Spotlight on Number Crunching the Climate Controversy

August 22, 2013

22 Aug (PRINCIPIA-SCIENTIFIC)I have written articles recently (here and here) which have caused considerable controversy.  This despite the fact that I provided reputable references based on sound accepted science.

by Ross McLeod

I then presented an analysis of the results of my experiment. This is real data and my analysis was again based on recognised sound science, principally the Stefan-Boltzmann equation. And of course even more controversy followed quickly.

I want to leave that aside to later in this article where I will offer a defense of my experiment. Right now I want to again discuss how to sum radiative fluxes with a very simple analysis with a view to proving the assertion that Q + Q = 2Q is completely wrong.

In my experiment I used two 150 Watt spotlights to heat a thermometer.  Leaving aside the controversy of the supposed paradox some find in my experiment simply consider the following.

The ambient air temperature is 18 degrees C.  The thermometer reads 18 degrees C and is in thermal equilibrium with the air temperature. It does not matter how the thermometer is heated by the air – conduction or radiation or a combination of both.

The simple fact is it is at 18 degrees C or 291 Kelvin.

At this temperature the Stefan-Boltzmann equation says the thermometer bulb is emitting ~407 Watts per square metre.  Convection or conduction do not matter – it is in thermal equilibrium with the air at 18 degrees C.

Now I turn on one spotlight.

The thermometer heats to 30 degrees C.  Now it is no longer in thermal equilibrium with the air.

Clearly the only possible mechanism of this heating is the radiation from the spotlight – if the air were being heated and in turn heating the thermometer the whole room would have to heat up as there is no restriction on air movement.  The picture below shows the impossibility of that assertion.

Figure 1 – Experimental Set-up.

At this temperature – 30 degrees C or 303 Kelvin – the Stefan-Boltzmann equation says the thermometer bulb is emitting ~478 Watts per square metre.

So what happens when we heat an object by radiative “forcing” – to coin a climate science expression.

All of the climate science models I have seen, and all of the supporters of the “Steel Greenhouse” proposal, make the same basic claim – all of them.

This claim is that it is valid to add the magnitude of 2 or more discrete radiative fluxes and use that simple sum to calculate the temperature that will result under the influence of these radiative fluxes.

I say that is just completely wrong – it is not real science.

I want to make it quite clear I firmly believe if you double the power of one discrete source of radiation the temperature of the object being heated by that radiation will increase by a factor of the  fourth root of 2.  Tfinal = x Toriginal

However, I know that the sum of 2 discrete equal radiative fluxes is not the same thing as doubling the power of one !

Clearly the thermometer has increased in temperature by the action of the radiation from the spotlight and as a result it is emitting ~71 Watts per square metre more than before the spotlight was turned on.

Thus there are only 2 possible reasons for this.

1.         The spotlight is supplying a mere 71 Watts per square metre in total in accordance with climate science models which always show a simple sum of flux.  Climate science says that 407 from the ambient air plus 71 from the spotlight = 478 emitted by the thermometer; or,

2.         The spotlight is supplying 478 Watts per square metre at the “surface of the imaginary sphere” where the thermometer bulb is situate.

If you accept claim number 1 you have to reconcile how it is possible for a spotlight (which will cause severe burns if you touch the glass surface) to supply energy that has an equivalent temperature of ~188 K or about minus 85 degrees C !

That proposition is absurd !

If you accept claim number 2 you have to reconcile the fact that the “first” 407 Watts per square metre of the radiation from the spotlight have no thermal effect.

Well that is exactly what well established science says occurs !

Remember Qnet = A ξ σ (T4 – T04) ?

If T = 303 K and T0 = 291 K the result of this calculation is Qnet = A ξ σ (3034 – 2914)

= 71 x A x ξ  Watts.

This obviously means that while “back radiation” is all around us all the time it has no thermal effect on objects that are the same temperature or warmer than the source of the back radiation.

I assert that this also dismisses the “Steel Greenhouse” proposition absolutely because the energy doubling proposition relies on back radiation heating and this is not science !

I want to conclude with a short defence of my experiment.

Some people complained I was supporting the notion that energy flows from hot to cold.  Without any real evidence they emphatically assert their opinion that the resulting final temperature simply cannot be more than 36 degrees C – the temperature induced by the spotlight closest to the thermometer.

These critics claim I am advocating that energy flows from a cold object to a hotter object thus increasing the hotter object’s temperature.  I was called a fraud and a “warmist”.

The people who jumped to that conclusion are simply completely wrong.  Obviously they clearly do not understand what they are claiming.

The radiation causing the heating effect originates from two 150 watt spotlights, both of which create considerable heat.

There is no “cold” object heating a “warm” object in this experiment set-up – none at all – it is clearly two very hot objects transferring different amounts of radiant energy to a considerably cooler object !

All the energy came from extremely hot sources – the filaments of the spotlights with temperatures in excess of several thousand Kelvin.

Also both of the radiant energy sources produced a temperature greater than the ambient air temperature.

I had originally tried heating the thermometer to 42 degrees C with one spotlight and then turning on the “30 degree C” spotlight fully expecting no further increase in temperature but I was wrong.

Like it or not, the effect of combining the “net” radiation is real – it is easy for any doubter to verify cheaply.  Try it !

But those who claim my experiment is in error because it requires cold heating hot are completely wrong !

Also some claim that my experiment is at fault because it is conducted in the air and not in a vacuum.

To those criticisms I say :-

1.         I have found no evidence the original cavity radiation experiments were conducted in a vacuum.  Also, I believe this would have posed great difficulty for the experimenters because they had no mechanism to relate radiation to temperature before the development of the equations in the late nineteenth and early twentieth centuries.

If anyone has a reference that suggests otherwise please provide it – I would like to know.

2.         The effects of conduction and convection are always present – both for the “before” and “after” temperature readings.

3.         All I measure is temperature shown on the thermometer.

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