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A discussion of the Slaying the Sky Dragon science: Is the Greenhouse Effect a Sky Dragon Myth?

 “Skeptics” are described as if they are one small block of  fringe extremists, but not only is half the population skeptical in some sense, in this debate I am not on either extreme, but a centrist, smack in the middle. On the one hand, alarmists are convinced the climate is headed for a catastrophe, and on the other some people are convinced there is no greenhouse effect at all. Wes Allen, sits in the middle with me, and he’s been engaged in an intense debate with people on both ends of the spectrum. After a scorching critique of Tim Flannery’s work, he has swung his attention the other way. Here is his synopsis of the Slayers book, for discussion, and I’m sure it will generate a long passionate defence and debate, just as previous posts on this topic have. (eg: Why greenhouse gas warming doesn’t break the second law of thermodynamics and So what is the Second Darn Law?). I know the Slayers are keen to discuss their ideas. I’m hopeful people can remain polite, as that’s where progress may be made… many thanks to Wes here who has done a diligent write up, and has gone to great lengths to get the details right. The man is in a relentless pursuit of answers. Some may prefer to read the full PDF, I’ve only posted parts of the first 4 pages here. Sorry I can’t post it all up, but it is long! – Jo


Is the Greenhouse Effect a Sky Dragon Myth?

A Dialogue with the Authors of Slaying the Sky Dragon

Dr D Weston Allen – meet the author here          30th September 2012


My book, The Weather Makers Re-Examined, published in 2011 by Irenic Publications, was a comprehensive and damning critique of Tim Flannery’s alarming best seller which claimed ‘we are The Weather Makers’.  I now examine Slaying the Sky Dragon (SSD), a full frontal attack on the greenhouse theory or ‘sky dragon’ by eight authors who refer to themselves as the ‘Slayers’ (p.358) – a term I adopt when referring to them.  This 358 page book was published in 2011 by Stairway Press in WA (USA).

Defining the sky dragon

The ‘greenhouse theory’ gradually evolved from the seminal work and limited understanding[i] of Joseph Fourier in the 1820s, John Tyndall in the 1860s, Svante Arrhenius in 1896-1908, Guy Callendar in 1938 to Gilbert Plass in the 1950s.  It holds that solar radiation penetrates Earth’s atmosphere to reach the surface which is warmed by the absorption of this electromagnetic energy.  The warmed surface emits infrared radiation, and much of this outgoing longwave radiation (OLR) is intercepted by trace gases in the atmosphere.  Some of this energy is radiated back to Earth’s surface where it is absorbed as thermal energy, thus enhancing solar warming of the surface by day and slowing cooling by night.  Since glass on a greenhouse also absorbs and re-radiates infrared (IR) radiation, this atmospheric phenomenon became known as the ‘greenhouse effect’ (GHE), and the trace gases are referred to as ‘greenhouse gases’ (GHG).

As real greenhouses work primarily by limiting convection, and GHGs by promoting it, SSD refers to them as ‘IR-absorbing gases’.  Comprising less than half of one percent (0.5%) of Earth’s atmosphere, these gases are scattered somewhat unevenly through the atmosphere and across the globe.  Most of the GHE, particularly over the tropics, is due to water vapour (H2O) and clouds in the troposphere, the bottom layer of the atmosphere where convective mixing and weather occurs.  The tropopause, separating the troposphere from the stratosphere, increases in altitude from about 8km over polar regions to about 17km over the tropics.  Above the stratosphere is the cold mesosphere (about 50-85km altitude) and then the very warm thin thermosphere which merges into the exosphere (at 350-800km altitude depending on solar activity).   The troposphere contains about 80% of the mass of the atmosphere and the top of the atmosphere (TOA) is generally considered to be about 100km above Earth’s surface.

Without any IR-absorbing GHGs in the atmosphere, all radiative energy losses balancing solar input would occur at Earth’s surface.  According to the laws of radiation, the average temperature at the surface would then be about -18⁰C, nearly 33⁰C colder than the observed mean value.  While IR is radiated to space from the surface and atmosphere, the average loss occurs where the temperature is actually -18⁰C at an altitude of around 5km.  The more GHGs in the atmosphere the higher this average radiative layer; and since the temperature below it increases by about 6.5⁰C/km (the lapse rate), the higher this layer the higher the temperature at Earth’s surface.  The enormous complexities of this are explored later.

Setting the stage for the battle

We know that carbon dioxide (CO2) has been accumulating in the atmosphere for several centuries, particularly over the past fifty years; and it is generally considered that the main reason is the burning of fossil fuels.  This increase in atmospheric level and its greenhouse effect is widely thought to be a significant factor in the global warming observed over that time.  Global warming also results in increased evaporation and atmospheric water vapour; and this is thought by mainstream climatologists to produce a positive feedback cycle.  Whereas it is generally agreed that ‘climate sensitivity’ to doubling atmospheric CO2 is about 1⁰C, positive feedbacks in climate models increase this to 3⁰C (1.5-4.5⁰C).  While ‘alarmists’ accept this without question, sceptical scientists (e.g. Richard Lindzen and Roy Spencer) argue that the models are too sensitive to CO2; that the net feedback is negative due to increased evaporative cooling and cloud cover, and that climate sensitivity is therefore less than 1⁰C.  Such sceptical scientists do not deny the greenhouse effect or question whether human activity is warming the planet, but only by how much.

Since global warming became apparent and political in the 1980s with the birth of the Intergovernmental Panel on Climate Change (IPCC), attitudes and positions have become increasingly polarised.  The 1992 Rio Earth Summit’s cleverly contrived definition of ‘climate change’ as being ‘anthropogenic change only’ resulted in two opposing groups of deniers: those who deny any prehuman ‘climate change’ and those who deny any manmade climate change.  While the former imagine a runaway greenhouse catastrophe, the latter deny any greenhouse warming at all.  We thus have extreme alarmists and extreme sceptics.

Slayers of the sky dragon

The authors of Slaying the Sky Dragon are firmly in the latter camp.  They don’t deny climate change, only man-made climate change; but they do deny any greenhouse effect or greenhouse gas.  Indeed, they claim that all IR-absorbing gases including water vapour have only a cooling effect.  They deny any human contribution to global warming; and they refer to those who regard such warming as real but fairly trivial, compared to natural variability, as ‘lukewarmers’ or ‘lukes’.  This author happily confesses to being a ‘lukewarmer’ aligned with neither extreme.

Setting out to slay a sky dragon that they don’t believe exists; the Slayers confidently seek to engage the enemy.  Presumably speaking for the whole team, Hans Schreuder laments:

The authors would much like to exchange ideas about the scientific basis upon which human-caused climate alarm is based, but sadly no debate – through no fault of the Slaying the Sky Dragon authors – has ever been entered into. Despite many detailed written exchanges, no scientific debate has ever been held between truly scientific skeptics and the obviously unscientific alarmists; only between the alarmists and the lukewarm skeptics, all of whom subscribe without question to the concepts of a ‘greenhouse effect’, ‘greenhouse gases’ and ‘radiative forcing’ (p.209).

Perhaps the Slayers might have more luck entering into such a debate if they refrained from ad hominem attacks and calling would-be opponents ‘obviously unscientific’, ‘academic eggheads’ (p.52).  They could also show more willingness to exchange ideas and concede points rather than debating opponents to score points.  Schreuder thinks lukewarmers simply have the wrong winning strategy: “’Human-generated greenhouse gases are warming the earth but not as much as alarmists say’ never was a good debating strategy for skeptical academics and it’s probably too late for them now.” (p. 223)

There is a great deal in SSD with which I wholeheartedly agree, much of which I ignore in this critique.  On the other hand, I found many arguments that reveal misunderstandings, misrepresentations, errors or half-truths.  There are also contradictory statements by different authors and sometimes by the same author.  These include fundamental differences on how the atmosphere is heated and how it radiates that heat.

I have learnt a lot about atmospheric physics while critiquing this book, and I am grateful for that.  I am also grateful to Professor Will Happer and Vincent Gray for their assistance.  I also thank John O’Sullivan and other SSD authors for their helpful feedback (see Appendix), for detecting several errors and for prompting the revision of some sections of this critique.

Arguments presented in Slaying the Sky Dragon

Read the whole work in PDF (3.4Mb)


[i] Vincent Gray, 2011: The Greenhouse and its Effects. http://nzclimatescience.net/index.php?option=com_content&task=view&id=756&Itemid=1

Past posts on the theme “Slayers“:

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