By Andy May
This post was updated 9/24/2021 to reflect reader comments.
The phrase “greenhouse effect,” often abbreviated as “GHE,” is very ambiguous. It applies to Earth’s surface temperature, and has never been observed or measured, only modeled. To make matters worse, it has numerous possible components, and the relative contributions of the possible components are unknown. Basic physics suggests that Earth’s surface is warmer than it would be with a transparent atmosphere, that is no greenhouse gases (GHGs), clouds, or oceans. If we assume Earth is a blackbody, then subtract the solar energy reflected, from the hypothetically non-existent clouds, atmosphere, land, ice, and oceans; we can calculate a surface temperature of 254K or -19°C. The actual average temperature today is about 288.7K or roughly 15.5°C. This modeled difference of 35°C is often called the overall greenhouse effect.
A blackbody is usually defined as a perfectly black cavity kept at a constant temperature. All energy that enters the cavity is absorbed by the cavity walls, and they emit exactly the same amount of energy, but the wavelength of the emitted radiation is not the same as the energy captured. Instead, the emitted radiation has a wavelength determined by the cavity temperature, which is held constant. The Earth is nothing like this. It isn’t black and both the atmosphere and the oceans absorb and redistribute solar energy, often the absorbed energy is circulated for a long time, even centuries or millennia, before it is reemitted. A blackbody absorbs and reemits energy with a delay of less than a second. Earth’s surface temperature is not constant, like a blackbody’s temperature, it varies a lot by latitude, altitude, season, and/or ocean depth. The Moon has a calculated blackbody temperature of 270K, no atmosphere or oceans, and an average temperature, at the equator and low latitudes, of around 215K, so even the Moon is not an ideal blackbody.
Some unknown portion of the overall GHE is probably due to atmospheric greenhouse gases (GHGs). These include, CO2, H2O, CH4, N2O, and O3. Dr. William Wijngaarden and Dr. Will Happer examine the likely influence of these greenhouse gases using the HITRAN line-by-line molecular transmission and absorption database maintained at Harvard University (Wijngaarden & Happer, 2020). We discuss Wijngaarden and Happer’s important paper in this post and refer to it as W&H. HITRAN stands for high-resolution transmission molecular absorption. The database compiles spectroscopic parameters that computer programmers can use to model the transmission and emission of light in the atmosphere. W&H use the database to model a hypothetical mid-latitude temperature and GHG atmospheric profile to derive a representative climate sensitivity to doubling the gases. We have previously written about the GHE and will not cover the same ground in this post, which is mostly about the W&H model.
Dr. Clive Best also studied the HITRAN database, but just for CO2 (Best, 2013). Best also investigated the effect of gravity or air pressure on Earth’s surface temperature and concluded that they must contribute something to the overall greenhouse effect but was unable to model the amount. According to the second law of thermodynamics, a thermally isolated atmosphere will reach a constant temperature throughout its height if entropy remains constant. For a closed system that does not exchange heat or work with the surroundings, entropy can only increase. Earth’s atmosphere is not closed, since it is being heated by the Sun and losing heat by radiating to space.
Also, gravity does positive and negative work on the atmosphere, it does positive work on air parcels that sink. The work causes their temperature to rise and it can cause their entropy to reduce. But, since reducing entropy means taking heat out of the system, a cooling effect, which is stronger? This constant battle of contradictory forces keeps the entropy per kilogram of air approximately constant in the troposphere. The entropy of the stratosphere increases with altitude due to warming by ozone and stronger ultraviolet radiation than the troposphere receives. As temperature increases, entropy increases and radiation emissions from the GHGs increase. The overall proportions of surface warming due to GHGs, and gravity-induced warming, if any, remains unknown.
As far as recent—past 120 years or so—warming is concerned, gravity has not changed. However, the CO2 added to the atmosphere has increased the surface pressure slightly, since CO2 is 50% denser than dry air. Measurements suggest that the total water vapor in the atmosphere has decreased slightly, but these measurements are disputed due to the quality of the instruments used. Water vapor is 40% less dense than dry air, so how much the surface air pressure has changed due to differences in these two important molecules is unknown.
In this post we will ignore the effects of gravity and surface air pressure, even though gravity causes the Sun to fuse hydrogen into helium and emit the sunlight that warms our planet. Trying to figure out how much gravity contributes to the overall GHE, and recent warming only gives me a headache, and it creates furious arguments in the comments. The reason for the furious arguments, and my headaches, is that it is a complicated thermodynamic argument, and no one really understands thermodynamics. So, we just acknowledge it must have some effect on the total GHE and leave it at that.
Gravity has no direct effect on radiation transfer, but since gravity determines how the air pressure changes with altitude, there is an indirect effect because the air pressure influences the density of greenhouse-gas molecules. Thus, it also has a large effect on their total capture cross sections that contribute to the opacity of the atmosphere. For cloud-free air, the radiation flux is determined by only two quantities, how the opacity of the atmosphere varies with altitude and how the temperature varies with altitude. W&H took the altitude profiles of both temperature and opacity from experimental observations. The HITRAN data is based on observations. It is not theoretical data.
Because Earth’s atmosphere is transparent to most solar radiation and the Earth’s surface is opaque, the surface absorbs twice as much radiation as the atmosphere. Per the laws of thermodynamics, a planet tries to emit as much radiation as it receives. If Earth emits more, it cools; if it emits less, it warms. The global average temperature of Earth varies about three degrees every year, it is just over 12 degrees in January and just under 16 degrees in July. The Earth’s temperature controls the type of radiation it emits, and it emits mostly in the thermal infrared. The range of emitted frequencies, plotted as wavenumbers, with units of 1/cm, are shown in Figure 1.
The frequency and the power emitted by molecules are determined largely by the molecule’s kinetic temperature. In Figure 1, if the atmosphere is transparent and contains no infrared absorbing molecules, like CO2, the 288.7K emission spectrum would look like the blue curve. The y axis in Figure 1 is the spectral flux, or the amount of energy passing through the top of the atmosphere per unit frequency, in this case frequency is expressed as a wavenumber, or the number of waves per cm. Mathematically, ѵ (frequency) is the inverse of the wavelength.
A perfectly transparent atmosphere would radiate all surface emitted energy according to the blue line in Figure 1. All the curves plotted overlay in the atmospheric window (“Atm window”) from 824 to 975 cm-1. In this window the surface radiation can go straight to space, so it is labeled 0 km. This means the emission temperature (as determined from the spectral flux) reflects the modeled surface temperature of 288.7K or 15.5°C. Other example departures from the ideal Planck brightness blue curve, are labeled with the approximate altitude of the emissions, based on their brightness temperature. At these locations the atmosphere below these altitudes can be considered opaque to surface radiation due to the combination of GHGs modeled.
The green curve is the computed spectrum with all the greenhouses gases present, in their current concentrations, except for CO2. The black and red lines are the computed energy flux for CO2 concentrations of 400 ppm and 800 ppm respectively. The area difference between the green line and the black line is representative of the CO2-caused warming from zero CO2 to today’s concentration of 400 ppm. The area difference between 400 and 800 ppm, is much smaller and will result in much less warming.
The marked altitude of 84.8 km, in the middle of the CO2 caused divot in the energy curve, means that the emissions at that frequency range, roughly 609 to 800 cm-1, come from that altitude. Below that altitude, CO2 blocks the radiation at those frequencies. In this critical CO2 region of the spectrum, CO2 is saturated and cannot block anymore radiation. 84.8 km is nearly the top of the atmosphere, very high in the mesosphere. Additional CO2 makes the divot a little wider though, as the red curve illustrates and the widening causes a bit more radiation at the edges of the enlarged divot to be blocked.
As CO2 doubles from today’s concentration, the radiation emission level moves upward at all altitudes. As it moves upward in the troposphere, if cloud cover does not change, the emission temperature decreases, and the amount of energy emitted decreases. Since less energy is emitted to space, Earth’s surface should warm. When the sky is clear, radiation fluxes can be calculated accurately, but the conversion to a temperature change can get complicated. Emission height is strongly dependent upon frequency, as Figure 1 shows, and an average emission height has little meaning, just as a global average temperature has little practical meaning.
But at higher altitudes, in the middle stratosphere, temperature begins to warm with altitude. The warming is due to an increase in ozone (O3) as shown by the dotted red line in the right-hand graph of Figure 2. The increase in unattenuated solar ultraviolet light with altitude also has a warming effect. This means as the emission moves higher, more energy is emitted. This results in cooling, and we see this effect at the bottom of the CO2 divot in Figure 1. The red and the black curves reverse their positions and adding CO2 causes cooling. The reason why is illustrated in Figure 2.
The left graph in Figure 2 shows the atmospheric temperature profile used for the W&H model. In the real world, the temperature profile varies a lot from location to location and with time, especially in the troposphere, but W&H use a single set of values that are representative of the “standard atmosphere” in the mid-latitudes for their model.
There is very little H2O above the tropopause and N2O and CH4, already minor greenhouse gases in the troposphere, also decrease. In the stratosphere ozone (O3) warming is dominant and temperature increases, until the mesosphere is reached where ozone decreases rapidly and CO2 cooling begins to dominate. At the top of the mesosphere, roughly 86 km, changes in the energy flux are negligible, so W&H call this the top of the atmosphere or TOA.
Convection is minimal above the tropopause, but in the troposphere, it provides about half of the total heat transfer from the surface to the tropopause. As Figure 1 shows, except for the atmospheric window, the lower troposphere (below 2.8 km) is opaque to Earth’s OLR, or outgoing longwave (infrared) radiation, except in the IR window. The evaporation of water transports much of the surface emitted thermal energy, as latent heat, to higher altitudes where it can be radiated away from Earth. Thermal energy emissions, released from condensing water vapor, begin to appear at the base of low-level clouds, and continue throughout the cloud. Clouds are a very important component of Earth’s cooling system but cannot currently be modeled, so they are not included in the W&H model.
Clouds are included in the IPCC general circulation models (GCMs), but the IPCC assumes the cloud parameters and impact, they cannot calculate them. The IPCC AR6 report acknowledges that “clouds remain the largest contribution to overall uncertainty in climate feedbacks (high confidence).” (IPCC, 2021, pp. TS-59). While researchers are trying to model clouds, we share their high confidence that clouds are the largest source of uncertainty in computing the impact of humans on climate change.
The W&H emissions model is a clear sky model and only accurate above the clouds and in areas where there are few clouds, such as the poles and over deserts. Clouds excluded, W&H do try and account for GHG warming feedbacks. They investigated three cases, fixed relative humidity with a constant tropospheric lapse rate, fixed relative humidity with a variable lapse rate, and fixed absolute humidity. The resulting climate sensitivity values are shown in Table 1.
W&H also compared their resulting emissions calculations for three specific areas, the Sahara Desert, the Mediterranean and Antarctica. The comparison is shown in Figure 3.
The intensity values plotted in Figure 3 are different than the spectral flux values given in Figure 1 by 1/pi. The spectral flux values are energy passing an elevation in all directions, the values in Figure 3 are for brightness or intensity measured by a satellite. The difference is just in the units, they both measure emissions from Earth. The red Planck brightness curves in the left graphs are characteristic surface temperatures for the locations indicated, 320K (47°C) for the Sahara Desert, 288.7K (15.5°C) for the Mediterranean, and 190K (-83°C) for Antarctica. Notice the CO2 and H2O emission temperatures in Antarctica are warmer than the surface in the atmospheric window, this means the air above the ground is warmer than the ground and that the GHGs are cooling, not warming the air.
Summary and Conclusions
In summary, W&H have provided us with a detailed and accurate emissions model that shows only modest warming (2.2 to 2.3°C), inclusive of likely water vapor feedback, but not counting the feedback due to cloudiness changes. Both the magnitude and sign of net cloud feedback to surface warming are unknown. Lindzen has shown it is likely negative (cooling) in the tropics, but outside the tropics no one knows.
The water vapor feedback to surface warming is also very unclear, Ferenc Miskolczi (2014) has written:
“As long as the Earth has unlimited water supply (in the oceans) with its three phases permanently present in the atmosphere and two phases on the ground surface, the stability of the planetary climate will be controlled by the equations [see paper, page 19]. These two equations, together with the Clausius-Clapeyron equation, will regulate the transfer of the latent heat through the boundary layer in such a way that the net amount maintains the planetary radiative balance.” (Miskolczi, 2014).
Miskolczi, and others have found that total water vapor in the atmosphere has gone down in the past 70 years, although this is questioned. The work by W&M on radiation emissions suggests that future warming due to GHGs will be modest. Speculation about the warming feedback due to clouds and changes in total water vapor is just that, speculation.
The results of the study are summarized in Table 2.
Table 2 shows that the main GHGs are CO2, H2O and O3, doubling the methane or N2O concentration changes the outgoing forcing by less than one percent. Due to the properties of water vapor, its atmospheric concentration is very unlikely to double, but if it did, it would only increase the forcing by eight percent at 11 km. Doubling CO2 only increases the forcing by four percent at 11 km.
The combined current 11 km and 86 km forcing values in the table are not the sum of the individual values due to overlap. It is very clear from this table that all GHGs are saturated and adding to the current concentrations will make very little difference. Doubling CO2 will cause the stratosphere to cool about 10°C, but the changes in surface temperatures from this model are all less than 2.3°C, as shown in Table 1. This is much less than the preferred IPCC AR6 value of 3°C (IPCC, 2021, pp. TS-57). Considering that the current net effect of clouds is cooling and it seems likely that total water vapor in the atmosphere is decreasing or staying flat, these results suggest we have little to worry about regarding increasing GHGs.
Download the bibliography here.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
One of the major problems with this study and its conclusions is that it only applies to areas of the earth with clear sky conditions. This is only a minority of the surface of the earth.
To quote from the following page at NASA:
https://earthobservatory.nasa.gov/images/85843/cloudy-earth
“One study based on nearly a decade of satellite data estimated that about 67 percent of Earth’s surface is typically covered by clouds. This is especially the case over the oceans, where other research shows less than 10 percent of the sky is completely clear of clouds at any one time. Over land, 30 percent of skies are completely cloud free.”
So, this study deals with perhaps 1/3 of the earth’s surface. At most.
Moreover, they acknowledge that there are areas of the earth where temperature inversions exist, which radically alter the structure of the temperature in the atmosphere – and to which their calculations do not apply.
Perhaps the best known area with significant temperature inversion is Antartica. However, there are other studies showing that major areas of the northern land masses also experience temperature inversions during the winter portion of the year. Such inversions are often associated with cloud-free conditions.
So the real picture is much more complex – and this leaves aside the impacts of convection, which is a major aspect of the transport of heat from the surface to the upper parts of the atmosphere, especially in the tropics.
A comprehensive study of the effect of increased CO2 levels would have to take into account these other conditions of the real earth.
All good points.
The science of climate change is settled, they tell us. Settled and driven by CO2. But we don’t understand the effects of gravity on temperature. We don’t include the effect of wind currents. No one understands thermodynamics. Clouds are poorly understood.
We do, however, have a good map of frequency related effect of individual GHGs. And we can model these well enough to match very closely areas where the factors that are not well understood are minimized. And, what do these limited models tell us? That the effect of CO2 on temperature is limited to a narrow band of frequency, overlaps with H2O, and is saturated in its effect.
Can we stop doing stupid stuff to make anything carbon related expensive now? Can we unsettle the science and get back to real scientific inquiry?
Andy- You say the term “Greenhouse Effect” or GHE is ambiguous. I’m not sure what is ambiguous about it. People often say the greenhouse analogy is inappropriate because the physics involved is somewhat different. I say yes and no. Both the greenhouse roof and the earth’s atmosphere are transparent to the incoming short wave, and when that radiation hits the ground, it is absorbed and causes the ground to heat up. I believe the greenhouse and the earth are the same in that respect. Once the ground is heated, it begins to lose that heat by radiation. The earths’ atmosphere impedes the loss of heat from the earth because the long wave energy being radiated is absorbed by the atmosphere, causing the atmosphere to warm up somewhat. But, the heat eventually leaves, it just leaves at a temperature higher than it would if the atmosphere were transparent to LW as well as SW radiation. The greenhouse which is also warmed by the incoming solar must also eventually lose the heat, heat and some is lost by radiation, and some by conduction. There may be convective heat transfer inside the green house, just as there is in the earth’s atmosphere, but ultimately all the heat leaves either by conduction or radiation.
As for only being modeled and not measured, if you mean we cannot get the temperature of the earth with an LW transparent atmosphere or no atmosphere. I supposed that is true, but we only have to look at the moon to see what happens to surface temperature without an atmosphere. What is the point of saying we cannot measure the greenhouse effect?
Tom,
The lower troposphere, especially the lower few meters are opaque at the CO2 and H2O frequencies, so in the general case the Earth loses the energy via convection, very little makes it to space via radiation until a high altitude is reached, as detailed in the post. Greenhouses warm by restricting convection, so do blankets and tents. Radiation plays no role at CO2 and H2O frequencies.
The very poorly defined GHE has us spending billions of dollars trying to fix a nonexistent problem. It cannot be measured and is ambiguous. W&H have proposed a quite solid and rigorous definition, if you accept their definition, it is clear the money is wasted.
That is the point.
Very interesting, as usual, Andy, congratulations. This is complicated stuff and even the experts disagree on some points. I do not pretend to be right, as I am not an expert, but I do have my point of view and this makes for a great discussion subject.
Not really. Only if it wants to keep the same temperature, but the Earth does not keep its temperature. At present it is about 14.5°C, but 52 Mya it was 23.8°C, and only 20 kya it was 9.5°C. And these are yearly averages. Currently the Earth surface is at 12.1°C in January, and at 15.9°C in July, a 3.8°C difference over the year! They compensate that change for the temperature anomaly graphs or the warming would not be visible. It is clear that the Earth does not emit as much radiation as it receives, at times it emits more and at times it emits less.
There is a very serious problem with averaging radiation over the year, one simplifies the problem running the risk of erring the solution.
Greenhouse gases fulfill two crucial roles to keep the planet full of life. On the lit side of the planet they reject about 30% of the incoming energy. On the dark side of the planet they keep enough heat to prevent deep freezing at all latitudes. Without them the lit side would be >100°C and the dark side would be <-50°C, which is what happens in the Moon, and life would not be possible even to the Fremen of Dune.
I do not think GHGs are saturated. We could obviously have more clouds at night and the planet would be warmer, or more clouds at day and it would be cooler. More CO2 would thicken the troposphere and push the tropopause higher, so the planet would be warmer and with more convection. I don’t think the saturation argument is a good one.
Changing the temperature of the stratosphere would change the climate of the Earth big time. This is what solar variability does, it changes the temperature of the stratosphere by a lot less than 10°C and it affects the climate greatly. What happens in the stratosphere does not stay in the stratosphere.
The CO2-hypothesis of climate change is obviously wrong. It is unable to make succesful predictions other than warming is going to continue. However, the fundamental problem is that its challengers look even less convincing (all but one). You cannot cause centennial or longer warming of the planet by moving heat around the climate system, which is what internal variability does. The ocean is tremendously cold with an average temperature of 3.9°C. Luckily it is very stratified or we would freeze to death. The planet could cool down by stirring the ocean a little bit more, but we are in an ice age, we cannot warm the planet with heat from the ocean. So to have global warming for a period far longer than the multidecadal atmospheric-oceanic oscillations the energy imbalance of the planet MUST be altered. That’s why many scientists accept the CO2-hypothesis despite its serious shortcomings and despite lots of evidence that contradict it. The science corpus does not abandon a hypothesis for no hypothesis. For the same token it does not accept a new hypothesis if it does not understand it no matter the amount of evidence that supports it. It is what happened to Alfred Weggener. His hypothesis was not accepted because scientists could not understand how continents could move (they weight a lot).
Clouds (liquid water) are opaque to IR.
Great perspectives. Have always been interested in your opinions, here and on Climate Etc.
“..the earth does not keep its temperature.” Requires some definition. Usually people are talking about a steady state condition, and over some lengthy period of time. If the earth were out of heat balance for one reason or another, it would be either be net heating up or net cooling down. The temperature fluctuates over time, but is largely stable for the purpose of these discussions. The reason it is not completely constant is due to many factors, but in the long run the earth can be said the be in heat balance with the energy it receives from the sun.
Tom, How long a run? The current Ice Age is either 2.5 million years old or 30 million years old, depending upon whether we measure from the polar ice cap or the Antarctic one. I don’t think the Earth has ever been in thermal equilibrium.
Tom, the Earth is always changing its temperature, from day to day, month to month, year to year, decade to decade, century to century, millenium to millenium, million year to million year. There is no steady state but a constantly changing push (Sun)-mix (ocean/atmosphere)-respond (OLR). Equilibrium, balance, steady state, certain period, are wrong concepts that get people lost. Stability is OK if properly defined, for example as life-compatible.
If the planet can change its surface temperature one year to the next by +0.42°C (Feb 2015 to Feb 2016) it is clear that it is not stable, nor in balance.
The stability of the Earth temperature is due to the constancy of the Sun and the equalizing role of the ocean, not to some supposed radiative balance that does not exist.
Javier.
“Not really. Only if it wants to keep the same temperature, but the Earth does not keep its temperature. Earth is always changing its temperature, from day to day, month to month, year to year, decade to decade, century to century, millenium to millenium, million year to million year.
You seem to have jumped from the contention of energy in equals energy out to discussing temperature instead, which is not what the comment was about.
You were better using this line
“”he stability of the Earth temperature is due to the constancy of the Sun and the equalizing role of the ocean, not to some supposed radiative balance that does not exist.”
which did seem to contradict your previous assertion re temperature even though here you presumably mean energy.
Energy and temperature are not he same thing.
On the one hand you say, “…the Earth is always changing its temperature..”, and on the other you say, “The stability of the Earth temperature is due to the constancy of the Sun and the equalizing role of the ocean, not to some supposed radiative balance that does not exist.”
Here’s some information for you. The earth only receives of and disposes of energy by radiation. There is no conductive or convective transfer of heat to or from outer space. If the earth was not shedding to outer space via radiative heat loss approximately the same amount of energy that it constantly receives from the Sun, then it would be over the long run constantly heating up, or vice versa. It is a dynamic equilibrium, so the temperature at any point in time or space is not constant, but, it is an equilibrium, and the controlling factor is radiative energy transfer.
The temperature of the Earth is stable in the sense that it has varied between 8°C and 28°C during the past 540 Ma. It has not been 3°C or 33°C or we would not be here. That’s what I mean by stable. Changing only by plus/minus 10°C is very stable considering the temperature of other planets.
Equilibrium = a state in which opposing forces or influences are balanced.
Balance = 4 : a state in which things occur in equal or proper amounts
At any point in time the temperature of the Earth is not in equilibrium and the radiative energy “in” is not the same as the radiative energy “out”.
From July to January the Earth cools by 3.8°C. From January to July the Earth warms by 3.8°C. This is despite the Earth receiving a lot more incoming radiation in January than in July, because it is closer to the Sun. But the total outgoing radiation (reflected+longwave) is maximal in November-December.
So both temperature and radiation are changing a lot constantly and often in opposite directions. The Earth sometimes warms despite receiving less radiation, because it emits even less, and then it does the opposite and cools despite receiving more radiation because it emits even more. Describing that as equilibrium or balance is silly.
I think you know a lot less about this than you think you know. Perhaps you should start with this figure from the Wikipedia article on seasons:
Javier
“At any point in time the temperature of the Earth is not in equilibrium and the radiative energy “in” is not the same as the radiative energy “out”.
Please.
No matter how far away the heating source is at any time of the year the energy in equals the energy out.
It is called TOA as it is the theoretical level where energy in equals energy out regardless of how much is coming in.
One does not talk of the temperature as being in equilibrium.
You are in error Angech. At any time of the year, energy in does not equal energy out. Check figure 1 in:
Carlson, Barbara, et al. “Spectral signature of the Biosphere: NISTAR finds it in our solar system from the Lagrangian L‐1 point.” Geophysical Research Letters 46.17-18 (2019): 10679-10686.
The yellow curve is energy arriving at ToA over the course of the year (TSI). The green curve is energy departing ToA (TOR = RSR + OLR).
Javier Reply to angech
You are in error Angech. At any time of the year, energy in does not equal energy out. Check figure 1 in:
Carlson, Barbara, et al.
The yellow curve is energy arriving at TOA over the course of the year (TSI). The green curve is energy departing TOA (TOR = RSR + OLR).
–
Oh dear.
The time to dot the I’s and cross the T’s again.
Javier
“At any point in time the temperature of the Earth is not in equilibrium and the radiative energy “in” is not the same as the radiative energy “out”.
Basic concepts.
We were dealing with the earth’s energy purely from heating from the sun and space, at least I thought we were and are.
But to be clear, Earth is not a non heat producing source so there is more energy going out than what comes in always.
Most discussions focus on the heat questions ignoring this and concentrate on the issues of what happens to the energy coming in.
Let us both focus on the usual scenario.
The heat coming in [just considering the sun] varies as to the distance from the earth plus any albedo changes.
Full stop.
The TOA is where the energy coming in balances the energy going out.
By definition.
Therefore it is not possible to have a radiative imbalance.
Just not possible.
So we have a conundrum.
Carlson, Barbara, et al. want to find an imbalance to warm up the earth.
Which is illegal by definition.
The yellow curve is energy arriving at TOA over the course of the year (TSI).
Wonderful, legal.
Note there is more heat TSI coming in in winter NH when the sun is closest to the earth? Is this correct?
It varies by 22W/M 2 Willis 2014.
Now the magic claim.
The green curve [ Ceres] is energy departing TOA (TOR = RSR + OLR).
Illegal.Why
TOA, by definition is where the outgoing must match the incoming energy.
If it does not then either it is not the TOA or she and her team have made a miscalculation or a wrong assumption.
None of the TOR listed are real, can be reral
ISCCP blue dots straight line [dead giveaway] is a 1982 system current average guesstimate.
annual mean current estimate is a straight red line
Pre industrial dotted straight red line is a made up historic estimate
TOR wavy line is a made up estimate
TOR red wavy line is a made up estimate
Crees green wavy line made up estimate
TOR wavy blue ISCCP made up estimate.
Normalized.
Faked by putting in values
“.For more explicit comparison of the relative seasonal variability, the ISCCP data have been normalized to match the 0.7-W/m2 CERES value for the global annual-mean energy imbalance. Often cited as the smoking gun of global warming, the 1.1-W/m2 GCM value is substantially larger than the CERES 0.7 W/m2.””
GCM has shortcomings “the seasonal variability of TOR, RSR, and OLR in response to solar forcing is sufficient to provide diagnostic information on GCM shortcomings in ocean heat transports and energy sequestration.”
Not able to be assessed but we assessed it anyway,
“Given the inherent difficulties in determining TOR with sufficient accuracy and with adequate sampling of the diurnal cycle, and given also similar difficulties in modeling climate, it would be premature to draw definitive conclusions.”
So we went a million miles out where the spectral values were reduced to a more accurate single data point of information which could be filtered through all our other data sources to tell us where which clouds were on any given day on the earth, a million miles away at thast precise second. Just like an exoplanet 40 light years away.
“”This is where the new perspective that is now available from NISTAR data may help to resolve this issue.”
Jvier, you like to present accurate data.
Could you please give a more reliable comparison if you wish your argument to be taken seriously.
You have probably moved on, but I’ll give it another shot. Your chart has a simple explanation, and it is not relevant to what I said. What I said was that the earth only receives and sheds thermal energy by radiation. Any other sources of thermal energy such as burning fossil fuels or radioactivity are completely insignificant. If the radiant energy did not balance out over the long run, then the would be net heating or cooling, which there is not. It’s not really very complicated. And if there were no GHE, the earth would be much colder and we would not be having this discussion. No one disputes that.
“The science corpus does not abandon a hypothesis for no hypothesis.”
I don’t like the wording on this statement. Science should abandon a hypothesis once it is disproven, not because someone posits a different hypothesis.
CO2 driven climate change is kept on life support by hiding declines, adjusting historical records, and by shutting down opposing viewpoints, not by the strength of its evidence.
The CO2 hypothesis has been disproven by the long pauses in temperature vs increasing CO2. This is a proof that CO2 DOES NOT control temperature. If warming exists it is due to a combination of things and there is no proof that changing CO2 will modify anything.
The scientific consensus is like that person that hates to be single and will stick with his/her ugly girlfriend/boyfriend until someone better comes along. No matter how ugly the CO2-hypothesis, it will not be abandoned until a better hypothesis shows up. We skeptics can point how ugly it is until exhaustion, it won’t matter.
Brilliant, as always Javier!
I should have written that the planet always tries to emit as much radiation as it receives.
Their calculation that the stratosphere will cool by 10 degrees at 800 ppm surprised me, but it is probably correct. What effect will it have on the troposphere? Perhaps you can tell us in a future post. I look forward to that.
someone above made a comment about Planck.
“I should have written that the planet always tries to emit as much radiation as it receives”
No. You were right.
Why change it for Javier?
There is no “tries to emit as much radiation as it receives”
It does not have a brain to try with or a battery to store with.
I will have to push this point until the penny drops for people.
Science absolutely dictates that a body must emit as much radiation as it receives.
The reason for this is obvious.
A non heat producing body is given some extra energy.
It is now in energy imbalance.
Structured as it was, entropically stable, perfect, it needs to return to its normal state by discharging all the energy.
It could not hold on to or store any more energy before or it would already have had it and not needed it.
It emits all it receives to return to its steady state.
A body must emit according to its skin temperature. No connection, directly, at how much radiation it receives.
Exactly. And the efficiency of radiative cooling is determined by GHGs (particularly clouds), and the nature of the surface (land, ocean, ice).
The fact that energy in takes place mainly at the tropical band and energy out is lower than energy in at the tropics and higher at mid and high-latitudes demonstrates that the radiative equilibrium is a myth. There is nothing that can impose such equilibrium and as a result the temperature of the Earth is constantly changing. Compensating mechanisms to change by the coupled ocean-atmosphere are responsible for homeostasis that some people mistake for balance.
Scientists are very keen at assuming simplified conditions, like a radiative equilibrium, that allows them to use simplified mathematics to describe the system. The problem is that at the end the assumption has to be checked and see how it affects that it is incorrect, because otherwise the solution obtained is invalid. Assumptions escape the scientific method.
Per the laws of thermodynamics, a planet must emit as much radiation as it receives.
Not really.
Jupiter emits twice as much radiation energy as it receives:
http://ircamera.as.arizona.edu/Astr2016/lectures/jupiter.htm
Key takeaway line—that I wish had received greater emphasis in the above article—is from the last paragraph:
So, how many tens of $trillions are nations around the globe going to spend on reducing “carbon emissions”?
Hint: cue President Joe Biden’s speech yesterday to the United Nations, with its call for worldwide action on “climate change” (almost universally associated with increasing atmospheric CO2 concentration).
There is the old saying: “Science and politics don’t mix.” It’s exemplified in the above juxtaposition.
“Fig. 9 as well as Tables 2 and 4 show that at current concentrations, the forcings from all greenhouse gases are saturated. The saturations of the abundant greenhouse gases H2O and CO2 are so extreme that the per-molecule forcing is attenuated by four orders of magnitude…””
Err, No.
At present the effective height of emission to space of terrestrial LWIR is ~ 8km or 5ml.
That is, at that height more is directed to space than is directed back to Earth.
So, considering “The marked altitude of 84.8 km, in the middle of the CO2 caused divot in the energy curve”
That leave another 77km/48ml of atmosphere before the effective emission height “saturates”
(see below for Roy Spencer’s comment)
From this thread :
https://wattsupwiththat.com/2020/10/26/study-suggests-no-more-co2-warming/?utm_source=dlvr.it&utm_medium=facebook
in which Nick Stokes (chiefly), critiqued this paper …
““We could emit as much CO2 as we like; with no effect.”
The paper says nothing like that. It goes through the old argument between Arrhenius and Angstrom; the Arrhenius argument prevailed, and this paper does not contradict it. The key outcome is probably Table 5, where they compare their CO2 sensitivities with those calculated 50 or so years ago by Manabe, and by Hunt and by Kluft (recent). The fixed relative humidity numbers are 2.9(2.2), 2.2, 2.7, 2.3. The last number is theirs, and is completely in line with the earlier results, and certainly does not say that CO2 could be added with no effect. It says the CS would be 2.3C per doubling.
The forcing increments due to GHG increase are shown in Table 3. They explicitly say, correctly,
“The forcing increments in Table 3 are comparable to those calculated by others.””
“The “saturation” is what it is. The GHE still works. And, I repeat, their calculated CS is 2.3C/doubling. Right in the IPCC range. They have basically repeated the old calculation of Manabe with updated radiative properties, and got a very similar result.”
Nick on why it wasn’t published in a peer-review journal …..
““In science opposing visions SHOULD be published.”
It isn’t an opposing vision. It is a rehash of an old calculation yielding a very similar result. It is always going to be hard to publish that in a research journal.”
““We could emit as much CO2 as we like; with no effect.”
The paper says nothing like that. It goes through the old argument between Arrhenius and Angstrom; the Arrhenius argument prevailed, and this paper does not contradict it. The key outcome is probably Table 5, where they compare their CO2 sensitivities with those calculated 50 or so years ago by Manabe, and by Hunt and by Kluft (recent). The fixed relative humidity numbers are 2.9(2.2), 2.2, 2.7, 2.3. The last number is theirs, and is completely in line with the earlier results, and certainly does not say that CO2 could be added with no effect. It says the CS would be 2.3C per doubling.
The forcing increments due to GHG increase are shown in Table 3. They explicitly say, correctly,
“The forcing increments in Table 3 are comparable to those calculated by others.””
And possibly most damning from denizens’ perspective comes from this thread:
https://wattsupwiththat.com/2020/11/29/slight-beneficial-warming-from-more-carbon-dioxide/
From Roy Spencer:
“I’m afraid I have to agree with Nick on this. The authors used detailed line by line calculations and get the same radiative forcing from 2XCO2 others have gotten. How much warming occurs largely depends upon feedbacks, which were not the main subject of the paper. Talk of near-saturation is nothing new, this is known and included in climate models. There is no such thing as total saturation of the GHE. Ask Venus (with over 200,000x our CO2).
The science:
“So, if a skeptical friend hits you with the “saturation argument” against global warming, here’s all you need to say: (a) You’d still get an increase in greenhouse warming even if the atmosphere were saturated, because it’s the absorption in the thin upper atmosphere (which is unsaturated) that counts (b) It’s not even true that the atmosphere is actually saturated with respect to absorption by CO2, (c) Water vapor doesn’t overwhelm the effects of CO2 because there’s little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and (d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.”
Anthony Banton,
It took me a while to realize that you were quoting the paper and not my post.
Err, yes. The calculations are correct and the attenuation is four orders of magnitude. You deftly change the subject. W&H are not discussing the average emission height, which is as useless a number as the global average surface temperature. They are talking about H2O and CO2 additional forcing per molecule, which is frequency dependent. Their numbers are correct in the clear sky case.
But, in any case I have no serious problem with what Nick or Roy wrote. I do not think the GHE causes all of the surface warming on Venus, there are other factors at work there. But, 96% CO2 and no water are certainly big factors. We need to remember that Earth’s surface (bottom of the ocean to TOA) contains 5 times as much thermal energy as Venus’ atmosphere. Yet, Earth’s surface temperature is 15C and Venus’ is 464C. The lack of water on Venus, due to it’s strong electrical field, is another big problem. Venus’ total atmospheric heat capacity is appalling low.
See here: Can Earth be compared to Venus? | Andy May Petrophysicist
I liked W&H because it brings us back to Earth, it elegantly describes the GHE and how the climate models work. I’ve read the older papers you refer to, they are not nearly as good as this one.
The basic W&H clear sky radiation calculations do show us there is no problem with additional CO2, even if we assume water vapor goes up with temperature. That H2O will necessarily go up is an assumption with no evidence at this time. The billion dollar GCM’s are no more accurate than the W&H model.
What we are left to consider is what clouds will do if the surface temperature warms about two degrees. And, as acknowledged in AR6, no one knows. The argument is not about the radiative effect of CO2, it is about clouds, feedbacks, and convection.
I hope this paper is the end of the CO2 radiative effect discussion. It doesn’t matter. It doesn’t disappear, it just doesn’t matter. The feedbacks, if they are significantly positive might matter, but nobody even knows if they are net positive, much less what their value is. Certainly, two degrees of warming from today, at 800 ppm, is nothing to worry about. Primates evolved and dispersed widely when global temperatures were 10 degrees warmer than today during the Paleocene-Eocene Thermal Maximum. It is unclear to me that sufficient economic fossil fuels exist to get us to 800 ppm in any case.
Andy May, just so! Excellent response.
It is not the lowest altitude at which, across LWIR spectral bands, Earth’s atmosphere radiates to space and how that varies as a function of concentration of GHGs, but rather the highest altitude at which GHGs have effectively reached the asymptotic “limit” (i.e., become “saturated”) in absorbing the LWIR radiation off Earth’s surface and then having thermalized that associated, available energy with N2 and O2 as a result of extremely rapid (on the order of nanoseconds) collisional energy exchanges.
The science supports that the thermalization of GHG-intercepted LWIR off Earth’s surface is essentially complete within the first 10 km of altitude, with realization that there is a portion of the LWIR spectrum (the “atmospheric window” noted in Figure 1 of your article) where combined GHG’s just do not absorb radiated energy.
Per K-T diagram accounting/balancing of power fluxes under assumed equilibrium conditions, 40 W/m^2 escapes through the “atmospheric window” whereas 199 W/m^2 comes off the atmosphere, including N2 and O2 thermal radiations . . . the “atmospheric window” accounts for only about 17% of Earth’s total radiation.
Sorry, should have said the top quote was from Harper’s paper.
I have no quarrel with the numbers. I posted comments from Nick and Spencer to cover that – and you agree.
Turns out the paper is of little concern to the consensus science.
My concern was with the obviously incorrect statement in the paper that “the forcings from all greenhouse gases are saturated”
They are not, as they as climate scientists should know.
And as such should discredit any pretensions of unbiased (or at least knowledgeable) scientific enquiry.
Anthony Banton
“Sorry, should have said the top quote was from Harper’s paper.”
Yes.
You said
“My concern was with the obviously incorrect statement in the paper that “the forcings from all greenhouse gases are saturated
They are not, as they as climate scientists should know.”
Surely that comment depends on context, and as you are making up an argument for arguments sake. you need to provide the context.
Ie you needed to quote exactly what conditions were specified in that article for them to make what seems like a perfectly adequate scientific statement under certain conditions.
You know, like “In this paper considering all fully saturated GHG there is no room for more forcing”‘
Since you did not present any context and are not discussing this post specifically you therefore appear to be making a bogus statement about some personal beef or misunderstanding?
As you said “A blog comment is not scientific backing.”
Anthony,
I agree with angech and will not repeat what he wrote, but I have two additional points that are important, IMHO.
W&H provide us with a rigorous definition of the radiative clear-sky GHE. They do this very well and this is a great contribution and sorely needed. Unfortunately the IPCC has not provided one and uses the term in many different ways. They do this in an attempt to persuade, rather than educate.
One observes they do not define the term, because when properly defined, anyone can see it is not threatening.
Both Wijngaarden and Happer are physicists uniquely qualified for this work. Happer has studied atmospheric physics since the early 1980s and was a co-author of one of the very early investigations into the effect of CO2 on climate.
The term “climate scientist” today usually refers to climate modelers. These modelers have yet to devise a successful climate model, even after spending billions of dollars and millions of man-hours in the attempt. Saying a proper scientist is not a climate scientist is a compliment, IMHO.
Thank you!
“According to the second law of thermodynamics, a thermally isolated atmosphere will reach a constant temperature throughout its height if entropy remains constant. However, gravity bunches up the molecules of air near the surface and reduces their entropy, raising the temperature. ”
Finally, scientific backing for the idea that air pressure has something to do with a planet’s surface temperature (compare Venus, Earth, and Mars, say), and not just GHEs.
A blog comment is not scientific backing.
High pressure of itself does not create persistent warming. Note the word “persistent”.
When you pump up your bike tyres they get warm – you can feel the heat at the end of the pump (Charles’ law).
But the pump and the tyre cools and so does an atmosphere after any compression takes place (eg mass subsidence in a HP cell).
Anthony, Lets distinguish between case 1: the total GHE, and case 2: the enhanced GHE, that is adding CO2.
Case 1: No atmosphere like the Moon versus an atmosphere like Earth’s. Or if you prefer, a transparent atmosphere, versus one with GHGs.
I’m not sure what the temperature of the transparent atmosphere would be, but suspect it would be a uniform temperature from some high altitude to the bottom and that the temperature would be larger than the blackbody temperature and most of that temperature increase would be due to pressure according to the PVT law. We would assume that the atmosphere does not circulate, even though I’m not sure what gas that would be. It would also have to a perfectly transparent gas.
Case 2: enhanced GHE, adding CO2. Gravity doesn’t change, but CO2 is much denser than dry air and H2O is much less dense. How these volumes change and how fast, could make a difference in surface temperature, how much is uncertain. But, we are talking about very small temperature changes. probably only 0.13 degrees per decade according to Dr. Spencer. Some portion of that 0.13 change might be due to air pressure changing.
I don’t follow your statement that “most of that temperature increase would be due to pressure according to the PVT law.” Now, if solar heating makes the surface temperature non-uniform, the (by hypothesis, perfectly transparent) atmosphere’s heat capacity would slightly reduce the non-uniformity and thereby make the average surface temperature slightly higher than it would be if the surface temperature had more variance.
Absent that (presumably negligible) effect, though, I don’t see how an isothermal atmosphere, no matter how heavy, would affect the equilibrium surface temperature. Say the surface temperature is somehow irradiated so isotropically as to assume a uniform temperature. That uniform temperature must at equilibrium be such that the surface radiates out as much as it absorbs.
This follows from the fact that a perfectly transparent atmosphere can gain or lose heat only by conduction with the surface, and at equilibrium the net conduction is zero by definition. This is true independently of the atmospheric pressure.
In short, it seems to me that Mr. Banton has the better of the argument. What am I missing?
Only a static atmosphere can become isothermal. A gaseous atmosphere can never be static due to temperature and density variations in the horizontal plane. As soon as convection starts the GHE develops.
No convection, no GHE.
Or is it no GHE, no convection?
Stephen Wilde stated:
Oh, no. Stop the presses! You must immediately inform all weathermen and airplane pilots that there can never be such a thing as stable temperature inversion layer in Earth’s atmosphere.
They will be simply amazed to hear of this update.
Joe Born
Reply to Andy May
“I don’t [want to] follow your statement that “most of that temperature increase would be due to pressure according to the PVT law.”
” Now, [If I change what Andy May said to some other situation] if solar heating makes the surface temperature non-uniform”
Let’s just stick to the argument as formulated, Joe, tangents are not helpful.
“I don’t see how an isothermal atmosphere, no matter how heavy, would affect the equilibrium surface temperature.”
Perhaps this might help.
Only a guess.
With an extremely dense but transparent atmosphere Gravity has made the air molecules at the bottom closer together and more capable of interacting.
Radiation returns to space in two ways. By IR from the surface and by conduction at the air surface interface.
The heated molecules rise and induce a lot of convection in the dense lower atmosphere.
Convection helps spread the possible radiating area further out
This reduces the intense heat going out from under the sun and leads to a far larger surface area warming up to radiated the convected heat.The now warmer colder large areas are at a higher temperature than they were and the average surface temperature rises as the hot surface are dips a lot more than the cold ares go up.
Part of the reason for Venus being warm all over according to some ?
You called my first paragraph’s assumption of a non-uniform surface temperature a tangent, but you assumed exactly the same thing (“the intense heat going out from under the sun“, “The now warmer colder large areas“).
The effect you then describe is exactly what my first paragraph referred to, i.e., the atmosphere’s reducing the surface temperature’s non-uniformity and thereby increasing the average temperature required (because of the fourth-power relationship) to achieve the same average radiation.
As you correctly observed, though, that’s not what Mr. May assumed in his Case 1: for that case he assumed “uniform temperature” in the atmosphere and that “the atmosphere does not circulate,” so he’s ruling out the effect that you describe (and, again, that I referred to in my first paragraph).
That’s why I prefaced my second paragraph with “Absent that (presumably negligible) effect. . . .”
To me it appears that Mr. May is basing his discussion on bad physics. It’s hard to tell, though, because he didn’t write clearly for us to be sure. I’m not criticizing his writing, because we all leave latent ambiguities. But to me it’s a red flag that he doesn’t seem inclined to clarify.
Joe Born to Andy May
“I don’t follow your statement that “most of that temperature increase would be due to pressure according to the PVT law.”
It is quite simple and someone of your repute is being disingenuous to an extreme when you say you do not understand or admit that there is a relationship between pressure and temperature.
Anthony Banton himself wrongly commented
“High pressure of itself does not create persistent warming.”
Objects come together when their vectors intersect.
Gravity comes into play to cause passing objects to come together.
Gravity the results in a pressure effect as the size of the joining objects grows.
Ultimately high pressure causes suns to form and produce persistent heat.
Atmospheres with a gravity distribution of molecules at different densities results in heat generation.
Gas giants do not need a sun to produce heat.
On earth we need the sun but that does not prelude a relationship,embedded in physics, between pressure and temperature.
Ruling out the role of Co2 as having an important relationship is wrong as well because these relationships are all important facets of science.
Thank you for your considered, and polite reply to me. perhaps you could treat Mr May’s views with courtesy also?
No one denied PV=NRT. No one denied that the higher surface temperature of Venus results at least partially from its heavier atmosphere.
But Mr. May made a statement in which he appeared to indicate that at equilibrium a planet that has a perfectly transparent high-pressure atmosphere would have a higher surface temperature than an otherwise-identical planet whose atmospheric pressure is lower. Nothing about PV=NRT requires such a result, so I see nothing discourteous in extending Mr. May an opportunity to clarify his statement.
To Andy May above at 4.43 am Thanks for the answer to my request for the location of the NYT paper.Very kind of you.
Ed.Nalton.
Sorry, you need to determine why your tire cools. It is not because the pressure stabilizes and has no further change. Think conduction to the air and heat loss.
Compression and decompression is a continuous process in an atmosphere so the system doesn’t cool in the way a tyre does when pumping stops.
The issue is that pressure does cause a permanent increase in temperature unless there is another variable change. PV = nRT!
Yes it does.
It does not. It does not have a solid impermeable barrier.
Andy,
I know that CO2 is referred to as a well-mixed gas. However, a movie made by NASA with OCO-2 data shows minor variation in concentration spatially, and more vertically.
Therefore, I’m surprised that Fig. 2 (RH side) shows CO2 concentration as constant. Even more surprising is that only the ‘magic molecule’, CO2, is constant with altitude. This seems unlikely to me. How do W&H justify their assumption(?) that only CO2 is constant with altitude?
Good question, I do not know. I will ask.
Clyde, The atmospheric concentrations came from their reference 18, Clough, 1986. You can download it here:
(PDF) AFGL Atmospheric Constituent Profiles (0.120km) (researchgate.net)
I see that the paper, describing the Standard Atmosphere, for doing atmospheric corrections of satellite imagery, was published decades before OCO-2 was launched. I imagine that better data are now available.
I don’t know. That is the only reference I’m aware of.
I checked vW and Happer. It is theory. Unfortunately my finding is that the practical results do not support the theory.
See here
https://breadonthewater.co.za/2021/01/26/am-i-a-climate-denier-denialist/
If you ask me what is wrong? I don’t know. I think there is no Planck curve for earth? If I board a plane and keep watching the T at 10km it stays at -50C with very little variation….there is no curve….it is discrete.
Note this post, especially the presentation of the warming at the end of the post. My own results show same even more dramatic. I measured ca. 0.05K/ year warming in the arctic which gradually goes down per latitude in the NH to almost no warming in the SH and even cooling in the antarctic areas.
https://breadonthewater.co.za/2021/04/05/unexpected-ice/
Sorry if I did not make this clear. If the ghg theory of vW and Happer were correct, which plays out in the atmosphere , we should see a rate of warming that is more or less the same whereever I measure on earth.
Henry,
The W&H model is just that, a model. It explains the radiation effect of the common GHGs, it does not include convection or clouds. It is just a very detailed and precise definition of the radiative GHE.
They do not claim their model reflects reality. It just shows the CO2 effect is very small.
Andy,
In the end they made claims on the contribution to deltaT by delta[CO2} en delta [CH4], 0.01C/annum and 0.001C/annum respectively, if I remember correctly.
However, in the discussion here:
https://www.scirp.org/journal/paperinformation.aspx?paperid=99608
the question is raised whether CO2 indeed does contribute anything to the increase in temperature.
The theory is wrong.
I am going with Aleksandr
From the post:”Since the energy emitted to space is less, Earth’s surface must warm.”
I am not sure how this is possible. You have a fixed frequency range and E = h*f with h being a constant adding more molecules will emit more energy not less.
mkelley,
The surface will warm, but the stratosphere will cool dramatically. The reason? The CO2 and water vapor in the troposphere block emissions in their respective frequencies. The thermal energy (heat) from the surface is carried to higher altitudes by evaporated water and natural convection. At the higher altitudes and latitudes, the water vapor is gone, and the additional CO2 emits radiation to space cooling the stratosphere. They calculated the stratospheric cooling will be 10 degrees.
Depends where you are.
“If we assume Earth is a blackbody, then subtract the solar energy reflected, from the hypothetically non-existent clouds, atmosphere, land, ice, and oceans; we can calculate a surface temperature of 254K or -19°C. The actual average temperature today is about 288.7K or roughly 15.5°C. This modeled difference of 35°C is often called the overall greenhouse effect”.
The temperature of the Earth’s surface is constantly changing over time and in different places. The concept of the average global temperature of the Earth (AGT) has no physical meaning, as well as the arithmetic mean of the measured temperatures used as a measure of the AGT. This value (15 оС) is also incorrect from the point of view of statistics due to the uneven distribution of meteorological stations. Even the IPCC admits that 15 °C is the average temperature of the Earth “excluding Antarctica” (2nd Report, Technical Summary, 1995). In fact, Greenland and many other uninhabited places should also be excluded.
Of course, using the Stefan-Boltzmann equation to determine the temperature of the Earth’s surface is incorrect. The problem is not only that the Earth is not a completely black body, but also that the 240 W/m2 value used to calculate the temperature using this equation is unreliable. Obviously, each mini-area of the surface differs to a different degree from an absolutely black body, and also absorbs and reflects a different amount of energy. Averaging of energy in this case is also not reliable and unjustified, like averaging temperatures.
Comparison of the two dummies is in itself a fiction, not to mention that there is no physical evidence that the difference between them is due to the so-called “greenhouse effect”.
Agree completely. Have you been reading my notes? 😁
I agree with you. Good points and well said.
I just hope will get a little warming out of improving CO2 levels. The next LIA is due and will be worse than the last since the Holocene is definitely cooling and is itself due to end and the next glacial period begin. https://www.reddit.com/r/climateskeptics/comments/e9gwxa/prof_numlocks_ultimate_climate_lecture/
Several years ago, I did calculations similar to W&H’s with results that were very similar though not as detailed. In the course of doing the calculations it occurred to me that I’ve never seen a calculation of the Earth’s atmospheric temperature if it only contained nitrogen, oxygen, and argon, which make up 99.96% of the air and are all infrared inert. I have read that a climate model was run without any CO2 and had a final state atmospheric temperature of 0 K, a tiny bit implausible.
If you measure the temperature in a tank of nitrogen gas it will be the same as room temperature and will track room temperature as the room heats and cools. The heat is transferred to the gas via conduction and convection. Just because there is no transfer of energy by radiation does not mean that the gas temperature will go to zero. The Earth’s atmosphere should behave similarly.
Sunlight heats the Earth’s surface. This heats the air by conduction which then convects aways from the surface. The air cools adiabatically as it rises. This occurs all over the daylight side of the Earth with the hottest spot directly underneath the Sun. The rising air will mix and create convection currents in the atmosphere. The surface will radiate to outer space.
On the night side, there is no incident solar radiation but the surface still radiates its heat outward to space and contact between the surface and air will still transfer heat between the two.
Two processes control the exchange of heat between the atmosphere and the surface on both the daylight and night side of the Earth.
A downward air convection current will heat the surface by conduction if the air is warmer than the surface. This will also increase the rate of surface radiation. Since the surface absorbs heat from the air, it will also cool the air suppressing convection at the surface.
If the downward air current is cooler than the surface, i.e., the surface is warmer than the air, the surface will cool off while warming the air. The radiation will decrease since the surface has cooled but convection will be increased since the air has warmed.
To summarize, heat enters the Earth via Sunlight, the surface radiates heat to outer space, and the air acts as a store of heat that it exchanges with the surface via the two processes above.
After a long time the atmosphere will come to thermodynamic equilibrium, a state of constant uniform temperature at all altitudes. That temperature can’t be zero Kelvin. Sunlight heating any part of the surface would initiate convection air currents via the two processes discussed above, resulting in the atmosphere no longer in equilibrium.
I think that surface/atmosphere temperature would be a uniform 389 K = 116 C, the radiative temperature due to the 1300 W/m^2 of incident solar flux. It can’t be hotter by the second law of thermodynamics. The rotation of the earth makes sure the there is no longitudinal variation in temperature. If the poles were colder than the low latitudes, the second law again would ensure that heat would flow to the poles. The net effect is that at equilibrium the atmosphere is isothermal at 389 K.
This means that there is no need for CO2 to heat the atmosphere, it’s naturally hot. I think that what actually happens is that sunlight heats the oceans, the water evaporates and rises to the top of the atmosphere where it condenses and radiates its energy away, cooling the air and giving us a livable . At best, carbon dioxide acts as a weak coolant at the top of the atmosphere.
I’ve always been highly sceptical that removing trace CO2 from the atmosphere would have any significant climatic effect – if we assume that plants and most (nonmicrobial) life would miraculously not go extinct. (To hypothetically remove the confounding variable of biosphere extinction).
CO2 cools all air above the tropopause. During cold outbreaks in winter there are often stratospheric incursions. So CO2 cooling of the stratosphere can bring a cooling effect down to the troposphere and the earth’s surface.
The statement “Per the laws of thermodynamics, a planet must emit as much radiation as it receives” is an approximation since our planet converts a significant portion of incoming radiation into potential energy in the form of chemical bonds via photosynthesis. Even if this is only one percent of the incoming energy, this is significantly more than the estimates of the difference between incoming and outgoing radiation. Hence the supposed imbalance may be completely explained by a more comprehensive energy balance.
What about cause and effect?
The Greenhouse Effect is impossible without at lapse rate. If the lapse rate is zero then the effective radiation height is zero (the surface).
But the lapse rate is caused by convection, not greenhouse gas. Thus the Greenhouse effect is a result of the lapse rate and thus a result of convection.
I was hoping Andy would also take a look at Coe et al 2021 and compare their results with W&H. Both use HITRAN and ignore clouds but give significantly different results. I haven’t seen any refutation yet of the Coe paper.
The Coe paper shows a sensitivity of 0.46 C without feedbacks and 0.5 C with water vapor feedback. It would be nice to know how two skeptical papers could produce such different results.
E=mc’2 and c=pi r’2 seem to be unknown to climate scientists.
Yet they helped get man to the moon and back , now heading to Mars.
NASA and others seem to be off track with their priorities .
Too many variables in climate for any ‘scientist or body’ to claim its settled .
The insulating effects of our atmosphere is entirely due to a convective rather than a radiative greenhouse effect. The only thing that a change in CO2 could do to change the surface temperature of the Earth would be to change the surface pressure. That change is negligible for a doubling of CO2 so hence the climate sensitivity of CO2 must be negligible..
Yes, no convection means no GHE.
Refer back to the various posts here by me and Philip Mulholland.
They describe how the GHE arises.
“A perfectly transparent atmosphere would radiate all surface emitted energy according to the blue line in Figure 1.”
So the GHE-Earth radiates less than the blackbody Earth. A body that radiates less is cooler than a body that radiates more, because T^4. This means that the greenhouse effect cools the Earth.
The GH effect began billions of years ago when IR absorbing gases first appeared in the atmosphere. We know that life began almost 4 billion years ago so the warming of our planet from 255k to 288k must have taken place before then. I’m just making two simple points, the GHE didn’t start yesterday and it has already caused a lot of warming.
We also know that the relationship between the absorbance of IR by greenhouse gases and the gas concentration in the atmosphere is approximately logarithmic. The greatest increase in absorbance/warming was due to the first increase in greenhouse gas. Successive additions of gas had smaller effects. We are now approaching the other end of the curve where the increases in gas concentration have only very small effects on absorbance and warming.
The effect will never reach zero but it is sufficiently small that there is no justification for alarmism or counteractive measures. This applies to all greenhouse gases mixed in the atmosphere, regardless of their greenhouse characteristics when measured individually.
“3 W/m2, the area between the black curve and the red curve [in Fig.1]”
The black curve – where it exists – seems identical to the red curve. What did you want to prove?
Just that. The green curve to the black curve is the CO2 caused forcing from 0 ppm to 400 ppm. The tiny difference between the black a red curves is the forcing from 400 ppm to 800 ppm. Next to nothing.
What a tragedy to see that the whole world is going into self destruction mode because of a completely wrong theory or ‘model’.
Good remarks by Aleksandr and Paul but Paul has the 99.96 slightly off. I think water is on average 0.4 or 0.5% and CO2 is 0.04%
More carbon is OK!
ANdy May; I admit I only read as far as your figure 1 but the annotations on that figure are so clearly impossible that it calls your entire essay into question.
The atmosphere does mechanical work, wind is mechanical work, raising water to high altitudes is mechanical work and so on. The energy from this clearly comes from absorbed solar energy. That makes the atmosphere the working fluid of a classical heat engine as described by Carnot in about 1810. Two things stand out about heat engines. Firstly 100% efficiency is impossible, there must be a hot junction where heat is injected into the working fluid and a cold junction where heat is abstracted from the working fluid. The working fluid cycles between the hot junction and the cold junction. The second things is that the cold junction must be at a point where the pressure is significantly lower than that at the hot junction.
These conditions are of course met in our atmosphere since the hot junction is the surface and especially the surface near the equator. The cold junction is the top of the convective loop – the tropopause. Heat is abstracted from the atmosphere at this altitude by GHG’s radiating to space. Interestingly, if there were non GHG in our atmosphere there could not be a cold junction and without that no convection. No convection means no lapse rate, isothermal and saturated atmospheric column, no clouds, no wind, no net evaporation, insolation average around 340 watts/sqM and a average surface temperature (whatever that means) of around 270K – about the same as the moon. More significantly the surface temperature is determined by the insolation level and the thermal time constant of the surface. Consider how fast beach sand or a concrete footpath or even dry grass and soil heats up in summer (less than 1 hour) and it is obvious the surface time constant is very short. Peak insolation at the equator is around 1340 watts/sqM at noon corresponding to a surface temperature on land of around 113C. At latitude 37 its still around 70+C. Of course at night its far far below freezing. We can see that by looking at the temperatures reached inside a closed car in summer.
But to return to your figure 1, your annotations show no radiation to space from that altitude which means no cold junction so how could convection stop at that point. A rising air column continues to rise because its internal energy is higher than that of the surrounding air (that is a combination of its temperature pressure water vapour content etc). It stops rising when its internal energy ceases to be higher than the surrounding air but for that to happen the rising air has to lose energy. In our atmosphere the top of the convective loop is at the tropopause, indeed it defines the tropopause. The tropopause is the coldest point in the atmosphere so how could the rising air at the tropopause lose energy other than by radiation to somewhere even colder ie: radiation to space? If the cold junction was set by CO2 according to your diagram convection would rise to 84 km, if set by water vapour it would only rise to 2.8 km. The tropopause however is at around 12 km average (18km in the tropics)
I think you will find the apparent 2.8 km radiation altitude for water vapour comes about because there are huge number of very closely spaced lines. Radiation from between the lines comes from the surface, cloud tops etc, radiation at the lines comes from the tropopause. The lines are simply too close together to be resolved by the satellite spectrometers. Radiation from CO2 shows an emission temperature of around 220K which is the temperature of the tropopause.
Absent any GHG including water, there would still be convection. You should notice that the lapse rate depends on gravity (pressure) not GHG gases. They don’t enter into the lapse rate calculation.
Non-GHG gases can still be heated by conduction with the earth’s surface. Therefore there is still a “hot” plate for the engine. The lapse rate insures that there is a “cold” surface at lower pressure .
Lastly, because of the oceans, there will always be water vapor rising and cooling. Water is the predominate GHG and I doubt that the removal of non-condensing GHG gases will affect much.
No Jim; You are correct to say the lapse rate does not depend on GHG’s. It comes about because as the air rises it expands and adiabatic cooling occurs but I didn’t say the lapse rate occurs because of green house gases. I said it comes about because of convection and is maintained by convection.
Your point about a cold junction being created by lapse rate is not correct. To consider the cold junction in terms of temperature is a very dangerous way of looking at things, yes the temperature falls as the air rises but conversely the temperature will rise as the air falls again. BY the time it got back to the surface it would be back to the same temperature at which it starts so what would drive convection. This is an adiabatic process which means “without energy transfer” ie: the internal energy of the air does not change. But for a heat engine to function energy must be lost from the working fluid at the cold junction and it is this loss of energy which allows the air to be recompressed back to the surface using less energy than was released in the expansion. The air at the tropopause can ONLY lose energy by radiation to space since it is already colder than the air above and below. But any gas that can radiate energy in the thermal infrared (which, given the temperatures involved, is the only band where significant radiation can occur – Planks law) is BY DEFINITION a green house gas. No GHG’s no energy loss. Without that energy loss convection stops, the atmosphere over time will become isothermal due to conduction and will also become saturated wrt to water vapour simply because for water to condense means it has to lose energy and without GHG’s it cannot lose energy. If the atmosphere is saturated net evaporation stops. I admit there are secondary processes, heavy dew at night when the surface gets very cold and some surface evaporation as it warms up again but these are very local surface effects which would not give rise to weather as we know it.
Michael,
Completely incorrect. You forget that frequency matters. If a molecule at the tropopause emits radiation at a frequency absorbed by a molecule in the stratosphere, say CO2 or O3, that molecule can become excited and warm the surrounding air. This process goes on until the radiation can finally be emitted to space.
At some frequencies, like 700 cm^-1, the final emission to space does not occur until 84 km, in the mesosphere.
Emission height is frequency dependent, a point often ignored.
In Figure 1, you can see the reversal of the black and red lines at the bottom of the CO2 divot, this means the final emissions at 800 ppm are cooler than the 400 ppm emissions. The extra CO2 is cooling the mesosphere, and probably the upper stratosphere.
Andy; you state “Completely incorrect. You forget that frequency matters. If a molecule at the tropopause emits radiation at a frequency absorbed by a molecule in the stratosphere, say CO2 or O3, that molecule can become excited and warm the surrounding air. This process goes on until the radiation can finally be emitted to space.”
This is a very interesting comment because what you are essentially claiming is that the colder tropopause radiates NET energy to the warmer stratosphere which then radiates it away to space. Sure colder objects can and do radiate to warmer objects but then the warmer objects also radiate back towards the colder ones at the same wavelengths and because they are warmer the radiation is higher so net energy flow is ALWAYS from warmer to colder. Its the second law of thermodynamics.
The reason that the final emissions at the line edges are cooler at 800 ppm cf 400 ppm is because as concentration rises the line broadens. Emission/absorption lines are lorenzians which are extremely close to gaussian profiles. If you double the concentration it is equivalent convolving the gaussian profile with itself. The result is also a gaussian but with a wider spread (larger standard deviation). As a result the total absorptivity of the gas column at the edges of the line increases so the last 1 abs comes from closer to the top of the gas column ie: higher in the atmosphere where it is a little colder.
Michael, I’m sorry you comment makes no sense. Your comment:
Is completely incorrect. Refer to Figure 2 in the post.
Your rambling comment is nonsense. Read the post, in full, I’ve tried to make it clearer and more understandable. W&H have defined the GHE in a very robust and precise way, something the IPCC should have done decades a go, but didn’t because if you understand the radiative GHE you realize we have nothing to worry about.
Andy; There are so many points in your article that I find utterly incompatible with what I know of spectroscopy that its difficult to know where to start. For example you say
“A blackbody is usually defined as a perfectly black cavity kept at a constant temperature. All energy that enters the cavity is absorbed by the cavity walls, and they emit exactly the same amount of energy, but the wavelength of the emitted radiation is not the same as the energy captured.”
Nope, that not the definition of a black body I am familiar with. A blackbody is simply an object with an absorptivity (or emissivity) of 1 at the wavelength of interest. Nothing whatever to do with a cavity or temperature and no not all the energy is necessarily absorbed, it depends on the wavelength. Also the amount of energy emitted is not necessarily the same as the amount absorbed. If the body is warming up the energy emitted is less and vice versa if it is cooling down. You are correct that wavelength matters and it is quite possible for an object to be a black body with respect to 1 wavelength yet have a low absorptivity at other wavelengths. For example, glass has very high absorptivity in the IR yet very low absorptivity in the visible which is why it can be used as a heat filter. That means glass is a black body (or very close to it) in the IR but not in the visible.
You also say
“According to the second law of thermodynamics, a thermally isolated atmosphere will reach a constant temperature throughout its height if entropy remains constant. ”
I dont see what entropy has to do with it, infact if the atmosphere is thermally isolated but with different temperatures with altitude then as the temperature equilibrates through the column the entropy will increase. Entropy is defined as
“a thermodynamic quantity representing the unavailability of a system’s thermal energy for conversion into mechanical work”.
Initially the temperature difference between the top and bottom of the atmosphere could be harnessed to do work, but once equilibrated that difference no longer exists so no work can be extracted ie: entropy has increased as the temperature equilibrates. If the atmosphere is thermally isolated ie: no heat in or out then sure conduction will eventually ensure it becomes isothermal.
I could go on but these posts become too long for people to read.
It would appear you do not understand my points regarding heat engines. The topic is too large to go into in detail in this context but you can look it up readily on the web.
Dear all,
I can´t believe that the CO2 radiation comes from the mesosphere in 84km. Also the CO2 concentration is the same as at 0km, the density of the atmosphere at 84km is much too low to emit this amount of radiation. Normally I would suggest CO2 radiation from a 100mbar level at about 8-12km at the end of the troposphere. This would also explain the small increase at its main absorption band (15µm) coming from a hotter stratosphere. Perhaps I am wrong. Could please someone check this?
Dear Eike; you are absolutely correct. If you look up Heinz Hug you will see he measured the absorption profile of CO2 at the pressure and concentration prevailing at sea level. There are 3 bands, the P band, Q band and R band. P and R are quite broad, the central Q band is stronger but much narrower. The absorbance of the P and R bands is around 0.125 abs/meter whereas the Q band is around 0.3 abs/meter. For our entire atmosphere this translates to around 1000 abs for the P and R branches and about 2400 abs at the Q band. These figures were for 357 ppm at 410 ppm they would be 1150 abs and 2760 abs respectively. 90% of the emission to space comes from the last 1 abs of the CO2 column, 99% from the last 2 abs. That says the last 1/1150 of the CO2 is at an altitude of around 8-12 km and the last 1/2760 of the CO2 column is slightly higher where the temperature is warmer. Since the air column extends far higher ( your figure of 100 mbar implies 1/10 of the air column is above the tropopause) it implies CO2 is pooled in the lower stratosphere. This should not be too surprising given the stratosphere is static – little mixing – and CO2 at molecular weight 44 is considerably denser than air molecular weight 29. Indeed I remember an experiment in primary school (many decades ago) where we filled a beaker with CO2 (vinegar and sodium bicarbonate) and were able to pour it from beaker to beaker as shown by a candle in the 2nd beaker which went out as we poured. Could do it a few times before it mixed with the surrounding air.
Congratulations in your very acute observation of the central spike in the emission over the CO2 band. There have been many cases where very significant conclusions follow from what seem like tiny artifacts and this one is indeed significant.
Michael, your arguments make no sense and are irrelevant to her question.
Andy; you showed in a reply to Eike a plot of the absorption spectrum of CO2 . The left hump is the P branch, the middle spike is the Q branch and the right hump is the R branch. Your plot was taken at extremely low pressure which is why it shows hyperfine structure, if you look up Heinz Hug you will see what it looks like at 1 atm 357 ppm CO2.
Are you familiar with the concept of absorbance. it is defined as
absorbance = -log(Iout/Iin)
I absorbance absorbs 90% of the incident radiation transmitting 10%. 2 absorbance absorbs 99% transmitting 1%.
Heinz Hug’s measurements on a Bruker IR spectrometer showed CO2 at sealevel over the P and R branches has an absorbance of 0.125 abs/meter. At the 80 km altitude you claim the air pressure is 0.01 torr = 1.3e-5 atmospheres. At this altitude, assuming CO2 is well mixed, the absorbtivity (which matches the emissivity) will be 1.6e-6 abs/meter. A one abs column which will have an emissivity of 0.9 compared to a black body being 1 will be 1/1.6e-6 meters = 625 km, far more than the distance down to the surface. Eike is EXACTLY right, the pressure is far too low for emission at that altitude.
The plots I have seen of the top of atmosphere radiation to space taken by Nimbus 4 show black body overlays and the show an emission temperature to space of 220K which matches the temperature of the tropopause except at the peak of the Q branch where the temperature is slightly higher because the emission is coming from the stratosphere. The conflicting issue is the claim that CO2 is well mixed throughout the stratosphere. If that was the case there would be about 100 abs above the tropopause so emission would be from higher in the stratosphere where the temperature is warmer. The clue is Eike’s excellent observation that emission from the peak of the Q branch shows higher emission temperature which gives a clue to where the last vestiges of CO2 is and its still in the low stratosphere so CO2 is pooled in the lower stratosphere. Not unexpected since the stratosphere is very calm and CO2 is much heavier than air.
By the way , just thought I would mention I spent 40+ years doing research for a large multinational spectroscopy company.
Michael, from W&H:
Refer to the paper for the equations, they are straightforward. At 667.4 cm^-1, tau, the emission optical depth (eq. 38, 39) is 51,688 and z is 84.8km. W&H use very conventional definitions, I’ve seen them in many papers of this type. Attached is their plot. Their data on GHG vertical distribution is also shown and referenced.
You are using one dimensional data to refute a 3D argument, the academic equivalent of bringing a knife to a gunfight. Read the paper, go through the math, it is rock solid.
Eike, I’ve checked W&H’s calculations and they are correct. In the CO2 divot the emissions to the satellite are from 84 km and none from lower than that. As CO2 increases to 800 from 400 ppm the only thing that happens is the divot broadens slightly, so that some extra radiation on either side of the divot is blocked. This is not ambiguous or an opinion, this is completely verifiable, basic physics.
Eike, I think you mean the spike in the center of the CO2 divot. That is a result of an unusual part of the CO2 absorption spectrum. I’ve attached a plot.
Your remaining point about 8-12 km, the temperature there is around 220K. The emissions from the bottom of the CO2 divot are much colder than that. Less than 200K. The density of the atmosphere at 84 km is not too low to emit that much radiation, it is exactly the right density. At those frequencies, radiation is blocked nearly to the TOA. The emission altitude is determined by frequency, so an average emission altitude is very misleading.
Dont know if this is going to work, I have tried to attach an image. It is a plot of top of atmosphere radiation to space from Nimbus 4 along with black body temperature profiles overlayed. As you can see the emission temperature in the CO2 band is consistent with the temperature of the tropopause
The temperature you show is lower than the temperature of the tropopause in the standard atmosphere used by W&H. See Figure 2. But determining the emission height of a spectra involves much more than just the temperature, I don’t want to get into the math here, it is explained very well in the paper if you’ve had a class in calculus. Just read the paper.
Andy; you keep simply reiterating the W&H paper as a defence without making any attempt to address the contrary points being made. So lets make it really really simple. There is no doubt whatsoever that the temperature at the tropopause is colder than at both lower and higher altitudes.
Question, how does the temperature at that altitude remain colder than its surroundings without as you claim losing energy to an even colder sink (space). Are you suggesting net heat flow from the cold tropopause to the warmer stratosphere? Are you suggesting the tropopause remains cold without losing energy? What about the energy being radiated into it from the troposphere and stratosphere? If you have an answer, could we use it as a super efficient air conditioner in our homes? After all a region which can remain colder than its surroundings without any heat pump would be a fantastic cool store.
By the way Andy; you say
“But determining the emission height of a spectra involves much more than just the temperature”.
Virtually any GHG species in our atmosphere is so far into saturation it is going to look like a black body emissivity=1 at its absorption wavelength. All that changes with concentration is the depth of the emitting layer. Given that, Planks law precisely links emission intensity to temperature, thus if you know the emission intensity you know the temperature and if you know the temperature you know the emission altitude. The only time there would be uncertainty would be if there were 2 altitudes with the same temperature. So I have to say I do not agree with your claim.
Michael, You are being silly, or perhaps willfully ignorant. You claim to know something about radiation and spectra, but then write stuff like these two comments. Not sure what to think.
This is very near the top of the atmosphere.
It’s different for every frequency. W&H’s model matches satellite observations almost perfectly. See Figure 3. Spend less time writing transparent gobbledygook and read the paper.
To illustrate the power of CO2, we can use the University of Chicago MODTRAN, attached is the spectra for 0 ppm, next I will show the spectra with 1 ppm and then 10 ppm.
Point3: “CO2 has about the same concentration from the surface to the mesosphere”
Now I get it. Concentration is the amount of molecules in a given volumen, expressed in g/volumen or mol/volume. ppm is the relation to other molecules in our case O2 and N2. The CO2,O2 and N2 concetrations (mol/volume) are dropping exponatially in our athmosphere. Because pressure is dropping exponatially with altitude.As the air gets thinner and thinner the ppm´s stay the same because they are all dropping at the same rate. Absorbtion is dependet on the concentration of gas (not the ppms) and the distance ligth has to travel through it.
Here is 1 ppm
Here is 10 ppm
Sorry here is 10 ppm
Finally 100 ppm, 25% of today. The website is here:
MODTRAN Infrared Light in the Atmosphere (uchicago.edu)
Spend some time with it and you will see why W&H are correct. Notice that by 100 ppm the CO2 divot has almost reached 220K. Most of what you have written is true, it is just irrelevant to my post or their paper. Like I said, you are examining a 3D problem with 1D tools.
Andy May:
You clearly do not understand what a black body is
You clearly do not understand what entropy is
You claim the CO2 emission temperature of around 215K is too low to be coming from the tropopause yet several websites sites I found in less than 2 minutes searching clearly state the tropopause at the poles is around -50C (223K) and at the equator it gets down to -80C (193K).
I point out the measured absorbance of CO2 at sealevel is 0.125 abs/meter measured so at 84 km assuming co2 is well mixed it will be .125 * (.01/760) = 1.6e-6abs/meter or 0.0016 abs/km. Since 90% of the emission to space comes from the last 1abs of the column that implies an emission depth of 625 km which is clearly ridiculous. You obviously do not understand this, implying you do not understand the concept of absorbance.
I ask how the troposphere can remain colder than its surroundings if, as you claim, no energy is lost to space from that altitude. An extremely valid question which you do not answer other than to claim the question ridiculous. I can only assume either you don’t understand the question or you don’t know the answer.
You clearly don’t understand the operation of heat engines and specifically the need for a cold junction where energy is lost from the system at the end of the expansion phase. This is at 12-18km yet you claim energy is only lost at 2.6km and 84 km neither of which would support a convective loop from sea level to 12-18 km.
You don’t understand the point of water having a huge number of very closely spaced lines so that the indicated emission height is really an average of a bimodal distribution – sea level between lines and close to tropopause at line peaks.
Your approach when your writings are questioned is simply to declare the questions meaningless gobblygook and irrelevant rather than trying to address them. I can only assume because you don’t know enough to address them or maybe even understand them in the first place.
Your approach when dismissing the questions as meaningless gobblygook does not work is to become insulting towards the questioner.
When I comment, I start off by assuming the author knows what he is talking about and is willing and able to discuss sensible critique. You have now convinced me that this assumption does not apply to you so there is no point in continuing this interaction.
I’ll ignore the personal attacks, but on your specifics.
I never wrote that. W&H’s calculations demonstrate that the altitude of emissions to space (ze, computed from the optical depth tau-e, see equations 33 to 39 in the paper) is dependent upon the radiation frequency. Radiation at some frequencies comes from the surface or troposphere. At some specific frequencies, like 667.4, it comes from very high in mesosphere.
You seem to have latched on to temperature as the only variable in the calculation, it isn’t. The atmospheric temperature profile and the profile of the GHG concentrations, as well as the atmospheric density, latitude, and especially the frequency all play large roles in the calculation.
Back to gobbledygook. Tau=51,688 (optical depth) and ze (emission level, as defined in the paper) is 84.8km.
tau-e, the emission optical depth, from which ze is computed, is the level where half of the energy flux at the top of the atmosphere (~86 km in the mid-latitudes) comes from (eq. 38). So, at a frequency of 667.4, half of the total emissions received at the satellite come from 84.8km.
Perhaps you don’t understand calculus, in which case, further discussion is pointless.
Dear all,
thanks for the many replies. Getting more than one opinion I tried to read the paper and to be honest I ignored all calculations (sorry no degree in physics). Andy is probably right with his claim that the math is correct and at this frequency 667.4 the emission comes from 84.8 km.
And my idea of completely ignoring the mesosphere may be a little bit too simple. But the paper also claims this to be an “extreme blanket frequency”.
And in figure 6 it claims:
“An exception is the band of frequencies near the center of the exceptionally strong bending-mode band of CO2 at 667. Here doubling CO2 moves the emission heights to higher, warmer altitudes of the stratosphere, where molecules can more efficiently radiate heat to space.”
The increase in w/m2 at around 667 is emitted from a hotter stratosphere, it maybe much more complicated on a line by line view.
The problem I have with the WUWT article is following statement.:
“The marked altitude of 84.8 km, in the middle of the CO2 caused divot in the energy curve, means that the emissions at that frequency range, roughly 609 to 800 cm-1, come from that altitude.”
For me this sounds like the whole CO2 emission to space comes from a fixed layer at 84.8km.
And because the mesosphere is only cooling with height I don’t find any reason for the increase in radiation in the middle of the 15µm band. Nor do I find any explanations for the CO2 cooling effect over antarctica.
Sorry I still don´t get it
Thanks a lot for your time.
Eike,
It is complicated and very hard to explain without the math. I did the best I could. Both the paper and the post are correct. The whole range of frequencies from 609 to 800 have an emission height in the mesosphere, but not exactly 84.8 km, that is the example calculation for 667.4 cm^(-1). It varies by frequency.
The cooling effect in Antarctica is simply because the CO2 is at a higher temperature than the surface, that causes the CO2 greenhouse effect to reverse and cause cooling. Remember thermal energy (“heat”) always moves from warmer bodies to cooler bodies, in the case of Antarctica, the flow is from the atmosphere to the surface, so any radiation from CO2 to space or to the surface cools the atmosphere. This is opposite of what happens most other places.
The key thing to remember is that the emission height is frequency dependent, there is not just one height. I’ve seen many PhD climate scientists and physicists make the same mistake.
Play around with the U of Chicago ModTRAN, it helps visually show the complex math:
MODTRAN Infrared Light in the Atmosphere (uchicago.edu)
Hi Andy,
if I replace all CO2 molecules from 0-1km with the CO2 molecules from 84-85km the ppm´s drop from 400 to 0.0036. ModTRAN spectra attached.
Interesting, thanks.
Andy May wrote:
“Both the frequency and the power emitted by molecules are determined by the molecule’s temperature.”
You might want to clarify the above.
That applies to blackbody radiation ( which is emitted by solids, liquids, and gases of sufficient density that blackbody radiation emission/absorption swamps spectral radiation).
For spectral radiation, the frequency (and hence wavelength) is a function of the differential between the energy of the two quantum states (the original higher quantum state, and the new lower quantum state which is quantum jumped to), whether that quantum state be a rotational mode quantum state, a vibrational mode quantum state or an electronic mode quantum state.
So something along the lines of:
“For blackbody radiation, both the frequency and the power emitted by an atom/molecule are determined by that atom’s /molecule’s kinetic temperature.”
The above also delineates that there’s a difference between kinetic temperature (the temperature associated with the kinetic energy of an atom/molecule, this is a single number associated to a single temperature, not an average) vs. the thermodynamic temperature (the average temperature associated with the average kinetic energy of an assemblage of atoms/molecules with kinetic energy distribution describing a Planckian curve).
Jimmy,
Well said! Thank you. I was sloppy in my writing. The math makes it so easy. Translating the math into words is hugely difficult.
How much would an additional 3 w/m2 of forcing cause the temperature to increase?
Just asking.
That is the conversion where all the mischief occurs. The radiative forcing can be calculated fairly accurately, but the temperature response can’t. Recent estimates based on data suggest 0.1 to 0.2 degrees per W/m^2. The IPCC modeled values are much higher, 0.5 degrees or more. No one knows.
Climate Sensitivity to CO2, what do we know? Part 1. | Andy May Petrophysicist
Thank you for that info.