Guest essay by Dr. Ira Glickstein
We’ve reached a turning point where it is hard for any Global Warming Alarmist to claim (with a straight face) that the world as we know it is about to end in the coming decades unless we stop burning fossil fuels. Anyone deluded or foolish enough to make such a claim would be laughed at by many audiences.
GLOBAL WARMING IS REAL
Yes, the world has warmed 1°F to 1.5°F (0.6°C to 0.8°C) since 1880 when relatively good thermometers became available. Yes, part of that warming is due to human activities, mainly burning unprecedented quantities of fossil fuels that continue to drive an increase in carbon dioxide (CO2) levels. The Atmospheric “Greenhouse” Effect is a scientific fact!
BUT GLOBAL WARMING IS NOT A BIG DEAL
Alarmist Theory is Handcuffed to High Estimates of Climate Sensitivity
As the animated graphic clearly indicates, the theoretical climate models used by the Intergovernmental Panel on Climate Change (IPCC) are handcuffed to inordinately high estimates of climate sensitivity (how much temperatures are expected to rise given a doubling of CO2). Since the advent of good satellite-based global temperature data in 1979, observed temperatures have risen at a fraction of the IPCC predicted rate even as CO2 continues to rise.
Relax, there is not and never has been any near-term “tipping point”. The actual Earth Climate System is far less sensitive to CO2 than claimed the IPCC climate theory, as represented by their computer models. Global Warming since 1880 is mainly due to Natural Cycles and Processes not under human control. Yes, the same Natural Cycles and Processes that were responsible for the many Ice Age cycles that repeatedly occurred about every 100,000 years or so.
A GREAT TIME TO PUT ALARMISTS IN THEIR PLACE
Last week, by a stroke of good fortune, I happened to be scheduled to present “Visualizing the Atmospheric ‘Greenhouse’ Effect – Global warming is real, but how much is due to human activities and how big is the risk?” to the Philosophy Club in the Central Florida retirement community where I live.
Everyone in the highly interactive and supportive audience was aware of newspaper and TV reports of the drama of those ill-fated Global Warming “Research” activists whose Russian ship, the Academik Shokalskiy, got stuck in the summer ice of the Antarctic. (Fortunately, those people are safe, having been rescued by a helicopter from a Chinese icebreaker.) In addition to the Antarctic adventure gone wrong, in the week leading up to and following my talk, the media was overrun by stories of the “polar vortex” literally freezing large parts of the US and even causing Florida temperatures to drop below 30°F (0°C).
Of course, everyone knows that the cold wave is only anecdotal evidence and “weather is not climate”. However, photos and videos of researchers stuck in the Antarctic summer ice as well as scenes of American life frozen in place for days on end, when combined with clear and irrefutable evidence of a slowdown in warming since 1979 and no statistically significant warming since 1996 (as depicted in the graphic above), has considerable emotional impact. Audiences often react more to emotions than their reason.
My animated PowerPoint Show, which should run on any Windows PC, is available for download here. (NOTE: I knew that many members of the Philosophy Club audience, while highly intelligent and informed, are not particularly scientifically astute. Therefore, I kept to the basics and invited questions as I proceeded. Since most of them think in Fahrenheit, I was careful to give temperatures in that system. By contrast, my 2011 talk to the more scientifically astute members of our local Science and Technology Club Skeptic Strategy for Talking about Global Warming was more technical. Both presentations make use of animated PowerPoint charts and you are free to download and use them as you wish.)
My presentation is based on my five-part WUWT series entitled “Visualizing the ‘Greenhouse Effect'” – 1 – A Physical Analogy, 2 – Atmospheric Windows, 3 – Emission Spectra, 4 – Molecules and Photons, and 5 – Light and Heat. The series, which ran in 2011, generated tens of thousands of page views at WUWT, along with thousands of comments. I wrote the series this website attracts some viewers who reject the basic physics of the Atmospheric “Greenhouse” Effect.
HOW A REAL GREENHOUSE WORKS
I explained how a real physical Greenhouse works and how that is both similar and different from the Atmospheric “Greenhouse” Effect. The Greenhouse descriptions I learned in high school, as well as those available on the Internet, consider only the RADIATIVE effect. The glass roof of the Greenhouse allows visible light to pass through freely, heating the soil, plants, and air, but is opaque to the resultant infrared radiation, which is partly re-radiated back down into the Greenhouse, warming it further. That part is true, but far from the whole story. The MAIN reason a Greenhouse stays warm is that it is airtight to restrict CONVECTION and it is insulated to restrict CONDUCTION. In fact, it is possible to construct a successful Greenhouse using a roof made from materials that allow both visible and infrared to pass freely, but is impossible to make a working Greenhouse that is not both airtight and insulated.
HOW THE ATMOSPHERIC “GREENHOUSE” EFFECT WORKS
All warm objects emit radiation at a wavelength dependent upon the temperature of the object. The Sun, at around 10,000 °F, emits “short-wavelength” infrared radiation, centered around 1/2 micron (one millionth of a meter). The soil, plants, and air in the Greenhouse, at around 60°F to 100°F (15°C to 40°C), emit “long wavelength” radiation, centered around 10 microns (with most of the energy between 4 and 25 microns).
The Atmospheric “Greenhouse” Effect works because:
- Short-wavelength radiation from the Sun passes freely through the gases that make up the Atmosphere,
- About a third of this Sunlight is reflected back by white clouds, dust, and light-colored objects on the Surface, and that energy is lost to Space,
- The remaining two-thirds of the Sunlight energy is absorbed by the Sea and Land Surface and causes it to warm,
- The warm Surface cools by emitting long-wavelength radiation at the Bottom of the Atmosphere, and this radiation passes towards the Top of the Atmosphere, where it is ultimately lost to Space,
- On the way to the Top of the Atmosphere, much of this radiation is absorbed by so-called “Greenhouse” gases (mostly water vapor and carbon dioxide) which causes the Atmosphere to warm,
- The warmed Atmosphere emits infrared radiation in all directions, some into Space where it is lost, and some back towards the Surface where it is once again absorbed and further warms the Surface.
- In addition to the RADIATIVE effects noted in points 1 through 6, the Surface is cooled by CONVECTION and CONDUCTION (thunderstorms, winds, rain, etc.)
THANK GOODNESS FOR THE ATMOSPHERIC “GREENHOUSE” EFFECT
If not for the warming effect of “Greenhouse” gases, the Surface of the Earth would average below 0°F (-18°C), which would prevent life as we know it. This effect is responsible for about 60°F (33°C) of warming. According to the Intergovernmental Panel on Climate Change (IPCC), the Earth Surface has warmed about 1.5°F (0.8°C) since good thermometer data became available around 1880. Some skeptics (including me) believe the actual warming is closer to 1°F, and that government agencies have adjusted the thermometer record to exaggerate the warming by 30% or more. However, it doesn’t really matter whether the actual warming is 1°F or 1.5°F (0.6°C or 0.8°C) because we are arguing about only 0.5°F (0.2°C), which is less than 1% of the total warming due to the Atmospheric “Greenhouse” Effect.
HOW SENSITIVE IS THE CLIMATE TO HUMAN ACTIVITIES?
The IPCC claims that the majority of the warming since 1880 is due to human activities. It is true that we are burning unprecedented amounts of fossil fuel (coal, oil, gas), and that we are making land use changes that may reduce the albedo (reflectiveness) of the Surface. Most of the increase in Atmospheric CO2 (a 40% rise from about 270 to nearly 400 parts per million by volume) is due to human activities.
The IPCC claims that Climate Sensitivity (the average increase in Surface temperatures due to a doubling of CO2) is between 3°F and 8°F (1.5°C and 4.5°C). Some skeptics (including me) believe they are off by at least a factor of two, and possibly a factor of three, and that Climate Sensitivity is closer to 1°F to 3°F (0.5°C to 1.5°C). As evidence for our conclusions, we point to the fact that virtually ALL of the IPCC climate models have consistently over-estimated future temperature predictions as compared to the actual temperature record. Indeed, for the past 17 years as CO2 levels continue their rapid climb, temperatures have leveled off, which is proof that Natural Cycles, not under human control or influence, have cancelled out warming due to CO2 increases. Thus, Natural Cycles must have a larger effect than CO2.
VISUALIZING THE ATMOSPHERIC “GREENHOUSE” EFFECT
As I noted above, I wrote the “Visualizing” series for WUWT (1 – A Physical Analogy, 2 – Atmospheric Windows, 3 – Emission Spectra, 4 – Molecules and Photons, and 5 – Light and Heat) because some WUWT viewers are “Disbelievers” who have had an “equal and opposite” reaction to the “end of the world” excesses of the Global Warming “Alarmists”. By failing to understand and accept the basic science of the Atmospheric “Greenhouse” Effect, they have, IMHO, “thrown the baby out with the bathwater”.
Albert Einstein was a great theoretical physicist, with all the requisite mathematical tools. However, he rejected purely mathematical abstraction and resorted to physical analogy for his most basic insights. For example, he imagined a man in a closed elevator being transported to space far from any external mass and then subjected to accelerating speeds. That man could not tell the difference between gravity on Earth and acceleration in space, thus, concluded Einstein, gravity and acceleration are equivalent, which is the cornerstone of his theory of relativity. Einstein never fully bought into the mainstream interpretation of quantum mechanics that he and others have called quantum weirdness and spooky action at a distance. He had trouble accepting a theory that did not comport with anything he considered a reasonable physical analogy!
So, if you have trouble accepting the atmospheric “greenhouse” effect because of the lack of a good physical analogy, you are in fine company.
Well, getting back to the Atmospheric “Greenhouse Effect, a “disbelieving” commenter on WUWT suggested we think of the Sunlight as truckloads of energy going from the Sun to the Earth Surface, and the infrared radiation from the Surface as equal truckloads going the other way. How, he asked, could these equal and opposite truckloads do anything but cancel each other out as far as the amount of energy on the Surface of the Earth? In reply, I posted a comment with an analogy of truckloads of orange juice, representing short-wave radiation from Sun to Earth, and truckloads of blueberry juice, representing longwave radiation between Earth and the Atmosphere and back out to Space.
That thought experiment triggered my creativity. I imagined the Sun as a ball-pitching machine, throwing Yellow balls towards the “Earth” Surface (representing short-wave radiation) and Purple balls (representing long-wave radiation) bouncing back towards Space and interacting with the Atmosphere. The graphic below is one of my depictions of the physical analogy. Follow this link for more graphics and detail.
I imagined the Earth as a well-damped scale. The Yellow balls would bounce off the Surface and turn into Purple balls (representing long-wave radiation as the Earth absorbed the short-wave radiation and then emitted an equal quantity of long-wave radiation). The scale would read “1” unit.
If there was no Atmosphere, or if the Atmosphere contained no “Greenhouse” gases to obstruct the flight of the Purple balls, they would fly out towards Space.
I then imagined the Atmosphere as an obstacle that absorbed the Purple balls, split them in two, and emitted half of the smaller balls to Space and the other half back towards the Earth. The balls going towards Earth would be absorbed, further heating the Earth, and the warmed Earth would emit them back towards the Atmosphere. The process would be repeated with the balls being absorbed by “Greenhouse” gases in the Atmosphere, and then emitted with half going out to Space, and half back to the Earth. The sum of 1 + 1/2 + 1/4 + 1/8 +1/16 … = 2 (approximately), so the scale reads “2” units.
Thus, in my simplified analogy, the “Greenhouse” gases in the “Atmosphere” cause the scale reading to double. So, the Atmospheric “Greenhouse” Effect causes the Earth Surface to be warmer than it would be absent the “Greenhouse” gases. I think Einstein would be pleased! Read more detail, including the 340 responses.
A real greenhouse has windows. So does the Atmospheric “greenhouse effect”. They are similar in that they allow Sunlight in and restrict the outward flow of thermal energy. However, they differ in the mechanism. A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases” (GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.
There are two main “windows” in the Atmospheric “greenhouse effect”. The first, the Visible Light Window, on the left side of the graphic, allows visible and near-visible light from the Sun to pass through with small losses, and the second, the Longwave Window, on the right, allows the central portion of the longwave radiation band from the Earth to pass through with small losses, while absorbing and re-emitting the left and right portions.
Sunlight Energy In = Reflected Sunlight Energy Out + Thermal Energy Out
The graphic is an animated depiction of the Atmospheric “greenhouse effect” process.
On the left side:
(1) Sunlight is shortwave radiation with a wavelength centered around 0.5μ (microns, millionths of a meter). That energy streams through the Atmosphere towards the surface of the Earth.
(2) A portion of the Sunlight is reflected by clouds and other high-albedo surfaces and heads back through the Atmosphere towards Space. The remainder is absorbed by the Surface of the Earth, warming it.
(3) The reflected portion is lost to Space.
On the right side:
(1) The warmed Earth emits longwave radiation with a wavelength centered around 10μ towards the Atmosphere. This consists of thermal energy from about 4μ to about 25μ. For convenience in description, I have divided this range into three bands: ~7μ, ~10μ, and ~15μ.
(2) The ~10μ portion passes through the Atmosphere with litttle loss. The ~7μ portion gets absorbed, primarily by water vapor (H2O), and the 15μ portion gets absorbed, primarily by H2O and CO2. The absorbed radiation heats the H2O and CO2 molecules and, at their higher energy states, they collide with the other molecules that make up the air, mostly nitrogen (N2), oxygen (O2), ozone (O3), and argon (A) and heat them by something like conduction. The molecules in the heated air emit radiation in random directions at all bands (~7μ, ~10μ, and ~15μ). The ~10μ photons pass, nearly unimpeded, in whatever direction they happen to be emitted, some going towards Space and some towards Earth. The ~7μ and ~15μ photons go off in all directions until they run into an H2O or CO2 molecule, and repeat the absorption and re-emittance process, or until they emerge from the Atmosphere or hit the surface of the Earth.
(3) The ~10μ photons that got a free-pass from the Earth through the Atmosphere emerge and their energy is lost to Space. The ~10μ photons generated by the heating of the air emerge from the top of the Atmosphere and their energy is lost to Space, or they impact the surface of the Earth and are re-absorbed. The ~7μ and ~15μ generated by the heating of the air also emerge from the top or bottom of the Atmosphere, but there are fewer of them because they keep getting absorbed and re-emitted, each time with some transfered to the central ~10μ portion of the longwave band.
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The Atmospheric “Greenhouse” effect has been analogized to a blanket that insulates the Sun-warmed Earth and slows the rate of heat transmission, thus increasing mean temperatures above what they would be absent “greenhouse gases” (GHGs). Perhaps a better analogy would be an electric blanket that, in addition to its insulating properties, also emits thermal radiation both down and up. The graphic below, based upon actual measurements of long-wave radiation as measured by a satellite LOOKING DOWN from the Top of the Atmosphere as well as from the Surface LOOKING UP from the Bottom of the Atmmsphere, depicts the situation.
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Description of graphic (from bottom to top):
Earth Surface: Warmed by shortwave (~1/2μ) radiation from the Sun, the surface emits upward radiation in the ~7μ, ~10μ, and ~15μ regions of the longwave band. This radiation approximates a smooth “blackbody” curve that peaks at the wavelength corresponding to the surface temperature.
Bottom of the Atmosphere: On its way out to Space, the radiation encounters the Atmosphere, in particular the GHGs, which absorb and re-emit radiation in the ~7μ and ~15μ regions in all directions. Most of the ~10μ radiation is allowed to pass through.
The lower violet/purple curve (adapted from figure 8.1 in Petty and based on measurements from the Tropical Pacific looking UP) indicates how the bottom of the Atmosphere re-emits selected portions back down towards the surface of the Earth. The dashed line represents a “blackbody” curve characteristic of 300 K (equivalent to 27ºC or 80ºF). Note how the ~7μ and ~15μ regions approximate that curve, while much of the ~10μ region is not re-emitted downward.
“Greenhouse Gases”: The reason for the shape of the downwelling radiation curve is clear when we look at the absorption spectra for the most important GHGs: H2O, H2O, H2O, … H2O, and CO2. (I’ve included multiple H2O’s because water vapor, particularly in the tropical latitudes, is many times more prevalent than carbon dioxide.)
Note that H2O absorbs at up to 100% in the ~7μ region. H2O also absorbs strongly in the ~15μ region, particularly above 20μ, where it reaches 100%. CO2 absorbs at up to 100% in the ~15μ region.
Neither H2O nor CO2 absorb strongly in the ~10μ region.
Since gases tend to re-emit most strongly at the same wavelength region where they absorb, the ~7μ and ~15μ are well-represented, while the ~10μ region is weaker.
Top of the Atmosphere: The upper violet/purple curve (adapted from figure 6.6 in Petty and based on satellite measurements from the Tropical Pacific looking DOWN) indicates how the top of the Atmosphere passes certain portions of radiation from the surface of the Earth out to Space and re-emits selected portions up towards Space. The dashed line represents a “blackbody” curve characteristic of 300 K. Note that much of the ~10μ region approximates a 295 K curve while the ~7μ region approximates a cooler 260ºK curve. The ~15μ region is more complicated. Part of it, from about 17μ and up approximates a 260ºK or 270ºK curve, but the region from about 14μ to 17μ has had quite a big bite taken out of it. Note how this bite corresponds roughly with the CO2 absorption spectrum.
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In this part, we consider the interaction between air molecules, including Nitrogen (N2), Oxygen (O2), Water Vapor (H2O) and Carbon Dioxide (CO2), with Photons of various wavelengths. This may help us visualize how energy, in the form of Photons radiated by the Sun and the Surface of the Earth, is absorbed and re-emited by Atmospheric molecules.
The animated graphic has eight frames, as indicated by the counter in the lower right corner. Molecules are symbolized by letter pairs or triplets and Photons by ovals and arrows. The view is of a small portion of the cloud-free Atmosphere.
- During the daytime, Solar energy enters the Atmosphere in the form of Photons at wavelengths from about 0.1μ (micron – millionth of a meter) to 4μ, which is called “shortwave” radiation and is represented as ~1/2μ and symbolized as orange ovals. Most of this energy gets a free pass through the cloud-free Atmosphere. It continues down to the Surface of the Earth where some is reflected back by light areas (not shown in the animation) and where most is absorbed and warms the Surface.
- Since Earth’s temperature is well above absolute zero, both day and night, the Surface radiates Photons in all directions with the energy distributed approximately according to a “blackbody” at a given temperature. This energy is in the form of Photons at wavelengths from about 4μ to 25μ, which is called “longwave” radiation and is represented as ~7μ, ~10μ, and ~15μ and symbolized as violet, light blue, and purple ovals, respectively. As noted above, the primary “greenhouse” gases (GHG) are Water Vapor (H2O) and Carbon Dioxide (CO2). The ~7μ Photon is absorbed by an H2O molecule because Water Vapor has an absorption peak in that region, the ~10μ Photon gets a free pass because neither H2O nor CO2 absorb strongly in that region, and one of the 15μ Photons gets absorbed by an H2O molecule while the other gets absorbed by a CO2 molecule because these gases have absorption peaks in that region.
- The absorbed Photons raise the energy level of their respective molecules (symbolized by red outlines).
- The energized molecules re-emit the Photons in random directions, some upwards, some downwards, and some sideways. Some of the re-emitted Photons make their way out to Space and their energy is lost there, others back down to the Surface where their energy is absorbed, further heating the Earth, and others travel through the Atmosphere for a random distance until they encounter another GHG molecule.
- This frame and the next two illustrate another way Photons are emitted, namely due to collisions between energized GHG molecules and other air molecules. As in frame (2) the Surface radiates Photons in all directions and various wavelengths.
- The Photons cause the GHG molecules to become energized and they speed up and collide with other gas molecules, energizing them. NOTE: In a gas, the molecules are in constant motion, moving in random directions at different speeds, colliding and bouncing off one another, etc. Indeed the “temperature” of a gas is something like the average speed of the molecules. In this animation, the gas molecules are fixed in position because it would be too confusing if they were all shown moving and because the speed of the Photons is so much greater than the speed of the molecules that they hardly move in the time indicated.
- The energized air molecules emit radiation at various wavelengths and in random directions, some upwards, some downwards, and some sideways. Some of the re-emitted Photons make their way out to Space and their energy is lost there, others back down to the Surface where their energy is absorbed, further heating the Earth, and others travel through the Atmosphere for a random distance until they encounter another GHG molecule.
- Having emitted the energy, the molecules cool down.
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As noted above, Sunlight Energy In = Reflected Sunlight Energy Out + Thermal Energy Out ! That’s old news to those of us who understand all energy is fungible (may be converted to different forms of energy) and energy/mass is conserved (cannot be created nor destroyed).
Answering Some Objections to the Atmospheric “Greenhouse”Effect
Some WUWT commenters seem to have been taken in by scientific-sounding objections to the basic science behind the Atmospheric “Greenhouse” Effect. Their objections seemed to add more heat than light to the discussion. This section is designed to get back to basics and perhaps transform our heated arguments into more enlightened understanding :^)
The main scientific question for me, is how much does the increase in human-caused CO2 and human-caused albedo reduction increase the mean temperature above what it would be with natural cycles and processes? My answer is “not much”, because perhaps 0.2ºC to 0.4ºC (0.1ºC to 0.2ºC) of the supposed 1.5ºF (0.8ºC) increase since 1880 is due to human activities. The rest is due to natural cycles and processes over which we humans have no control. The main public policy question for me, is how much should we (society) do about it? Again, my answer is “not much”, because the effect is small and a limited increase in temperatures and CO2 may turn out to have a net benefit.
So, my motivation for this Visualizing series was not to add to the Alarmist “the sky is falling” panic, but rather to help my fellow Skeptics avoid the natural temptation to fall into an “equal and opposite” falsehood, which some of those on my side, who I call “Disbelievers”, do when they fail to acknowledge the basic facts of the role of H2O and CO2 and other gases in helping to keep temperatures in a livable range.
Objection #1: Visual and near-visual radiation is merely “light” which lacks the “quality” or “oomph” to impart warmth to objects upon which it happens to fall.
Answer #1: A NASA webpage targeted at children is sometimes cited because they say the near-IR beam from a TV remote control is not warm to the touch. Of course, that is not because it is near-visual radiation, but rather because it is very low power. All energy is fungible, and can be changed from one form to another. Thus, the 240 Watts/m^2 of visible and near-visible Solar energy that reaches and is absorbed by the Earth System, has the effect of warming the Earth System exactly as much as an equal number of Watts/m^2 of “thermal” mid- and far-IR radiation.
Objection #2: The Atmosphere, which is cooler than the Earth Surface, cannot warm the Earth Surface.
Answer #2: The Second law of Thermodynamics is often cited as the source of this falsehood. The correct interpretation is that the Second Law refers to net warming, which can only pass from the warmer to the cooler object. The back-radiation from the Atmosphere to the Earth Surface has been measured (see lower panel in the above illustration). All matter above absolute zero emits radiation and, once emitted, that radiation does not know if it is travelling from a warmer to a cooler surface or vice-versa. Once it arrives it will either be reflected or absorbed, according to its wavelength and the characteristics of the material it happens to impact.
Objection #3: The Atmospheric “Greenhouse” Effect is fictional. A glass greenhouse works mainly by preventing or reducing convection and the Atmosphere does not work that way at all.
Answer #3: I always try to put “scare quotes” around the word “greenhouse” unless referring to the glass variety because the term is misleading. Yes, a glass greenhouse works mainly by restricting convection, and the fact that glass passes shortwave radiation and not longwave makes only a minor contribution.
Thus, I agree it is unfortunate that the established term for the Atmospheric warming effect is a bit of a misnomer. However, we are stuck with it. But, enough of semantics. Notice that the Earth System mean temperature I had to use to provide 240 Watts/m^2 of radiation to Space to balance the input absorbed from by the Earth System from the Sun was 255 K. However, the actual mean temperature at the Surface is closer to 288 K. How to explain the extra 33 K (33ºC or 58ºF)? The only rational explanation is the back-radiation from the Atmosphere to the Surface.
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Ira says: “Notice that the Earth System mean temperature I had to use to provide 240 Watts/m^2 of radiation to Space to balance the input absorbed from by the Earth System from the Sun was 255 K. However, the actual mean temperature at the Surface is closer to 288 K. How to explain the extra 33 K (33ºC or 58ºF)? The only rational explanation is the back-radiation from the Atmosphere to the Surface.”
Using your numbers here is basic radiation heat transfer equation with a missing input. The missing input is for the back radiation from the atmosphere to the surface.
288 K = 390.1 W/m^2
390.1 W/m^2 = 5.67E-8 * e* (XXXX^4 – 255^4) (e is emissivity use 1 for ease of operation)
There is your claimed net transfer of heat with the missing (XXXX) temperature for the atmosphere.
So what does the temperature of the atmosphere have to be to warm the surface 33 K?
I have yet to see a radiation heat transfer equation showing how the atmosphere sends heat back to the surface warming it.
Yes, part of that warming is due to human activities, mainly burning unprecedented quantities of fossil fuels that continue to drive an increase in carbon dioxide (CO2) levels.
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No. Attribution of the circa 1980-1997 temperature increase to CO2 is conjecture with only theoretical support, which theory is incorrectly applied. The rise is in fact due to SST increase during that era which increase is not attributable to the greenhouse effect. Your assertion is also refuted by the temperature record of the last 17 years.
I agree that climate is determined largely by H2O in its various phases, or lack of it. CO2 makes no appreciable contribution to the greenhouse effect, as the recent temperature records prove.
Thanks MikeB for your kind words.
I agree it is a pity that the true “Disbelievers” have come out in force in responses to this thread. Many of them seem beyond reason. Even those who show the ability to reason in their postings seem to be determined not to believe.
This proves Newton’s Law about “equal and opposite reactions”. The Alarmist BS, and the actions of the official Climate Team, including “cooking the books” by repeatedly “adjusting” the temperature record, are so outrageous that the true “Disbelievers” have an opposite and equally outrageous reaction.
My posting and your comment may not change too many of their minds, but, IMHO, “It is better to light one little candle than to curse the darkness.” (That is, until the Alarmist politicos make it illegal to sell candles and matches :^)
Ira
Mr Lynn says:
January 13, 2014 at 7:41 am [” … “]
Excellent comments, both yours and Richard Courtney’s. Scientific EVIDENCE is necessary. But there is still no evidence for AGW.
AGW may exist. But without evidence it cannot be quantified, and without that, it is hardly science.
What if we all have it wrong? What if the GHG’s are the result of a misinterpretation of the (long ago) fundamental experiment, the 1859 Tyndall experiment? To me, the real elephant in the room are the non- GHG’s (N2 and O2):as they ‘apparently’ do not absorb IR, we right them out of the argument, but they are 98% of the atmosphere. If it were the universe we were arguing, we’d call them something like the dark gases. But they have a Specific heat capacity similar to the GHG’s – they absorb (IR) energy : it’s just that they are transparent to IR detectors(!) at the frequencies of interest – but so is salt, and is thin plastic.
I think, and can prove (as an amateur) that the real issue is the Tyndall apparatus, the thermopile and the way it reads (or not) IR opacity. One only has to use and understand a thermal camera to understand the limitations of such devices, and I argue that it is this flaw, this magic trick, that has gone on too long, and has lead us into this mess. Just think of the IR similarities of glass and CO2: both visibly transparent, and both IR (thermopile) opaque. So why then is glass not considered a greenhouse solid, and thus a climate problem?
In my blog I have attempted to isolate the issues surrounding CO2 – without mentioning changes of climate. I would love to develop my discoveries with someone.
1. Where does CO2’s heat trapping property repeat and explain other phenomena where is it present? http://www.fractalnomics.com/2013/03/5-fractal-record-of-heat-trapping-co2.html
2. Thermopile magic, ‘the greenhouse gases’: http://www.fractalnomics.com/2013/12/the-gassy-messenger-magic-of-ir.html
Richard111 says:
January 13, 2014 at 1:03 am
Radiation is transport of energy not heat. High frequency radiation has high energy levels and low frequency radiation has low energy levels. Planck’s rule.
If you could create a laser that emits a very narrow band of radiation of about 2 or 3 microns wide and direct that radiation at a black body, Wien’s Law will predict the maximum possible temperature. The black body, being a black body, will be radiating a much wider band of radiation and thus will not quite reach the predicted temperature. EVER!
You appear to misunderstand Wien’s law which gives the wavelength of peak emission at a certain temperature. The technique of laser induced incandescence uses a laser beam of about 1micron wavelength focussed onto soot (a black body) which is heated up to about 5,000K (hence the incandescence).
CO2 molecules in the atmosphere are effectively black bodies with an emissivity/absorbance factor of 1 over the electromagnetic range 13 to 17 microns and two further bands centred around 2.7 and 4.3 microns. The CO2 molecules have ZERO emissivity/absorbance at all other radiation frequencies (apart from one very weak band at ~1.9 microns which seems to be ignored).
CO2 is a gas with a lower heat capacity than standard air thus the CO2 easily aquires the local air temperature via kinetic collisions with other molecules in the atmosphere. These collisions effect the vibrational levels of the CO2 molecule to raise the molecule’s temperature to the local air temperature.
CO2 has a higher heat capacity (28 J/K) than N2 and O2 (21 J/K). The collisions primarily effect the translational energy of the molecule not the vibrational levels unlike absorption which directly excites the vibrational level. The 667cm^-1 CO2 energy level corresponds to a temperature of ~950K.
Peak radiative temperature of 13 microns is ~223K (-50C) from Wien’s Law.
Wien’s Law says that a radiating black body at a temperature of 223K has its peak emission at 13 microns, you have it backwards).
From the surface to the tropopause, some 80% of the total atmosphere, the air temperature is much warmer than -50C. Thus all the CO2 molecules in the atmosphere, from the surface to the tropopause, will be fully occupied RADIATING over the 13 to 17 micron band. These molecules are in no condition to ABSORB any 13 to 17 micron radiation from the surface. Also the surface will be unable to absorb any so called ‘back radiation’ from the CO2 as IT IS ALSO TOO WARM!
You have this completely wrong, look up the Boltzmann distribution, the probability that the vibrational levels will be excited by those collisions is extremely small. In addition the vibrational levels have a long lifetime compared with collisional rates so the excited molecule predominantly loses energy by collision in the lower atmosphere. Only in the high troposphere/stratosphere is the collision rate sufficiently low that emission is the dominant route.
When the sun is shining the CO2 in the atmosphere can absorb energy in the 2.7 and 4.3 micron bands and little, if any, of that energy will reach the surface. The CO2 molecules are unlikely to re-radiate in the 2.7 and 4.3 micron bands as this requires the molecules to reach temperatures in excess of 200C, not encountered in the atmosphere, but those CO2 molecules can emit strongly at the lower frequency levels of 13 to 17 microns but the surface is too warm to absorb at those bands. CO2 has some 3,800 lines of absorbance/emittance over the 13 to 17 micron band making it quite effective at converting high energy radiation to low energy radiation.
Increasing or decreasing the quantity of CO2 in the atmosphere will not change the radiative characteristics of the CO2.
There is very little solar irradiance in those bands, however if a molecule is excited by 2.7 micron light it is able to re-emit at that wavelength provided it isn’t first deactivated by another process such as collision.
http://www.pvresources.com/portals/0/Images/SiteAnalysis/spectrum_irradiance.png
Also your idea that the surface can’t absorb the 15micron band because of temperature is a complete misunderstanding of radiational heat transfer.
CO2 cools the atmosphere but is most effective above the tropopause where radiation can escape directly to space. By cooling the top of the atmosphere CO2 helps maintain the convective path for heat up through the atmosphere otherwise known as the lapse rate.
To blame CO2 in the atmosphere for hurricanes and other extreme weather events is absolutely ludicrous.
David A:
Your post to me at January 13, 2014 at 8:29 am concludes saying
OK. My suggested links did not meet your need. Sorry.
I provided those because – as I said – the subject is large and as introduction I thought links to writings by Ira Glickstein were the most appropriate in a thread discussing a new article by him.
You ask;
“A planet with no GHG would continuously conduct heat to the atmosphere, until the atmosphere at the surface reached equilibrium with the surface, via back conduction, instead of back radiation??”
Well. Yes, but so what? The Earth’s atmosphere does include GHGs.
Perhaps it would help if you looked at the cartoon of Trenberth’s energy budget and you solidified your questions in relation to that. You can see it at this link
http://www.cgd.ucar.edu/cas/Topics/energybudgets.html
Please note that I agree the diagram but dispute several of the numbers on it so I don’t want you to think I am commending it as ‘truth’. I am saying it shows how the energy arrives from the Sun and how it distributes prior to returning to space, which I think that is what you are asking.
I ask you to be assured that I am trying to help.
Richard
The atmosphere is not opaque to infrared – long wave radiation leaves the toa in a constant stream maintaining the equilibrium or heat balance otherwise we would overheat and boil.
This is a very simple question for those that believe CO2 causes warming.
What caused the Cooling from the 1930/40s to the 1970s when CO2 was Increasing?
Ditto for the so called “Pause” for the last 17 years?
Even if the CO2 had stayed stationary during those periods the Earth should not have cooled, the temperature should also have been kept stationary by the CO2 and it was not.
Please do not use the “natural causes” excuse, as you believe CO2 dominates.
Robert S, of course overall the atmosphere is not totally opaque to IR but in certain lines of primarily of h2o and co2 the immediate radiation from the warm surface is totally (but really never exactly zero) opaque to those lines and bands, just look at the transmittance spectum provided courtesy of the navy: http://en.wikipedia.org/wiki/File:Atmospheric.transmittance.IR.jpg, looks opaque to me in those bands. But high in the troposphere and higher this lack of transmittance gradually opens to allow the radiation to space that cools our planet.
Notice how the transmittance from any and all frequencies are not 100% transparant but at most 80-85%. Our atmosphere as a whole due to this collision induced temporary dipole, the weaker gray body radiation, that causes all matter to Planck radiate when above absolute zero, even non-vibrational molecule gases. To this lower degree our entire atmosphere is a bit as a “greenhouse” gas and this effect grows as the direction approaches the horizon instead of zenith, its why you can look unprotected at the sun as it rises or sets, all frequencies are affected by about 34 times weaker horizontally.
@ur momisugly Konrad “Still having a good day Gareth?”
I am in indeed Konrad and thank you for asking. By the way there appears to be some confusion between a poster called Garret Phillips and myself Gareth Phillips. It may be easy to quote the wrong person when answering posts due to our similar names, but we may be on quite different sides of the debate.
Blair M says:
January 13, 2014 at 9:30 am
What if we all have it wrong? What if the GHG’s are the result of a misinterpretation of the (long ago) fundamental experiment, the 1859 Tyndall experiment? To me, the real elephant in the room are the non- GHG’s (N2 and O2):as they ‘apparently’ do not absorb IR, we right them out of the argument, but they are 98% of the atmosphere. If it were the universe we were arguing, we’d call them something like the dark gases. But they have a Specific heat capacity similar to the GHG’s – they absorb (IR) energy : it’s just that they are transparent to IR detectors(!) at the frequencies of interest – but so is salt, and is thin plastic.
You have this completely wrong! N2 and O2 are transparent to IR in the range emitted by the earth, CO2 is a strong absorber in the 15micron band. It has nothing to do with the detectors!
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png
Note the log scale, black is CO2 as you’ll see its absorption is multiple orders of magnitude stronger than N2 and O2. Specific heat has nothing to do with it.
I have measured the temperature of the clear sky around dawn and found that on some days it warms a few degrees before the sun is above the horizon. I’m am guessing this is the greenhouse gasses, including moisture, heating up
I have seen a graph showing air temperatures during an eclipse in the desert where the air temperature, which is above the ground temperature before hand, looses its heat rapidly.
The ground on the other hand retains its heat very well. If the ground heated the air, then why does the air temperature fall to well below the ground temperature at the height of the eclipse?
On a day with nimbus clouds flying rapidly across a blue sky, you can see the temperature of the ground, shaded from the sun, changing rapidly up and down. I assume this is reflection and not the ground temperature changing.
On a rainy day the cloud temperature is at almost at the same temperature as the ground and air temperatures. Almost100% of the radiation is being reflected back. This would mean that any heat we generate is also reflected back.
In a temperature inversion highest temperatures are at ground level, again any heat we generate is trapped at ground level.
I can no way believe that the near non existent CO2 can heat up the rest of the atmosphere which out numbers it 2500 to 1.
“You have this completely wrong! N2 and O2 are transparent to IR in the range emitted by the earth, …”
This is BS…. if so, 100% transparent, we would not need IR telescopes in space for we could then just pick some freqencies that are devoid of the GHGs lines and view away, perfectly clear, from right here on the surface but that does not happen, all frequencies are affected from attenuation by passing through our atmosphere. This is one of the half-truths that so irks me as if no one ever seems to read what asronomers think of such blanket statements about ir radiation outside the vibrational lines and bands (that is in o2 and n2’s realm). Nice try though Phil.
Scanning through this thread – I find there are some who do not accept a GHE.
Even a reasonable post from one who was observant enough to note the effect of clouds in “warming” the ground is dismissed without respect.
No, believe this or believe it not….
However – I have spent many professional hours observing closely both air (2m), ground (road surface) and in some respects sub-surface temps.
This whilst on duty for the UKMO in winter as part of a service for local councils in the Midlands of England that involved both forecasting overnight RST’s (road surface temps) and passing on updates of any serious deviations from that forecast temp graph. (This whilst doing many other things eg forecasting for rail/energy/local media/radio and for the local airfields (Birmingham/Coventry/Nottingham).
No, it’s not mysterious, magic, strange or controversial, it just happens – that cloud/humidity DOES “warm” the ground (via slowing cooling and allowing the sub-surface heat-flux to warm the surface). The algorithm for the forecasts we did incorporated it as a major variable. Countless times (annoyingly as it involved a lot of work in the small hours of the morning), unexpected cloud spreading over a road sensor would lift the temperature away from the forecast graph … or worse the opposite and unexpectedly clearing cloud would allow the RST to plunge – with a consequent risk of ice.
On top of that, the cloud did not have to be obviously thick – just thin high Ci cloud 6 miles up at a temp of –30Cish could do the same. ( to a smaller degree but given cold enough RST’s it’s presence lifts/lowers the temp of a road surface ).
How many here have not seen a frost forming, say in an early winter evening and then noticed cloud spread over – resulting in the frost melting – or worse, the opposite late in the night say where condensation/rain on your car would freeze in the last hour of the night (often after dawn) making the car lock freeze up? or black ice on roads.
Look, there just is a GHE. Full stop. The only question is what effect CO2 has in this.
BTW: Those that say that 0.04% CO2 content would have no effect – please consider that ~99% of the atmosphere is non-LWIR radiating, leaving only ~1% that is.
Oh, and there’s even less CFC’s (ppt or a factor of 10^6 less) up there – but it managed to create the O3 hole.
Taking ENSO and low global cloud levels into account only see 0.1c per 30-40 years for AGW. Considering this approach we will only see a rise by 2100 of about 0.25c due to AGW. This small rise can be easily hidden by larger natural factors and will not be quite big enough to cause global temperatures beating records without a strong El Nino in future.
Phil says:
“You have this completely wrong! N2 and O2 are transparent to IR in the range emitted by the earth, CO2 is a strong absorber in the 15micron band. It has nothing to do with the detectors!..CO2 as you’ll see its absorption is multiple orders of magnitude stronger than N2 and O2. Specific heat has nothing to do with it.”
If SHC has nothing to do with it, it still begs the question: how is it that the atmosphere is warm – at all? And, what exactly is IR? IR is energy radiation felt to us as heat last time I looked, and the affect that heat energy has on a substance is the SHC – of which O2 and N2 have an average of around 1 (no units) and Co2 of 0.8, H2o vapour 2. If o2 and N2 have nothing to do with it, do not count, wouldn’t we either fry or freeze like in the vacuum? They’re there alright. Raman spectroscopy picks them up. Raman sees what IR doesn’t. Watch this and see.
Wayne: the way I make it is that they (n2 and o2) are transparent to the (thermopile) detectors the astronomers use. Buy a detector ( a non contact IR thermometer) and have a play; you cannot measure the temp of the atmosphere with them as they don’t see it. They do see water, glass, Co2 and the like though. It’s mainly the H2o that’s the problem to ground based IR telescopes -so they go out of the atmosphere.
wayne says:
January 13, 2014 at 10:58 am
“You have this completely wrong! N2 and O2 are transparent to IR in the range emitted by the earth, …”
This is BS…. if so, 100% transparent, we would not need IR telescopes in space for we could then just pick some freqencies that are devoid of the GHGs lines and view away, perfectly clear, from right here on the surface but that does not happen, all frequencies are affected from attenuation by passing through our atmosphere. This is one of the half-truths that so irks me as if no one ever seems to read what asronomers think of such blanket statements about ir radiation outside the vibrational lines and bands (that is in o2 and n2′s realm). Nice try though Phil.
Sorry you’re so biased that you can’t accept the truth!
Picking frequency ranges that CO2 and H2O can’t absorb is exactly the strategy that has been employed prior to satellite observation, see for example:
http://en.wikipedia.org/wiki/United_Kingdom_Infrared_Telescope
As shown in the spectra that I cited previously, N2 and O2 only have some exceptionally weak bands which are ~10 orders of magnitude weaker than CO2. Try reading some basic physical chemistry texts which cover spectroscopy and you’ll see the reasons for the transparency of homonuclear diatomics.
Elizabeth says:
January 12, 2014 at 3:29 pm
You are assuming that some of the “warming” is due to humans/ Well as a scientist with 4 higher degrees in statistics I am assuming that you are 100% wrong you do not have the faintest clue whether it is or not/ Sorry I am now a 100% denialist and proud of it. I think time will vindicate me.
Haha! If you want to pass yourself off as someone capable of attaining “4 higher degrees” at least learn to write like one with the required intelligence.
With a nod to Richard S. Courtney, could one also say,
“What can be said is that the last seventeen years shows no evidence for discernible global warming from increased atmosperic levels of carbon dioxide, so any contribution from it to future global warming is trivial if it exists.”
Then we should push the debate to what an optimal atmosphere and temperature for life on Earth is. I agree with an earlier poster who recommended 1000 ppm atmospheric CO2. That seems to be the optimal level for plants, and thus, animals. As far as temps, I wouldn’t object to it being a couple of degrees warmer, but that’s clearly debatable. Seems to me there are many places too cold to support advanced life, but none too hot (just too dry).
A reasonable scientific endeavor in this direction could shut the door on the EPA’s efforts (in the States) to control CO2 emissions, and maybe I wouldn’t have to convince so many liberal planetary saviors that 0 ppm of CO2 is NOT a good thing!
Kelvin Vaughan says:
January 13, 2014 at 10:57 am
I have measured the temperature of the clear sky around dawn and found that on some days it warms a few degrees before the sun is above the horizon. I’m am guessing this is the greenhouse gasses, including moisture, heating up
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The most likely explanation of this is a slight stirring of wind mixing warmer air above the surface inversion down to your thermometer. I have never noted an effect caused by radiation at that time.
“I have seen a graph showing air temperatures during an eclipse in the desert where the air temperature, which is above the ground temperature before hand, looses its heat rapidly.
The ground on the other hand retains its heat very well. If the ground heated the air, then why does the air temperature fall to well below the ground temperature at the height of the eclipse?”
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Doesn’t happen like that ..
See here http://www.climate4you.com/Longyearbyen%20SolarEclipse%2020080801.htm
“Diagram showing both ground surface and air temperatures before, during, and after the solar eclipse. The wind speed and -direction is given in the grey bottom panel. The temperature variations measured at the ground surface (red graph) is considerably larger than the air temperature variations (blue graph). The ground surface temperature decrease during the eclipse is about 14oC, compared to the 1.4oC decreases in air temperature.”
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“On a day with nimbus clouds flying rapidly across a blue sky, you can see the temperature of the ground, shaded from the sun, changing rapidly up and down. I assume this is reflection and not the ground temperature changing.”
It is simply the shadowing of solar SW from the ground. And if your thermometer was subject to incident sunshine, then yes you were just measuring the temp of the thermometer in/out of sunshine. If shaded from the sun it was indeed recording accurately a change in the surface temp.
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“On a rainy day the cloud temperature is at almost at the same temperature as the ground and air temperatures. Almost100% of the radiation is being reflected back. This would mean that any heat we generate is also reflected back.”
? What height is the cloud at?
There exists sensible heat in the atmosphere – a typical Nimbus (raining) cloud level, say at 2000ft in summer, could typically be, say 10C, whilst the ground/air could indeed be similar due cooling via evaporative cooling. This has little to do with radiation it is mostly sensible and LH transport effects.
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“In a temperature inversion highest temperatures are at ground level, again any heat we generate is trapped at ground level.”
A temperature inversion traps colder air at the surface, with a layer of warmer air above it. And “any heat we generate” is irrelevant as we are talking of a global effect, and not a very minor local effect.
BTW: It’s NOT prevented from cooling further, as cooling occurs from the top of the inversion to space (given clear enough skies). Hence fog can continue to thicken vertically as a night progresses without the surface temperature cooling much further. The wedge of cold air at the surface gets thicker (height wise) via radiative cooling to space.
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I can no way believe that the near non existent CO2 can heat up the rest of the atmosphere which out numbers it 2500 to 1.
My previous post highlights that indeed small quantities of some things can have major effects, given the process involved and especially so, because the more we find out about the Earth’s functions, the more it is obvious that everything is minutely balanced.
Tom says:
January 12, 2014 at 6:03 pm
I can’t find the link at the moment, but last year Mr. Watts put a demonstration of warming the heat source by placing a barrier between it and the heat sink on YouTube.com and posted it here. Some decades ago a higher efficiency incandescent light bulb was developed using an IR reflective coating (gold?) inside to raise the temperature of the filament, thus producing more light in the visible rang despite a lower percentage passing through the coating – unfortunately decreasing the lifespan as well.
Oops! “range” not “rang” I shouldn’t trust spell checking.
“If not for the warming effect of “Greenhouse” gases, the Surface of the Earth would average below 0°F (-18°C), which would prevent life as we know it. This effect is responsible for about 60°F (33°C) of warming.”
Some of that 33°C has to be accounted for by massive thermal reservoir of the oceans, as well as poleward heat transport.
TB:
Your post at January 13, 2014 at 1:14 pm concludes saying
Huh!
You say, “everything is minutely balanced”. That cannot be true or we would not be here.
The Earth’s climate system is observed to be extremely stable within each of its observed states (e.g. glacial and interglacial states, probably determined by its chaotic strange attractors).
For example, in the ~2.5 billion years since the Earth obtained an oxygen-rich atmosphere the Sun (a g-type star) has increased its radiative forcing of the Earth by ~20%. That has not had a direct effect on the Earth’s global temperature: if this increase in radiative forcing had provided such a direct effect then the oceans would have boiled to steam by now.
So, please explain why ~0.4% increase from radiative forcing from a doubling of atmospheric CO2 would be catastrophic when ~20% increase in radiative forcing has had no discernible effect.
Richard