Note: This was a poster, and adopted into a blog post by the author, Ned Nikolov, specifically for WUWT. My thanks to him for the extra effort in converting the poster to a more blog friendly format. – Anthony
Expanding the Concept of Atmospheric Greenhouse Effect Using Thermodynamic Principles: Implications for Predicting Future Climate Change
Ned Nikolov, Ph.D. & Karl Zeller, Ph.D.
USFS Rocky Mountain Research Station, Fort Collins CO, USA
Emails: ntconsulting@comcast.net kzeller@colostate.edu
Poster presented at the Open Science Conference of the World Climate Research Program,
24 October 2011, Denver CO, USA
http://www.wcrp-climate.org/conference2011/posters/C7/C7_Nikolov_M15A.pdf
Abstract
We present results from a new critical review of the atmospheric Greenhouse (GH) concept. Three main problems are identified with the current GH theory. It is demonstrated that thermodynamic principles based on the Gas Law need be invoked to fully explain the Natural Greenhouse Effect. We show via a novel analysis of planetary climates in the solar system that the physical nature of the so-called GH effect is a Pressure-induced Thermal Enhancement (PTE), which is independent of the atmospheric chemical composition. This finding leads to a new and very different paradigm of climate controls. Results from our research are combined with those from other studies to propose a new Unified Theory of Climate, which explains a number of phenomena that the current theory fails to explain. Implications of the new paradigm for predicting future climate trends are briefly discussed.
1. Introduction
Recent studies revealed that Global Climate Models (GCMs) have significantly overestimated the Planet’s warming since 1979 failing to predict the observed halt of global temperature rise over the past 13 years. (e.g. McKitrick et al. 2010). No consensus currently exists as to why the warming trend ceased in 1998 despite a continued increase in atmospheric CO2 concentration. Moreover, the CO2-temperature relationship shows large inconsistencies across time scales. In addition, GCM projections heavily depend on positive feedbacks, while satellite observations indicate that the climate system is likely governed by strong negative feedbacks (Lindzen & Choi 2009; Spencer & Braswell 2010). At the same time, there is a mounting political pressure for Cap-and-Trade legislation and a global carbon tax, while scientists and entrepreneurs propose geo-engineering solutions to cool the Planet that involve large-scale physical manipulation of the upper atmosphere. This unsettling situation calls for a thorough reexamination of the present climate-change paradigm; hence the reason for this study.
2. The Greenhouse Effect: Reexamining the Basics
Figure 1. The Atmospheric Greenhouse Effect as taught at universities around the World (diagram from the website of the Penn State University Department of Meteorology).
According to the current theory, the Greenhouse Effect (GHE) is a radiative phenomenon caused by heat-trapping gases in the atmosphere such as CO2 and water vapor that are assumed to reduce the rate of surface infrared cooling to Space by absorbing the outgoing long-wave (LW) emission and re-radiating part of it back, thus increasing the total energy flux toward the surface. This is thought to boost the Earth’s temperature by 18K – 33K compared to a gray body with no absorbent atmosphere such as the Moon; hence making our Planet habitable. Figure 1 illustrates this concept using a simple two-layer system known as the Idealized Greenhouse Model (IGM). In this popular example, S is the top-of-the atmosphere (TOA) solar irradiance (W m-2), A is the Earth shortwave albedo, Ts is the surface temperature (K), Te is the Earth’s effective emission temperature (K) often equated with the mean temperature of middle troposphere, ϵ is emissivity, and σ is the Stefan-Boltzmann (S-B) constant.
2.1. Main Issues with the Current GHE Concept:
A) Magnitude of the Natural Greenhouse Effect. GHE is often quantified as a difference between the actual mean global surface temperature (Ts = 287.6K) and the planet’s average gray-body (no-atmosphere) temperature (Tgb), i.e. GHE = Ts – Tgb. In the current theory, Tgb is equated with the effective emission temperature (Te) calculated straight from the S-B Law using Eq. (1):
where αp is the planetary albedo of Earth (≈0.3). However, this is conceptually incorrect! Due to Hölder’s inequality between non-linear integrals (Kuptsov 2001), Te is not physically compatible with a measurable true mean temperature of an airless planet. To be correct, Tgb must be computed via proper spherical integration of the planetary temperature field. This means calculating the temperature at every point on the Earth sphere first by taking the 4th root from the S-B relationship and then averaging the resulting temperature field across the planet surface, i.e.
where αgb is the Earth’s albedo without atmosphere (≈0.125), μ is the cosine of incident solar angle at any point, and cs= 13.25e-5 is a small constant ensuring that Tgb = 2.72K (the temperature of deep Space) when So = 0. Equation (2) assumes a spatially constant albedo (αgb), which is a reasonable approximation when trying to estimate an average planetary temperature.
Since in accordance with Hölder’s inequality Tgb ≪ Te (Tgb =154.3K ), GHE becomes much larger than presently estimated.
According to Eq. (2), our atmosphere boosts Earth’s surface temperature not by 18K—33K as currently assumed, but by 133K! This raises the question: Can a handful of trace gases which amount to less than 0.5% of atmospheric mass trap enough radiant heat to cause such a huge thermal enhancement at the surface? Thermodynamics tells us that this not possible.
B) Role of Convection. The conceptual model in Fig. 1 can be mathematically described by the following simultaneous Equations (3),
where νa is the atmospheric fraction of the total shortwave radiation absorption. Figure 2 depicts the solution to Eq. (3) for temperatures over a range of atmospheric emissivities (ϵ) assuming So = 1366 W m-2 and νa =0.326 (Trenberth et al. 2009). An increase in atmospheric emissivity does indeed cause a warming at the surface as stated by the current theory. However, Eq. (3) is physically incomplete, because it does not account for convection, which occurs simultaneously with radiative transfer. Adding a convective term to Eq. (3) (such as a sensible heat flux) yields the system:
where gbH is the aerodynamic conductance to turbulent heat exchange. Equation (4) dramatically alters the solution to Eq. (3) by collapsing the difference between Ts, Ta and Te and virtually erasing the GHE (Fig. 3). This is because convective cooling is many orders of magnitude more efficient that radiative cooling. These results do not change when using multi-layer models. In radiative transfer models, Ts increases with ϵ not as a result of heat trapping by greenhouse gases, but due to the lack of convective cooling, thus requiring a larger thermal gradient to export the necessary amount of heat. Modern GCMs do not solve simultaneously radiative transfer and convection. This decoupling of heat transports is the core reason for the projected surface warming by GCMs in response to rising atmospheric greenhouse-gas concentrations. Hence, the predicted CO2-driven global temperature change is a model artifact!
Figure 2. Solution to the two-layer model in Eq. (3) for Ts and Ta as a function of atmospheric emissivity assuming a non-convective atmosphere. Also shown is the predicted down-welling LW flux(Ld). Note that Ld ≤ 239 W m-2.
Figure 3. Solution to the two-layer model in Eq. (4) for Ts and Ta as a function of atmospheric emissivity assuming a convective atmosphere (gbH = 0.075 m/s). Also shown is the predicted down-welling LW flux (Ld). Note that Ld ≤ 239 W m-2.
Figure 4. According to observations, the Earth-Atmosphere System absorbs on average a net solar flux of 239 W m-2, while the lower troposphere alone emits 343 W m-2 thermal radiation toward the surface.
C) Extra Kinetic Energy in the Troposphere.
Observations show that the lower troposphere emits 44% more radiation toward the surface than the total solar flux absorbed by the entire Earth-Atmosphere System (Pavlakis et al. 2003) (Fig. 4). Radiative transfer alone cannot explain this effect (e.g. Figs. 2 & 3) given the negligible heat storage capacity of air, no matter how detailed the model is. Thus, empirical evidence indicates that the lower atmosphere contains more kinetic energy than provided by the Sun. Understanding the origin of this extra energy is a key to the GHE.
3. The Atmospheric Thermal Enhancement
Previous studies have noted that the term Greenhouse Effect is a misnomer when applied to the atmosphere, since real greenhouses retain heat through an entirely different mechanism compared to the free atmosphere, i.e. by physically trapping air mass and restricting convective heat exchange. Hence, we propose a new term instead, Near-surface Atmospheric Thermal Enhancement (ATE) defined as a non-dimensional ratio (NTE) of the planet actual mean surface air temperature (Ts, K) to the average temperature of a Standard Planetary Gray Body (SPGB) with no atmosphere (Tgb, K) receiving the same solar irradiance, i.e. NTE = Ts /Tgb. This new definition emphasizes the essence of GHE, which is the temperature boost at the surface due to the presence of an atmosphere. We employ Eq. (2) to estimate Tgb assuming an albedo αgb = 0.12 and a surface emissivity ϵ = 0.955 for the SPGB based on data for Moon, Mercury, and the Earth surface. Using So = 1362 W m-2 (Kopp & Lean 2011) in Eq. (2) yields Tgb = 154.3K and NTE = 287.6/154.3 = 1.863 for Earth. This prompts the question: What mechanism enables our atmosphere to boost the planet surface temperature some 86% above that of a SPGB? To answer it we turn on to the classical Thermodynamics.
3.1. Climate Implications of the Ideal Gas Law
The average thermodynamic state of a planet’s atmosphere can be accurately described by the Ideal Gas Law (IGL):
PV = nRT (5)
where P is pressure (Pa), V is the gas volume (m3), n is the gas amount (mole), R = 8.314 J K-1 mol-1is the universal gas constant, and T is the gas temperature (K). Equation (5) has three features that are chiefly important to our discussion: a) the product P×V defines the internal kinetic energy of a gas (measured in Jules) that produces its temperature; b) the linear relationship in Eq. (5) guarantees that a mean global temperature can be accurately estimated from planetary averages of surface pressure and air volume (or density). This is in stark contrast to the non-linear relationship between temperature and radiant fluxes (Eq. 1) governed by Hölder’s inequality of integrals; c) on a planetary scale, pressure in the lower troposphere is effectively independent of other variables in Eq. (5) and is only a function of gravity (g), total atmospheric mass (Mat), and the planet surface area (As), i.e. Ps = g Mat/As. Hence, the near-surface atmospheric dynamics can safely be assumed to be governed (over non-geological time scales) by nearly isobaric processes on average, i.e. operating under constant pressure. This isobaric nature of tropospheric thermodynamics implies that the average atmospheric volume varies in a fixed proportion to changes in the mean surface air temperature following the Charles/Gay-Lussac Law, i.e. Ts/V = const. This can be written in terms of the average air density ρ (kg m-3) as
ρTs = const. = Ps M / R (6)
where Ps is the mean surface air pressure (Pa) and M is the molecular mass of air (kg mol-1). Eq. (6) reveals an important characteristic of the average thermodynamic process at the surface, namely that a variation of global pressure due to either increase or decrease of total atmospheric mass will alter both temperature and atmospheric density. What is presently unknown is the differential effect of a global pressure change on each variable. We offer a solution to this in & 3.3. Equations (5) and (6) imply that pressure directly controls the kinetic energy and temperature of the atmosphere. Under equal solar insolation, a higher surface pressure (due to a larger atmospheric mass) would produce a warmer troposphere, while a lower pressure would result in a cooler troposphere. At the limit, a zero pressure (due to the complete absence of an atmosphere) would yield the planet’s gray-body temperature.
The thermal effect of pressure is vividly demonstrated on a cosmic scale by the process of star formation, where gravity-induced rise of gas pressure boosts the temperature of an interstellar cloud to the threshold of nuclear fusion. At a planetary level, the effect is manifest in Chinook winds, where adiabatically heated downslope airflow raises the local temperature by 20C-30C in a matter of hours. This leads to a logical question: Could air pressure be responsible for the observed thermal enhancement at the Earth surface presently known as a ‘Natural Greenhouse Effect’? To answer this we must analyze the relationship between NTEfactor and key atmospheric variables including pressure over a wide range of planetary climates. Fortunately, our solar system offers a suitable spectrum of celestial bodies for such analysis.
3.2. Interplanetary Data Set
We based our selection of celestial bodies for the ATE analysis on three criteria: 1) presence of a solid planetary surface with at least traces of atmosphere; 2) availability of reliable data on surface temperature, total pressure, atmospheric composition etc. preferably from direct measurements; and 3) representation of a wide range of atmospheric masses and compositions. This approach resulted in choosing of four planets – Mercury, Venus, Earth, and Mars, and four natural satellites – Moon of Earth, Europa of Jupiter, Titan of Saturn, and Triton of Neptune. Each celestial body was described by 14 parameters listed in Table 1.
For planets with tangible atmospheres, i.e. Venus, Earth and Mars, the temperatures calculated from IGL agreed rather well with observations. Note that, for extremely low pressures such as on Mercury and Moon, the Gas Law produces Ts ≈ 0.0. The SPGB temperatures for each celestial body were estimated from Eq. (2) using published data on solar irradiance and assuming αgb = 0.12 and ϵ = 0.955. For Mars, global means of surface temperature and air pressure were calculated from remote sensing data retrieved via the method of radio occultation by the Radio Science Team (RST) at Stanford University using observations by the Mars Global Surveyor (MGS) spacecraft from 1999 to 2005. Since the MGS RST analysis has a wide spatial coverage, the new means represent current average conditions on the Red Planet much more accurately than older data based on Viking’s spot observations from 1970s.
Table 1. Planetary data used to analyze the physical nature of the Atmospheric Near-Surface Thermal Enhancement (NTE). Information was gathered from multiple sources using cross-referencing. The bottom three rows of data were estimated in this study using equations discussed in the text.
3.3. Physical Nature of ATE / GHE
Our analysis of interplanetary data in Table 1 found no meaningful relationships between ATE (NTE) and variables such as total absorbed solar radiation by planets or the amount of greenhouse gases in their atmospheres. However, we discovered that NTE was strongly related to total surface pressure through a nearly perfect regression fit via the following nonlinear function:
where Ps is in Pa. Figure 5 displays Eq. (7) graphically. The tight relationship signals a causal effect of pressure on NTE, which is theoretically supported by the IGL (see & 3.1). Also, the Ps–NTE curve in Fig. 5 strikingly resembles the response of the temperature/potential temp. (T/θ) ratio to altitudinal changes of pressure described by the well-known Poisson formula derived from IGL (Fig. 6). Such a similarity in responses suggests that both NTE and θ embody the effect of pressure-controlled adiabatic heating on air, even though the two mechanisms are not identical. This leads to a fundamental conclusion that the ‘Natural Greenhouse Effect’ is in fact a Pressure-induced Thermal Enhancement (PTE) in nature.
NTE should not be confused with an actual energy, however, since it only defines the relative (fractional) increase of a planet’s surface temperature above that of a SPGB. Pressure by itself is not a source of energy! Instead, it enhances (amplifies) the energy supplied by an external source such as the Sun through density-dependent rates of molecular collision. This relative enhancement only manifests as an actual energy in the presence of external heating. Thus, Earth and Titan have similar NTE values, yet their absolute surface temperatures are very different due to vastly dissimilar solar insolation. While pressure (P) controls the magnitude of the enhancement factor, solar heating determines the average atmospheric volume (V), and the product P×V defines the total kinetic energy and temperature of the atmosphere. Therefore, for particular solar insolation, the NTE factor gives rise to extra kinetic energy in the lower atmosphere beyond the amount supplied by the Sun. This additional energy is responsible for keeping the Earth surface 133K warmer than it would be in the absence of atmosphere, and is the source for the observed 44% extra down-welling LW flux in the lower troposphere (see &2.1 C). Hence, the atmosphere does not act as a ‘blanket’ reducing the surface infrared cooling to space as maintained by the current GH theory, but is in and of itself a source of extra energy through pressure. This makes the GH effect a thermodynamic phenomenon, not a radiative one as presently assumed!
Equation (7) allows us to derive a simple yet robust formula for predicting a planet’s mean surface temperature as a function of only two variables – TOA solar irradiance and mean atmospheric surface pressure, i.e.
Figure 5. Atmospheric near-surface Thermal Enhancement (NTE) as a function of mean total surface pressure (Ps) for 8 celestial bodies listed in Table 1. See Eq. (7) for the exact mathematical formula.
Figure 6. Temperature/potential temperature ratio as a function of atmospheric pressure according to the Poisson formula based on the Gas Law (Po = 100 kPa.). Note the striking similarity in shape with the curve in Fig. 5.
where NTE(Ps) is defined by Eq. (7). Equation (8) almost completely explains the variation of Ts among analyzed celestial bodies, thus providing a needed function to parse the effect of a global pressure change on the dependent variables ρ and Tsin Eq. (6). Together Equations (6) and (8) imply that the chemical composition of an atmosphere affects average air density through the molecular mass of air, but has no impact on the mean surface temperature.
4. Implications of the new ATE Concept
The implications of the above findings are numerous and paradigm-altering. These are but a few examples:
Figure 7. Dynamics of global temperature and 12-month forward shifted cloud cover types from satellite observations. Cloud changes precede temperature variations by 6 to 24 months and appear to have been controlling the latter during the past 30 years (Nikolov & Zeller, manuscript).
A) Global surface temperature is independent of the down-welling LW flux known as greenhouse or back radiation, because both quantities derive from the same pool of atmospheric kinetic energy maintained by solar heating and air pressure. Variations in the downward LW flux (caused by an increase of tropospheric emissivity, for example) are completely counterbalanced (offset) by changes in the rate of surface convective cooling, for this is how the system conserves its internal energy.
B) Modifying chemical composition of the atmosphere cannot alter the system’s total kinetic energy, hence the size of ATE (GHE). This is supported by IGL and the fact that planets of vastly different atmospheric composition follow the same Ps–NTE relationship in Fig. 5. The lack of impact by the atmospheric composition on surface temperature is explained via the compensating effect of convective cooling on back-radiation discussed above.
C) Equation (8) suggests that the planet’s albedo is largely a product of climate rather than a driver of it. This is because the bulk of the albedo is a function of the kinetic energy supplied by the Sun and the atmospheric pressure. However, independent small changes in albedo are possible and do occur owning to 1%-3% secular variations in cloud cover, which are most likely driven by solar magnetic activity. These cloud-cover changes cause ±0.7C semi-periodic fluctuations in global temperature on a decadal to centennial time scale as indicated by recent satellite observations (see Fig. 7) and climate reconstructions for the past 10,000 years.
Figure 8. Dynamics of global surface temperature during the Cenozoic Era reconstructed from 18O proxies in marine sediments (Hansen et al. 2008).
Figure 9. Dynamics of mean surface atmospheric pressure during the Cenozoic Era reconstructed from the temperature record in Fig. 8 by inverting Eq. (8).
D) Large climatic shifts evident in the paleo-record such as the 16C directional cooling of the Globe during the past 51 million years (Fig. 8) can now be explained via changes in atmospheric mass and surface pressure caused by geologic variations in Earth’s tectonic activity. Thus, we hypothesize that the observed mega-cooling of Earth since the early Eocene was due to a 53% net loss of atmosphere to Space brought about by a reduction in mantle degasing as a result of a slowdown in continental drifts and ocean floor spreading. Figure 9 depicts reconstructed dynamics of the mean surface pressure for the past 65.5M years based on Eq. (8) and the temperature record in Fig. 8.
5. Unified Theory of Climate
The above findings can help rectify physical inconsistencies in the current GH concept and assist in the development of a Unified Theory of Climate (UTC) based on a deeper and more robust understanding of various climate forcings and the time scales of their operation. Figure 10 outlines a hierarchy of climate forcings as part of a proposed UTC that is consistent with results from our research as well as other studies published over the past 15 years. A proposed key new driver of climate is the variation of total atmospheric mass and surface pressure over geological time scales (i.e. tens of thousands to hundreds of millions of years). According to our new theory, the climate change over the past 100-300 years is due to variations of global cloud albedo that are not related to GHE/ATE. This is principally different from the present GH concept, which attempts to explain climate changes over a broad range of time scales (i.e. from decades to tens of millions of years) with the same forcing attributed to variations in atmospheric CO2 and other heat-absorbing trace gases (e.g. Lacis et al. 2010).
Earth’s climate is currently in one of the warmest periods of the Holocene (past 10K years). It is unlikely that the Planet will become any warmer over the next 100 years, because the cloud cover appears to have reached a minimum for the present levels of solar irradiance and atmospheric pressure, and the solar magnetic activity began declining, which may lead to more clouds and a higher planetary albedo. At this point, only a sizable increase of the total atmospheric mass can bring about a significant and sustained warming. However, human-induced gaseous emissions are extremely unlikely to produce such a mass increase.
Figure 10. Global climate forcings and their time scales of operation according to the hereto proposed Unified Theory of Climate (UTC). Arrows indicate process interactions.
6. References
Kopp, G. and J. L. Lean (2011). A new, lower value of total solar irradiance: Evidence and climate significance, Geophys. Res. Lett., 38, L01706, doi:10.1029/2010GL045777.
Kuptsov, L. P. (2001) Hölder inequality, in Hazewinkel, Michiel, Encyclopedia of Mathematics, Springer, ISBN 978-1556080104.
Lacis, A. A., G. A. Schmidt, D. Rind, and R. A. Ruedy (2010). Atmospheric CO2: Principal control knob governing earth’s temperature. Science 330:356-359.
Lindzen, R. S. and Y.-S. Choi (2009). On the determination of climate feedbacks from ERBE data. Geophys. Res. Lett., 36, L16705, doi:10.1029/2009GL039628.
McKitrick, R. R. et al. (2010). Panel and Multivariate Methods for Tests of Trend Equivalence in Climate Data Series. Atmospheric Science Letters, Vol. 11, Issue 4, pages 270–277.
Nikolov, N and K. F. Zeller (manuscript). Observational evidence for the role of planetary cloud-cover dynamics as the dominant forcing of global temperature changes since 1982.
Pavlakis, K. G., D. Hatzidimitriou, C. Matsoukas, E. Drakakis, N. Hatzianastassiou, and I. Vardavas (2003). Ten-year global distribution of down-welling long-wave radiation. Atmos. Chem. Phys. Discuss., 3, 5099-5137.
Spencer, R. W. and W. D. Braswell (2010). On the diagnosis of radiative feedback in the presence of unknown radiative forcing, J. Geophys. Res., 115, D16109, doi:10.1029/2009JD013371
Trenberth, K.E., J.T. Fasullo, and J. Kiehl (2009). Earth’s global energy budget. BAMS, March:311-323
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This post is also available as a PDF document here:
Unified_Theory_Of_Climate_Poster_Nikolov_Zeller
UPDATE: This thread is closed – see the newest one “A matter of some Gravity” where the discussion continues.
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You know, I have now typed so much on this topic, with a 2 year-old and a baby distracting me, that my memory of exactly what the authors said is getting foggy in my mind, and perhaps I should go back and re-read. But there is a pervasive that the ideal gas law is causative, in that a given P, V, and n will cause a particular temperature. You can see this in the comments here, and I find it to be common among my second and third year engineering students. I sensed it to be part of what the authors were implying. That is the idea I am trying to squash. Temperature results from energy balance. Pressure and density then follow according to the ideal gas law and the total material (n) in a system.
“Gravity in effect determines pressure, energy balance determines temperature”
Ummmm.. what?
Second, you ask “… when the temperature then rises due to more energy input, what does the pressure do? It rises….” No it does not. What occurs is that the atmosphere expands. in fact, let’s look at what happens on Earth.
As you say, let’s actually look at what happens on Earth. When energy is introduced to the atmosphere the atmosphere expands, true… but to say it only expands is to ignore gravity. Since Earth actually has a gravitational field, that gravity creates pressure and denies fully free expansion of the gas, so that added energy will in part expand the atmosphere, and it part heat the atmosphere. As such, the gravitational pressure that heat.
James Reid says:
December 29, 2011 at 9:03 am
Do I hear deathly silence from the Lazy Teenager and R Gates?
Haha! You read my mind!
The word ‘energy’ is ambiguous in multiple ways. For the purposes of this discussion, an important use of the word ‘energy’ has to do with the Earth-Sun system of radiation exchange so familiar from Warmist models. With regard to that system, Earth does not create energy.
But there are other uses of the word ‘energy’. Windmills are created to transform the energy of the winds into electricity. In that use of the word ‘energy’, the reference is not to the Earth-Sun system and the statement is perfectly meaningful.
Because the article under discussion departs from the “radiation only” model of the Earth-Sun system used by the Warmists, when the authors write or imply that energy is being created they are referring to a set of physical hypotheses that is independent of the Earth-Sun system. Give them a chance. Try to understand their use of the word ‘energy’ by reference to the physical hypotheses that they are attempting to elucidate.
There was a video distributed here earlier (in the debunking of Al Gore’s “24 hours of realism” video) that touched on this theory as well. It took a slightly different tack in proving it’s point by arguing that, when you account for the difference is solar irradiance, Venusian atmosphere is actually roughly the same temperature as Earth’s atmosphere at equal atmospheric pressure.
I think that video “Greenhouse in a Bottle, Reconsidered” has been taken down now, but it espouses the same theory. It would be nice if someone had a copy of it and could post it. I can’t seem to find it.
Stephen Wilde – thank you for your continuing climate educational efforts.
Kevin Kilty says:
December 29, 2011 at 12:33 pm
Sir, I don’t disagree with what you say. As I said last time I agree. I was being more narrowly focused as to what the equation says. However, work is seldom mentioned (which is a shame) in discussions of climate.
Surely the average temperature of the earth without an atmosphere wouldn’t be the same as the moon because the rate of rotation is different?
Joe says:
December 29, 2011 at 12:59 pm
“Gravity in effect determines pressure, energy balance determines temperature”
Ummmm.. what?
Second, you ask “… when the temperature then rises due to more energy input, what does the pressure do? It rises….” No it does not. What occurs is that the atmosphere expands. in fact, let’s look at what happens on Earth.
As you say, let’s actually look at what happens on Earth. When energy is introduced to the atmosphere the atmosphere expands, true… but to say it only expands is to ignore gravity. Since Earth actually has a gravitational field, that gravity creates pressure and denies fully free expansion of the gas, so that added energy will in part expand the atmosphere, and it part heat the atmosphere. As such, the gravitational pressure that heat.
The closest (simple) analogy to the atmosphere as Joe describes would be a balloon. As the air heats the pressure inside increases and the outside expands. If you think of gravity as the skin of the balloon then you will see that the pressure inside the balloon increases but not at the rate one would expect if the balloon was rigid. It’s far more complex than I have explained here but I hope you get the gist.
So , “Gravity in effect determines pressure, energy balance determines temperature” If you look deeply into this phrase you will note that the author might have a point but may not have expressed in a way that makes it easy to understand what he/she actually meant to say.
I’m not going to bother rehashing the greenhouse effect physics. I gave an explanation of why pressure is indeed more important than backradiation here: http://judithcurry.com/2010/12/02/best-of-the-greenhouse/ Professor Curry splits my explanation into two sections, so scroll down.
However, it’s not true to say that it is purely due to pressure, or that greenhouse warming would occur with a totally transparent atmosphere.
Somebody asked for a more extensive list of issues with the paper. Here are just a few I picked out going through.
“According to the current theory,…”
While this theory is commonly found in explanations to the general public, it is not in fact the one used by climate scientists for actual calculations. Those calculations take convection and pressure effects fully into account.
“To be correct, Tgb must be computed via proper spherical integration of the planetary temperature field…”
It’s still not correct. The actual temperature with an atmosphere will also involve horizontal heat transfer via convection cycles, and the loss of heat from the surface is not just by radiation but also latent and sensible heat. Heat storage, and surface thermal conductivity also have an effect because of the day/night cycle. The temperature is proportional to the fourth power of the heat radiated, so to get the ‘radiative average’ temperature, you have to take the fourth root of temperature to get power, average, and then raise to the fourth power again to get a single equivalent temperature. The difference is not so large.
“Can a handful of trace gases which amount to less than 0.5% of atmospheric mass trap enough radiant heat to cause such a huge thermal enhancement at the surface?”
Yes. If it wasn’t for convection, the average surface temperature on Earth would be about 65-70 C. And CO2 is not the only GHG – water vapour constitutes more than 0.5%.
“Modern GCMs do not solve simultaneously radiative transfer and convection.”
As I understand it, they do – although they sometimes fudge the details somewhat.
“the term Greenhouse Effect is a misnomer”
True, but I think that’s well-accepted, even by advocates.
“…guarantees that a mean global temperature can be accurately estimated from planetary averages of surface pressure and air volume…”
No, because it also depends on their vertical distribution, and because the volume is a function of the temperature distribution (which in turn is due to radiation/convection effects), not vice versa. Cause and effect are reversed.
“…related to total surface pressure through a nearly perfect regression fit…”
You have a number of planets with no atmosphere, to which the regression is insensitive, and only three planets are used to define the curve. Since you have four free parameters, a perfect fit is not surprising. It’s not significant.
Folks ,
Somewhere in the midst of this melee , one of the authors ( I forget which and don’t hace the time to look ) commented that this was just a preview of what are to become four papers that they will submit for peer reviewed publication . No point in getting too worked up over this . BTW the harshest critics here are probably doing the authors a tremendous service , whether they mean to or not .
Brian H says:
December 29, 2011 at 8:47 am
Hmm. I don’t know beans about air pressure differences in the geologic past. I’ll call my geologist brother to fill me in.
Brian’s links are far more fascinating than the vitriol over gas laws. I thought we settled some of that stuff in the Venus threads. Everyone, climb a mountain and chill out from the adiabtic expansion! Then read those links. BTW, they argue that big flying things needed “at least 3.7–5.0 bar” when they were around 100-65 Mya. That’s a lot more than the 1.6 bar from figure 9 at 65 Mya.
I really, really like to see multiple lines of research support some outrageous claim. Clearly more study is needed.
I think the dinosaur blood pumping question is not nearly so good. The real question is what was the venous blood pressure, and what kept the veins from collapsing or developing a vacuum.
GeologyJim says:
December 29, 2011 at 8:54 am
A claim in the second link is that the Earth’s carbonates hold the equivalent of 55 bar of CO2. So the answer may be that Earth did not lose its CO2, but by keeping its H2O, pathways opened to take CO2 out of the atmosphere and put it underfoot.
We can attempt to enrich the CO2 of volcanoes maybe by dumping limestone into them or something. Maybe we could inject nuclear waste on the subducting side of thrust faults, I don’t know. Nuclear power is pretty much the only answer, though, long term.
Kevin Kilty says:
December 29, 2011 at 12:45 pm
George Turner says:
December 29, 2011 at 12:26 pm
Kevin, are you saying that high altitude areas are colder than low altitude areas because of differences in radiative balance, not the difference in pressure?
This is a cause and effect problem. Kevin, I had to read your comment several times to get the gist.
The feeling of cold at altitude is due to the lack of pressure. The reason there is a lack of pressure is because there is a lack of gas. The reason there is a lack of gas is down to gravity. Work is done when the state of a mass is changed from steady to accelerating. In the lower atmosphere where an anticyclone (high pressure) is present for a long period what is the profile of temperature through the lower atmosphere and where a low pressure is present how does that change the temperature profile.?
simpleseekeraftertruth says: “If this pans out then Nobel Prizes (at least) are in order.”
And Nobel Prizes in SCIENCE no less.
I am going to use one of those equations just posted above to form of a conclusion to this Ideal Gas Law controlling the temperature.
P•M = ρ•R•T can rewrite as T = P/ ρ • M/R. Now that is curious, P/ ρ is just pressure per density ratio and M/R is just the molar mass ratio to the gas constant. What can possibly change?
The mean averaged pressure over all of the earth is ~101325 Pa and except for local weather effects has not changed for a many, many years. It depends on the gravitational acceleration which depends on the Earth’s mass and it has not changed significantly. It also depends on the surface area of the Earth and it has not changed. And it is dependant on the mass of the Earth’s mass, well, covered that above.
And the mean density (ρ) has not changed either since the mass of the atmosphere is basically constant as well as the surface area of the Earth.
How about R, the gas constant, well, it IS a constant.
The only term left is M, the mean molar mass of the atmosphere’s components and per the Engineering Toolbox and Wikipedia at 28.97 g/mol and 28.966 according to the Handbook of Chemistry and Physics (1968). If these are correct then this is the only parameter in the Ideal Gas Law above and so T may have changed by 0.004/28.966 or 0.0138% from 288.15 listed as the mean temperature in 1968 and that would be 288.15 • 0.000138 or 0.039 K.
We know the atmosphere is no an ideal gas per se but I can’t find any feasible deviations from an ideal gas that would affect the equation above when speaking of anomalies, as the +0.039°C anomaly calculated since 1968.
So am I wrong, I see no way by the above calculations using the Ideal Gas Law that the Earth’s mean temperature could EVER change without something very catastrophic as a meteor hit, ejecting a sizeable amount of our atmosphere’s mass into space. I don’t see it.
If my calculations above are wrong, please tell me.
Expected geomagnetic storm in progress now
http://flux.phys.uit.no/cgi-bin/plotgeodata.cgi?Last24&site=tro2a&
This is interesting and I am still reading it. Fast comments.
Equations 7 and 8 are just curve fittings, regression equations that are said to resemble the natural gas laws which is demonstrated in figures 5 and 6. Please, rewrite that and show that observations match the theoretical calculations.
How does this theory explain Earth’s Thermosphere?
opps… mistake above at December 29, 2011 at 1:40 pm :
“And it is dependant on the mass of the Earth’s mass, well, covered that above.”
should have been more like…
“And it also dependant on the mass of the Earth’s atmosphere and it has not been known to have changed significantly.”
Interesting.
Will reward a second reading, and probably a third.
Not sure my maths is up to a full comprehension – of the paper or of the various comments.
However, taken together, there appears to be a very strong feeling [feelings are NOT science, I know] that there are many [very many] factors at work in weather and climate.
Some of these are new to this dilettante observer.
One or two, shall we sy, seem to be unfamiliar to the Team.
Certainly a thought-provoking paper, and the thoughts provoked, on this thread alone [Tallbloke, your comments noted!], will make the science stronger [if a little less-settled, hey, Team?].
Looks like good work all round – science that is being reviewed by [near]-peers, challenged and – please – talked about.
Where are the comments from George Monbiot, say? Or Geoffrey Lean, even?
Might this paper be t h e game-changer?
I don’t know, but it does ask questons that I, for one, would like to see answered.
Finally, happy New year to all reading this – pro/anti/neutral whatever it is!
Gary Pearse says:
Okay…fine…Let’s deal with the two aspects of their post that haven’t yet been shredded to pieces.
(1) The ideal gas law: Who would think that if you calculate the surface pressure and number density then you can use the ideal gas law to determine the temperature? Wow…That’s quite a shock! It certainly won’t surprise my intro physics students who I already tell that the ideal gas law works very well for real gases as long as you stay away from high (close to liquid) densities. But just knowing that there is this relationship between pressure, temperature, and density doesn’t get you very far in uniquely determining the surface temperature of a planet.
(2) Their Equation (7): They’ve written down an expression relating temperature and pressure with 4 free parameters that they have fit to data for various bodies in our solar system and now they are shocked that it does a pretty good job for 3 or 4 of them and (and not for hot for others). And we’re supposed to impressed by this?
Nullus in Verba: 1.28 pm.
I read the Curry blog piece and I must disagree with the ‘back radiation ‘ part, also 33K present GHG warming.. This is where climate science has gone horribly wrong.
1. ’33 K’. Take out the atmosphere and albedo falls from 0.3 to 0.07 [no clouds or ice] so equilibrium radiant temperature to space =~0°C meaning maximum GHG warming is 15 K. Do a proper calculation including the aerosols and it falls to ~9 K with 24 K lapse rate warming at the surface.
2. ‘Back Radiation’:Imagine two parallel plates at the same temperature. Put a radiometer in the gap and it measures ‘back radiation’ Turn it 180° and it measures the same in the opposite direction. So, ‘back radiation’ is cancelled out at equilibrium. A Dutch researcher showed over a height of 800 feet at night, up-down fell exponentially to zero, Beer’s law absorption of IR from the Earth’s surface with zero net IR from the atmosphere towards the Earth’s surface.
So, back radiation can do no thermodynamic work. It’s a measure of temperature and emissivity. It is the means by which the density of IR states in the emitter communicate with those in the absorber and vice versa, hence Kirchhoff’s law of Radiation. It is ‘Prevost Exchange Energy.’.
As I said, in my view climate science has gone horribly wrong because of serious misunderstanding of the heat transfer and the real GHG scaling. It gets out of the trap by incorrect aerosol optical physics and the imaginary negative net AIE There’s a second optical effect which makes this slightly positive now but much more in ice ages or polar regions. I am publishing this, wjich is another GW/AGW mechanism. GHG-GW/AGW is very much smaller than claimed [maximum of 15% of the IPCC median 3 K climate sensitivity].
Great Paper! It is very good to see physics and inter-planetary studies at last making a come-back in the arguments. What we need now are similar papers on the effects of the Oceans and the hot core in the earth and we will be drawing aside the last of the veils.
Congratulations on a good start..
Joel Shore says:
December 29, 2011 at 9:30 am
“Hölder’s inequality only has a significant effect if the temperature range on the planet is very large on an absolute temperature scale. For the Earth, the temperature range is moderate enough on an absolute scale that the difference between averaging the temperature and taking the fourth root of the average of T^4 is quite small.”
The daily range is routinely over 100 degrees and at maximum approaches 150 degrees, that doesn’t strike me as all that moderate relative to an average of 288.
“So am I wrong, I see no way by the above calculations using the Ideal Gas Law that the Earth’s mean temperature could EVER change without something very catastrophic as a meteor hit, ejecting a sizeable amount of our atmosphere’s mass into space. I don’t see it.”
Depends what you mean by ‘mean’ temperature. To get at that you need to somehow obtain a n average temperature for the entire atmosphere and oceans combined. Not easy.
I prefer the concept of system energy content defined as solar energy that has arrived in the system and not yet departed.
That isn’t easy to measure either but we can work out a few general principles and they go way beyond the Ideal Gas Law.
As regards the total system energy content I don’t think that does change much at all, just as you say.That is because total system energy content is a function only of solar energy input, atmospheric pressure and the power of the bond between water molecules (which is itself affected by pressure).
If anything seeks to change that balance all one gets is a negative system response which alters the rate of energy flow through the system so as to maintain the background equilibrium.
The Ideal Gas Law is involved but only from surface upward. It has no relevance to the background rate of energy flow from ocean to air.
Since the ocean energy content (which is released at variable rates) controls the temperature of the air above, the Ideal Gas Law does not give any accurate guide as to the temperature of the system as a whole or even the actual temperature of the air above the oceans.
The temperature nominally derived from the Ideal Gas Law would be different from the actuality if the release of energy from the oceans were to vary and apparently it does due to internal oceanic oscillations.
The item missing from your calculation is the rate of energy release from the oceans.