You do realize we are talking about something Vineeto said to Jon “in passing” some years ago? This was not “Vineeto presents her case against Anthropogenic Global Warming”. This was Jon telling us that Vineeto is “biased” because she makes “bad arguments” such as the “earth is too big”, and Vineeto replying that she wasn’t saying that to make an argument at all, she was just pointing out it’s not necessarily a given that humans can affect the climate (which is a “given” in many circles) due to the size of the atmosphere and that it might be hubris to assume so.
Somehow this morphed into an assumption that Vineeto was satisfied with “leaving it there” and wasn’t even curious enough to have ever done a two second Google search on the topic. You do realize Richard spent weeks researching this topic and that they most likely have discussed it at length? How can you give them so little credit to assume they aren’t even aware of the contents of the arguments of the most basic Google searches on the topic while simultaneously being confident in what they say?
Indeed, but there’s a few critical pieces that are missing to complete the picture.
Firstly you left out the next bit:
At typical planetary temperatures, this energy being shed to space is in the infrared part of the electromagnetic spectrum. In fact, all objects with a temperature [i.e. including oxygen & nitrogen] emit some form of radiation, and the infrared emission to space results from contributions by the planetary surface and atmosphere.
That is, the warm atmosphere (all 100% of it, not just 0.04% of it) is also emitting IR to space (and therefore contributing to the Earth losing its energy to space), not just the surface of the Earth.
But then, one might ask, could not some extra CO2 trap this IR and heat the entire (surface plus atmosphere) as a whole, more than it otherwise would be, since the IR now cannot escape to space?
The key to resolving this is in understanding the mechanism by which the CO2 is said to ‘trap’ IR, and from there putting the magnitude of this effect into perspective.
The way in which CO2 in the atmosphere is said to ‘trap’ the IR is none other than by being heated up by it:
Carbon dioxide and other
heat-trapping[sic(!): radiation-trapping] gases have molecular structures that enable them to absorb infrared radiation. The bonds between atoms in a molecule can vibrate in particular ways, like the pitch of a piano string. When the energy of a photon corresponds to the frequency of the molecule, it is absorbed and its energy transfers to the molecule.
The “energy transfers to the molecule” is a way of saying that it heats up. This link puts it more explicitly:
When photons bump into other atoms, some of their energy can get the electrons in those atoms resonating or moving faster than they were before - that’s what we call heat. The properties of these molecules and their bonds determine if a gas in the atmosphere will absorb infrared radiation or not.
[link]
That is, the claim is that the CO2 that makes up 0.04% of the atmosphere, is being heated up by the IR it absorbs from the surface of the Earth, and afterwards re-radiated (just like anything else that gets hot), some back into space (therefore cooling the planet) and some back towards the surface (therefore warming the planet).
But… no matter the means by which a gas is heated, regardless it will emit IR due to being an object that is hot! This applies to oxygen and nitrogen as well. If the oxygen and nitrogen gets heated – which it does by conduction and convection, and more efficiently than the CO2 does by radiation – then it, too, will thereafter emit IR in the same manner that CO2 is said to do it, some back into space (therefore cooling the planet) and some back towards the surface (therefore warming the planet). Not to mention that the CO2 itself is also being heated up far more by the convection & conduction than it is by the IR!
This is why it was critical to correct the misrepresentation earlier that oxygen and nitrogen “did not absorb heat”. They do, and far more of it than the CO2 does. The only way this claim can appear to be credible is by this conflation of heat and infrared radiation.
To perhaps belabor the point a bit – 100% of the atmosphere contributes to being heated by the surface of the Earth and thereafter re-heating the surface due to IR emissions – not just 0.04% of it. So if we take it as a given that the stated mechanism of the planet being hotter than it would be with no atmosphere is due to the atmosphere being heated up by the surface and re-emitting IR radiation back to the surface — then the magnitude of this effect is far, far greater from the 99.96% of the atmosphere than it is of the 0.04% of the atmosphere.
This is the point. The entire claim is predicated upon the 0.04% being responsible for the entire effect of heating the surface – and therefore couldn’t even a simpleton see (
) that increasing that 0.04% to say 0.08% could lead to drastic effects since that’s the only way the Earth ultimately loses heat to space?
But the point is that it’s really the 99.96% that is responsible for the vast majority of the effect of heating the surface. The effect of the 0.04% is much smaller than it’s made out to be. The premise of the magnitude of the effect of the 0.04% is unfounded. So it’s not clear or unequivocal at all that increasing this will net increase the temperature of the planet. Further evidence is required – and models and predictions and evaluations and computer simulations with this false premise as a basis do not constitute further evidence.
[EDIT: Note that the discussion about global warming/climate change continued on another thread.]