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.
“linkinghub.elsevier.com/retrieve/pii/0019103576901573 entitled “Can internal heat contribute to the high surface temperature of Venus” that concludes:
In summary, this exercise yields an approximate but quantitative demonstration of what everyone suspected anyway–that the maximum contribution to the surface energy budget from internal heat is down by at least one and probably two orders of magnitude from the solar contribution. This conclusion is independent of any model for the source of the internal energy. In the absence of any other plausible heat source, the one calorie per square meter provided each second by the Sun is all there is to maintain a 750°K surface temperature. Thus, we can assert with confidence that a very efficient atmospheric trapping mechanism (greenhouse effect) is operating, whether or not the details of this mechanism are fully understood.”
I would like to read that paper; is it available for free somewhere?
It takes a lot of energy to keep the atmosphere in the state that it’s in, and that energy must be measurable as temperature. Probably about 18 C more than sans atmosphere 🙂
Stevo:
“See here for Held and Soden 2000, look at figure 1 and the discussion just above and below it, to see the IPCC-cited version.
http://www.gfdl.noaa.gov/reference/bibliography/2000/annrev00.pdf”
That little discussion has been used thousands of times. Unfortunately, it ignores details like convection.
Mark T (22:56:04)
I agree with you that the concept of increasing temperatures causing a release of CO2 which causes an additional increase in temperature seems like a legitimate single pole feedback. But like you, I don’t know either (a) what delay to assign to this phenomenon, or (b) what multiplicative factor to apply. I also agree that such a feedback loop would be stable if the absolute value of it’s multiplier was less than one. Finally, I agree that at certain frequencies, such a stable loop will likely have a finite gain larger than one. But just a comment. For any frequency other than zero, although the gain may be larger than one, the output must cycle through positive and negative values. If the system inputs/outputs are degrees Kelvin, negative temperatures are a physical impossibility. I have no idea how to overcome this apparaent contradiction other than to assume such a feedback system applies to “temperature changes” relative to a “nominal value”. Provided the gain at all non-zero frequencies is “small enough” that the sum of the “nominal value” and the most “magnitude” of the output at that frequency is positive, such a system wouldn’t contradict the fact that zero degrees Kelvin is as low as temperatures get.
Like you, I am confused. That is why I asked for a circuit diagram or a flow diagram or whatever someone wants to call it. Without such a diagram, I don’t know how to attack the problem. I have no, zero, nada plans to try to create such a diagram because (a) if I did, it would be incorrect, and (b) it would Agive GW supporters ammunition to argue that the AGW-denier Reed Coray doesn’t know what he is talking about–which is probably true anyway.
Finally, given how complex the environment is, my belief is that it can’t be represented by a linear, time-invariant system. It may be possible to “linearize” the environment over a small temperature range; but I even doubt that.
Best wishes, Reed Coray
Anthony,
It has been suggested that the term “AGW-alarmist” is pejorative. Although I like to use humor and sarcasm to express some of my thoughts, I don’t want to cross the bounds of decency. Since this is your blog, I’ll let you be the judge. Specifically, for posting on your blog, is the term “AGW-alarmist” unacceptable?
REPLY: Or simply “alarmist” either works, thanks for checking – Anthony
jae says:
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.
jae says:
I believe that you can just set up a free account at that ScienceDirect website and then you’ll have access to it free…at least it seemed to work that way for me.
is the term “AGW-alarmist” unacceptable?
REPLY: Or simply “alarmist” either works, thanks for checking – Anthony
Can I check also, Anthony? Is the term ‘denialist’ acceptable? Personally I think good discussion will be undermined by assigning labels, but I’d like to know if you consider it ok on one side only or on both.
REPLY: Denialist is not, due to its connotations with “holocaust denier”. Alarmist has no such connotation. Similarly “septic”, sans the c or k, depending on regional use, is not acceptable either. The two preferred terms are “skeptic” and “alarmist” or alternately if you prefer “AGW’er” Simon, let me clear on this point, no further discussion of it since I see your intent. I’m not interested in a debate on semantics with you. My blog, my rules. Abide or abstain. – Anthony
Here is something else that doesn’t make sense
Plug 0 into the IPCC CO2 forcing calculation to determine the total forcing of 280ppm of C02 prior to 20th century (or any concentration for that mater).
Solution
CO2 forcing = infinity w/m2
just slightly fishy!
try it yourself
5.35ln 280/0 = infinity lol
I don’t get this greenhouse metaphor. Couldn’t we just say that the atmosphere absorbs radiation from the sun as well as the earth. And additionally, since atmosphere is itself matter it emits a certain amount of radiation to itself. To the degree the atmosphere absorbs energy it inhibits radiative cooling of the earth into space.
No one has pointed out that CO2 is used to make infrared lasers because CO2 not only absorbs infrared but emits it as well.
My blog, my rules. Abide or abstain. – Anthony
Ok, Anthony, I’ll abstain. I’m not interested further in contributing to the sense of ‘authenticity’ of a blog where the proprietor sanctions name-calling. Your statement “The two preferred terms are “skeptic” and “alarmist”” is comically revealing of your intent. I don’t suppose you’ll post this, but you’ll read it, so cheerio. I really do dislike people pretending to be disinterested when their bias is so obvious. Have the balls to post this, why don’t you? It’s my last word anyway – I’ll look for places that have some objective standards to post my views. Not here – not after your active encouragement of name-calling, the base resort of those lacking any substance in their arguments.
Hank: No one has pointed out that CO2 is used to make infrared lasers because CO2 not only absorbs infrared but emits it as well.
Yes, you’re right; CO2 absorbs almost the same amount of IR than it emits. The problem here is that the absorptivity-emissivity of CO2 have been exaggerated as if our atmosphere excerpted a pressure of hundreds atmosphere-meter. At its current Pp, i.e. 0.00034 atm m, the absorptivity of CO2 is 0.001. Just compare this cipher, taken from experimental work, whith the cipher applied by AGW proponents which is 0.75, which, in some cases has been exaggerated to 0.9.
Some literature that will guide you to real parameters:
Bakken, G. S., Gates, D. M., Strunk, Thomas H. and Kleiber, Max. Linearized Heat Transfer Relations in Biology. Science. Vol. 183; pp. 976-978. 8 March 1974.
Manrique, José Ángel V. Transferencia de Calor. 2002. Oxford University Press. England.
McGrew, Jay L., Bamford, Frank L and Thomas R. Rehm. Marangoni Flow: An Additional Mechanism in Boiling Heat Transfer. Science. Vol. 153. No. 3740; pp. 1106 – 1107. 2 September 1966.
Pitts, Donald and Sissom, Leighton. Heat Transfer. 1998. McGraw-Hill.
Potter, Merle C. and Somerton, Craig W. Thermodynamics for Engineers. Mc Graw-Hill. 1993.
Schwartz, Stephen E. 2007. Heat Capacity, Time Constant, and Sensitivity of Earth’s Climate System. Journal of Geophysical Research. [Revised 2007-07-16]
Van Ness, H. C. Understanding Thermodynamics. 1969. McGraw-Hill, New York.
Wagner, F., Aaby, B., and Visscher, H. Rapid atmospheric CO2 changes associated with the 8,200-years-B.P. cooling event. Proceedings of the National Academy of Sciences. September 17, 2002; vol. 99; no. 19; pp. 12011-12014.
Wilson, Jerry D. College Physics-2nd Edition; Prentice Hall Inc. 1994.
Steven Goddard (07:16:36) :
Phil,
Your explanations are appreciated, but appear to be missing something important. If the CO2 is losing all of it’s excitation energy in nanoseconds near the surface, how can there be excited CO2 at 1mb altitudes?
Because at 1/1000th of the pressure the mean time between collisions is much longer and the excited state stays that way for longer and therefore radiation takes place. (think of it as a Poisson process)
According to this chart, the 15um absorption spectrum is saturated.
http://www.globalwarmingart.com/wiki/Image:Atmospheric_Transmission_png
That’s little more than a cartoon at such low resolution that it doesn’t show the individual lines with the gaps between. See below for a portion of the CO2 spectrum, the top graph shows the spectrum at mars conditions and the lower at earth conditions, illustrating the effect of broadening.
http://i302.photobucket.com/albums/nn107/Sprintstar400/Mars-Earth.gif
Correction to my post (13:48:11). Instead of
Provided the gain at all non-zero frequencies is “small enough” that the sum of the “nominal value” and the most “magnitude” of the output at that frequency is positive, such a system wouldn’t contradict the fact that zero degrees Kelvin is as low as temperatures get.
I meant to say
Provided the gain at all non-zero frequencies is “small enough” that the difference between the “nominal value” and the “magnitude” of the sinewave at the output (“nominal value” minus “output magnitude”) at that frequency is positive, such a system wouldn’t contradict the fact that zero degrees Kelvin is as low as temperatures get.
“”” gary gulrud (11:14:37) :
“Fi = S/4 (1 – A) where S is TSI [1361 W/m2] and A is the albedo [=0.3].”
I stand corrected on the detail of energy input to the calculation. “””
Gary, applying this expression; which does seem to be standard practice; also is part of the problem.
The relation between temperature and radiant emittance (or absorbtance) is not a linear relation (it is 4th power of T) but other processes such as thermal conduction are linear with temperature (like Ohm’s Law)
So if you average the correct solar irradiance (1367 W/m^2) over 4 times the area, to get that fictitious 342 W/m^2, then you don’t get the correct distribution between radiation and conduction, so you get the wrong answer.
At 4 times the irradiance, the surface temperature gets much hotter, but the conductive flow only goes linearly with the temperature rise, whereas the radiative component goes as the 4th power of the absolute temperature. The two answers aren’t the same, and the hotter it gets the more unequal they are.
George
Which is why I don’t like the “forcings” model. Maybe it is no surprise, that the only standard “Climatology” lingo that I can find in my CRC Handbook of Chemistry and Physics, is “Albedo”.
No tables of forcings, or feedbacks, or climate sensitivities, or anomalies, or any of that; just ordinary conventional Science terms; like Temperature.
So when those Japanese Scientists referred to Pachauri’s UN IPCC stuff as “ancient Astrology”, they perhaps were insulting ancient astrolgy.
There’s some impressive debate going on here. Steve, you did a good job of getting the pot stirred in your attempt to educate some of us who are less up to date. I appreciate it and hope you don’t feel like you’re getting beat up too much. Many of the posts involve issues which seem to be addressed by the link I gave on the previous article regarding CO2 and glacial cycles. I can’t vouch for Dr. Hug’s research but it certainly seems, at least, to have significance relating to the IPPC mention of…what are they called…wings(?) that are frequently invoked.
http://www.john-daly.com/artifact.htm
RobJM:
The formula stating that forcing is logarithmic in concentration is only approximate, although a quite good approximation over the concentrations of interest to us. At low enough concentrations, it is no longer logarithmic but rather linear.
I notice that “Simon Evans” has once again promised to go away, because this site won’t give in to his demand that it should be OK for AGW skeptics to be equated with holocaust deniers.
Well, we’ll see. Last time he said he wouldn’t post here any more, it lasted about 36 hours.
Joel Shore:
I seem to recall that those ‘low enough’ concentrations are around 20 ppmv. Since most life on the planet would not survive very low CO2 levels, it’s a moot point, isn’t it?
I’m still waiting for real world evidence, which shows that higher CO2 levels are detrimental in any way.
There is a considerable amount of misinformation propagated about the greenhouse effect by people from both sides of the debate. This is true, but all the graphs and data will not convince joe sixpack of anything. The pros and cons even among the comments here bring questions. Joe sixpack worries about more taxes, does not want to give up his hemi powered pickup, and has no idea what a carbon foot print is. While science provides us with the needed information, Rush, and those like him constantly regail against it. Joe has disregarded the science and believe that climate change is natural, from a wobble in Earths orbit, a change in the sun, or the end of the last ice age. He may even believe there is no climate change at all. Joe believes there is no reason to change anything, as natural, we did not cause it, we can not change it, therefore nothing can be done about it. Going green is foolishness. An electric or hydroelectric car is pointless. If joe sixpack was the republican hero, than Homer Simpson is his archtype. To evolve from the horse drawn wagon to the gas powered automobile was easy, to evolve beyond that is more than Joe can handle. Maybe he has a point, Consider this, In one mans life span we have gone from horse drawn wagon, to the automobile, to the jet airplane, then to walking on the moon. Throw in the atom bomb, Vietnam, and computers, maybe it is more than Joe can handle. With the last President, science was ignored. Perhaps now with President Obama things will change. If the U.S. continues its downward trend regarding it economic downturn, then the climate change problem will be put on the back burner. Europe and Asia could lead the way for change. Greed is greed though. What drove us drives them as well. To Joe anything that changes his lifestyle is a loss of freedom. A seatbelt use law is like a communist plot. Even though it is for everyones good, to mandate any change for going greener, would be viewed as some sort of government restriction on Joes freedom. His motto is family, land and his rifle. Any change to deal with climate change will have to be done with out him. Alkataba
alkataba, whatever are you ranting about??
Contrary to your misguided understanding of the scientific method, it is not the accepted status quo that has the burden of defending the long held theory of natural climate variability; the burden is on the AGW/CO2 “tipping point” fanatics to explain how the climate is acting differently now than it has previously. So far, they have failed to show anything that is not explained by completely natural climate change.
Commenters on this “Best Science” site repeatedly ask why no one has ever been able to falsifiy the hypothesis that the observed temperature changes are the result of entirely natural climate variability.
But hey, maybe you can be the first to falsify that accepted theory.
See, until someone provides convincing evidence that the current climate is not fluctuating naturally, and well within normal parameters, then it’s all red-faced, AGW/CO2 flying-spittle “what if” arm-waving on one side of the argument, and ho-hum on the other.
Smokey says:
I suppose. I was just answering a question from RobJM who was wondering why you get an infinite result when you use the logarithmic formula to try to calculate how much forcing is occurring relative to the case of 0 ppm CO2.
Alkataba
“Even though it is for everyones good, to mandate any change for going greener, would be viewed as some sort of government restriction on Joes freedom. His motto is family, land and his rifle.”
It’ll be ok Al. Drink some chamomile tea and have a good night’s sleep. Maybe tomorrow you’ll be able to find the blog you meant this post for.
Joel Shore says the logarithmic formula should not be used for low concentrations of CO2. (CO2 has never been below 180 ppm so why should the formula and a chart showing these very unlikely low values be used at all?)
Because showing the entire spectrum of possible CO2 values provides an important insight into what the warmers are assuming for the “more normal” values of CO2.
They are assuming of course that CO2 is responsible for nearly the entire greenhouse effect. As CO2 creates an increase in atmospheric temperatures, the atmosphere is “capable” of holding more water vapour and the increase in temperatures does, in fact, result in a proportional increase in the water vapour content of the atmosphere.
The increased water vapour content then results in an amplified greenhouse effect. Since water vapour is the most potent greenhouse gas.
So when this post and others cites 33C as “the greenhouse effect”, it is important to note that the current estimates of 3.0C per doubling of CO2 assumes CO2 is responsible for nearly the entire greenhouse effect because water vapour will increase in lock-step with any increase in CO2.
If CO2 is Zero, then water vapour will effectively be Zero as well and we don’t want a chart shown to the general public which demonstrates this impossibility.
I don’t like theory that only applies to a small slice of possible values because that could indicate the theory is not “robust” – to use a warmers term, and could easily be faulty. The math needs to work backwards and forwards or there is likely a problem in the math.
In the case of the IPCC theory of global warming theory, CO2 is THE ONLY GHG because it is controls water vapour as well.
The empirical evidence to date does not support this assertion of course.
Here is the chart Joel Shore doesn’t want you to see.
http://img216.imageshack.us/img216/9652/logwarmingillustratedkn7.png
And here is how the data to date stacks up on those two lines – Zoomed-in to the Joel-favoured limited range of CO2.
http://img254.imageshack.us/img254/2626/tempobsrvvsco2ct4.png
One could say at this point that the estimates should be reduced in half.
Steve Goddard, thanks for a post that has generated 447 comments at the time of mine. When I first read it, I disagreed with a number of issues you raised. (Actually, I felt annoyed.) However, after living through the many knowledgable “rebuttals” of aspects of your argument, I have been able to re-educate myself. Yes, the main science issue today for combatting the nonsense of AGW-Climate Change is agreeing on the “real warming” effect of CO2 and deciding if there are any “forcings” or “feedbacks” –such strange animals. I see these molecules dancing around and slinging their LWs back at earth ad infinitum. Warm until you tip!
This is a real stretch for me, but doesn’t the basic physics of all the atmospheric gases together solve the problem?
I still believe that your acceptance of the idea of CO2 as a “Greenhouse Gas” complicates the problem of communication to a large audience. Analogies are great, but this one is a real loser. It reinforces the idea of human/divine omnipotence for good or ill regarding the climate. The idea of a greenhouse will immediately call up an image of Someone building those glass walls and someone else adding the gas. Flash point. Tipping point. I think we need to return to clear scientific terms.
Thanks for being willing to put your ideas forward to all us rowdies.