As we hopefully all know by now, the claim that Earth's temperature is higher than it 'should' be is based on sleight of hand - they use two quite distinct definitions of 'surface' and flip back and forth between them depending on what point they are trying to make.
Definition A is 'the surface you can see from space', which is largely the upper surface of clouds and some land/ocean that is not below clouds. Definition B is the land/ocean surface (ignoring clouds).
B is at a lower altitude than A, and hence B is warmer than A because of the gravito-thermal effect. The Alarmists pretend that A and B are inter-changeable, compare the expected temperature of A with the actual temperature of B and then say the reason is 'heat trapping gases'. They might as well blame it on The Seventh Curse of Zog; if you compare the expected and actual temperature of A, there isn't any definite difference and nothing needs to be explained.
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The problem with basing a theory on what is basically a Big Fat Lie is that you have to keep making up more lies to explain other phenomena.
From NASA's brainwashing for kids site:
So clouds can have both a cooling effect and a warming effect. When it comes to Earth’s climate, do clouds warm more than they cool, or is it the other way around? Well, that depends on where the clouds are in Earth’s atmosphere. [Actually, this is nonsense. The surprising conclusion is that clouds warm things up overall. But that's for a future post.]
Clouds within a mile or so of Earth’s surface tend to cool more than they warm. These low, thicker clouds mostly reflect the Sun’s heat. This cools Earth’s surface.
Clouds high up in the atmosphere have the opposite effect: They tend to warm Earth more than they cool. High, thin clouds trap some of the Sun’s heat. This warms Earth’s surface.
They also completely fudged the picture, the Sun is not 'a bit higher than the highest cloud' and can't sneak through the gap. To all intents and purposes, the Sun's rays are parallel. If you redraw the picture with parallel rays arriving directly from above, this would be obvious.
The correct explanation is far simpler and more coherent:
Clouds are primarily warmed by the sun from above!
There, easy. Once you accept that obvious statements, the rest follows.
* The temperature the clouds (are trying to) reach is the same, regardless of altitude (they are getting the same amount of sunlight).
* As a separate issue, the temperature below the clouds rises with decreasing altitude, at (say) 6.5 degrees per km (gravito-thermal effect).
* So the land/ocean surface below the high clouds is warmer.
* It's like two people who walk at the same speed, but one of them (the higher cloud) sets off earlier (higher up) and gets further (warmer) by a given end-time (the surface).
Here's a very simplified diagram to illustrate the point. 255K is the 'effective temperature' of Earth and its clouds - the sunlight hits the clouds first, so 255K is close to the actual temperature of clouds:
ii. This also neatly explains why it's colder than 255K at higher altitudes. According to Alarmist theory everything must be at least that warm. The top of Everest gets sunshine, there's little cloud cover and there is still plenty of CO2 in the air above it. But it's colder than 255 K, not warmer.
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I realize that there is a lot more to all this; I am just addressing the narrow point about high clouds v low clouds.