A simple argument is put forth against the idea that the radiative properties of an atmosphere somehow serve as the CAUSE of elevated steady-state planetary surface temps. Continue reading
I want to applaud Joseph Postma and his latest blog post, spelling out his grievances against the “Greenhouse Apologists” and how they consistently manage to worm their way out of ever providing a definitive, coherent clarification of how the hypothetical “Radiative Greenhouse Effect” (RGHE, rGHE) is actually meant to work physically, brushing all sceptical objections to their vague – as it seems, deliberately equivocal – contentions aside by simply claiming that our differences are purely of a semantic nature. It doesn’t matter to them whether we describe one and the same process as “reducing cooling” or “increasing warming/heating”, because the end result – a higher temperature – will allegedly be the same either way, ignoring the simple fact that, in reality, these are two fully distinct (as in ‘opposite’) thermodynamic processes: 1) INSULATION, 2) HEATING. And so, conflating them, as if they were somehow basically the same process, causes confusion.
Unnecessary confusion. Scientifically pointless confusion.
Postma puts it very neatly and succinctly: Continue reading
Be sure to read Part 1 first, now …
DEFINING THE rGHE THROUGH THE ERL.
How is the rGHE defined in the most basic way? If you have a planet with a massive atmosphere, the strength of its “greenhouse effect” is defined as the difference between its apparent planetary temperature in space and the physical mean global temperature of its actual, solid surface. The planet’s apparent temperature in space is derived simply from its average radiant flux to space, not from any real measured temperature. It is assumed that the planet is in relative radiative equilibrium with its sun, so is – over a certain cycle – radiating out the same total amount of energy as it absorbs.
If we apply this definition to Venus, we find that the strength of its rGHE is [737-232=] 505 K. Earth’s is [288-255=] 33 K.
The averaged planetary flux to space is conceptually seen as originating from a hypothetical blackbody “surface” or ‘radiating level’ somewhere inside the planetary system, tied specifically to a calculated emission temperature. This level can be viewed as the ‘average depth of upward radiation’ or the ‘apparent emitting surface’ of the planet as seen from space. Normally it is termed the ERL (‘effective radiating level’) or EEH (‘effective emission height’).
The idea behind the ERL is pretty straightforward, but does it accord with reality? The apparent planetary temperature of Venus in space is 231-232K, based on its average radiant flux, 163 W/m2. Likewise, Earth’s apparent planetary temperature in space is 255K, from its mean flux of 239 W/m2. In both of these cases, the planetary output is assumed to match its input (from the Sun), so one ‘simple’ method one could use to derive the apparent temperature of a planet is by taking the TSI (“solar constant”) at the planet’s (or moon’s) particular distance from the Sun, and multiply it with 1 – α, its estimated global (Bond) albedo, a number that’s always <1, finally dividing by 4 to cover the whole spherical surface. Determining the average global albedo is clearly the main challenge when going by this method. The most common value provided for Venus is 0.75, for Earth 0.296.
But does the resulting value really say anything about the actual planetary temperature? If the planet absorbs a mean radiant flux (net SW) below its ToA, then how this flux affects the overall system temperature very much depends on the system’s total bulk heat capacity. If it is large, the flux will have little effect, if it’s small, the flux will have a bigger effect.
We’re still discussing Willis Eschenbach’s ‘Steel Greenhouse’.
How come the warming EFFECT of putting the shell around the sphere is real but Eschenbach’s “back radiation” EXPLANATION of how it comes about is wrong?
Simply put, it’s because the effect doesn’t violate the 2nd Law of Thermodynamics, but the explanation does.
In Part 1 and Part 2 we established some fairly basic principles of thermodynamics that we can now put to use in analysing Eschenbach’s explanation of why and how the radiating central sphere needs to warm with the steel shell surrounding it:
“In order to maintain its thermal equilibrium, the whole system must still [after the steel shell is placed around the sphere] radiate 235 W/m2 out to space. To do this, the steel shell must warm until it is radiating at 235 watts per square metre. Of course, since a shell has an inside and an outside, it will also radiate 235 watts inward to the planet. The planet is now being heated by 235 W/m2 of energy from the interior, and 235 W/m2 from the shell. This will warm the planetary surface until it reaches a temperature of 470 watts per square metre. In vacuum conditions as described, this would be a perfect greenhouse, with no losses of any kind.”
The first part of this paragraph simply describes the necessary conditions for reaching a new dynamic equilibrium upon putting the steel shell up around the radiating sphere. Nothing mysterious about it at all.
But then (in the bolded part) Eschenbach starts ‘explaining’ how he sees this new state of dynamic equilibrium to be accomplished.
And this is where any connection to basic, ordinary physics – and hence, to the real world – appears to be lost.
Let’s parse what he’s saying: Continue reading
Happy New Year to everyone! Hope you all had a pleasant celebration.
I will unabashedly start off in 2015 with … another attempt at exposing the chasm that lies between what real physics tells us about the processes of nature (plus what we actually observe in the real world) on the one hand, and what the ‘physics’-like concoctions of the radiative GHE/AGW-establishment proclaim on the other.
The general public understanding (or should we rather call it ‘perception’?) of how the presence of an atmosphere would make the solar-heated planetary surface underneath warmer than if the atmosphere weren’t there, is so riddled with misconceptions and flawed ideas about how the world works, on such a fundamental level, that something needs to be done.
People simply need to understand that the official (and, I’m afraid, ‘authoritative’) rGHE/AGW ‘explanation’ is based altogether on self-invented nonsense physics.
The best way to let people realise this is to explain how things really work and to have this juxtaposed with the standard rGHE postulates advertised by ‘Climate ScienceTM’. Continue reading
‘Climate ScienceTM’ (represented and promoted by the IPCC) has so corrupted ordinary people’s way of thinking, that in order to demonstrate why there is no ‘atmospheric radiative greenhouse effect’ (rGHE), you have to start all the way from scratch. You have to step completely outside the framework of their concocted ‘mental model’ within which they shape their arguments.
‘Climate ScienceTM’ is afflicted with a dual case of monomania, two major fixations that they cannot and will not drop under any circumstances.
The first one is a complete linear trend line mania. They are unable to look at a data time series and not mentally project one onto it. The data – and especially the variation in it – basically doesn’t matter. Only the straight trend line plastered across it, from the one end to the other, does.
The second one, of direct relevance to this post, is their peculiar obsession with radiative flux intensities and their perceived direct correlation with the surface temperature of objects, expressed by the purely radiative Stefan-Boltzmann relationship. They clearly misinterpret and hence stretch the applicability of this law in the real world far beyond its actual justified range of operation, but absolutely refuse to recognise it. They worship (and use) it as sanctified truth.
Basically, they see the world in terms of radiation first and last. Everything in their world is in the end determined and controlled by thermal radiation. When it comes down to it, according to the warmists, you can simply scrape away everything else and just look at instantaneous radiative emission fluxes and directly know surface temperatures. As if we all lived in Max Planck’s conceptually pure radiative universe.
‘Climate ScienceTM’ thinks (or promotes the idea) that the temperature of any object – even real-world objects on Earth – is determined strictly by its radiative energy output (its emission flux), likewise that this final temperature is known and fixed even from the onset of heating, simply by the instantaneous intensity of its radiative energy input (the absorbed flux) minus convective loss (!).
In other words, if you only know the total (added) intensity of the instantaneous radiative energy flux input to the surface of an object and you are at the same time able to determine its energy loss through convection per unit of time, you will be able to tell its final temperature, no actual thermo-measurement required. Or, turn it around, if you know the temperature of an object, you instantly know the intensity of its radiative energy output, regardless of any simultaneous convective loss of energy.
(Well, you also need to know its surface emissivity/absorptivity, but according to ‘Climate ScienceTM’ most relevant real-world materials (like soil, rock, water, vegetation) possess emissivities close to unity anyway, and so can be approximated as (convecting) black bodies …!) Continue reading