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Climate Hustle

A Scientific Guide to the 'Skeptics Handbook'

Posted on 1 July 2010 by John Cook

Not long ago, I read the Skeptics Handbook which displays some fundamental misunderstandings of how our climate works. I wondered whether a rebuttal of this document would be worthwhile but when I floated the idea to a few people, the general response was "been there, done that". It turns out there are a number of detailed rebuttals of the 'Skeptics Handbook'. Desmogblog wrote a 3 part series in 2008 (parts 1, 2 and 3). has a useful set of short rebuttals with links to longer answers. Tim Lambert also examined some of the arguments. So the 'Skeptics Handbook' had been rebutted on multiple occasions.

Nevertheless, there was something else that needed to be said. The 'Skeptics Handbook' begins by asking "what evidence is there that more CO2 forces temperatures up further?" It then lays out 4 arguments: the greenhouse signature is missing, CO2 lags temperature, it's not warming and the CO2 effect is saturated. The great irony of the 'Skeptics Handbook' is when you examine these 4 arguments and the full body of empirical evidence that goes with them, what you actually find is the evidence that more CO2 forces temperatures up further. Here's a brief description of how the Scientific Guide examines 4 human fingerprints on climate change:

  1. As greenhouse gases stop heat from reaching the upper atmosphere, a distinct greenhouse signature is a warming lower atmosphere and cooling upper atmosphere. This is exactly what's observed by satellites and weather balloons.
  2. Satellites measure more heat being trapped by CO2. On top of this, ice cores find temperature affects the amount of CO2 in the air. So warming causes more CO2 and more CO2 causes warming. Put these two together and you get positive feedback.
  3. The surface temperature record shows that the number of warm nights are increasing faster than warm days. This is another effect of greenhouse warming.
  4. To find out whether the CO2 effect is saturated, we just have to look at direct measurements - satellites find CO2 is trapping more heat and surface measurements find more heat returning back to Earth.

All 4 arguments highlight 4 distinct human fingerprints on climate change. Once I'd compiled all the evidence into a single document, I sent it around to a handful of climate boffins to nitpick any inaccuracies in the text. Much thanks must go to the scientists who examined the Scientific Guide and helped clarify the text (they're all acknowledged in the inside cover). Much proofreading credit must also go to my wife Wendy who offered a crucial layman (laywoman?) perspective. Scientists tend to take technical language for granted and she was instrumental in boiling down much of the jargon into plain English. She also created the design which I think has a pretty awesome look.

You can download A Scientific Guide to the 'Skeptics Handbook' as an A5 PDF. The booklet is actually designed to be printed out on A4 then folded to A5. So if you want to print out the booklet, here's the A4 imposed version. I hope you all enjoy the Scientific Guide and feedback is welcome.


Many thanks to all those who generously donated their time to translate the Scientific Guide into other languages.









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Comments 1 to 50 out of 73:

  1. Jo Nova still asserts that weather balloons have failed to find the hotspot and she produces a temperature map to support her case.
    How does a layman deal with one side that says balloons have found a hot spot and the other side that says balloons have failed to find a hotspot?
    BTW .. the guide is well produced and it went into the hands of most attendees to the WUWT tour. Lets hope they all read it.
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  2. John,
    You have done a good job, and please pass on our thanks to Wendy (behind every great man....)

    My big issue with climate change is our failure to present a compelling case to people not caught up in the debate. To often we do not balance precision with impact.

    so, once again thanks, and job well done
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  3. JC,

    Nova's actual assertion is:

    The greenhouse signature is missing.
    Weather balloons have scanned the skies for years but can find no sign of the telltale "hot-spot" warming pattern that greenhouse gases would leave. There's not even a hint. Something else caused the warming
    The problem for Nova is that the tropospheric hot spot is not a unique 'greenhouse signature'. What is a unique greenhouse signature is the fact the troposphere is warming and the stratosphere is cooling. Note there is a difference between the troposphere at large, and the tropospheric hot spot.

    The existence of the actual unique signature is supported by strong observational data. Nova just gets very confused and conflates the two points.

    There is a good argument to say the 'hot-spot' has been found - see here and here - but it's absence would not imply that humans are not causing warming, it would imply that there is no warming - something which would be at odds with all of the surface and satellite data. With this in mind I find John's arguments fairly persuasive.

    The hot-spot is very much not as much of an issue as Nova would like to have you believe.
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  4. An excellent little booklet, John; I will circulate it to all my sceptical friends.

    Just a couple of points. Having titled it "A Scientific Guide to the 'Skeptics Handbook'", it then doesn't mention what the 'Skeptics Handbook' is and therefore will confuse some readers who might come across it (one would hope) out of context. It would be good at the start to put a thankyou to Jo Nova for inspiring this handbook, plus a very brief explanation as to why the booklet was necessary (my tongue is in my cheek slightly -- but I'm serious).

    The other point is that some of the graphs are very low resolution. Would it not be possible to redraw them? The same applies to the UWA logo on the back cover.
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    Response: Good advice. Have mentioned the Handbook on the inside cover as well as my authorship, which I forgot to put in the first edition. Have also created the PDF with higher rez graphics. It pushes the filesize up from 330Kb to 800Kb which is still pretty small.

    For the record, when Wendy created the initial PDF, it was the proper resolution. It was only when I got involved in the process that the file went fuzzy.
  5. are you planning on doing translations? nova has her book translated into the following languages:

    Spanish ("El Manual del Escéptico")
    Japanese ("スケプティックハンドブック")
    Danish ("Håndbog for skeptikere")
    Balkans Translation (Bosnia, Croatia, Serbia)
    Portuguese ("O Manual dos Céticos")[5]: Fake Climate
    Turkish ("Şüphecilerin El Kitabı")
    Finnish ("Ilmastoskeptikon käsikirja")
    Ilmastofoorumi (
    Norwegian ("Skeptikerens håndbok")
    Swedish ("Handbok För Klimattänkare")
    French ("Manuel du Sceptique")
    German ("Das Skeptiker-Handbuch")

    i'm not sure that makes sense; as her book has a very low level of entry, and i guess that most copies are hawked online, i don't think that many non-english speakers will stumble about your fine book.

    however, if you think translations would make sense, i could do the German one.
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    Response: Just like the translations of the skeptic arguments (see flags at top of page), translations are very welcome. Anyone interested in translating the scientific guide, please contact me. Captain Pithart, I'll email you directly to organize details.
  6. Hi John,
    Would you mind clarifying (or choosing) the terms you've released your Scientific Guide under ( has a nice permissions picker if you want to use a CC licence).
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  7. John,

    Thank you for providing us with this material. I will definitely hand it out to my denying friends.

    I am just curious if you (or Alexander et al) didn't get the years wrong in the figures for Human Fingerprint #3, Nights warming faster than days. It seems to be a bit too many 1950's.
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    Response: You can check out the full paper of Alexander et al 2006 (refreshingly, the full paper is freely available online). I pulled the graphs from Figure 2 on page 7.

    UPDATE: okay, I see what you mean, thanks for pointing out the glitch with the years in the Alexander x-axis. Have fixed it.
  8. John

    Your Scientific Guide to the Skeptics Handbook is a terrific resource that will be of great value in setting the record straight. However, there is one point that is misleading if not erroneous.

    On p. 4 the guide states “In the past when the ocean warmed, this caused more CO2 to be released to the atmosphere.”

    This is true, but it implies that changing ocean temperature was the primary cause of past changes in CO2 observed in ice cores. This is not the case.

    Holding everything else constant, atmospheric CO2 will increase about 10 to 12 ppm for every degree C that the entire ocean (i.e., mainly the deep ocean) warms due to the temperature dependence of CO2 solubility in seawater. From the peak of the last ice age, about 20,000 years ago, to preindustrial times the deep ocean warmed approximately 2.5 to 3°C.

    Therefore, given the temperature dependence of CO2 release noted above, warming of the ocean can account for 25 to 36 ppm 1/3 to less than half of the 80 ppm rise in CO2 after the last ice age ended.

    However, all else was not held constant. The ocean also became less salty as the ice age ended. Melting of ice on land lowered the salt content of seawater by about 3%. The solubility of CO2 in seawater increases as the salt content decreases. The decrease in salinity of the ocean as the ice age ended lowered atmospheric CO2, offsetting about half the effect of rising temperature.

    Considering the combined effect of changing temperature and salinity, one can account for only a small (albeit significant) part of the rise in atmospheric CO2 since the end of the last ice age.

    Other processes must have controlled most of the change in CO2 seen in ice cores. Although there is still no consensus among scientists about the relative importance of various processes that regulate atmospheric CO2 levels, the processes are known. Two recent papers provide nice summaries of these processes, one in Science last week and one in Nature this week.

    Denton et al. (The last glacial termination, Science, 25 June 2010) describe the sequence of events that cause an ice age to end, including processes that raise the CO2 content of the atmosphere. This paper provides evidence of why temperatures in Antarctica began to rise before CO2 levels rose detectably as the last ice age came to an end.

    Sigman et al. (The polar ocean and glacial cycles in atmospheric CO2 concentration, Nature, 1 July 2010) reviews the various ocean processes that are thought to affect atmospheric CO2 concentrations. These processes are most important in the ocean around Antarctica, and they are linked tightly to climate. This coupling accounts for the tight correlation between CO2 and temperature that is clearly evident in the Antarctic ice core records.
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  9. Hello John,
    Have to agree with a poster who was concerned with the reproduction quality of the graphs. Also I noted on p11 'The Trend in Downward Infra-red Radiation' had an absence of data from the USA. Was this because the USA doesn't cause climate change? :-) Maybe your country is distancing themselves from responsibility for climate change? :-) Or is it another attempt by the USA to blame everyone else on the planet for the crisis? :-0) Yes, I am joking but some people will read the evidence, just like they do the sceptical arguments, (and read it exactly as I have suggested, albeit I was being tongue-in-cheek with my interpretations here) and believe the evidence as proof of blame should they finally lose the battle to say its all a con. The arguments can cut both ways like any good sword.
    Maybe also some explanation about the data source would suffice to dissuade the critics from being to literal.
    I also believe some reference to the original book would be justifiable. What is the point of a rebuttal without a target?
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    Response: It's not my country, I'm Australian :-)

    Re the downward infrared radiation figure, here is the original pic from Wang 2009:

    The reason for the lack of observations in the USA is explained on page 9. The figure shows the trend over a 25 year period. Over this period, the US and Canada changed their way of observing clouds from a human visual assessment (someone looking out a window?) to instrument measured. So there's no single continuous data series lasting 25 years in the US or Canada.
  10. JC #1 said: How does a layman deal with one side that says balloons have found a hot spot and the other side that says balloons have failed to find a hotspot?

    This is a very good question that most laypeoble should ask themselves, and persue it if they really want to have an informed opinions about this subject.

    My own attempts to overcome this problem were these:

    - Check the credibility of the claimer. Very subjective, and in principle nothing more than an authority argument. In practice, though, I think it's reasonable to attribute more credibility to NASA or NOAA or some Nature papers (specially if they concur with each other) than some loose claim in a blog. Or loose claim in many blogs. Understanding the difference between general media and peer reviewed papers helps, too.

    - Try to really understand the basics. The basic science involved is (to a large extent) accessible to, say, a good high school graduate. There's tons of information in the internet in research organizations and universities. Even some blogs (like this one) usually explain the basics including the relevant references (which is the important bit).
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  11. Great effort John, and an excellent idea! Have you emailed a copy to Ms. Nova?

    Perhaps one could consider this version 1, and it can be updated as new information comes along?

    Maybe one could expand on this sentence a bit "So the hot spot is the result of surface warming and is not unique to the enhancd (?) greenhouse effect. For example, surface warming from increased solar output would also cause a hotspot."

    I say "enhanced", because some might argue "well why is there not a tropical hotpsot before CO2 increased?" Well, there probably has been there ever since we've had a greenhouse effect, it all depends what baseline you use to calculate the anomalies.

    Also, I agree with others that the quality of some of the figures is not the best, but I realise that you may have had to grab them from low-res PDFs.

    You say that "As there are no air conditioners or cars in space to..."

    Maybe I'm being picky, but while the satellites are in space, the measurements are being made in layers high above the ground in the earth's the atmosphere, and yes up there there is no impact from the UHI.

    Conceding up front that one simply cannot cover all the bases in such a short booklet, I am disappointed that there is no reference to the increase in OHC or SSTs (did I miss it?). That would, however, tie in nicely with the "reality of global" warming-- no UHI over the oceans.

    Other have noticed this too, but is there any chance of "fixing" the x-axis labels in the Alexander figure? That is just the kind of thing to get Ms. Nova hopping. You know, falsum in uno, falsum in omnibus.

    And one last observation, perhaps it is worth noting that some of these "skeptical arguments" were trotted out in the early 20th century, over 100 years ago in some cases. The theory of human-caused global warming is robust and held up to immense scrutiny and new observations from satellites etc.

    PS: Will people be able to view this on their Blackberries or iPhones? Yes, I know, I am technically challenged....
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    Response: When I first mentioned "enhanced greenhouse effect" to Wendy, she thought enhanced made it sound like a good thing. Ditto for positive feedback. Nowadays, I called it the increased greenhouse effect.

    Re expanding on sentences, there is a lot more content that could go in there (and indeed was in there on the first draft). But as you say, you simply can't cover all bases in such a short booklet. And I don't think you should cover too much if you're trying to reach a broad audience. I would love to have got the Murphy ocean heat graph in there but well, there's only so much real estate. Basically, the website offers longer, more comprehensive versions of all these arguments. I'll eventually set up a page that makes all these longer webpages easily accessible from the one place.

    BTW, have fixed the x-axis labels in the Alexander figure and the low-rez graphics.

    Lastly, sorry, no plans for an iPhone version. But all this content is there in longer form in the iPhone app complete with all the goodies mentioned above.
  12. Captain Pithart #5

    Well spotted. I'll try to find some time to do the Portuguese one, as well. I'm not very good at formatting the text to make it look like the original, though.
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  13. John, you probably already know about this ... but if not, check out the booklet Climate sceptic arguments and their scientific background.

    It's similar to what you do here, and what the US EPA did earlier this year.

    What makes this one interesting, however, is that it's put together by a large corporation that sees climate change as a serious threat to its financial future.
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  14. I should note that I learned about that from Nick Stokes at his blog.
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  15. I looked at your Handbook this morning I liked it for the first production draft. I agreed with much of the constructive critique in the above posts so didn’t add anything.

    Being the kind of guy who's always trying to get inside the thinking of others, I found myself at the jonova website and have spent the last couple hours being frustrated and I will admit getting a bit overwhelmed. Especially, after down loading and looking over that masterpiece poster "Climategate: 30 years in the making" Quite the profession production... but with one thing in mind - to win their point of view.

    The spooky part is when "winning" becomes everything, where does that leave learning and adapting. When so much of the story must be ignored to prop up ones own point of view, where is the value in that?
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  16. It should be pointed out that even if the CO2-effect were "saturated", additional CO2 would still warm the Earth.

    As CO2 concentrations increase, the altitude of the "top of the atmosphere" (TOA) increases. (The TOA is defined as roughly where most of the outgoing IR can escape directly into space instead of being absorbed/reradiated by CO2 above it).

    As the TOA altitude increases, its temperature decreases (thanks to the lapse-rate that deniers have been flogging recently). Since the amount of IR escaping into space from the TOA is a function of its temperature, the new, "higher altitude" TOA will have to warm up so that the energy leaving in the form of IR balances the incoming solar radiation (first low of thermo).

    Since we now have a greater distance from the TOA to the surface, the lapse rate means that the Earth's surface must warm as the TOA warms in order to restore the incoming/outgoing energy balance. This will happen whether or not the CO2-effect is "saturated" at lower altitudes.

    Deniers keep forgetting that "CO2-saturation" at the surface does not mean "CO2-saturation" at high altitudes. They also keep forgetting that CO2 doesn't just absorb IR; it reradiates it.
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  17. Regarding the Handbook, in light of my visit at jonova and her commentators, there is much ridicule about scientists now using wind speed voodoo, to get the results "we expect."

    from the handbook:
    “Confirmation of the hot spot comes from measurements of wind trends. As there’s a direct relationship between temperature and wind shear, this gives us an independent way to calculate temperature trends. This method finds peak warming above the tropics, just as we expect.”

    Is there someway to give an explanation of how this works, perhaps a link.

    In fact, all the way around a little more meat, or citations would have been good.

    Although with handbook like this we almost need three different grade levels: simple: high school; college.

    Nice job though, with a great look too.
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    Response: The general plan will be the Handbook is the shorter, broader version - the website will contain the longer, more detailed, more technical explanations. This is probably preferable to having multiple versions of the Scientific Guide, particularly if I want to get any sleep at all :-)
  18. caerbannog #16 can you offer some links to this information? thanks
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  19. Hi John,
    I'm still a bit new to this so forgive me if this is a point made before.
    Why do skeptics need a handbook ?
    Seems to me it's more "the habitual contrarian's handbook"
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  20. Ned #14 - I originally wanted to say "Thank you Ned, nice stuff!" but in that case I'll make it "Thank you, Nick! (And Ned.)"

    And yes, the Guide booklet is nice-looking stuff too! *ponders what it would look like in Dutch* *ponder ponder ponder*
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  21. #18

    Tamino ( had a very nice explanation -- unfortunately, it doesn't appear to be on-line now.

    For the time-being a copy can be fished out of the Google cache here:


    As we add more CO2 to the atmosphere, it becomes optically thicker for those wavelengths of infrared. This means that to escape the atmosphere, it must be radiated from ever-higher altitudes. The temperature at the altitude at which the infrared actually escapes to space is determined by the incoming energy from the sun, and so does not change as we add more CO2 to the atmosphere. But the temperature at the surface will be higher than the temperature of this high-altitude air, by an amount which is governed by the lapse rate (which doesn’t change much) and by the height of that radiating layer.

    So, even if the atmosphere has so much CO2 that it is saturated in those infrared wavelengths, adding more CO2 raises the altitude at which those wavelengths of infrared escape to space, increasing the distance to the ground, and therefore increasing temperature difference between the radiation layer and the ground (which is the product “lapse rate” x “distance”).

    That’s one of the reasons that arguments that CO2 absorption of infrared is saturated, and hence adding more CO2 won’t increase global warming, are mistaken. Because of the lapse rate, raising the altitude of CO2 radiation escaping to space will still warm the surface.
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  22. caerbannog, all of Tamino's posts from before March of this year seem to have disappeared. I'm not sure what happened over there.
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  23. Well John here is a report from a Ph.D. physicist that does not agree with you or your readers that still believe that the "greenhouse gas effect "exists. Lets see how John butchers some real physics.
    30 June 2010
    On Some Flaws in Greenhouse Gas Global Warming
    I have just finished reading an excellent article by Alan Siddons called The Hidden Flaw in Greenhouse Theory on American Thinker from way back on 25 February 2010. The article is a little slow in developing, but finishes with a death blow to the usual theory put forth by catastrophic anthropogenic global warming advocates. I intend to explain more concisely what Siddons explained and to add comments of my own in this post which make the deathblow much more gory.

    First of all, I am going to enlarge the context of the discussion. The primary source of heat for the surface of the Earth is the radiant energy of the sun. The solar wind of the sun, materials dumped into the atmosphere from space, heat from the deep interior of the earth, and the interplay of changes in the Earth's magnetic field and the sun's magnetic field are also contributors of heat, though the sum of these is much less than that from the sun's radiant energy spectrum of ultraviolet (UV), visible, and infra-red (IR) light. The entire catastrophic greenhouse gas hypothesis ignores effects upon the incident IR portion of this spectrum of light from the sun. This is foolish.

    UV light is 11% of the radiant energy from the sun. The UV light variance of 0.5 to 0.8% with the solar cycle is much larger than is the visible light variance of 0.22%. UV light is absorbed throughout the atmosphere, but much still reaches the ground and is absorbed there. The amount of UV radiation absorbed in the upper atmosphere is highly dependent upon the amount of ozone there. The amount of ozone is highly dependent upon the solar wind, CFCs, and volcanic activity. When UV light is more absorbed in the stratosphere than the ground, its surface warming effect is diminished. The absorbed energy is re-emitted as IR radiation and much of that energy is quickly lost to space.

    The entire atmosphere is transparent to visible light which is the form of 44% of the radiant energy from the sun, so aside from reflection from clouds and aerosol particles, the visible light reaches the ground or oceans and warms them near their surfaces.

    Finally, the IR radiation is not absorbed by nitrogen, oxygen, and argon gases which make up 99% of the atmosphere, so a large fraction of it directly warms the Earth's surface. Some, is absorbed by the dominant greenhouse gas, water vapor, and small amounts are absorbed by carbon dioxide and other greenhouse gases. The incoming IR radiation absorbed in the atmosphere is less effective in warming the Earth's surface than is that which is absorbed by the Earth's surface directly. This is because some this energy absorbed in the atmosphere then is radiated again in the form of IR radiation, but now half or more of that is directed out to space. In other words, more water vapor and CO2 in the atmosphere results in a less effective warming of the surface than does less of these gases with respect to the incoming IR energy from the sun. The greenhouse gases have a cooling effect on the original solar radiance spectrum for the 45% of the solar energy in the form of IR.

    In each case, whether UV, visible light, or IR, not all of the radiation of that form striking the Earth's surface is absorbed. Some fraction is reflected and the fraction is very dependent on whether the ground is covered with snow, plowed earth, grasses, forests, crops, black top, or water. There are two real ways that man does have some effect on the Earth's temperature. He changes the surface of the earth over a fraction of the 30% of its surface which is land. He also converts fossil and biomass fuels into heat. Compared to the overall natural effects, these man-made effects are small, yet they are probably large compared to the effect of his adding CO2 and methane to the atmosphere.

    Wherever the atmosphere is heated, there is transfer of heat. In the outer, very low density atmosphere, the primary means of heat transfer is radiant transfer by IR emission from an energetic molecule or atom, since collisions of molecules and atoms for direct energy transfer are rare. In the denser atmosphere, most energy transfer is due to collisions and the convective flow of masses of warmed air. Near the Earth's surface, almost all of the energy lost by the warmed surface is due to gas molecules striking the surface and picking up heat and then colliding with other molecules to transfer heat from one to another. Once a body of air is so heated, then masses of warmed molecules are transported upward into the cooler atmosphere at higher altitudes or laterally toward cooler surface areas by convection. Any warmed molecule, most of which are nitrogen, oxygen, and argon will radiate IR radiation. However, no molecule or atom at a low temperature such as that near the Earth's surface is a very effective energy radiator, since the Stephan-Boltzmann equation depends upon the fourth power of the absolute temperature, which commonly near the Earth's surface is about 290K. Thus, gas molecule collisions and convection are the very dominant means of heat transfer. These processes on balance cool the surface of the Earth and redistribute some of the heat back into the upper atmosphere and cooler places such as those shaded from the sun or the arctic regions.

    The favorite claim of the catastrophic greenhouse gas global warming people is that an increase of carbon dioxide and methane gas in the atmosphere will cause energy radiated into the atmosphere from the ground to be absorbed by these molecules and they will radiate half of it back toward the ground, where that energy will warm the surface again and reduce the cooling due to the ground originally radiating that heat into the atmosphere. According to Alan Siddons, less than 1% of the cooling of the Earth's surface is due to IR emission of the surface or the gases near the surface. More than 99% is due to direct contact and convection.

    Since the dominant source of energy warming the surface of the Earth is the sun, let us do a simple calculation based upon the facts presented above. Let us say that greenhouse gases absorb a fraction f of the incoming IR radiation from the sun, which is 45% of the sun's incoming energy. Thus the energy absorbed by greenhouse gases from the incoming spectrum of solar energy is 0.45f and a fraction of this, say k is radiated back into space without coming near the surface. NASA says k is 0.5, but it is actually slightly larger than that given that much of this absorption occurs at appreciable altitudes. The total cooling due to greenhouse gases, somewhere in the atmosphere, is now 0.45fk. Of this energy, had it become incident upon the surface as IR radiation, a part would have been reflected rather than absorbed. The fraction that would have been absorbed is q. The net energy then lost to the warming of the surface is then 0.45fkq.

    Now, let us suppose that a fraction g of the total energy from the sun is absorbed in the Earth's surface or in the very lower part of the atmosphere. We know that g is a larger fraction of 1 than is f, since most of the solar radiation does reach the ground, including that part in the IR part of the spectrum. Of the energy g absorbed in the surface, only 0.01 times it is emitted as IR radiation according to Siddons. Since the greenhouse gas content of the atmosphere is unchanged the amount of outgoing radiation, serving to cool the surface, is now 0.01gf. A fraction j of this energy will be emitted by the IR warmed greenhouse gas molecules back toward the ground. NASA has said this fraction is 0.5. Let us then say j is about 0.5. The greenhouse gas warming of the surface due to absorbing IR radiation from the ground would then be about 0.005gfq, where q is the fraction of back-reflected IR radiation that was incident upon the surface and absorbed. Remember that some radiation is reflected.

    Now we will compare the greenhouse gas cooling effect upon the incoming solar radiation of 0.45fkq to the re-warming of the surface due to 0.005gfq times the total solar radiant energy. Breaking down the parts:

    0.005 is much less than 0.45, in fact it is 0.011 times as large.
    f appears in both factors, so the comparative effect is cancellation.
    The factor q appears in both the cooling and the warming quantities, so it cancels.
    k is somewhat more than 0.5, while g is the surface absorptivity for the entire solar spectrum and is likely to be near 0.7, or quite comparable.
    So let us say g and k are an approximate trade-off.
    Thus the net cooling effect of greenhouse gases is very greatly dominant because the re-heating effect is approximately 0.01 times the cooling effect.
    In sum, using a simple calculation we can approximate the effect of greenhouse gases on the surface temperature of the Earth. It turns out that the cooling effect due to keeping incoming solar IR radiation away from the surface is about 100 times the re-heating effect proclaimed by greenhouse gas alarmists. Now, if the effect were very large in either case, this might be cause for concern. We would likely be better off heating our planet than cooling it. But, then we are heating with land use changes and the release of energy from fossil fuels, so the generation of cooling CO2 may simply be compensating for these other small effects. Much more important to this issue than CO2 and methane is water vapor in any case. So, most of this cooling effect is due to water vapor and only a small part is due to CO2 and methane.

    Now, of course so much is going on here that this calculation is but an indicator of the likely net effect of greenhouse gases. A more careful calculation would consider the different weight of IR frequencies in the original spectrum of the sun and in the Earth surface emission spectrum. But, any changes due to these secondary issues are likely to be small compared to a factor of 100. In any case, this calculation makes mincemeat of the usual simple rationale for greenhouse gas warming alarmism. It is insane to focus only on the outgoing IR radiation from the Earth's surface while ignoring the large part of the sun's total incident radiation which is IR from the get-go. It is also insane to ignore gas collisions and convection currents as mechanisms for heat transfer.

    I used the greenhouse gas term in the presently conventional way, but in reality, all gases when warm radiate IR energy and as pointed out by Alan Siddons, they are all really greenhouse gases. But, here I used the term only for those gases that absorb IR energy.
    Posted by Charles R. Anderson, Ph.D. at Wednesday, June 30, 2010
    Labels: Alan Siddons, CO2 emissions, greenhouse gases, solar radiation
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    Response: The evidence for the greenhouse effect comes from multiple lines of direct measurements. Airplanes measuring the infrared radiation escaping out to space find a big bite taken out of the spectrum at CO2 wavelengths. This is confirmed by surface measurements that find that big bite of heat returning to the Earth's surface:

    We cover this topic at Has the greenhouse effect been falsified?. Please continue any discussion there.
  24. Factfinder - I read the article on the web. His hypothesis runs into some troubles with actual measurements, which show ~24W/m^2 heating of the atmosphere by conduction/convection, ~78W/m^2 by evaporation (latent heat), and ~396W/m^2 by IR. That's just under 80% by IR.

    Alan claims 1% by IR, 99% by conduction?

    I've said this before, I'll say it again - if your hypothesis is directly contradicted by the evidence, you need a new hypothesis.

    As to "all gases when warm radiate IR energy" - well, actually, no, certainly not with the same efficiency. N2 and O2 are basically transparent to IR, and very hard to heat/cool with it. It's like trying to heat glass with a heat lamp. CO2, water vapor, methane, etc. are very efficient IR absorbers/radiators, like heating a matte black surface.

    I don't think Alan has the science background to realize that; he's certainly not demonstrating it with that article.
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  25. factfinder: learn to link. That whole essay is here:

    If and when that diatribe is accepted for publication in a peer-reviewed science journal, it will be worth discussing. At that point, I will give more credence to the proposition that the fact it doesn't make much sense to me is my fault, rather than the author's.
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  26. Was it Siddons who wrote this?

    Compared to the overall natural effects, these man-made effects are small, yet they are probably large compared to the effect of his adding CO2 and methane to the atmosphere.

    "Probably large?" Not exactly authoritative. Something was lost in translation there, perhaps, or regurgitated incorrectly.

    Anyway, Alan Siddons has a record of conveying drastically wrong impressions. Readers should take his work with a grain of salt.
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  27. I note that Alan Siddons' paper was published on a site ('Climate Realists') that declares (in its 'About' link), "Climate Realists will actively promote the proposition that there is no such thing as Man Made Climate Change...". Does not that sound wholly political and as far away from the aims of science as it is possible to be? In consequence should not the paper lose all credibility for anyone in search of true scientific understanding?
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  28. Factfinder, you're missing a very important point. In fact, 100% of energy leaving the Earth leaves by radiation. There's no other way for it to leave. So your 1% number is way off. Even if it's correct for heating of the boundary layer of air at the ground (that's the first few mm, depending on wind), it's completely wrong for the net energy balance.

    Siddons may have a Ph.D., but he's kind of forgotten how to do physics.
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  29. FactFinder... You say that Alan Siddons is a "PhD physicist" but I'm having a hard time confirming this. I'm find that he is a "former radiochemist" but that's about it. In the interest of accuracy do you have better information than I'm currently finding on his credentials?
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  30. factfinder,
    That post argues against a complete misrepresentation of how the greenhouse effect works.

    GHG warming does not come from the absorption of incoming radiation, it comes from the fact that incoming radiation from the sun is mostly in or near the visible light wavelength, to which our atmosphere is largely transparent (which that post did not dispute). When that energy is radiated back out from the surface, it is at IR wavelengths, which GHG's absorb and reradiate, some of which goes back down to the surface. So the rate of energy leaving the surface is slowed down relative to the rate of energy coming in, causing an accumulation of heat energy.

    The closest this post comes to addressing the true cause of the GHG effect is here:
    According to Alan Siddons, less than 1% of the cooling of the Earth's surface is due to IR emission of the surface or the gases near the surface. More than 99% is due to direct contact and convection.

    Most heat loss directly from the surface is indeed via conduction or convection. In reality the greenhouse effect applies mostly to a "surface" at the low-to-mid-troposphere, with radiation becoming more dominant as an energy transfer source the higher you go.
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  31. "As greenhouse gases stop heat from reaching the upper atmosphere, a distinct greenhouse signature is a warming lower atmosphere and cooling upper atmosphere."

    Ive gotta ask... i understood the mechanism to be considerably different than the one stated here for the predicted stratospheric cooling.... basically arising from the fact that in the stratosphere CO2 works more as a coolant... with the heating o the stratosphere arising from UV breakdown o O2 and the subsequent formation o O3, and the absorption by O3 of UV being the heating mechanism in the stratosphere, but with the thinness of the atmosphere at those altitudes, CO2 works as a net emitter of LW, radiating more LW to space, after being excited by the aforementioned heating mechanism in the stratosphere. Thus more co2= more heat radiated away.
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  32. hi John,
    Have you considered the choice b/w Pielke snrs invitation and hypotheses 2a and 2b? (Invitation On Assessing Three Climate Hypotheses) You seem to support 2b judging by your handbook's CO2 emphasis but 2a may be a better fit for the evidence

    Hypothesis 2a: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.

    Hypothesis 2b: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and are dominated by the emissions into the atmosphere of greenhouse gases, the most important of which is CO2. The adverse impact of these gases on regional and global climate constitutes the primary climate issue for the coming decades.
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    Response: I hadn't seen Pielke's hypotheses. It seems to me 2a and 2b aren't mutually exclusive - any climate scientist would agree that CO2 is not the only driver of climate and that we need to take into account all forcings. The reason for the emphasis on CO2 is because it is the most dominant and fastest rising forcing. The emphasis on CO2 in the Scientific Guide is also necessary as the 'Skeptics Handbook' fails to recognise the many lines of evidence that more CO2 forces up temperature - this is a somewhat more extreme stance than the more nuanced views of Roger Pielke Snr.
  33. For really fanatical enthusiasts, Roger Pielke Sr., Gavin Schmidt and Eric Steig explore Pielke's invitation on a thread at RealClimate, beginning here.
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  34. "As greenhouse gases stop heat from reaching the upper atmosphere, a distinct greenhouse signature is a warming lower atmosphere and cooling upper atmosphere."

    I might be being pedantic.... But i do find that this first point really grates with me, and it dosnt seem to be clarifies at all in the document... Obviously most of the LW that leaves the troposphere escapes directly to space.. and although the stratosphere indirectly effects pressure systems etc, for the most part the stratosphere and troposphere are independently effected by co2(although more H2O vapor in stratosphere will also contribute to cooling, and there will still be back radiation from stratosphere, but not overly significant)

    I know you are just keeping it simple, but i think this may be over simplifying... Maybe something more detailed as to the why of the stratospheric cooling in the document, to clarify the point. Because as it stands, it misleads on the mechanisms.
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  35. Joe Blog #31/34, actually every source I've ever seen explains the stratospheric cooling as John has here.

    Yes, there is ALSO cooling in the stratosphere due to ozone depletion... but that is a completely separate issue.

    You can find a basic overview of both at;
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  36. *gives it a try, still keeping it simple*

    Imagine a stable situation where neither lower nor upper atmosphere warms up or cools down. Now scatter millions of tiny "heat mirrors" throughout the atmosphere, which scatter outgoing radiation in all directions, instead of straight up (from earth to space).

    Result: some of the heat won't reach the upper layers and stays in the lower layers. The lower layers warm up more than they shoud, the upper layers cool down.

    (Okay, maybe this was *too* simplistic.) ;)
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  37. CBDunkerson... Yeah, you know, I've heard that argument of "the heat reradiates out to space" quite a few times on various blogs. Joe Blog puts it fairly succinctly in saying "thus more co2= more heat radiated away." In particular I've seen this stated by people on the JoNova site.

    It makes no logical sense to me that CO2 would reradiate heat in only one direction. But being that this argument is getting spread around it probably warrants some more research. You know, once these things start to fester...
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  38. robhon, and CBD, ill be the first to admit its totally counter intuitive, and its not a Q of it radiating in one direction, it still radiates in all directions... But in the stratosphere this is how it works. This thread here is one of the better ones for getting it conceptually.

    And this paper may help with understanding stratospheric temps;2

    Yah gotta remember the greenhouse works by increasing the optical path length for the LW spectrum, so it increases the energy capacity of the troposphere.... that dosnt mean LW is prevented from leaving the troposphere... there will still be for all intents and purposes LW going from the troposphere UP... Some of that will be absorbed higher up, no doubt, but the temperature profile in the stratosphere is reversed. with heat increasing with altitude... so from this we can probably safely conclude, that radiative heating from GHG in the troposphere isnt the cause of the temperature profile in the stratosphere( its self evident)
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  39. I'll try these links again
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  40. robhon at 02:23 AM, the radiation of heat is always in one direction, from the warmer body to the cooler.
    The trick is working out is which is the warmer body and which is the cooler, which seems to be the basis of much of the debate over global warming.
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  41. JC, re your comment added on #9,"Over this period, the US and Canada changed their way of observing clouds from a human visual assessment (someone looking out a window?) to instrument measured. So there's no single continuous data series lasting 25 years in the US or Canada."

    That implies that there is no way of correlating or merging visual assessment with instrument measurement.
    This begs the question, are all the other points on the chart being measured by the one method, either visual or instrument?
    If there is a mixture of methods then the should the chart be considered a valid representation.
    Does the inability to merge the visual and the instrument data also condem the realibilty of any visual assessments?
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    Response: I would assume there's a boffin somewhere doing a reanalysis to merge the older US & Canada data with the newer instrumental measurements. It just hadn't been done when Wang et al was written.
  42. JohnD posits that photons must have some means of discriminating between objects warmer or cooler than the body from which they are emitted and then somehow selecting their direction of emission so as to only travel in the direction of cooler objects. There is no mechanism to produce such behavior and there is simply no room in physics for it to be found.

    In a perfect world JohnD would apologize for blurting out such a shockingly misleading assertion and thus possibly conveying a phenomenally defective concept into the minds of people who may not realize they're being told breathtakingly incorrect fiction.

    Such a remark is worth remembering and even pointing out every time JohnD makes an assertion on this site.
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  43. johnd > the radiation of heat is always in one direction, from the warmer body to the cooler.
    No John, that is incorrect. The net radiation absorbed + emitted is dependent on an object's surroundings, but all objects warmer than absolute zero emit thermal radiation. Perhaps you are thinking of conduction? The amount of thermal radiation emitted by an object is determined entirely by its own temperature, not by the temperature of its surroundings.

    The trick is working out is which is the warmer body and which is the cooler, which seems to be the basis of much of the debate over global warming.
    The surface of the earth is warmer than the atmosphere at higher altitudes, the earth itself is warmer than empty space, and the sun is warmer than the earth, nothing "tricky" about it.
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  44. To add slightly to my comment above:

    ... all objects warmer than absolute zero emit thermal radiation in all directions.
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  45. doug_bostrom at 07:49 AM, what you appear to be saying is that if a molecule of CO2 is at point A, and another molecule of CO2 is at point B, if molecule A is cooler than molecule B, molecule A has no way of knowing that the energy being radiated towards it by molecule B is greater than the energy it, molecule A is transmitting, and molecule A will still radiate and transmit energy to molecule B.

    Making the analogy with your car, if you happen to enter onto a one way road the wrong way, you'll continue down the off ramp on until the car travelling up the off ramp collides with you enabling your car to transfer it's lower energy to the other higher energy car.
    It seems to me that if that occurred that neither car would be transferring it's energy from it's point of origin to it's destination other than to the point of collision where it is dissipated.
    However if the collision was between your car and a bird, which gets stuck in your radiator, your car having the greater energy would absorb the energy being dissipated by the bird and be able to continue on to deposit the nett result at your destination as long as the bird was the only other traveller on the road travelling against your direction.
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  46. e at 07:55 AM, the wood fire we have burning right now is not keeping the room warm enough.
    According to what you have stated, if I get a block of ice from the freezer and put it in the room, the ice will emit extra thermal radiation into the room in all directions because it can't sense any incoming radiation.
    How far would I have to stand from the block of ice to benefit from such additional thermal radiation given I am colder than the fire but warmer than the ice?
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  47. johnd,
    think about net radiation fluxes and everything turns out to be quite obvious. The ice cube emits radiation, more than any object at a lower temperature in fact. If ambient temperature is colder than the ice cube, it will "warm" you, if we agree that "warm" means that you loose less heat.
    Also, remember that thermodynamics works with a large number of objects, with just two molecules it does not make any sense. A molecule will emit it's excess energy regardless of the surrounding.
    But we are way offtopic here.
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  48. johnd, doug_bostrom - you agree. NET heat aways moves from hot to cold, at a rate determined by the sum of energy fluxes in all directions.

    johnd - Just so you know: this was actually a long and painful topic a while back, where certain posters stated "heat always goes from hot to cold", claiming that no energy went from cold to hot, arguing that the greenhouse effect violated thermodynamics. They were quite wrong, of course, but that particular phrase was code for quite an argument. Hence visceral gut-clenching reactions for a number of people, myself included!
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  49. I find it absolutely astonishing how confident JohnD is as he attempts to validate his idea that photons can control their direction of emission by observing their surroundings, or are selected for particular destinations by some mechanism having universal information on the temperature of surrounding objects.

    Yes, KR, of course it's about NET flow but JohnD is apparently not prepared to admit that because this is a favorite hobbyhorse of impressionists. "How can something cooler warm something that's warmer?" Not a hard question to answer, much more difficult is defending a theory requiring that photons be endowed with information from their future.

    Forget all the ice cube and fireplace business, JohnD. You're working with a failed idea. Think long and hard about how you were led into repeating it.
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  50. #32 and #33

    When you say "The reason for the emphasis on CO2 is because it is the most dominant and fastest rising forcing" you are supporting Pielke snrs hypothesis 2b and rejecting 2a. They are mutually exclusive by my reading.

    Doug and John,
    The Real Climate discussion that Doug links to predates Pielke snrs invitation for people to improve the wording of the hypotheses if they feel the wording is inadequate, as claimed by Eric in the Real Climate discussion. This Pielke snr post, which also predates the invitation, condenses the different viewpoints.
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