Let's just ignore the most important thing, as that would blow all our theories out of the water.

From Pseudoscience of Doom:

We are still looking at how radiation travels and interacts with the atmosphere before anything changes.

This is a cloud-free sample – clouds are very common, but really make life complicated and we are trying to provide a small level of enlightenment. Simple stuff first.

There follows a tortuous series of calculations based on certain arbitrary assumptions which inevitably prove their point.

Q. Why do they always ignore clouds, which cover average two-thirds of the Earth at any one time? They are more than “very common”. They are the norm.

A. It is because clouds actually explain pretty much the whole of the so-called ‘greenhouse effect’.

1. The “average height of emission” concept is actually very useful in mathematical terms, although they are applying it to the wrong thing and in the wrong direction..

2. If we are going to simplify things, it makes more sense to round up that two-thirds to ‘all of the Earth’s surface’ – 1 is nearer 2/3 than 0 is. And the upper surface of clouds is on average 5 km above the surface. Earth and its clouds have an average albedo of 0.3, so let’s assume these clouds have an albedo of 0.3.

3. As far as incoming solar radiation is concerned, the ‘effective surface’ is the upper surface of clouds (except on Mars, where there aren’t any, where the ‘effective surface’ and the hard surface are the same thing), and a planet’s ‘effective temperature’ is, in real life, very close to the actual observed temperature of the upper surface of clouds.

4. The temperature at the hard surface (land of ocean) is simply the temperature of the upper surface of clouds, plus their altitude x the lapse rate (the ‘gravito-thermal effect’ which is dictated by basic maths, GCSE level physics and a bit of common sense).

5. The simple approach from 4. neatly explains the hard surface temperature of…
a) Venus. ‘Effective temp’ and actual temperature of upper surface of clouds = 232K. Upper surface of clouds altitude (call it) 63 km. Lapse rate 7.9 K/km. Hard surface temperature = 232 + (63 x 7.9) = 733K.
b) Earth. ‘Effective’ and actual temperature of upper surface of clouds = 255K. Upper surface of clouds altitude = 5 km. Lapse rate 6.5 km. Hard surface temperature = 255 + (5 x 6.5) = 288K.
c) Mars. ‘Effective’ and actual temperature of hard surface (no clouds) approx. 215 K, no ‘greenhouse effect’.

6. There’s always the question of cause-and-effect. Is the “average height of emission” dictated by ‘greenhouse gases’ and the clouds just happen to form with their upper surface at the altitude as the “average height of emission”? Or, more likely, the clouds have their own rules, they form where they form, and their upper surface is, in practice, the “average height of emission”, because they are the only  surface that can emit radiation directly to space?

7. Then *drumroll* there’s the ‘trapped radiation’ myth. The hard surface is 288K and emits, mathematically, 390 W/m2. Measured from space, Earth emits 240 W/m2. The myth is that one-third of radiation emitted from by the hard surface is ‘trapped’ by ‘greenhouse gases’. Nope. When you measure from space, you are measuring the radiation emitted by the upper surface of clouds, which are colder and emit 240 W/m2, the same as what they absorb from the Sun.

(8. There is a completely separate system going on between the hard surface and the lower surface of clouds, it’s the clouds that do the ‘trapping’, they get radiation from the hard surface, absorb some and reflect some back down again. Let’s not go there for now.)