It does not necessarily follow that just because there is more CO2 in the atmosphere that more heat will actually be retained; it is conditional on the requisite temperature and pressure conditions . This is proven by the missing hot spot in the critical pressure region about 400 – 200 hPa at 8 – 12 km altitude above the tropics

http://joannenova.com.au/2008/10/the-missing-hotspot/

If the required temperature is not being observed, he’s wrong.

Case 1) For increased density of a set volume (mass increase):

Increased CO2 and WV will both increase the heat capacity of the set volume,

The entire atm volume remains the same and it’s heat capacity is increased. But what would cause density to increase (there’s no constraint)?

Case 2a) For same density of a set volume (mass – no change):

Increased CO2 will lower the heat capacity of a set volume.

The entire atm volume is increased by the gases displaced by the CO2 but the volume displaced has a higher heat capacity than it would be if it had CO2 in it. What then is the nett effect? [I haven't got the time to do this calc at present]

Case 2b) For same density of a set volume (mass – no change):

Increased WV will increase the heat capacity of a set volume/

Tthe entire atm volume is increased by the gases displaced by the WV but the volume displaced has a lower heat capacity than it would be if it had WV in it. What then is the nett effect? [I haven't got the time to do this calc either at present]

In both cases the entire atm mass is increased so total potential heat capacity must increase but that potential is only realized by the requisite temperature and pressure conditions.This ignores Renowden’s oxygen depletion issue which decreases total atm mass although the nett effect of that is probably still increased potential heat capacity.

I’m not convinced by your argument Huub but the picture is a little clearer regardless of whoever is on the right track and my head doesn’t hurt as much.

Your move.

Do you have a reference to the specific heats? On second thoughts, you would probably just refer me to a science text book, or an encyclopaedia. The kind of thing where you look up details of the Periodic Table or check the speed of light — right? I’ll Google it!

http://www.c3headlines.com/2009/11/the-global-warming-boogeyman-it-only-comes-out-at-night-scientists-confirm-1.html

Of course, this doesn’t conclusively “prove” anything, but then science is, or should not be, about “proving” things, but be about creating falsifiable statements

Anyway, this would support the idea that the night-heating effect is only due to UHI (including for weather stations that are supposed to be rural but are contaminated by buildings, tar seal etc.)

Takes a while to read through your entire comment but I can short-circuit part of it by making the point that adding any CO2 to the atmosphere will LOWER the specific heat capacity of the system. That is for the simple reason that, at around 0.79 kJ/kg/K, the specific heat of CO2 is lower than that of air as a whole, about 1.0 kJ/kg/K. Add any CO2 and you will REDUCE the ability of the air to retain heat. Adding water vapour, on the other hand, will increase the specific heat capacity of the air because it has a higher specific heat capacity, at about 1.7 kJ/kg/K.

Does that make your analysis more interesting?

We know that there is a lot of UHI contamination in the temperature record.

Has anyone factored this out on the night versus day measurements?

The atmospheric carbon vs oxygen graph is interesting. Huub has got me thinking a great deal about the physics of Gareth’s statement:-

“More CO2 means more heat retained in the system”.

I think that it does not conform to AGW (or physics) and should be something like:-

“More CO2 means more WV retained in the atmosphere and therefore more heat retained in the [atmospheric] system IF temperatures rise or are maintained at high levels”

AGW is then disproved by either the empirical observation of declining heat content (atmosphere and ocean) AND/OR static or declining WV levels (starting to look that way on both counts).

But how do we know what is happening to the long-term composition (the heat sink) of 1 cubic km of atmosphere at altitude 10 km say? My reasoning is:-

1) Start with the composition of the atmosphere at initial satellite era levels (dry air plus WV, what was that composition?) .

2) Add CO2 increase and WV changes over the satellite era and adjust all the other constituents accordingly.

Position 2) is the atmospheric carbon vs oxygen situation (not just oxygen). This article linked is a commentary on the study that would probably be the original source of the data Gareth has presented:-

“Atmospheric Oxygen Levels Fall As Carbon Dioxide Rises”

Read more: http://blogcritics.org/scitech/article/atmospheric-oxygen-levels-fall-as-carbon/#ixzz1LN6dZbEA

From the lead scientist of the study (Dr. Ralph Keeling) :-

It is roughly true that the oxygen depletion is equivalent to a displacement by carbon dioxide. But it is not exactly true. First, some of the carbon dioxide produced has been absorbed by the oceans. This process involves inorganic chemical reactions which have no effect on O2. Second, the O2:C combustion ratio of a fossil-fuel depends on the hydrogen content. The ratio varies from about 1.2 for coal, 1.45 for liquid fuels, and 2.0 for natural gas. Taking these factors together, we are losing nearly three O2 molecules for each CO2 molecule that accumulates in the air.

Long-term addition of CO2, WV or anything else means (I think) that a proportion of all the other constituents are displaced from the 1 km^3 volume so that the atmosphere increases in total (TOA rises) but if there is also depletion of constituents e.g. oxygen, the situation becomes very complicated and my head starts to hurt.

And what if WV is now declining as indications are (but the comprehensive data is being withheld)?

Apart from all that, consideration of the atmosphere is a total waste of time because the ocean – atmosphere heat sink ratio is 4000 :1 i.e. it is what happens in the ocean that determines long-term warming/cooling trends and contrary to some of the more bizarre AGW reasoning, CO2 does not heat the ocean.

The links to Skeptical Science are worth following. The comments below each post often open up more questions.