The Earth is not a closed system. And we are not talking about heat flow, but radiation. Everything radiates if it is not at absolute zero. And a photon from a body does not care if it intercepts a warmer body than the one that emitted that photon. So, yes, radiation from a cooler body can add energy to a warmer body.
So then you can provide observed, measured examples of energy moving spontaneously from cool regions to warm regions? Of course you can't...but you just had to speak up anyway didn't you?
Well here it is. He finally said it:"So, yes, radiation from a cooler body can add energy to a warmer body"
And as soon as you point out that if it was this cooler body which added energy to the warmer then the cooler body would have had to cool down even more. We all know that can`t happen, so they "explain" it by pointing out that the warmer body radiates at the same time towards the cooler one which is why both will equilibrate at equal temperatures but below the temperature the warmer one had at the start...which unfortunately means it did not gain any energy but lost it to the colder one. At that point they all over sudden resort to a 3rd energy source, the sun and deny they
added energy to the warmer body by just using a cooler body.
Heat energy in whatever form is expressed in work units. It takes work (=energy) to raise the temperature of a mass and the colder body can not perform this work. Which is why there is no way around that except using the 3rd source, the sun again while obfuscating the "added energy from the colder body" process.
That is accomplished by ignoring the mass of each of the 2 bodies which in the end is what they need to do in order to use the CO2 to "add energy" to Ew. On average air has a specific heat of 0.24 btu per degF
and per pound. See how easy it was to do that CO2 and "energy adding" cheat by simply ignoring the mass ?