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
===============================================================
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.
Looking at the comments above, Joel Shore and Kevin Kilty seem to understant what they’re talking about. There may be some others mixed in, but they’re the ones who jump out as the competent ones.
Many of the other commenters are suffering from one confusion or another, or many at the same time.
Myrrh, the solution to your conceptual difficulty is as follows:
1) Even in perfectly still conditions, the scale height of CO2 would not be that much smaller than that of the other components;
2) Diffusion is a powerful effect that tends to keep things mixed equally. It is entropically much more favorable for gases to be mixed evenly than separated. Gravitational settling will occur in very quiescent conditions, and under high gravity (such conditions exist in white dwarf stars,where everything heavier than hydrogen sinks out of sight), but in the earth’s atmosphere it’s just not important.
Absolutely excellent posting. It’s a good thing to see more climate scientists like Dr. Nikolov and Dr. Zeller speak out against AGW.
Kevin Kilty says:
December 29, 2011 at 12:23 pm
OK, Kevin. Engineering degrees at 10 paces. Ready?
I may be misreading what you are trying to say but, your proposition that the irradiance on Venus is “absorbed predominantly high in the atmosphere”, flies in the face of the following ‘facts’:
1. The density there is lowest.
2. The atmosphere is transparent to incoming irradiance.
So how does convection get the high, hot, ‘thin’ stuff down to the ‘relatively cool’ surface? Won’t convection tend to keep the hot stuff high up. Hot CO2 rises, cool CO2 falls, n’est-ce pas?
You do mention the surface having a high temperature, but ascribe this to energy absorbed at TOA. I don’t follow your thinking about ‘little irradiance absorbed at the surface’. ( I make no comment about your ‘parcels’ bringing it down.)
So, I’m with Ned and Karl at present and you are not swaying my thinking one little bit, yet.
The only thing wrong with that explanation is it does not match with reality. In the real world CO2 is not well mixed when it is only subject to simple diffusion. A classic example is CO2 pooling in a stable layer in abandon mines or storage tanks where the only force to mix the gasses is diffusion.
In those environments CO2 will form a stable layer along the floor of the mine or tank.
Every year a few people die in such situations as the walk into that stable layer.
The classic scenario in mine rescue is the “mine tourist” walks into the mine a few hundred feet with no problem at all, then as they descend into that stable layer or their motion through it mechanically mixes it with the breathable air above, they suddenly pass out due to anoxia and then suffocate as they lie unconscious on the floor of the mine.
It is mechanical mixing from convection and stirring due to winds and turbulence as it moves past obstacles that keeps the gasses mixed. Without those forces our atmosphere would be a layer cake of gases sorted by density.
Larry
@Chesty Puller says:
Atmospheric greenhouse warming is a result of impedance in the free radiative path from surface to space. Greenhouse gas molecules intercept the radiation and essentially reflect about half of it back at the source. The authors are correct that this may result in greater rate of convection but that is acheived through a greater surface temperature which condutively heats the air to a greater degree making it that much lighter which in turn makes it rise faster. At the same time the higher surface temperature also increases the motive force of radiative transfer and more of it gets squeezed through the impedance of the greenhouse gases just like when you increase the pressure of water more of it will make through a pipe whose diameter remained constant.
Then how was/is the ghg, water vapor, able to stop its own ghg effect, and indeed keep it from “spiraling upward” ? Why would CO2 override the hydrological cycle any more than water vapor already couldn’t? And why would water vapor suddenly assist CO2 to do what it, water vapor, couldn’t do before?
Myrrh says “Wjat I would like to see … is the real basic properties and processes discussed in English”
Try my site: http://earth-climate.com and (seriously) I would appreciate feedback on anything you or others question, as this will become the basis of a planned small “simple English” book.
palindrom says:
December 29, 2011 at 6:44 pm
Myrrh, the solution to your conceptual difficulty is as follows:
1) Even in perfectly still conditions, the scale height of CO2 would not be that much smaller than that of the other components;
2) Diffusion is a powerful effect that tends to keep things mixed equally. It is entropically much more favorable for gases to be mixed evenly than separated. Gravitational settling will occur in very quiescent conditions, and under high gravity (such conditions exist in white dwarf stars,where everything heavier than hydrogen sinks out of sight), but in the earth’s atmosphere it’s just not important.
=======
I’m not the one here with a problem conceptualising.
Methane is lighter than air, it rises and rises locally, see Catatumbo. It doesn’t mix thoroughly in the atmosphere around all the Earth by diffusion. Water vapour is lighter than air, it is always evaporating, it evaporates more quickly the hotter it is but still it evaporates locally and doesn’t ‘diffuse into the mythical well mixed background’. Carbon dioxide is one and half times heavier than air – it will always sink displacing air – it does not spontaneously diffuse into the atmosphere but will move in local conditions – it is lumpy because it is local.
Which is where plants expect it to be, they have evolved with stomata on the underside of their leaves to take in carbon dioxide.
And everytime it rains whatever carbon dioxide is around in the atmosphere at the time will ALL come down as carbonic acid, which is what pure rainwater is. Again, local. Winds and rain will move it around, but that is local for the most part. The reality is totally at odds with the AGW claim that carbon dioxide is well-mixed proportionally in all the atmosphere.
hotrod —
Ah, I bet you’re right. The key insight would seem to be that the timescale for gravitational settling of the heavier species is much longer than the timescale for the atmosphere to re-mix. I suppose that my point about the scale heights (which would apply if the atmosphere were strictly collisionless, which it is far, far from) might have some relevance to how weak the tendency toward stratification is, but you’ve pretty much got to be right that a highly collisional, quiescent gas would have to stratify. Thanks.
Myrrh — hotrod has it right about the mixing. But here’s another point.
The source you quote gives the following properties of an ideal gas:
“1. An ideal gas is considered to be a “point mass”. A point mass is a particle so small, its mass is very nearly zero. This means an ideal gas particle has virtually no volume.
2. Collisions between ideal Gases are “elastic”. This means that no attractive or repulsive forces are involved during collisions. Also, the kinetic energy of the gas molecules remains constant since these interparticle forces are lacking.
(1) confuses mass with volume. An ideal gas has to be diffuse enough that the volume taken up by the molecules is a small fraction of the total. Air satisfies this condition pretty well.
(2) “Elastic” does not mean that there are no attractive or repulsive forces — otherwise there would be no collisions! — it means that the collisions preserve kinetic energy. So the “Also” phrase here is the tail that wags the dog. An example of an inelastic collision would be one in which some of the molecules’ KE were converted into other forms (e.g., excitation of a molecule’s energy levels). In air molecules, translational KE is frequently converted into rotational energy of the diatomic molecules, but this doesn’t affect the ideality of the gas to any great extent, since on average an equal amount of rotational energy is converted into kinetic.
Your source seems to have a rather shaky grasp on physics terminology.
Myrrh @7:48 —
You know, of course, that it’s possible to tell empirically whether a gas is well-mixed or not, without regard to theory. CO2 is well-mixed. Methane isn’t as well-mixed in part because its lifetime in the atmosphere is of order a decade.
The stomata of plants, being on the lower side of the leaves, are about a half-millimeter lower in elevation. Surely you aren’t claiming that this is a significant effect. I’d think keeping rainwater out would be a much more important driver.
Congratulations to the authors of this theory. I have only a small commentary: Pressure could be a source of energy if we associate it with gravity. Essentially, gravity field is a sink of thermal energy. The higher the system is placed with respect to the surface, the higher the unusable potential energy., i.e. potential energy that cannot be used to do work or to be transformed into thermal radiation.
Galane says:
December 29, 2011 at 8:55 pm
When is someone going to investigate the climatic effect of Earth’s decreasing axial tilt on the climate? As it tilts towards its minimum, ………
=====================================================
I agree, and I disagree. Assuming the earth is sphere, (it isn’t a perfect sphere) the tilt has nothing to do with the average global temp. If one part of the world tilts away from the sun, the other part will tilt towards the sun. So, everything will remain the same on the globe.
[snip . . you know the rules . . kbmod]
OzWizard says:
December 29, 2011 at 7:20 pm
Kevin Kilty says:
December 29, 2011 at 12:23 pm
“The surface temperature results from 1) irradiance that is absorbed predominantly high in the atmosphere leading to a high temperature there, and 2) then a lot of work input by gravity as convection takes parcels from up high to the surface. There is also a little irradiance absorbed at the surface which is what drives the convection.”
“OK, Kevin. Engineering degrees at 10 paces. Ready?
I may be misreading what you are trying to say but, your proposition that the irradiance on Venus is “absorbed predominantly high in the atmosphere”, flies in the face of the following ‘facts’:
1. The density there is lowest.
2. The atmosphere is transparent to incoming irradiance………..”
Ozwizard, the facts are there is almost no solar irradiance at Venus surface, the atmosphere is essentially opaque. Full facts and reference can be seen at page 11 et seq of http://www.climate-facts.com/pdf/challenge.pdf links to the papers and references cited are at page 19 of that documents.
Notably in the words of A. A. Lacis; “greenhouse effect requires that a substantial fraction of the incident solar radiation must be absorbed at the ground in order to make the indirect greenhouse heating of the ground surface possible” and this essential element just does not exist on Venus. As will be seen A.A. Lacis 2010 paper is falsified by his 1975 paper. (links to both papers and others are at the above link)
Per folks stressing over the temperature graph from Hansen 2008, I found this interesting paper by Hansen from 2011 (near as I can tell):
http://www.columbia.edu/~jeh1/mailings/2011/20110118_MilankovicPaper.pdf
that has substantially the same graph in it, but with the PETM “cooled” to about 12 C and with the start cooled to about 9 C; while the Pleistocene looks to me to have been “warmed” but one or 2 C.
Gee, if that 2008 Hansen paper can be found, it would be an interesting A/B study in how The Team cook the books over time to flatten things they want flattened and warm the present…
The wiki has a graph that looks like the start matches Hansen 2011, but leaves the Pleistocene (‘near now’) at -4 C for the ‘center of mass’ of the color.
http://en.wikipedia.org/wiki/File:65_Myr_Climate_Change.png
So looks to me like, at most, you have a couple of C in the PETM to argue about. Oh, and asking just how Hansen manages to keep cooling off the past and warming the present every time he touches any temperature data sets…
I did find one 2008 paper where he erases some of the recent cooling via “assigning” some of it to ice formation:
http://www.moraymo.us/2008_Hansenetal.pdf
So looks like he is able to make the changes in the record via “assignment”, as needed…
Or maybe those are adjustments… or corrections… or fudge… or whatever the current “term of art” is these days… “Climate Art”…. hmmm catchy, that 😉
So looks to me like Hansen is happy to have the numbers wander around over time from paper to paper as needed. Still, would be nice to have all the assumptions, er, assignments, detailed and just which paper had the version, variation, “artwork” with these numbers that Hansen made in it…
James Sexton says:
December 29, 2011 at 10:33 pm
Galane says:
December 29, 2011 at 8:55 pm
When is someone going to investigate the climatic effect of Earth’s decreasing axial tilt on the climate? As it tilts towards its minimum, ………
=====================================================
I agree, and I disagree. Assuming the earth is sphere, (it isn’t a perfect sphere) the tilt has nothing to do with the average global temp. If one part of the world tilts away from the sun, the other part will tilt towards the sun. So, everything will remain the same on the globe.
————————–
James, think a little more on this. The SH is about ? 8o% ocean, the NH is about ? 60% land. The earth in January recieves about 7% more insolation, or about 90 watts per sq M more energy, than in July, yet the earth’s atmosphere is, on average, 4 degrees cooler. The NH is reflecting more SWR to space, the SH is absorbing far more energy into the oceans then in July. If this were to persist would the oceans warming, where the residence time of energy is far longer, eventually overcome the atmosphere cooling due to the loss of energy entering the ocean and reflecting back to space?
@Jeff L says: December 29, 2011 at 6:31 am
IIRC, the increased air pressure in past eras shows up in larger insect sizes (they limit on oxygen transport through the joints as they must pump O^3 with mass increase but get only Area^2 increase in air flow with size). That’s why we could have 3 foot wingspan ‘dragonflies’ in the past, but not now. Also Megabat type Bats evolved during the Eocene IIRC too. Finally, there are those Pterodactyls that can not theoretically fly in the present atmosphere. IIRC they need about 2 x the present air density to have the aerodynamics vs muscle kinetics keep them in the air.
There are some other lines of reasoning that exist as well which all point to higher air pressures in the past. (Not the least of which is the volume of carbon in coal et. al. that WAS in the air before…)
Bottom line is that there is significant evidence for air pressure swings in the past, much of it to higher pressures (though at least once the 02 level plunged to near extinction for our proto-mammal ancestors… but a small rodent like critter survived, so you and I exist…)
… IIRC, the increased air pressure in past eras shows up in larger insect sizes (they limit on oxygen transport through the joints as they must pump O^3 with mass increase but get only Area^2 increase in air flow with size). That’s why we could have 3 foot wingspan ‘dragonflies’ in the past, but not now. Also Megabat type Bats evolved during the Eocene IIRC too. Finally, there are those Pterodactyls that can not theoretically fly in the present atmosphere. IIRC they need about 2 x the present air density to have the aerodynamics vs muscle kinetics keep them in the air. . . .
Now that is quite elegant. I’ve corresponded with an engineer and sci-fi author, sadly now deceased, who quite seriously argued that the planetary mass absolutely had to have changed, otherwise dinosaurs could not have walked around nor could the large pterodactyl’s have made it airborn.
Only last night I received a contribution from an experimentalist who has done the spectral analysis of ‘back radiation’, the concept by Aarhenius that underpins the CAGW scam.
It’s almost pure black body indicating it has little to do with GHGs. There is a contribution in clear skies but under clouds it is simply a measure of temperature.
The concept of trapped energy in a GHG blanket radiating energy spherically is pure, unadulterated bunkum.. Any professional scientist or process engineer knows you cannot use the S-B equation in this way for a single emitter. With no temperature gradient, that spherical radiation is exactly offset by incoming radiation from the inner surface of the circumscribing sphere. In a temperature gradient, net transfer of energy is down the temperature gradient.
This is the most spectacular failure of basic science in modern history. Aarhenius’ excuse was that the radiation laws, particularly Kirchhoff’s had only just been developed. There is no such excuse now those at whose untrained feet lies responsibility for this monumental cock up.
Not from what I’ve seen… Mostly just repeating AGW Talking Points and calling folks idiots (in various ways), and carping, near as I can tell. So while I encourage your efforts at improving the quality of the contributions, well, there’s this problem with teaching new tricks…
But while I’m on the subject:
John Wilkes Booth is just sooo wrong. To even start in an undergraduate program in biological sciences takes chemistry, and with it the Ideal Gas Law. Heck, I had it in high school as college prep. So a guy with a Ph.D in forestry is going to be up to his eyeballs in chem. Organic. Inorganic. Bio-chem up the wazoo. (Krebs cycle ring any bells? How about transpiration and the chemistry of CO2 absorption / respiration chem / redox happening reversibly day / night?)
The sheer mind-blindness to what it takes to understand chemistry and gas laws in learning how a forest works is just astounding.
I went to an Ag school and sat in on one lecture on soils chemistry. The physical and surface chemistry involved is, er, “not simple”. Dynamics of root dissolution of minerals in a complex mix of organic, inorganic, and biochemical stew is enough to make your head spin (and I’d already had the full series of chem, organic chem, and was starting bio-chem; oh and upper division genetics too).
So tell you what, JWB and similar “argument to authority” folks: Go sit in on some biochem classes, especially those involving stomata and gas transport with enzyme systems, then tell me that PV=nRT is not clear to those folks.
Pressure x Volume = amount-of-stuff x gas constant x Temperature.
As the ‘amount of stuff’ is pretty constant in the short term, and the constant is a constant, that pretty much puts Temperature dependent on Pressure and Volume. As in a 1 G field, pressure is directly proportional to G and ‘amount of stuff’, we’re pretty much left with V and T.
So look at the height of the air column for an isobaric point. During high solar activity, it went up. When the sun shut down the UV dramatically in 1998, it started dropping. T dropped with it. It really IS that simple, and that direct, and CO2 can do NOTHING to change that. At best it can crank the water cycle a trivial fraction of a percent faster and well below the error bars in what we measure.
Want to test these guys paper? Plot the orbit height that was calculated as “OK” over time based on where the drag was found to be high enough to matter. Plot it against sunspot cycles and solar UV output. Plot that against temperatures. I’m willing to bet dollars to doughnuts that it ends up being a 3 way match. V vs SolarHeat vs T. No way around it.
@JustAMom:
I’ve not finished all the comments yet, so maybe someone else gave you the simplified form. I did a posting of the intuitive form of this some time ago, but failed to take the time to work on through to this rather nicely done math exposition. Those very readable, but somewhat math deficient, postings are:
http://chiefio.wordpress.com/2010/12/02/does-convection-dominate/
http://chiefio.wordpress.com/2010/12/28/ignore-the-day-at-your-peril/
The “crib notes” version is pretty direct:
On the daylight side of the planet, heating happens only until convection picks up speed. A few hours later, massive quantities of heat are being dumped at the top of the air column. Water too. In the topics, you get huge storms from all that heat and water going well up in the air, to the base of the stratosphere. THAT is where the heat gets dumped. It just bypasses that whole IR argument with mass transport and heat of vaporization (and fusion for snow). At most a tiny percent increase in CO2 can cause a tiny percent increase in water cycling or height of the convection. The earth basically works like a giant heat pipe (and they can have thermal conductivity greater than solid metals).
http://chiefio.wordpress.com/2011/07/11/spherical-heat-pipe-earth/
Or, for a simple demonstration:
Put a pot of water on the stove. Turn the heat up until it boils. Now adjust the heat up / down. All that happens is the water boils out faster or slower. Put a lid on it (like massive greenhouse gasses) and all that happens is that the water still boils out as steam (escaping past the lid) but with more jiggling of the lid… (i.e. convection moving the CO2 around).
All that matters is heat in (sun) and mass transport (evaporation / convection). The temperature at which this happens will change with pressure, so at the top of a mountain the temperature will be lower, or at sea level higher, so changes in total air mass over time can shift the equilibrium temperature, but not much else…
@All the folks talking about loss of air to space:
One heck of a lot more of it went into ROCKS. Carbonates especially, but all those ‘banded iron deposits’ have bound O2 in them. Gasses react with metals and form solids. Iron Oxide. Calcium Carbonate. Magnesium Carbonate. Etc. (I hesitate to think of the amount of oxygen bound to the semi-metal silicon as silicates… or the Potassium and Aluminum bound oxygen in various mineral including all the feldspars…)
But for vulcanism doing recycle, we’d be hard vacuum now. Oh, and the nuclear decay driven recycle is going to end in a few hundred million years or so…. Either we get off this rock now, or life does not have time to re-evolve and try again…
Maybe it’s both GHG absorption and pressure. I found this paper: http://www.gps.caltech.edu/~jkirschvink/pdfs/Li_Pressure_Broadening_PNAS2009.pdf
They argue that higher pressure broadens the absorption lines of greenhouse gases, and that pressure may have been higher in earlier geological periods.
OT, but for those considering air density of the past and its effect on dinosaurs, David Esker’s site is a good read…
http://www.dinosaurtheory.com/
Is this a new paradigm and/or a unified theory of climate?
I do not think so.
That throughout the troposphere the temperature is a function of pressure is based on the gas law and the first law of thermodynamics. It is explained and calculated in any handbook on climatology that the pressure gradient (which originates from gravity) leads to a temperature lapse rate. By adiabatic expansion. With a specific surface temperature and pressure, the decrease of pressure cools the air at higher altitude. Not the reverse.
Forget about the ice ball metaphor. (See below) The essence of the scientific greenhouse theory is bases on the description of the radiation transfer process through the atmosphere with the Schwarzchild equation which is based on the law for absorption of Lambert-Beer and the law for emission of Planck. Each layer in the atmosphere with IR active molecules will emit upwards and downwards. The downwards radiation is what is named the back radiation. This phenomenon that a layer emits in two directions should not be denied and therewith also not the phenomenon of a radiation flux downwards to the surface. However, this does not ‘warm’ the surface, because the positive net flux to space is determined by the temperature difference between the surface and the effective temperature of the back radiating atmospheric layer.
The theory of the greenhouse effect, caused by the radiation transfer process, says that the effect is essentially that the temperature lapse rate moves over all altitudes to higher temperature, parallel to the one without radiation transfer processes, and also at the surface. This sounds logic at first sight. If one wants to disprove an effect of the radiation transfer processes, it is necessary to prove that the lapse rate does not move parallel. Here comes in the increase in convection and latent heat removal by evaporation if there is a potential rise of surface temperature expected. It does not sounds very logic to deny the existence of the radiation transfer processes as such, ruled by Lambert-Beer and Plank’s law.
Is the Nikolov&Zeller a ‘unified theory of climate’? No. It is a theoretical consideration of processes to occur in a single air column without taking in account the winds, ocean flows and the hydrological cycle in general.
Without an atmosphere, the globe would not be an ice ball. Because of the unequal insolation the temperature near the equator would reach 100 C. Because of the large coverage by oceans, a deep convection with evaporation occurs, and this limits the surface temperature of the tropic oceans to 29 C.. The surplus heat from the surface moves by the Hadley cells up to 18 km altitude. It is partly radiated out to space as IR, partly moved South and North with the winds, were the rest will be radiated out to space. The tropical winds and oceans flows keep the moderate and polar zones warmer, than the local insolation can produce. This is all classical climatology from the time before the CO2 obsession.
Modern measurements sustain the view that climate (temperature) at a global scale originates from the processes near the equator. The tropical ocean surface temperature shows an annual variance which may be as large as 1 C. Then it is observed that that global average temperature, calculated from all latitudes, follows this annual variation remarkably precise.
Then the radiation balance, which nowhere on earth is in an equilibrium state. In the tropical zone, between 40 south and north, it is negative, in the sense that more radiation is received from the Sun than radiated out as IR at the top of the atmosphere. In the moderate and polar zone the situation is the reverse: more IR is radiated out to space than radiation received from the Sun. (It looks here like a ‘negative’ greenhouse’ effect).
At latitudes 40 south and north, two global wind zones meet, warm winds from the tropics moving pole wards, and colder winds from the moderate zones to the tropical region. According to classical climatology, the (small) climate changes observed in historical times can be explained by changes in the borders of these meeting wind zones. Now it is also remarkable that at this latitudes also the global radiation balance changes from negative to positive. This leads to the suggestion that this change in local radiation balance is of major importance to rule the global climate, rather than the radiation transfer processes in a vertical air column in the troposphere. It seems to me that they who are obsessed by a CO2 effect, have forgotten about this (global) unified theory of climate.
You integrate the cosine of sun rays angle from 0 to 1…this only covers half a sphere…on the other half it goes from 1 to 0.
As a result, you integrate on half a sphere, and divide by surface of the whole sphere-> the result you get 154K should be doubled.
Am I wrong?