do; is the following statement true today? I submit is a failed hypothesis.
“Our climate model, driven mainly by increasing human-made greenhouse
gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than itis emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) theexpectation of additional global warming of about 0.6-C without further changeof atmospheric composition; (ii) the confirmation of the climate system’s lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration ofice sheet disintegration and sea level rise.”
It was already known in 2002 the “hot spot” theory ist kaput. Since then the effort has been to discredit satellite/radiosonde data using very creative methods, with Santer 2008 being the most recent sloppy science promoted as “robust”.
http://www.co2science.org/articles/V5/N14/EDIT.php
As jae eludes to, only an unrealistic and unphysical runaway strong positive water vapor feedback can save the CO2 AGW fairytale, and it doesn’t exist. Of course, we must ignore the discrepancies in GCM’s for water vapor:
http://www.cdc.noaa.gov/people/dezheng.sun/dspapers/Sun-Yu-Zhang-JC-revised.pdf
In conclusion, do you have empirical evidence to support CO2 AGW, or will we be treated to ever increasing long winded speeches?
The earth is capable of storing more energy than it emits- and is just as capable of emitting more energy than it stores. This is not a violation of thermodynamics. Cloud coverage changes daily, weekly, monthly, seasonally, yearly, locally and globally. The first image in your primer suggests cloud cover as a constant, but for what time period? If cloud cover changes yearly (and it does), then there is no balance of radiative energy from year to year. I would call that normal, but I would not call it ‘radiative heat balance’- THAT is a violation of thermodynamics. You brought of Homer Simsons’ quote, so that’s fair game. Lisa was violating the laws of GRAVITY, not thermodynamics. At least, that is why I laughed.
My bad. Someone told me that she was playing her sax on the ceiling- that would be gravity. Someone else told me that she built a perp motion machine- that WOULD be thermodynamics. Anybody see the episode? Constant rain here in Atlanta, shot an 88 with a bad rotator cuff. Enjoy your day…
Anthony: “The two preferred terms are “skeptic” and “alarmist”…”
Anthony, this seems to imply that “skeptic” and “alarmist” convey similar connotations. If so:
1. Would you say that “skeptic” is an honourable term?
2. Would you say that “alarmist” is an honourable term?
Bill Illis (19:06:59)
That could hardly be more incorrect Bill. The determination of climate sensitivity makes no assumption of the proportion of the greenhouse effect by CO2. For example, Steve Goddard has (incorrectly as it happens) referred to the analysis of Charnock and Shine (see graphs in the top post). If you read what Charnock and Shine actually report (a fairly standard, if earlyish, analysis), it’s clear that the complete removal of CO2 might be expected to reduce temperatures by around 1/3d to 1/2 of the total greenhouse effect warming:
““Corresponding estimates of the effect on the mean surface temperature of the Earth are much more complicated, as both Campbell and Tomkin say. But using a simple radiative convective model,1 with no other change, one finds that doubling the CO2 produces a 1.5 °C warming and removing it a 12 °C cooling. Including a simple relative humidity feedback (but no ice-albedo feedback) changes these values to 2.4 °C warming and 17 °C cooling”
Charnock H, Shine KP (1993) CO2s Greenhouse Contribution Debated Physics Today 4646, 66-66
The simple climate sensitivity analysis can’t be used at very low [CO2], if we’re interested in the real world. It simply doesn’t apply in that form at very low concentrations
Those charts don’t make sense. Where are they from? Whoever made them has made the pretty fundamental error of taking a model for an equilibrium response and plotting this with data defining a transient response. It’s wrong, and is bound to give an incorrect interpretation of the climate sensitivity.
One needs to be careful with models; firstly to understand what they mean, secondly to understand their range of applicability and thirdly to use them properly.
jae (08:41:45) :
…and then you refer me to someone’s blog. However the blogger doesn’t address the point at all. Lindzen was proposing something specific that turned out to be incorrect. That particular point is settled in standard scientific practice through testing against real world data.
If the hypothesis is “runaway AGW”, I would suggest “believers” and “skeptics” to describe the two camps.
Phil,
Why does your photobucket link show 750/cm instead of 650/cm? The wikipedia link I provided (which you described as a cartoon) also shows transmission at 750. Bu the band is centered at 650. I don’t see any discrepancy between the graphs – you just missed the center in yours.
You haven’t answered either of my questions yet.
foinavon:
Sorry. I pointed you to Spencer’s blog, because I thought he had a post that addressed that issue. But I don’t see it now…
Joel Shore (13:55:42) :
jae says:
That little discussion has been used thousands of times. Unfortunately, it ignores details like convection.
No…As Stevo nicely explained it is convection that is important in controlling the vertical thermal gradient that exists in the troposphere. Hence, it is not in fact being ignored at all.
Good to hear. So what the proportions of outgoing heat from the surface parameterised by the models?
Nothing like these I bet…
Sorokhtin, 2001a: Greenhouse effect: Myth and reality. Vestnik Russian Academy of Natural Sciences 1:8-21..
“According to our estimates, convection accounts for 67%, water vapor condensation in troposphere accounts for 25%, and radiation accounts for about 8% of the total heat transfer from the Earth’s surface to troposphere.”
foinavon (02:36:30) :
One needs to be careful with models; firstly to understand what they mean, secondly to understand their range of applicability and thirdly to use them properly.
And fourthly not to make rash alarmist assertions based on their output because they have never successfully predicted anything.
Steven Goddard (19:22:28) :
Phil,
I don’t think you understood my question. How did the CO2 get excited at 1mb in the first place? What event caused it to get excited?
Absorption of bb radiation and by collision with other molecules (Boltzmann distribution).
Brendan H (02:34:26) :
Anthony: “The two preferred terms are “skeptic” and “alarmist”…”
Anthony, this seems to imply that “skeptic” and “alarmist” convey similar connotations. If so:
1. Would you say that “skeptic” is an honourable term?
2. Would you say that “alarmist” is an honourable term?
Not stepping on Anthony’s turf just giving my take on the terms:
The issue isn’t honor. It’s accuracy. Skeptics are, in fact, skeptical about the quality of the science and thinking behind AGW hypothesis. They do not “deny”, they question.
The AGW hypothesis supporters have unfortunately earned the term alarmist. Look at anything from Hansen and AlGore in the last couple of years. End of the world as we know it, etc. Oh, and death of Gaia from Lovelock. So it is an acceptable term, to me, since it correctly describes behaviour and is devoid of pejorative nature. There are hundreds of examples of folks saying they need to raise the alarm level. They wear it as a badge of honor in many cases… It is not particularly a pejorative, especially if the alarm is valid.
Now me, I’ve moved from skeptic to a more direct denial that AGW is real. I’ve seen enough of the science (and lack of it on the part of AGW advocates) that I’m comfortable denying the correctness of their claims. (I do not deny that warming has happened for 30 years. It has; but was preceded by cooling for 30 years, and to be followed by cooling for 30 years…)
Unfortunately, the use of “denier” by the alarmists has been in a way charged with religious hate speech overtones, so they have contaminated the word with confounding hate. So I understand the ban on ‘denier’ as a pejorative. Just as I’m happy to call myself an “old fart” but would not expect the term to be acceptable in general public as a pejorative applied by others.
So I’m happy to call myself an old fart denier, but would not think it proper for others to do so. Hate speech is often like that, asymmetrical in it’s use. And I’d be happy to be called an “Anti-AGW alarmist” raising the alarm about all the harm it will do to our economy. By anyone. I’d wear it as a badge of honour…
tallbloke (07:03:30) :
Good to hear. So what the proportions of outgoing heat from the surface parameterised by the models?
Nothing like these I bet…
Sorokhtin, 2001a: Greenhouse effect: Myth and reality. Vestnik Russian Academy of Natural Sciences 1:8-21..
“According to our estimates, convection accounts for 67%, water vapor condensation in troposphere accounts for 25%, and radiation accounts for about 8% of the total heat transfer from the Earth’s surface to troposphere.”
Since those figures are total rubbish I’m sure they’re not! There’s no way that radiation is as low as 8%.
schnurrp (04:56:58) :
If the hypothesis is “runaway AGW”, I would suggest “believers” and “skeptics” to describe the two camps.
Or how about the skeptics and the unskeptical? “Proponents” is the word i tend to use when being polite.
And another thing. Proponents can be deniers too. Proponents deny my hypothesis that things will most likely continue on quite equably just as they have for centuries with humans adapting quite well to most anything short of another ice age.
Steven Goddard (05:37:01) :
Phil,
Why does your photobucket link show 750/cm instead of 650/cm?
Because I happened to have that one available, it shows the effect on the wing rather than the Q-branch.
The wikipedia link I provided (which you described as a cartoon) also shows transmission at 750. Bu the band is centered at 650. I don’t see any discrepancy between the graphs – you just missed the center in yours.
It’s difficult show the whole band at full resolution, the difference is that the cartoon by not showing the individual lines and therefore appearing to show a complete wide band completely misses the impact of line-broadening. Which is where the extra absorption with increased concentration comes from.
Here’s a whole band at a lower resolution which shows the effect of doubling [CO2] and also the edge effect.
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2spectra.gif
You haven’t answered either of my questions yet.
I did this morning, I guess they’re slow posting?
foinavon,
I will happily redo the log warming chart with the proper qualifiers when someone nails down what timeline should be used for the transient equilibrium response.
A little over a decade ago, it was only several years, then it changed to 30 years and now it seems much longer timelines are being discussed.
In Hansen’s newest writings, he has redefined it to take 1,500 years and apparently the NOAA, NCAR and Hadley Centre models agree with that (although it not clear whether they mean +3.0C in 1,500 years or +6.0C in 1,500 years).
If it is +6.0C in 1,500 years, then the log warming formulae will have to be revised of course. If it is just +3.0C in 1,500 years, then the log warming formulae should again be revised but this time the important time delay factor will have to be included.
I would like to be able to test the predictions against the empirical data to date to find out if we are on the right track or not. If the timelines are far too long to be tested, then we will have to go back to arguing about the theory again (albeit far into the future theory).
http://pubs.giss.nasa.gov/docs/2008/2008_Hansen_etal.pdf
DR says:
Well, if you read it so thoroughly, I don’t understand why you quoted one sentence from their introduction where they were basically setting up the background of what was understood before they embarked on their study. You would have given a much better overview of their conclusions if you had quoted their abstract.
As for the general question of tropical tropospheric amplification, I gave what I thought was a very fair summary of what is known and not known at the moment and I don’t have anything further to add to it.
Thanks for the link. I hadn’t seen that paper and it looks interesting…I’ll give it a read. Of course, there are also other papers (in addition to Dessler’s) that have looked into the water vapor feedback and reached the conclusion that it is being modeled quite well. See, for example, these two papers by Soden: http://www.sciencemag.org/cgi/content/abstract/sci;310/5749/841 and http://www.sciencemag.org/cgi/content/abstract/296/5568/727 [And, lest you try to claim that Soden is biased, I will note that he seems to call them as he sees them given that he is basically quite skeptical in regards to the effect of AGW on hurricanes as can be seen here http://www.sciencemag.org/cgi/content/summary/sci;322/5902/687 , which is one of the reasons why I emphasize that the science on this particular issue is still quite unsettled (although I was saying that even before this Soden paper appeared).]
Well, to save you the long-windedness, I could just refer you to the IPCC report, as there is plenty of such evidence in there. If you want me to throw out just one thing off the top of my head: the cooling of the stratosphere for which the data (compared to the issue with the upper troposphere) has a much higher signal-to-noise ratio. And, unlike the tropospheric “hot spot” issue, the cooling of the stratosphere actually is a fingerprint of AGW that distinguishes it from other warming mechanisms such as an increase in solar irradiance.
Phil,
Ahh… earlier you were arguing that IR excited tropospheric CO2 immediately loses it’s energy through collisions with N2 and O2 molecules. But now you are saying that those processes also work in reverse.
Previously you said –
Leif, the bolded statement is only true high in the atmosphere, ~stratosphere, near the surface any energy is exchanged via collisions with neighboring molecules almost immediately (timescale less than a nanosecond).”
and then you said-
Sorry N2 and O2 are homonuclear diatomics and dont radiate.
You described it initially as a one-way phenomenon, when actually it is more of an equilibrium. The N2 and O2 can also pass energy back to CO2, which does radiate.
Phil,
Thanks much for the new picture, which though more detailed, shows the same overall pattern as the Wikipedia 600-900 region.