The Emperor's New Clothes - "-19°C at a height of 5km"?

The Atmospheric Greenhouse Effect - Do you understand it?

The question might be expanded to ask "does anyone"? I ask it because it's taken me about 8 years to get my head around all (or at least most of) the subtleties of detail, and while I've been doing that, my realisation has grown that many, including scientists, technical authors, and well-respected bloggers, do not understand some of the basics, or at least give that impression in what they say and write. Even the authors of IPCC AR3 seem somewhat confused. Pure arrogance on my part you might think, but hear me out before you write me off or label me in some way I'd rather not know.

There's one concept expressed in many descriptions of the greenhouse theory; pet theories, objections and rebuttals are based on it, calculations of parameters are formulated using it. The concept is formed using mere words, but some people's minds have been so seduced by those words that they believe, are convinced even, that the concept in some way reflects physical reality. It does not; it's a chimera, the "Emperor's New Clothes".

The concept is this: the "effective emission temperature" of the combined Earth/atmosphere system. It leads to a major misunderstanding in the claimed magnitude of the greenhouse effect (GHE), that the Earth is some 33°C warmer as a result of the effect of greenhouse gases in the atmosphere. To understand how the misunderstanding arose, it's worth quoting IPCC AR3 WG1, 1.2 Natural Climate Variations 1.2.1 Natural Forcing of the Climate System

For a stable climate, a balance is required between incoming solar radiation and the outgoing radiation emitted by the climate system. Therefore the climate system itself must radiate on average 235 W/m² back into space. Details of this energy balance can be seen in Figure 1.2, which shows on the left hand side what happens with the incoming solar radiation, and on the right hand side how the atmosphere emits the outgoing infrared radiation. Any physical object radiates energy of an amount and at wavelengths typical for the temperature of the object: at higher temperatures more energy is radiated at shorter wavelengths. For the Earth to radiate 235 W/m², it should radiate at an effective emission temperature of -19°C with typical wavelengths in the infrared part of the spectrum. This is 33°C lower than the average temperature of 14°C at the Earth's surface. To understand why this is so, one must take into account the radiative properties of the atmosphere in the infrared part of the spectrum. Of the incoming solar radiation, 49% (168 W/m²) is absorbed by the surface. That heat is returned to the atmosphere as sensible heat, as evapotranspiration (latent heat) and as thermal infrared radiation. Most of this radiation is absorbed by the atmosphere, which in turn emits radiation both up and down. The radiation lost to space comes from cloud tops and atmospheric regions much colder than the surface. This causes a greenhouse effect. Source: Kiehl and Trenberth, 1997: Earth's Annual Global Mean Energy Budget, Bull. Am. Met. Soc. 78, 197-208.

Figure 1.2: The Earth's annual and global mean energy balance.

The key sentence is this

For the Earth to radiate 235 W/m², it should radiate at an effective emission temperature of -19°C with typical wavelengths in the infrared part of the spectrum. This is 33°C lower than the average temperature of 14°C at the Earth's surface.

... and the key word is effective, because the radiation to space is not emitted at an emission temperature of -19°C. Longwave IR radiation to space comes from three sources; from the "cloud tops and atmospheric regions" mentioned above (which are at different temperatures), and also the surface (implied but not explicit in the excerpt), which is at a very different temperature. There are thus three sources, all at different temperatures, radiating different amounts. For the quoted 235 W/m² outgoing flux to be input to the Stefan-Boltzmann equation to derive an emission temperature, it would have to be emitted by a single source, and would have to conform to the envelope of a Planck curve. It is not, and it does not. The "effective emission temperature" has no basis in reality, neither has anything based on it.

Here's a satellite view of longwave IR emitted to space over the western tropical Pacific. The surface at around 22°C or so is a little warmer than the 14 or 15°C (287 or 288°K) taken to be the global average surface temperature, but it illustrates the point well. The dashed lines represent Planck curves for their labelled temperatures in degrees Kelvin. The portion between 25µm and 17µm is emission from water vapour, from 17µm to just over 13µm from carbon dioxide, 13µm to 8µm from the surface (with a "bite" from ozone centred on 9-10µm), and the rest to the right from water vapour. The tiny downward spike over wavenumber 1300 represents methane. Note where a 254°K (-19°C) Planck curve would lie, just below the marked 260°K curve.

From G.W.Petty "A First Course in Atmospheric Radiation"

Worse, many (including IPCC authors) assume that 235 W/m² is what the Earth would radiate in the absence of either greenhouse gases (GHGs) or the entire atmosphere, and conclude that the resulting temperature would be the -19°C "effective emission temperature" (or -18°C calculated by some). That assumption and conclusion are not valid. If radiation to space is from three sources; GHGs, cloud tops, and surface, then removing two of those sources from the system leaves just one, the surface. It's an unjustified leap of logic to assume that the remaining source, on its own, would radiate what all three together did.

In the absence of an atmosphere there'd be no clouds to reflect incoming solar radiation, no water vapour to absorb much of the solar short-wave infrared, no ozone to absorb ultra-violet. All incident solar radiation (342 W/m² in Figure 1) would reach the surface. If we assume for this thought experiment that the surface would be as it is now (ocean/desert/rock/vegetation/ice), then some of it would be reflected, in the same proportion as shown in the diagram, that is 30/198 x 342 = 52 W/m², leaving 290 W/m² to be absorbed, and therefore to be emitted as radiation to restore the radiative balance. Using the Stefan-Boltzmann Law to calculate the emission temperature, assuming perfect emissivity and that the temperature of space is 2.7°K, results in a surface temperature of -5.5°C, not the -18°C or -19°C almost universally quoted.

Working out what the resulting surface temperature would be if the green house effect were simply "turned off", that is all elements of Earth and atmosphere are present, but GHGs wouldn't absorb or radiate longwave IR, is rather more complicated, and best left for another post, as is a critique of the Kiehl and Trenberth "energy budget" diagram shown in Figure 1.

The 5km mentioned in the title is derived from the adiabatic lapse rate (rate of cooling with height) using the fictional --19°C "effective emission temperature", so it too is a fiction, a fiction created entirely by IPCC authors in AR3 WG1 chapter 1.2:

The natural greenhouse effect

The atmosphere contains several trace gases which absorb and emit infrared radiation. These so-called greenhouse gases absorb infrared radiation, emitted by the Earth's surface, the atmosphere and clouds, except in a transparent part of the spectrum called the "atmospheric window", as shown in Figure 1.2. They emit in turn infrared radiation in all directions including downward to the Earth's surface. Thus greenhouse gases trap heat within the atmosphere. This mechanism is called the natural greenhouse effect. The net result is an upward transfer of infrared radiation from warmer levels near the Earth's surface to colder levels at higher altitudes. The infrared radiation is effectively radiated back into space from an altitude with a temperature of, on average, -19°C, in balance with the incoming radiation, whereas the Earth's surface is kept at a much higher temperature of on average 14°C. This effective emission temperature of -19°C corresponds in mid-latitudes with a height of approximately 5 km. Note that it is essential for the greenhouse effect that the temperature of the lower atmosphere is not constant (isothermal) but decreases with height. The natural greenhouse effect is part of the energy balance of the Earth, as can be seen schematically in Figure 1.2.

A fiction built upon a fiction, the "Emperor's New Clothes" are the wrong colour, and the wrong length. Don't get caught admiring them.

A game of Consequences; A question of scale (4)

Consequences, schmonsequences, all is consequences. We've been told, indeed we've had it proved to us by climate models (pause for snigger) that it's the atmosphere which drives climate. While I'm prepared, like the White Queen in Alice in Wonderland, to "believe as many as six impossible things before breakfast", it's now well after breakfast, and that notion is an impossible thing to believe. The atmosphere is a major component of climate; the atmosphere transports heat and fresh water around the globe, dumping them where they're needed, and sometimes where they're not wanted, or at least in quantities that aren't wanted, or not wanted just now.

Blaming changes in the atmosphere for causing changes in the atmosphere is a circular argument, and leads nowhere but back to square one, and delusion, and vast expenditure on research that's leading nowhere, and vast costs to cure a non-existent problem, or at least a problem that can't be solved by mankind. I'm of the opinion that everything that happens in the atmosphere is climate. Clouds are climate, rain is climate, temperature is climate, high and low pressure systems and the consequent winds and storms are climate, and the greenhouse effect is climate.

Many climate scientists, and meteorologists, and glaciologists, and marine biologists, appear to me to be particularly myopic. Every day, or at least every week, we see the results of another "study" published; studies which usually set out to "prove" something or other, and which therefore have an agenda up front. It's all too often that agenda (usually driven by funding sources) which dictates the conclusions drawn. If the conclusions are a bit thin, because the data is a bit thin, or murky, or both, then often models are used, and the output from those models is hailed as "evidence". In all such cases, the results are published with many caveats; X  "could", "may" "might" cause Y. In some cases, even with caveats included, the scientists "spin" the results by applying a liberal dose of their own beliefs and prejudices, either in their published conclusions, or in press releases, or both. That's not science, it's advocacy, and it's dangerous advocacy.

I introduced this topic because it's central to how the role of the atmosphere is perceived; warmer air, and/or long-wave radiation from that warmer air is said to be warming the ocean. Poppycock say I - it's the ocean (and to a lesser extend the land) which gave the atmosphere that temperature in the first place. Heat is transported into the atmosphere by conduction and convection, by evaporation, and by long-wave infrared radiation, a small proportion of the latter being absorbed by greenhouse gases, the most important of which is water vapour, which the ocean (and to a lesser extend the land) put there in the first place, complete with the additional heat energy that water vapour molecules have compared to water molecules in liquid water and ice.

it's not necessary to be a climate scientist, or a physicist to understand these basic principles. it's only necessary to have a basic grasp of the relative sizes of all these factors to have a grasp on the fundamentals of climate. I said earlier that only a small proportion of the infrared radiation emitted by land and water is absorbed by greenhouse gases, the rest escapes to space, and the emitted radiation is just a part of the heat lost by the Earth's surface. Only about half of the radiation absorbed by greenhouse gases is re-emitted back down towards the surface, and not all of that is absorbed by the surface; some is reflected. The overall picture is of a great deal of heat being lost by the surface, much of that escaping to space, and a small proportion of the emitted heat finding its way back to the surface. That small proportion is what the hullabaloo is all about. That's why I introduced the topic of myopic scientists.

Given that the proportion getting back to the surface is relatively small, and that the effect of CO2 as a greenhouse gas is small in relation to its bigger brother (sister, sibling, mustn't appear sexist) water vapour, and given that human-generated  CO2 emissions are tiny compared with those emitted by plants, animals, and yet again the ocean, it's not surprising that many wonder what the fuss is all about. It is surprising that many climate and other scientists haven't yet grasped this question of scale at all. I read recently that some scientists were surprised to discover that it wasn't slightly warmer air which melted sea-ice, but slightly warmer water. Not surprising to me, as I and more enlightened and informed others know full well that air, even moist air, has a heat capacity hundreds of times less than the same volume of water; even less if it's sea-water. See A Question of Scale (2).

Marine biologists examine a tiny part of the Great Barrier Reef, see what they interpret as problems, extrapolate that to the entire reef and declare it doomed. I don't believe it. Glaciologists examine the snouts (lower ends) of a few glaciers, see that they're melting, measure the rate of retreat of the snouts, and ignoring those rates and whether the glaciers may be accumulating mass at a greater rate far above in the mountains, declare that they'll all have melted by Christmas. I exaggerate, of course (sauce for the goose, etc.), it was Christmas 2035.

There are only about 300 glaciers studied in detail out of a conservative estimate of 160,000 worldwide. It's that question of scale again. Scale also crops up in relation to individual glaciers. A paper breathlessly announces an "alarming rate of retreat of the Gangotri glacier" of 22.5 metres/year, and mentions the totally misleading "fact" of how many people in Asia "depend on its meltwater" (it's a perpetuated myth), They don't do the simple arithmetic and disclose that even if their "alarming rate" doubled or tripled, the 35 km glacier would still be there in a thousand years. They don't mention that temperature drops with height, so any retreat will slow down in time. They don't study the accumulation zone at the top of the glacier which dictates what the thickness of ice will be at the snout in 2000-or-so years time; it's too cold up there and it would take time to do, and would likely utterly destroy their blinkered conclusions in any case. They're seemingly unaware that the ice they're studying was formed 2000 years ago, and it's the mass and thickness of that ice which largely dictates what's happening at the snout today. Remember, air has little heat capacity, and it's more likely that less cloud/more sun is the a factor (rarely mentioned in the literature). Perhaps the cooking stoves of gaggles of glaciologists is causing what they've come to measure! See a Cool Look at Glaciers

By now you may have grasped why I'm a sceptic. I'm anti-alarmist, not anti-warmist. The warmists can believe what they like - in my opinion they're looking through binoculars. Do just that, lower them and see how much of the scene before you is captured in their field of view. They and the sub-class of scientists I've discussed here are myopic, and the only correction is scepticism and an understanding of scale, and a sense of proportion.

Zen and the Second Law of Thermodynamics (2)

In Zen and the Second Law of Thermodynamics I dismissed the claim that the atmospheric "greenhouse effect" violates the second law of thermodynamics, invoking the correct (in my view, and most others) interpretation of the Stefan-Boltzmann equation. Here I will demonstrate that there is an overriding reason that the law cannot be violated in the mechanism of the "greenhouse effect", which is that it doesn't apply to radiative transfer of heat from greenhouse gases in the atmosphere to the Earth's surface.

Before I get into specifics of the mechanism, I should say that it appears to me that it's not only some sceptics who misunderstand it, but some atmospheric scientists too. That misunderstanding has led to the postulation of the so-called tropospheric "hot spot", which has proved so elusive, and thus an embarrassment to the scientists, and free ammunition for critics of the hypothesis. I should also say that this article in no way supports the hypothesis (it's not a theory in the strict sense) of catastrophic anthropogenic global warming (CAGW). It does support the general theory of the "greenhouse effect", its fundamentals can be tested, and effects measured.

First, some seeming irrelevancies which are important to understand. I'm going to describe how a fluorescent lamp works, in order to shed some light on the subject (I know it's a horrible pun, but I can't resist 'em). Before you switch off (there I go again), bear with me - it's important.

In an incandescent lamp, the filament is heated to the point where it emits near-white light, at a temperature of about 4000°C. A fluorescent lamp or tube works by electrically heated filaments exciting mercury vapour atoms, which then emit ultra-violet light. The light is absorbed by suitable phosphors (chemical compounds coating the inside of the glass tube) which re-emit visible white (or near-white) light. Neither the mercury vapour, nor the surrounding phosphors are at a high temperature, in fact neither are hot enough to cause a burn or even discomfort. The heating of the glass tube is almost entirely due to the hot filaments, and where the tubes are long, the centre part never feels more than just warm to the touch. The point is that it's impossible to deduce the temperature of a source simply by measuring its radiation spectrum. In the case of the incandescent lamp, the calculation would be correct; in the case of the fluorescent lamp, totally wrong.

Why is this important when considering the "greenhouse effect"? Because the absorption and emission of long-wave infra-red radiation by greenhouse gases is very much like the absorption and emission of light by the fluorescent phosphor, and the emission is not like that of a hot filament. All gases absorb and emit radiation to some degree (whatever you may read). Nitrogen comprises about 78% of the atmosphere, and absorbs/emits very weakly in the infra-red, about 5000 times less than CO2, molecule-for-molecule, but, and it's a very big but, there's about 2,000 times as much of it in the atmosphere, so why is is ignored? Oxygen absorbs/emits more strongly, and is included with ozone (O3) in the relevant IPCC diagram, a fact unknown to many.

The strongest absorbers/emitters are the multi-atomic molecules, in descending order, water vapour, methane, and CO2. I can't place ozone in the list because all references I've seen lump it in with oxygen. I'd guess it's between water vapour and methane, but of course it's a very minor component of the atmosphere. These molecules absorb long-wave infra-red photons and store the energy in their internal molecular bonds, in the form of twisting or flexing. The external, or kinetic energy of the molecule, and therefore the temperature of the gas is unchanged. When the energy is released a very short time later, the resulting photon is of the same energy and frequency as that absorbed. There is therefore no change in gas temperature during the entire process. This is therefore not a thermodynamic process, and so the Second Law doesn't apply. There is however, a finite chance that the internal energy can be transferred to another gas molecule in a collision; in that case, there is a temperature increase, though this isn't a major part of the process.

The surface emission and subsequent absorption/emission by GHGs is a "pumped" process; when the pumping stops, the process stops. The Sun is the pump input of course; it heats the surface (the atmosphere a little), the surface warms, radiates to the atmosphere, the GHGs absorb and re-radiate a portion of that, maintaining the surface temperature. Simple evidence for this is the change in temperature of the surface and atmosphere from just before sunset onwards. When the sun is high, the surface is much warmer than the atmosphere. As sunset approaches, the surface cools rapidly, and radiation from the atmosphere drops even more rapidly. Within a few hours, the surface is much cooler than the air above. In colder weather, ground frosts predominate, demonstrating the temperature inversion. Radiation and temperature measurements prove the case.

In my view, the postulated tropospheric "hot spot" is a chimera; the upper troposphere doesn't have to warm up very much as a result of the "greenhouse effect", unless there's a much higher proportion of energy transfers via collision rather than absorption/emission. I'd suggest its absence proves nothing, and that its claimed existence might indicate a misunderstanding by climatologists who proposed it. Of course, I might be wrong, something they fail to admit, claiming that it's not the hypothesis that's shaky, but the data; decades of radio-sonde measurements to a precision at least one-tenth of the size of the claimed "hot-spot" temperature increase fail to show anything remotely like it.

The Stefan-Boltzmann equation can't be used to calculate the radiation from the temperature of greenhouse gases, nor deduce their temperature from radiation measurements, because they emit in specific bands, and not over an entire Planck curve, which is necessary for the relationship to be applied. The Earth is ascribed an "effective emission temperature", calculated using the measured radiation to space, and the Stefan-Boltzmann equation. It's called "effective" because it's notional only. Neither the surface, nor the greenhouse gases which radiate, are at anything approaching that temperature. Attempts to deduce anything from that notional temperature are simply invalid. Stefan-Boltzmann is a two-body equation, right enough, but each body is a single source of radiation, radiating towards the other. The Earth/atmosphere combination is not a "single body" radiating to space.

The claim invoking the Second Law of Thermodynamics is that heat flow must be from hotter to colder, and that "a cool body cannot hear a warmer body". In my previous post I showed that the first is inevitably true, that the warmer Earth heats the cooler atmosphere, and that the second is wilful misunderstanding of the process; radiation from the cooler atmosphere merely slows the rate of transfer from the surface. I've shown here that the Second Law can't even be justifiably invoked at all.

Disconnects in Logic (4) - We don't do Physics

Ever come across the "space mirror"? If not (where were you, on Mars?), let me provide a little illumination. The mirror concept comes in several flavours, from the sublime to the ridiculous single large "sunshade" to trillions (I kid you not) of small sunshades, between the Earth and the life-giving deadly solar rays from our Sun. The intention is to reflect or filter or diffract a portion of the incoming insolation to offset "global warming" caused by life-giving deadly CO2 and other "pollutants" in Earth's atmosphere. Before I continue, I suggest you put down any drink, fragile artefact or large heavy object you might be holding, and swallow anything in your mouth - gum, toothbrushes, pens, thumbs and similar objects excepted - these should be removed. I fear for your safety, dear reader, should you laugh, chortle, guffaw or splutter while reading on.

One of the earliest ideas was for sunshades in orbit around Gaia, a simple and relatively inexpensive concept, one which could be phased over decades, and involve all those countries capable of putting such objects in orbit. International co-operation involving spending large sums is so easy to organise, as we all know. This would cost tens of billions of dollars per year over the coming decades. If you were paying attention, you might have noticed that I referred to this as "relatively inexpensive", which should give you a clue as to the cost of the other schemes. A major disadvantage is of course that roughly half of the orbiting parasols would be on the shady side of Earth at any given time, performing no useful function, and also spoiling things for astronomers beneath. Somewhat disconcertingly (and rather alarmingly) none of the articles I've read mention this problem. Logic disconnect number 1.

Because of the 50% redundancy and consequent additional cost involved, those engineers and scientists who had a well-thumbed copy of "101 things you didn't know about the Solar System" came up with a cunning wheeze to exploit something called a "Lagrange Point". Any object orbiting between the Earth and Sun would have a shorter orbit and greater speed, so would rapidly move away from the Earth, re-visiting in less than a year, if orbiting in contra-rotation (going the other way round) relative to Earth. Johannes Kepler (God rest his soul) discovered this and published his law  in 1619. If the orbiting object is not-too-far from Earth, gravity pulls it back a little, and if the distance is "just right" reduces the orbital speed to keep it stationary relative to the Earth.

Lagrange Points - Source: Montana State University, Department of Physics

L1 is the obviously useful one, the others being most useful if you want to remain a long way from your mother-in-law, though L3 is best to hide from the forces of loranorder. One concept is for a single, large (obviously) "wire mesh" disc at L1, to deflect 1% of the incoming sunlight. Lowell Wood and others have calculated that a screen made of one-millionth of an inch diameter aluminium wire forming a mesh of 1 thousandth spacing would act as a diffraction grating, and "bend" infra-red light away from Earth.

The flies in the ointment are that it must have an area of 1,600,000 sq. km (more than twice the area of Texas) with a diameter of 1427 km, and even with the too-thin-to see wire, with an estimated average mass of 1 gram/sq. metre including "ribs", weigh 1.6 million tons (I'll use the imperial ton,  tonnes are much the same). It's been estimated that using US launch vehicles, the cost of putting anything into Earth orbit is currently $44,000 per kilogram, or $440,000 per ton, and that doesn't include the cost of boosting mirror (parasol or sunshade) parts to the Lagrange point 1.5 m km. further out. Using the space shuttle would cost $175,000 per kilo just to Earth orbit. The mirror would weigh some 1,600,000,000 kilos. Assume the deployment costs reduce tenfold over time and do the sums yourself - I don't think my calculator display is big enough.

Don't employ these guys as fly-swatters because they've missed a few already, as I will show. First, all the diagrams I've seen show the parasol at 90° to the Sun-Earth axis, and the designers and most proponents seem to think it'll stay that way. I have news for them - without giving it a "twist" of one rotation per annum, the parasol would be parallel to the axis in 3 months, having no effect whatever. How it's possible to impart a rotation of exactly 360° per annum to a thinner-than a hair parasol 1427 km across I don't know. Someone suggested a steerable "hub", but hasn't heard of inertia. The parasol might have zero weight but it would have a mass of 1.6 million tons, and it would take some hefty steering jets to shift it. The "ribs" would have to be stiff enough not to flex unduly, adding considerably to the total weight to be lofted from Earth, perhaps doubling it. Brilliant idea, shame about the (lack of) physics. That faint sound is Newton turning in his grave.

There's more (of course there's more!) - the Lagrange points move. The system is not just Sun-Earth, but Sun-Earth-Moon. Objects in space orbit around their centre of mass, not their geometric centres. The centre of mass Sun-Earth is relatively very close to the centre of the sun, but the centre of mass of Earth-Moon (barycentre) is inside the Earth about 1,700 km. below the surface The Earth wobbles slightly therefore, changing the Sun-Earth distance, and also the Moon is either closer to, or further from the Lagrange point as the lunar month progresses. The important L1 and irrelevant L2 are most affected, oscillating by several km a month. In addition, the Earth's orbit ain't a circle but an ellipse, moving closer to, then further away from the parasol, compounding the problem. Our parasol now needs to be moved this way and that constantly to stay close to the elusive Lagrange point L1 and avoid us having to wave goodbye to it, and the trillions of dollars spent getting it up there. Then there's all the inevitable millions of tons of space junk orbiting the Earth at various distances, and the effect of all the CO2 and other gasses emitted during the construction of the parasol, the rockets or shuttles, their fuel, and the burning of that fuel in the atmosphere, none of the aforementioned even hinted at by the rose-tinted spectacle brigade. Unintended consequences, anyone?

The other scheme by astronomer Roger Angel involves 16,000,000,000,000 (16 trillion) pierced transparent 0.6 sq. metre 1-gram discs, forming a cylindrical cloud some 60,000 miles long orbiting in what he calls "L1 orbit". I see several difficulties, quite apart from the obvious, which you should be able to identify for yourselves. First, there's strictly no such thing as "L1 orbit", and even if there was, a 60,000-mile long cylinder oriented towards Earth would leave most of his "flyers" away from that orbit, meaning they'd drift Sunwards or Earthwards, speeding up or slowing down in orbit, and so spreading in all directions. At least he though of the effect of "radiation pressure" which would push the discs earthwards, and introduced a compensating mechanism. The "big parasol" team overlooked this, and also the Solar Wind of atomic particles, which Roger Angel seems to have ignored. Secondly he (Angel) says a 2% reduction in insolation over the entire surface would be "enough to balance the heating of a doubling of atmospheric carbon dioxide in Earth's atmosphere". A reduction of 2% averaged over the surface is around 7 W/m², or twice the IPCC AR4 estimate for a doubling of CO2. That 7 W/m² would be, from what I've absorbed from several years of surfing the net and absorbing concepts of radiative forcing like a solar parasol absorbs sunlight, enough to take the Earth into the next ice-age. Oops. Strong on ideas, short on physics and celestial mechanics, and should read more.

Here's my own "Cool It" plan

I reckon it'd be easier and cheaper just to deposit all that dosh in orbit. A dollar bill has an area of 103.4 sq. cm., and weighs a bit less than a gram, so a trillion of them would cover roughly 10,000,000,000 sq.metres or 10,000 sq. km. and weigh a million tons. Assuming each is oriented at 45° to the Sun on average, the effective area would be around 7071 sq. km. They wouldn't need complicated and expensive rockets, but could be blasted there in "super guns" - quite technically feasible (I know my history). The other advantage is that it doesn't actually cost 1$ to print a 1$ bill. Banknotes are paper and ink, and in some cases include a thin thread of metal (about as thin as the thread of logic in the other schemes). Banks wouldn't have to actually issue the notes as currency.

Each country could contribute a special "Cool It" note, with a picture of the incumbent political leader imprinted thereon. Just think - The US would have "Drill, baby, drill!" Obama waving his birth certificate, the UK would have "The NHS is safe with me" Cameron, Australia could have "No carbon tax" Gillard with a long nose, and Russia would have "It's me again!" Putin. I'm certain both democrats and republicans (though maybe not in equal numbers) would like to see Obama blasted into orbit, and citizens of other countries would be happy to contribute to see their beloved leaders actually doing something useful for a change. A side-advantage is that as the notes drift out of orbit they'd never fall fast enough to burn up, would float to the surface, and still be reflecting sunlight, increasing the albedo. Polar explorers would never run short of toilet paper... the list just goes on. Just think of all the thousands of "green-back" jobs Obama could point to as the election draws nigh. The Pentagon would be allocated funds to develop a "super gun" for the army, and the other services would be green with envy.

There's a Nobel Prize, or at least "Climate Crusader of the Year" in this for me, I'm sure. I may even get my handsome visage (He lies - Ed.) on a special edition banknote and join the political elite in orbit. I've changed my mind - geo-engineering is FUN!

Education or Muddled Disinformation and Propoganda?

From Cardiff University, where I spent some time in the 1960s:

A new bilingual educational resource developed by academics from the School of Earth and Ocean Sciences to help Welsh secondary schools deliver stimulating lessons about climate change has been launched by the Chair of Climate Change Commission for Wales.

The "pack" entitled Adapting to Climate Change in Wales is intended both for teachers, and for children at "key stage 4", that is between the ages of 14 and 16. The CU "Learning about climate change" news page continues

The Climate Change Educational Resource Pack for Key Stage 4 explains the scientific basis of climate change and explores how changes in climate could impact citizens of Wales. In particular it looks at how citizens could adapt to living in a different climate.

Aimed at pupils and teachers, the multidisciplinary pack is tailored to meet the requirements of the Welsh national curriculum. It will be distributed to at least 100 secondary schools in Wales to help teachers deliver high quality, balanced information and inspire young people to adapt their behaviour to ensure their future sustainability. Although the focus is on Wales, this packs draws on examples from all over the world and covers everyday issues such as how food supply, settlement, transport and health may be affected.

In the second paragraph, note "high quality, balanced information". How does the "pack" meet that description? Not too well, it seems. Right at the beginning of "Theme 1: The Global Climate Perspective" we find

Key learning outcomes

1. To understand key components of the greenhouse effect

2. To understand the influence of humans on climate

3. To understand predicted global climate changes

... and on the following page (page 7) is this, relating to item 1 of the "Key learning outcomes"

Principle of the “Greenhouse Effect”

The sun shines down on the surface of the earth. About half the heat naturally reflects back out into space. When greenhouse gases such as carbon dioxide and methane are released into our atmosphere, they trap heat and stop it reflecting back out into space. This causes additional warming of the earth surface, ocean and atmosphere… just like a greenhouse!

That would seem to encompass and explain precisely none of the "key components of the greenhouse effect", in my opinion. A greenhouse doesn't trap reflected heat. The glass transmits incoming solar radiation and traps the warmed air. Greenhouse gases don't trap reflected heat. The phrasing implies that they do that only when "released into our atmosphere" and not otherwise. It isn't difficult to briefly describe the essential components of the "greenhouse effect" for all 14-16 year-olds in a similarly short paragraph, though since this is intended as the scientific basis for the entire "pack", surely it deserves a longer (and accurate) description?

Slaying Your Own Argument

In a post entitled "CO2 as a radiation valve contravenes the laws of thermodynamics" our old friend and "Dragon Slayer" Alan Siddons analogises the atmosphere as a "radiation" valve. He imagines such a valve letting in solar radiation, but preventing any escaping to space. Of course, in such a system, the Earth's surface would continue to heat up because there's no exit for the heat generated in the surface. He claims that this disproves the "greenhouse effect" because "back-radiation" from the "valve" (the atmosphere) is somehow magnified and therefore causes a "runaway" heating cascade. But with no path for the heat to escape, such an effect is inevitable anyway, "greenhouse effect" or not. It's nosensical, of course, and proves nothing.

The second part of the post describes a "valve" which actually lets some radiation to escape, so is worth examining. However, in summary this is another example of a poorly labelled diagram, which in this case seems to have confused the author himself;

I urge you to notice that the valve's efficiency doesn't actually matter, either, because physical laws are violated even in a modest case. In some sense, in fact, the crimes get worse. For instance, let's install a 20% valve, so that 80% of the infrared escapes and 20% back-radiates. 

In this case, 0.8 exits while 0.2 is "retained" by the surface. But 0.2 also radiates back to the surface, so it gains 0.4 in total (again, as a minimum: further back-radiation effects must arbitrarily be halted). In other words, even when the oft-mentioned "net flow" favors the outward movement of thermal energy (a modeling effort to satisfy the Second Law), the alleged heating effect still contradicts the First Law because you're getting more energy than you put in. Any furnace manufacturer would eagerly exploit such a loophole in the law if it existed. 

"In this case, 0.8 exits while 0.2 is 'retained' by the surface" - yet the upward red arrow at the top reads 0.8, meaning that the red arrow below it must represent 1 unit in order for the "valve" to have absorbed 0.2 units. Not a good start, since if the surface "retains" 0.2 it can only radiate 0.8 with a corresponding 0.64 exiting the "valve". The 0.8 shown escaping plus the 0.2 "retained " by the surface plus the 0.2 absorbed by the valve add up to 1.2 and not 1. Earlier in his post he said "You can't obtain more energy than you put in", yet he's just done it! Apart from this fundamental error, if the surface retains a net anything the system can never reach equilibrium - it has built-in positive feedback from the word go. He says earlier "for every unit of sunlight going in", so if for every unit going in 0.2 is "retained" the surface will continue to heat up, and thus far in the process the the "valve" has played no part in any "feedback". So the diagram doesn't actually represent what the description says it does. In reality the surface never does actually radiate 1 unit, as implied in the diagram, unless the"valve" is initially set to allow all radiation through, and then activated. All that's needed (once again, as in "A Simpe Solution") is to consider the energy actually lost from the system to get a properly thought-out analogy or "model".

At equilibrium, 1 unit escapes through the valve, which means that the surface is radiating 1/0.8 = 1.25, and the "valve" is absorbing and re-radiating 0.25 downwards. But where does that "extra" energy come from? It comes of course from energy absorbed during the equilibrium process. initially the surface acquires 1 unit, absorbs that energy and heats up until it radiates 1 unit. The "valve" absorbs 0.2 of that, and it heats up until it radiates the same down. The process continues with diminishing increments - the 0.2 is absorbed by the surface, increasing its heat content until it radiates 1.2 units, with 0.96 escaping and a total of 0.24 absorbed by the "valve" and so on. Of course, the process doesn't actually have discrete steps - it's smooth and continuous. The heat content of surface and valve increase until radiation in and out of the system balances and equilibrium is obtained. No physical laws are violated, and "furnace maufacturers" are well aware that it takes time for their products to heat up to operating temperature when turned on.

There's the nub of the matter - the "Slayer's" misunderstanding of the difference between heat flow amd heat content. The surface of the Earth and the atmosphere don't radiate because they are absorbing radiation, they radiate because they contain heat. Radiation from the sun merely tops up the heat content. At night there is no radiation from the sun, yet of course the Earth/atmosphere system cotinues to radiate heat to space, slowly cooling. It's surely a simple concept to grasp, yet it appears to elude some.

Clutching at Straws, or "Scraping the Barrel"

I used to like the Hockey Schtick, often first with news of new scientific papers or articles on global warming, until the blog became a mouthpiece for the Dragon Slayers with their distortions and pseudo-science. A recent post there claims that a climate scientist  "inadvertently explains why greenhouse theory is wrong". The post links to a video of Professor David Archer of the University of Chicago giving a lecture to non-science majors on modelling the "greenhouse effect":

In lecture 5, The Greenhouse Effect, Archer uses the Stefan-Boltzmann equation to calculate the supposed temperatures of Venus, Earth, and Mars with and without a greenhouse effect. Archer's calculations show the greenhouse effect on Venus is wildly underestimated by 415C and wildly overestimated on both Earth (by 23C) and on Mars (by 19C) in comparison to actual observed temperatures. This is despite the fact that CO2 levels are very high and virtually the same on Venus and Mars (around 96%) and only trace (0.039%) on Earth. Archer says in the lecture that one would have to assume the Venus atmosphere behaves like multiple panes of glass in order to obtain an answer near the observed temperature, yet on both Earth and Mars one would have to assume the atmospheres behave like much less than one pane of glass. 

What is not said is that in the lecture, Archer develops a very simple atmospheric model, using a "pane of glass" to represent a totally absorbing atmosphere, and at the end shows that its results are wrong for all three planets. So this post is claiming that a very simple "one-layer" atmospheric model, which as Archer explains is being used as a step towards a more accurate "multi-layer" model, and which produces the wrong results somehow disproves the "greenhouse effect"! Give me a break! Incidentally, what's "much less than one pane of glass", which it's implied Archer has said (he does not)? The post continues:

H/T Professor Claes Johnson, who explains why Archer also uses the Stefan-Boltzmann equation incorrectly (and here)

The first link which purportedly "explains why Archer also uses the Stefan-Boltzmann equation incorrectly" doesn't mention Stefan-Boltzmann at all. Misrepresent what was being taught in the lecture, leave out relevant parts, come to an unsupported conclusion. and supply a link which doesn't address what you claim it does.The entire post is really scraping the barrel.

A Simpe Solution

In Zen and the Second Law of Thermodynamics I discussed claims of the non-existence of the so-called "greenhouse effect". Some of those claims use analogies or examples to "prove" the point. Most of these are misconceived at best and erroneous at worst. Most scientists and informed non-scientists accept the basic physics. I won't say "99%" or similar because I'm aware that 87.37% of statistics are made up on the spot, and in any case I don't know what the figure might be. This is not an "appeal to consensus" - the basic physics involved is well understood and founded on fundamental physical laws.

Here's such an analogy designed to "prove" that the infrared radiation ("back radiation") from the atmosphere to the Earth's surface either doesn't exist or cannot have the claimed effect. Not surprisingly, it's from one of the many authors of "Slaying the Sky Dragon" who thinks he's illustrated "perpetual feedback":

Say you have a blackbody plate (think of an electric heater) radiating 1000 W/m² toward another plate which, because of distance, absorbs half of that intensity, i.e., 500 W/m². At equilibrium, the receiving plate thus radiates 250 W/m² toward the 1000 W/m² plate. Question: Does the 1000 W/m² plate thereby rise to 1250 W/m²? If so, then, by raising the radiator's temperature without adding more energy, you've disproved the first law of thermodynamics. Effectively, you've made the radiator heat itself. Moreover, now at 1250 W/m², the radiator will heat the other plate still more, absorb another dose of back-radiated energy, and will reach 1562 W/m². And so on, ad infinitum.

This seems to prove a feedback causing a runaway heating in the system. However, the author (Alan Siddons) is confusing an infinite geometric series (with a finite sum) to a never-ending sequence of feedback. Let's look closer at the diagram. Something is missing (par for the course in these analogies). In this case it's the radiation lost from the system, and examining that will directly give us the equilibrium conditions.

At equilibrium, the two-plate system is receiving the equivalent of 1000 W/m² via the heated plate, so the system must lose that energy to the surroundings. If the heated plate is now radiating x W/m², then x/2 W/m² is being lost to the surroundings. The receiver is absorbing x/2 W/m², so must be radiating the same amount, with half of that radiation, x/4 W/m² lost to the surroundings. We have a simple expression to solve:

x/2 + x/4 = 1000   so 3x/4=1000  and x = 1,333.3

The heater radiates 1,333.3/2 = 666.7 (actualy 666.66 recurring) to the receiver, which radiates half, or 333.3 back:

Balance is restored and no runaway heating. But where does the "extra" radiation come from, which as claimed above "violates the First Law"? It comes from the heat energy stored in the system during the equilibrium process, and the amount depends on the specific heat of heater and receiver. There is no violation of the First Law, and no violation of the Second Law either. Net flow between the two plates is from hotter to cooler, with both plates heating up until overall equilibrium is restored. Al the heat energy in the system came from the heated plate, which has some of that returned to it from the receiver. The returned heat reduces the net heat lost from the heater, so because the input remains the same, it heats up until the heat lost from the system equals the heat input.

Does the cooler receiver "heat" the hotter heated plate? No, it simply replaces some of the energy radiated (and therefore lost) from the heater, so it's the continual 1000 W/m² energy input which does the heating. Mr. Siddons has himself said "a cooler body cannot heat a hotter body, it just slows the rate of cooing". This is a perfect example - initially the heater radiates 500 W/m² to the receiver, reducing to a net 666.7 - 333.3 or 333.3 W/m² at equilibrium, and the result is a hotter radiator, radiating a total of 1333.3 W/m².

The misconception arises from only considering the instantaneous input to the system and ignoring the heat stored during the equilibrium process, a common thread in such discussions. If you intend waving a big stick, make sure you've got hold of the right end of it first.

Zen and the Second Law of Thermodynamics

The Clausius expression of the Second Law of Thermodynamics:

No process is possible whose sole result is the transfer of heat from a body of lower temperature to a body of higher temperature.

This is unequivocal, so how does the "Greenhouse Effect" in the atmosphere raise the temperature of the Earth's surface? The atmosphere is cooler than the surface, so the flow of heat must be from the surface to the atmosphere, and so it is. Yet a number of people claim that this is proof that the "Greenhouse Effect" does not exist; "A cooler body cannot heat a warmer body" they proclaim, while in fact no-one has even suggested that this is the case. Some even go so far as to claim the so-called "back radiation" from the atmosphere to the surface doesn't exist.

Such claims have no basis whatsoever. Atmospheric longwave infrared "back radiation" has been measured, and its spectrum plotted, routinely since the 1950s. A simple web search can reveal summaries of some of the hundreds of scientific papers on the topic. It is part of the fabric of atmospheric physics. To ignore or dispute the existence of the phenomenon can only be termed denialism. However, disputing the effect(s) of this radiation in detail is another matter entirely. Such arguments can be examined for scientific logic and therefore veracity.