If you are still one of the people who believe the “Greenhouse theory” of warming, but don’t quite know why it sounds rubbish. Let me recap the advanced theory & the differences (CO2 used to mean all greenhouse gases including H2O).
- The greenhouse theory says CO2 absorbs IR – the advanced theory says it absorbs and emits IR
- The Greenhouse theory says that the greenhouse effect is strongest at the bottom of the atmosphere under the blanket of the atmosphere (BS). The advanced theory says the effect of CO2 has most effect at the top.
- The Greenhouse theory says the atmosphere doesn’t have any lapse rate through the atmosphere. The advanced theory says that as we rise up, the reduction in energy of the gas results in a loss of energy and so temperature.
- The greenhouse theory has a fictional atmosphere with no mass, no mechanism for convective currents and models it as a single temperature.
In short the “greenhouse” gas theory is not only wrong in name (greenhouses don’t work the way suggested) but it is wrong scientifically and no wonder so many people look at it and think it is BS.
To help understand the real atmosphere, I’ve shown a model below. In this atmosphere the temperature drops as we rise up from the ground according to the lapse rate (or as shown: adiabatic lapse rate – which ignores rain). The model then says that if we were to look at the source of most radiation (or at least the part active in Greenhouse warming), then most of it comes from the top layers of the atmosphere (although in reality as 90% of the atmosphere is in the troposphere, this “top” is quite low down in the actual atmosphere.)
So, the temperature of the top surface of the atmosphere can be calculated by assuming its a black body and that temperature comes out at around 255C. The surface is measured at around 288C. This shows that the temperature drop due to potential energy loss of energy moving from ground surface up to radiative surface equates to an average around 33C. This is what is called the “greenhouse effect” (wrongly)
The effect of CO2
With the addition of one extra piece of information, we can now work out the effect of changing CO2 – or at least work out what it means for the atmosphere. That extra information is the lapse rate of 6.5C/km.
I’m now going to work out the effect on the atmosphere of two levels of CO2 change. The first is the effective change in temperature due to CO2 over the 20th century which is around 0.15C. The second is the supposed change with a doubling of CO2 levels which is usually stated as 1C. However, using latest HITRAN database figures Herman Harde came to a figure of around 0.6C, which for convenience I’m calling 0.65C (if you disagree, then the maths might even be possible for Climate Extremists! – so most can do it themselves)
And what is that effect? If the earth rises by 0.65C, then this means the greenhouse effect must change by 0.65C, but as the above diagram shows, the greenhouse effect is the same as the total lapse rate from surface to effective top. So the total lapse rate must increase by 0.65C, but because the lapse rate itself doesn’t change, this means the effective top of the atmosphere will change and we can work this out as follows:
= temperature change/ lapse (meters)
= 0.65/6.5 = 100m
(I told you even climate extremist might be able to do it).
What this actually means is that because there is more gas to EMIT radiation (note we are not talking about absorption but emission), because there is more CO2 gas, there are more ways for CO2 higher in the atmosphere to emit direct to space. Or to put it another way, yes, some IR from lower down is blocked, and there is more emitted from the denser level of CO2 higher up. So, in effect the height from which the average IR is emitted rises. (If that still is not clear, think about looking down into the atmosphere like looking into a wood – the thicker the wood the less far you can see into it – so the less far we can see down into the atmosphere at the CO2 bands from outside – and hint: we see by light coming from the object we see)
And what has been the current effect for CO2 change leading to 0.15C warming?
=0.15 / 6.5 = 23m
Thus the entire effect of the total CO2 into the atmosphere so far, is equivalent to going up from the ground to the roof of a modest block of flats. This is the dramatic “change” that is supposedly destroying the earth! The equivalent of making the atmosphere 23m thicker. And the total change for doubling CO2 – that horrific doomsday event? About the same as going from the top of Big Ben on the UK parliament down to the ground! (I must look next time I go to London to see all the dead bodies caused by that massive temperature change!)
Note: this article is similar but not the same as the WUWT article: The Height Of Temperature Folly
[And to be honest, I believe Anthony Watts still does not understood how the actual greenhouse process works. As a result he still seems to think those talking about the lapse rate are nutters. OK, some clearly are “difficult”, others I have no idea what they are going on about, but … hey without the sensible ones I too would never have understood it myself and – I think I can forgive Anthony this one as we can’t all be perfect, all the time]