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Brexit or not, I'm very cynical about the EU's CO2 emissions targets. So far, we're seeing all kinds of great claims for progress, but on closer examination, it looks to me like the EU (and others) are just playing a numbers game. One of the favorite tricks is to shut down coal use while ramping up natural gas. While it's true that burning a given amount of coal puts out about twice as much CO2 an energy-equivalent amount of natural gas, this does not account for the fact that a significant percentage of the gas will leak into the atmosphere unburned. This is particularly true if the gas is produced by fracking.
What we call "natural gas" is methane, and it is at least 25 times more potent as a greenhouse gas than CO2. Some estimates claim the greenhouse potential is about 85 times - it depends on how long the methane remains in the atmosphere (it does break down in sunlight after more than a decade, producing CO2 and water). Even with the minimum figure of 25 times, it should be obvious that even a small percentage leak will negate any benefit of switching from coal to natural gas.
As I understand it, the EU gets most of its natural gas via pipeline from Russia, and that this is not produced by fracking. But the greatly increasing demand for natural gas to meet emissions targets is creating pressure for fracking in Western Europe. That would be disastrous. It's not just the well-known problem of water pollution we'd have to worry about, but the fact that an estimated 3 to 9% of fracked natural gas leaks out to the surface through zillions of cracks that are created in the fracking process. There is probably no way to contain that.
When natural gas in brought in from the Middle East on LNG freighters, you avoid fracking but you have another problem - about 40% of the natural gas gets consumed the process of creating LNG (by refrigerating it to −162 °C) and then bring back up to operating temperature so it can be burned. The longer the gas gets stored, the more gets wasted, because of the need to keep it so cold.
There is also the numbers game that I mentioned in a previous post, switching from coal to wood pellets. This has set off an enormous worldwide demand for firewood, which Germany (among others) is importing from North Carolina and Finland.
It's not only the EU that plays this numbers game, but also the USA, as well as several Asian countries such as Japan.
And Taiwan, where I live. Our recently elected new government here in Taiwan is busy trying to shut down the nuclear powerplants, and replace them with something that doesn't emit CO2. So we too will be joining the numbers game, with LNG and firewood as our new "green" technology.
The numbers may look impressive on paper, but the laws of physics will not be fooled. Keep spewing CO2 and methane into the atmosphere, and the world is going to get warmer.
DAK4Blizzard @1, ATTP has a post on the study which is more informative. In particular it shows a graph of observations of full depth ocean heat content compared to the CMIP5 models:
As you can see, OHC increased on average, over the period from 1970-1992, although with some periods of decline within that interval.
ATTP also produces a table from the paper showing the total increase in OHC over the intervals:
The change in OHC from 1970-1991 is, evidently, 28.3-13.5 = 14.8 (X 10^22) Joules. We thus have an average gain over the intervals of:
1970-2005 -— 0.49 W/m^2
1970-1991 -— 0.42 W/m^2
1992-2005 -— 0.6 W/m^2
To confuse things further ATTP quotes the paper as indicating changes in OHC of 0.68 x 10^22 Joules/Year from 1970-2005 and 1.22 x10^22 Joules/Year for 1992-2005, which resolve to 0.42 W/m^2 and 0.76 W/m^2 respectively. The later is 0.01 W/m^2 higher than the value given in the article above, but the former is 0.04 W/m^2 smaller. The annual values from the paper likely differ from the values quoted above because, firstly, I assumed a year of 365.25 days, whereas the actual average year lenght will have varied slightly depending on just how many leap years fall within a given interval. (Particularly a factor given that 2000 was not a leap year). Secondly, the annual values will differ because they will be based on the trendline, whose endpoint need not coincide with the terminal points of the actual values (and will not for the 1970-2005 interval, given the large inflection).
I do not know why the article above calculated a different W/m^2 value from the annual Joules/Year values cited in the paper. It may be because they took into account the actual number of leap years involved.
Only somewhat related to the original post, but are there any prospects in the near/medium term of making a direct measurement of the energy imbalance of the earth? In principle there is this nice clean interface at the top of the atmosphere where there is only shortwave radiation coming in from the sun, and only reflected shortwave and emitted thermal radiation from the earth. The imbalance should be about 0.75/340=0.2% so the precision of the two measurements must be better than that. Is this impossible? Or is it just that ignorance is strength (profit)?
As I calculate it, if in the 13 years between 1992 and 2005 the warming is 0.75W/m2 that would be a total warming of 13*0.75*(Sy*AE). For the 35 years between 1970 and 2005 you would have 35*0.46*(Sy*AE). For the 22 years between 1970 and 1992 you would have (35*0.46-13*0.75)*(Sy*AE) or an average warming of (35*0.46-13*0.75)/22=0.29W/m2.
So the earth was warming even then, though at a lower rate.
In the above Sy is the number of seconds in a year and AE the area of the earth (the cancel out).
I think it was Ken Caldeira who modelled the effect on forcing due to increasing boreal forest growth and he found it was actually a positive feedback due to the decreased albedo of greener (=darker) causing more radiation to be absorbed.
As you all point out, the "CO2 is a trace gas" myth is entirely purile. Spencer is supposedly a grown-up scientist and, although suffering from deep delusions, he is fully signed up to CO2 as a GHG and the forcing resulting from a doubling of CO2. More, he is also signed up to the temperature rise resulting from such a forcing prior to the operation of feedback mechanisms.
So why does Spencer's 'white paper' expend 10% of its waffle on this childish nonsense proclaiming "CO2 is a trace gas"? I don't believe Spencer has resorted to this specific argument before. Indeed, the question being addressed "Does an increasing CO2 level mean there will be higher global temperatures?" is not even answered but left with a "suffice it to say" comment which makes this section of the White Paper entirely propagandist in nature. Thus I brand it anti-scientific. Such a blatant level of disregard for science appears to me as a new departure for Spencer, assuming Spencer is the true author.
(Unlike some other phrases in the White Paper, that "suffice it to say" phrase is encouraging for Spencer-as-the-author in that the phrase is a Spencerism eg. as per this following Spencer quote describing the temperature of the Earth with zero GHGs, of which "trace gas" CO2 is the major not-so-temperature-dependent GHG. Note this quote also stands to demonstrate how far away this White Paper is from Spencer's usual blather. "If the atmosphere could not intercept (absorb) any of that surface-emitted IR energy, ...Suffice it to say the Earth would probably be too cold for most life as we know it to survive." )
Indeed, I once encountered someone on line who boasted about an AGW denying high school science teacher they knew who demonstrated to his students how little CO2 there is in the atmosphere by having them calculate how small a volume 400 ppmv of the school swimming pool was. I countered by suggesting that he next have his students add 400 ppmv of India ink to the school pool and report back. My suggestion didn't sit too well when I added that his students would then have learned something insightful.
Trace gas: 400 ppm of black ink will turn a 50 gallon aquarium tank of clear water dark.
I think this is an excellent example to contradict the "trace gas" meme. Pure water is transparent to visible light, and ink turns it dark, causing it to absorb visible light. It only takes a tiny bit of ink.
In much the same way the air, mostly nitrogen and oxygen, is transparent to infrared heat energy, but adding CO2 turns it dark to infrared, causing it to absorb infrared heat energy. It only takes a tiny bit of CO2.
This is a very familiar effect to just about eveyone, like adding chocolate syrup to milk to make chocolate milk, or adding coloring to white paint, or dyeing Easter eggs, etc. It's just very easy to understand, adding something dark to something light makes the light thing dark.
The very next sentence "with more CO2, the leaves' pores will absorb the gas more efficiently and in the process lose less water", and the later discussion that carbon uptake due to CO2 fertilisation and water retention are directly linked, clarify the confusion around this typo.
In the paragraph after the second picture, the second sentence states "as we fertilize the plants with carbon in the air, this directly decreases the amount of water the plants are able to retain". Shouldn't 'decreases' be 'increases'?
You might also be interested in this chapter by Crisp & Titov about the development of the understanding of thermal balance and radiative trannsfer in the Venusian atmosphere. The book was published in 1997 so more has happened since.
There are a number of extra factors that need to be consered.
Obviously pressure and temperature broadening of the existing absorption lines/bands.
Also Collision Induced Absorption. This is where molecules that may not otherwise be absorbers, or wavelengths where absorption may not normally occur at all become able to absorb during the transient time when a collision is occurring. For example, Nitrogen (N2) is the major GH gas on Titan due to CIA and Nitrogen/Hydrogen (N2/H2) collisions may have been a contributor to the GH Effect in the Early Earth atmosphere.
Scattering, which is negligible in the IR in Earth's atmosphere needs to be included when dealing with the much denser Venusian atmosphere.
Continuum Absorption is another mode of absorption that can occurr where a molecule absorbs over a continuus spectrum. H2O continuum absorption needs to be included when considering H2O vapour on Earth. CO2 also exhibits continuum absorption on Venus. At the time of writing of this book, the understanding of continuum absorption was still developing. It is better understood today.
Spectral data from the HiTran spectroscopic database doesn't apply for Venus, what is used is the HiTemp database of data for higher temperatures.
Consider Mike. Gases absorb in lines/bands but solids and liquids absorb/emit with continuous spectra. Venus has an atmospheric density nearly 100 times that of Earth. That means it has a density nearly 10% of liquid water. Is the lower Venusian atmosphere a thick gas or a thin liquid? At what density does the transition from discrete band/line absorption to continuous whole-of-spectra absorption occur?
I note that the Regina Leader Post has given Ross McKitrick right of reply to the excellent Michael Mann op ed linked above (McKitrick op ed published on Jul:25 - check the LP website). Needs another reply from someone who is on top of the details, methinks.
1) "There has been virtually no warming on the GBR"
On the contrary, there clearly has been warming on the Great Barrier Reef:
The resort to a limited time span (1982-2014) when more extensive data is easilly available, or to July temperatures (when the bleaching occurred over the Feb-April interval) clearly represents cherry picking.
What is more, the area of most bleaching experienced record SST over that period:
2) Hendy et al (2003) in addition to showing coral die of events in 1782-5 and 1817 also shows LIA GBR temperatures elevated to end 20th century values (figure 2, bottom panel). The LIA was a period of depressed global mean surface temperatures which need not have been represented by depressed temperatures everywhere and were not in the GBR. Including the missing evidence about LIA SST in the GBR shows the evidence that purportedly shows no temperature dependence in fact shows a relationship between die backs and elevated temperatures.
3) It is true that some reefs have recovered rapidly from die backs, but others have not, and some have recovered but only with a massive loss of biodiversity. One of the key factors in rapid recovery is the presence of nearby reefs with appropriate species to recolonize the site of the die back. In mass coral bleachings, the great extent of the bleaching makes that less likely. The greater the extent, therefore, the greater the long term loss in coral viability.
That leaves aside the obvious point that these mass bleachings are occuring at current temperaures. If the target for restraining global warming is met, we can expect an additional 1 C increase in global Mean Surface Temperatures relative to 2015. If not, it will be much more than that. The likely consequence is that we will experience mass coral bleachings not every decade or so, but every few years - meaning the bleachings will occure of reefs not yet recovered from the last bleaching. The consequence will be a long term loss of vitality for coral reefs - and that is considering only the effects of temperature based mass bleachings.
A very short way into reading 'A Guide to UnderstandingGlobal Temperature Data'by Roy W. Spencer, Ph.D. I start to question whether Roy Warren Spencer, Ph.D. is truly the author. I know the second page has a paragraph titled "About the Author" which provides a biog for Roy Spencer but, thinks, the rest of this booklet is so well packed with dubious nonsense, should we not ask whether the authorship it ascribes to itself is also dubious nonsense.
My actual reason for questioning the authorship is based simply on a quick reading of a couple of the sections. As such my conclusion is prelimenary. My initial take on this booklet is that, as I have read a lot of drivel from Spencer in the past, the content of this booklet, the narrative, its structure, its argumentation, its vocabulary - it does not read like the same Roy Spencer!!
Thanks for an interesting article. Clearly Spencers case is without substance, and all those arguments have been debunked.
Spencer has made a mish mash of multiple arguments, including some very silly arguments. This just weakens his case, and makes it look as though he has no one point he really believes in, and is just throwing everything at the issues hoping something will stick, or the sheer volume will create doubt. Therefore his presentation has no credibility to me. It certainly totally fails to get us any nearer the truth about anything.
The only sceptical point that deserves consideration is climate sensitivity, as we are not 100% sure. However the weight of evidence suggests it is moderate to high and the paleo climate evidence is compelling.
The small number of studies suggesting it is low are based on the slower period of warming from roughly 2002 - 2014 and are arguing that this slow rise shows climate sensitivity is low as either the greenhouse effect is not a strong as thought, or is overwhelmed by natural variation.
However this doesn't bear scrutiny. Obviously its dangerous to use a single short time frame, but the argument also falls down because recent science suggests the "pause" was largely because heat has been directed into the oceans, and this is because human aerosols have changed wind patterns. This means the pause is a temporary human caused event, unlikely to repeat, so cannot possibly be used as a basis to argue low climate sensitivity!
Even if climate sensitivity is lower than thought, and global temperatures increase more in the 2-3 degree range rather than 6 degrees, I have an instinct that weather patterns “themselves” and ice sheet stability may be more sensitive to low rates of temperature change than thought.
Consider that we have seen about 1 degree C of temperature increase since 1900, and ice sheets seem to be destabilising faster than early IPCC predictions and heatwaves are also ahead of predictions.
2. Paleo studies such as Hendy 2003 foudn warmer temperatures durng te LIA
3. Coral bleaching from and El Nino ismuch like a devastating forest fire from a dry La NIna spell. There is a natural recovery and coral often recover from natural bleaching faster than a forest recovers from a nautarl fire.
Northwest Australia's Scott Reef, the upper 3 meters lost 80 to 90% of its living coral and the disappearance of half of the coral genera. Yet researchers observed, “within 12 years coral cover, recruitment, generic diversity, and community structure were again similar to the pre-bleaching years.” A similar long-term study in the Maldives observed a dramatic loss of coral during the 1998 El Nino but by 2013 the reefs also had returned to “pre-bleaching values”. Although a reef’s recovery sometime requires re-colonization by larvae from other reefs, a process known as re-sheeting or Phoenix effect can facilitate a reef’s speedy recovery. Often a small percentage of living “cryptic” polyps with a more resilient symbiotic partnership were embedded within a “dead” colony and survive extreme bleaching. They then multiply and rapidly “re-sheet” the colony’s skeletal remains.
[GT] Link connected. Please use the link tool on the editing menu to create links. Please provide more than a link to an image. It is unclear from the link what the source of the data is, who generated it etc.
Gavin, thank you again for a cogent summary of a tremendous body of work by thousands of scientists.
Now I only fear the most damaging, it is a yet un-numbered myth: That we can ignore this, or somehow, temporarily disregard facing the problem.
Temporary denial, is still denial - and as psychotherapist Betty Merton said, "Of all the ways to deal with a problem, denial is the least effective."
Like going to the dentist, or seeing a doctor because of a pain that will not go away - now we are in the acting mode. We have the information and we are feeling the pain. Time to alleviate and mitigate.
We have all changed our lightbulbs, now the smallest task is to vote and/or support a candidate who is aware of the problem. Most politicans are sinfully unaware, or misinformed. (just my survey of a few state legislators, someone needs to do a study of this) And we have to tell them to face it. We must exhort everyone - especially leaders and manager - to face the facts and engage with the battle directly.
Just as an afterthought, one of the peculiarities of fake realities arguments is the insistence that the standard account of mean global insolation is that it represents a model with four cool suns because the formula for global mean insolation, TSI x (1- albedo)/4, contains a division by four. As he states @116:
"The reason is that you use an average flux density that is wrongly calculated by using TOA irradiation/m^2 and divide by four. That gives a surface flux equivalent to 4 small weak suns which heats a m^2 with an intensity of 259W, when the surface cools with a flux of 390W."
The division by four is fully explained as the ratio between the area of a cross section of the Earth defined by the terminators, and the area of the Earth's surface. It requires no further physical explanation ... something so obvious as to not normally require stating.
The peculiar thing, and the reason for this tardy note is that fake realities model requires a division of insolation by two. By his own reasoning, therefore, he is invoking two hot suns in his explanation of insolation. Not only is he glaringly wrong, but also outragiously inconsistent in his reasoning.
In your posts @143 and @147 you seem to agree with me that adiabatic processes can’t increase the average temperature of an atmosphere, but merely redistribute it. If the average temperature is determined by absorbed insolation only, one would expect the Venusian atmosphere with its very high albedo to be colder than the Earth’s, right? So, how do you explain this temperature/pressure profile?
As you see, about 50% of Venus’ atmosphere (by mass) is hotter than 385oC, nearly 90% is hotter than 222oC and nearly 99.9% is warmer than the average of the terrestrial atmosphere (about -20oC). If you calculate a "mass-weighted" average temperature based on this table the result is about 350oC. This is obviously much, much hotter than can be explained by any redistribution of heat. Something else must be going on! The graph below gives a clear indication of what this "something" is.
Only a very tiny fraction (~1 %) of the nearly 16,000 watts/m2 of IR radiation from the surface escapes to space. The lower and middle atmosphere is almost completely opaque to IR, so virtually all the heat loss to space happens from the very thin and cold upper layers that are more or less transparent. This raising of the effective emission altitude to colder, less emitting layers of the atmosphere is the very core of the atmospheric greenhouse effect. The lapse rate engine is not an alternative to this, but a crucial part of it, as Glenn Tamblyn has explained. An isothermal atmosphere (same temperature at all altitudes) full of greenhouse gases couldn’t raise the surface temperature because the effective emission altitude wouldn’t matter for the heat loss to space. And an atmosphere with normal lapse rate but no greenhouse gases would be transparent to IR and thus let the surface radiate directly to space as if the atmosphere wasn’t there at all.
An important point to consider. Changes in CO2 concentration are expected to produce an accumulation of heat. But where the heat is likely to go is the issue. All parts of the system will need to warm - atmosphere, oceans, land surface and Cryosphere (via ice melting). However it takes very different amounts of heat to produce the same temperature change - air is easy, water in the oceans is the big one. So we would expect most of the excess heat to go into the oceans, still only producing a small temperature change.
Which is what we are seeing. Around 93% of the heat being added to the system is appearing in the oceans. The rest is divided roughly between heating land, air and ice. So when you only look at what is happening to surface air temperatures you are looking at a very small part of the system. The tail rather than the dog. And since energy can also flow between the various parts of the system, changes in the energy flows between the air and oceans can have sigificant impacts on air temperatures while only impacting the ocean slightly.
So the air temperature record is looking at a small part of the system, thermodynamically, and a rather noisy part.
One site showing changes in ocean heat content is NODC here. The most relevant graph is panel 2 in the animation, 0-2000 meters.
It was a simple question from an interested layman, not critique. From this you extrapolated a non-existing disdain for all climate scientists. I was apparently not humble enough in my question. Anyway, thanks for your reply, it answered my question, kind of.
[PS] Jobel, you make a fair complaint, and Tom, I think your response was overly, and unnecessarily, aggressive. Sadly, SkS sees far too many fake skeptics, would-be Galileo's and other idiots. Frequent responders are inclined to assume the worst. I would ask everyone to be careful with tone.
Was it above wet bulb 33 or was it 35 degrees C that humans can't survive without some artificial cooling. We lived in the desert for many years but there, despite 40 degrees every day, the wet bulb temperature was down around 20 due to the dryness of the air. How much of the earth is going to become uninhabitable.
"... hope that someone can explain this in layman's terms"
In layman's terms the explanation is simple. Your purported facts are fictions.
The temperature series has not increased in a linear fashion except since shortly after 1960. And over the period 1960-2013 population also increased in a linear fashion (trend: 80.4 million per annum; Standard Deviation: 0.36 million; r squard: 0.999; correlation:0.999). Overall the correlation of population to Global Mean Surface Temperature from 1880-2013 was 0.900 From 1850-2013 it was 0.897, not as good as the 0.902 correlation between CO2 and GMST, but very impressive all the same.
You write that "If the heating of the planet was caused by human action then the smoking gun would be a correlation between number of people and global temperature but there is none." The key problem for you, however, is that there is a correlation - a high correlation - between population and temperature. That means when you asserted the contrary you simply made up a "fact" to suite your argument. It also means that if you actually believed that "If the heating of the planet was caused by human action then the smoking gun would be a correlation between number of people and global temperature", you would not accept that the global warming in the 20th century was anthropogenic.
Of course, by reverting to population rather than CO2 concentration, you are moving further away from the theory you purport to criticize. The warming is not a direct function of human population - but of increased greenhouse gas forcing. And while human population growth has contributed to the growth in emissions, and hence to the growth in temperatures; they do not have a linear relationship. Indeed, per capita emissions have grown approximately quadratically:
Temperature, in the mean time, grows with the forcing, ie the log of concentration. Combined the two effects mean that temperatures will grow at slightly below a linear rate relative to population. To determine the actual rate, however, we would need to compare the growth of all forcings vs population. That becomes a complicated and obscure way to check a theory which stands up to far more obvious and direct tests.
Finally, when you say a theory is refuted "looking at it from a pure logical viewpoint" you are saying the adherents to that view have made fundamental errors of reasoning that are easilly exposed. You are saying of the climate scientists who developed that view that they are either incompetent or dishonest. That hardly seems like a friendly approach to me. If you want friendly, try being a little less arrogant and begin with the assumption that the scientists are competent so that if you think you have a knock down argument against them, you are probably wrong. By all means then ask us to identify where the error lies - but don't assume that the thousands of scientists are wrong because of your bee coaster argument that you have not bothered fact checking.
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Thanks Tom for your answer. No need to be unfriendly, I am just curious. I thought it was obvious from my post that I am a layman, I am looking at it from a pure logical viewpoint. That said, I realize that I did a major error in my first post. I wrote about correlation between CO2 and temperature, but I meant number of people and global temperature levels. Very sorry about that!
So here is the third argument rephrased correctly:
“The planet is accumulating heat”: yes, the diagram clearly shows a drastic increase. But the time period starts 1960, if you instead look from 1880 you get a slightly different picture: the temperature has increased during the 20 century but in more of a linear fashion. If the heating of the planet was caused by human action then the smoking gun would be a correlation between number of people and global temperature but there is none. the number of people are increasing exponentially, global temperature increasing linearly.
Sorry for the error, hope that someone can explain this in layman's terms
The article made many points. I just posted it to see what people thought. I'm not too sure about pointing a fan at the window, but will experiment to see.
Cold baths are a great idea, but tedious to do all night. This is when the heat really gets to me as I'm a light sleeper at the best of times.
I agree air conditioning has partly got us into the high emissions problem, but we could ideally use solar powered fans and AC, with battery storage at night. Fans and small AC units dont draw much electricity.
Read the article again, guys. It says that "full body immersion" is the best method in an emergency, but not always available.
No, it is always available in virtualy every modern house: a bathtub. Mine usualy holds cold water in summer (which comes from my rain tank therefore costs nothing) so that I can dunk for a moment as needed - usually every hour of so in record heatwave days. Less water usage and more effective than shower, truely zero-emmision method, unlike fan, or dreadfully emmsion-heavy AC. By overusing AC, the civilisation increased the heatwaves and now people are trying to crank AC more to escape from heatwaves? Where does this nonsense ends?
You still fail to describe the workings of your proposed Lapse Rate Heat Engine. We can see from Glenn Tamblyn's comments @211/212 were he stands on the matter and that it is incompatable with your comments @208/210. Yet #208/210 does not give "any reader who argues for a runaway greenhouse effect on Venus" the slightest inkling of what you propose. In truth, anyone familiar with your input into this comment thread would still struggle, unable to glean whether you still incorporate any or all of the various fallacies you presented variously down this thread. The Unified Theory of Climate from denialists Nikolov & Zeller whose work you cited @121? A katabatic-type mechanism as you proposed @132, which is strangely a mechanism that does the exact opposite of what you appear to propose? The vertical-means-down fallacy you use at, for instance, @158? Or your fallacy that the surface of Venus would require more direct solar heating than it does so as to be hotter than the insulating atmosphere above it, as described say @208? How many of these fallacies do you still use to support your proposed Lapse Rate Heat Engine?
Simply, nobody else truly knows what it is your trying to say. Can you give it your best shot?
First I need to correct a basic mistake you have made wrt albedo. The figure you have cited of 0.65 is the simple albedo for Venus. The simple average of albedo's across a range of wavelengths. However if we were to use this to calculate how much energy is reflected we would get it wrong because energy isn't constant across all wavelengths obviously, it follows the Planck curve. So if for example albedo was higher at wavelengths that have high energy, near the peak of the Planck curve, this would reflect more energy. So we need to take an average that is weighted by energy density. This is called the Bond Albedo.
For Venus the Bond Albedo is 0.9.
Next, the graph you link to isn't what you think it is.
This is data for the Earth, not Venus!The site you have taken it from is here. As you will note, they don't dispute the role of the GH effect on Venus. However, they credit another site as the source, but do not give all the detail. The original source is here. And this is their discussion of that graph.
"There are two ways that Venus’ atmosphere could be responsible for keeping the surface hot, either individually or in combination. First, Venus’ atmosphere is very dense, and there is a physical relationship known as the ideal gas law that indicates that gases under pressure tend to be hotter. Second, robotic probes have measured Venus’ atmosphere to be about 97% CO2, and we can see from the image above (click for a larger version) that the absorption spectrum for CO2 (AT EARTH TEMPERATURE AND PRESSURE – VENUSIAN TEMPERATURE AND PRESSURE INCREASES THE WIDTH OF THE ABSORPTION BANDS, MAKING CO2 A STRONGER ABSORBER IN VENUS' ATMOSPHERE THAN IN EARTH'S) strongly overlaps the peak emission spectrum of Venus’ surface. The overlap in the spectra suggests that the greenhouse effect of so much CO2 is the cause" (my emphasis)
The graph you show is what CO2 does in Earth's atmosphere, not Venus!
What you are missing in this is referred to in the comment above about temperature and pressure increasing the width of the absorption bands. This factor is profoundly important.
The actual absorption properties of CO2 (and other GH gases) are that they have a large number (10's of 1000's) if distinct spectral absorption lines, spread over what we call bands. In principle each absorption line would be infinitely narrow, they would by exact wavelengths. However quantum mechanics imposes a minimum width restriction, based on Heisenberg's Uncertainty Principle. But this minimum width for each line is still extremely, extremely narrow.
A single molecule, at rest, not colliding with anything else would exhibit such idealised narrow absorption lines.
But two other factors produce what is known as 'line broadening'. This smears each line out, potentially till they overlap and possibly overlap over wider ranges of wavelengths.
Temperature Broadening is due to Doppler shift. Molecules aren't at rest, and their velocity distribution means that a proportion of molecules absorb at somewhat differing wavelengths from the primary wavelength of each line since the molecule is moving realtive to the photon it absorbs.
Pressure Broadening is due to the fact that absorption events for a single molecule may occur while that molecule is colliding or in close proximity to another molecule, again shifting the wavelength that the absorption occurs at.
At sea levle pressures hear on Earth Pressure broadening is already significant, as well as Temperature broadening.
When we move to Venus, with much higher temperatures, and pressures vastly higher than Earth, with also hugely higher CO2 proportions, broadening essentially smears absorption across the entire spectrum.
Mike, I think the mistake you are making is projecting what you know about IR absorption from an Earth context and assuming it is similar on Venus.
[JH] I inadvertently deleted a second response by Glenn Tamblyn. Here is the complete text of it.
Next Mike, I didn't 'recant' about the Lapse Rate Engine. It is central to understanding what is going on.
It sems here you haven't fully understood previous comments. You seem to think that the Lapse Rate is a process to be considered instead of the GH Effect.
As I have said before, the Lapse Rate is a part of the GH effect.
Let me reiterate. The GH effect arises as a result of 3 mechanisms.
Radiative Balance requires that the effective emission altitude (EEA), the altitude at which radiation to space, on average, originates from must tend towards the temperature required for the planet to be in radiative balance.
GH Gases determine the radiative properties of the atmosphere. They determine whatthe effective emission altitude will be.
These two process tend to drive the EEA to the required emission temperature. On Earth this tends to drive the 5 km level towards a temperature of -18 C. And for Venus this tends to drive the 50+ km level to a temperature between -80 and -90 C.
The Lapse Rate Engine then drives other layers above and below the EEA to matching temperatures.
So for example, on Earth Radiative Balance and GH Gases drive the 5 km layer towards -18C. The Lapse Rate engine then drives the surface towards + 15 C and the 10km level towards -41C.
On Venus Radiative Balance and GH Gases drive the 50+ km layer towards -80 - -90 C, and the Lapse Rate drives the surface towards 500 C warmer than this.
The Lapse Rate is a part of the GH Effect!
And your comment about incoming solar radiation being absorbed by the atmosphere. So what.
1/3rd of solar energy absorbed on Earth is absorbed in the atmosphere. It doesn't matter whether absorption happens at the surface or in the atmosphere. The air circulation behind the Lapse Rate redistributes energy within the atmosphere, irrespective of whether it was originally absorbed at the surface or in the atmosphere, to produce a temperature gradient, and allow the EEA to tend towards the needed balance temperature.
Venus is much hotter than Earth, and radiates a Planck curve with much shorter wavelengths. It appears to peak around 3 or 4 microns with the bulk between 2 and 10 microns. The 15 micron band is barely on the chart. The CO2 absorption bands within this Planck curve are very thin, so I ask again, how can you (we, or anybody) call this scenario a greenhouse effect, especially since most of the sun's radiation which Venus absorbs is absorbed by it's atmosphere on the way in?
nigelj @2, I note that there is a contradiction between the advise on the proper use of a fan, and the proper employment of windows.
In my experience there are at least two human physiological approaches to cooling. I, for example, will sweat copiously at even slightly above normal temperatures or levels of excertion. Provided I am bathed in an air stream of relatively dry air I remain cool at temperatures up to 40 C and even with high levels of excertion. Lacking that air stream, or if the air is humid, I swelter. (I have noticed this pattern in other people who, like me, have grown up in hot arid areas with plenty of drinking water.) In contrast my wife sweats little unless it is very hot. The result is that, unlike me, in typical Brisbane summer weather she does not become drenched (or dehydrated) and her skin continues to cool; but she cannot cope with very hot dry air.
It seems probable to me that the advise from the NZ herald (keep overall room temperature down) would be good for my wife and people like her. For me, however, there is no substitute for a high volume air flow over the skin, so I am best of sitting directly in the air stream from a fan turned to high. Likewise I often benefit more from increased natural air flows from open windows, even if the air is hotter than the still, inside air (within limits).
The following article describes the best way to use a fan. Basically it advises don't just blow air at the sofa or bed. It says point a fan at the open window at night, to blow hot air out of the room, and let the outside air which is sometimes cooler enter the room. Haven't tested the idea as yet.
When I went through 117 degree Fahrenheit heat a few years ago, I had no airconditioner in my apartment (The electrical wiring couldn't allow for it with all the appliances running.). Fans did not work above 100F even with frozen water bottles in front of them.
It was that temperature outside and inside my apartment. Other than walking naked around the house I decided to improvise. I put a small bucket of water into a freezer overnight and the next morning I removed it. It was not frozen except for a thin crust of ice on top. The water was ice cold though.
I dunked a tight fitting T-shirt into the water; wrung out the excess water; then I put the T-shirt on.
I shivered from the cold for less than 3 seconds and immediately after that I felt an intense sense of relief. I was still naked from the waist down but there was no one to notice.
At night, with the temperature no lower than the mid 90s F I dunked a bed sheet into that same water and had a small fan blowing besides my bed. That's the only time that a fan can provide relief.
I would also suggest keeping your hair short and have a beanie for your head also soaked in ice water.
Tom @153: Your numbers seem to agree pretty well with the energy flow chart in @137.
My reason for focusing on the IR part of the spectrum is the fact that an IR emissivity lower than 1 reduces the heat loss to space in a way that resembles the greenhouse effect. In a discussion on another blog (I don’t remember where) someone suggested that the 33 K warming of Earth was caused by a surface emissivity of about 0.61-0.62. If that was true, a surface temp of 288 K would be needed to emit 240 w/m2. But of course, measurements of many types of terrain show that the IR emissivity in general is > 0.95, so that doesn’t contribute much to the 33 K warming of Earth.