If you round up two-thirds cloud cover to 100% cloud cover and assume they have an albedo of 0.3, then the real reason for the apparent 33 degree Greenhouse Effect is immediately obvious, as I explained a month ago.
The Alarmists make a right muddle of this. They calculate Earth's albedo 0.3 based on average albedo of clouds and exposed surface, and then assume that this is the albedo of the land and ocean surface. This gives them space to fabricate an explanation why it's warmer at sea level than at the cloud tops - following their logic, these should be the same (duh). After that they ignore clouds, except for the bit where they reflect IR radiation from the surface back down. They also (implicitly) assume that only the land and ocean surface absorbs solar radiation and that clouds don't. Dear oh dear.
It's easier explaining it properly than picking holes in their approach - just because their explanation is deeply flawed (i.e. based on false assumptions and hence completely wrong) doesn't tell us what the right explanation is.
The next question to be answered is, why do clouds form so that the average altitude of their upper surface (the surface which absorbs and is warmed by solar radiation) is at about 5 km (with a resulting sea level temperature of 288K)? I've struggled with this for the past month, and, much head scratching, calculating, sketching and Bingling later, what it boils down to is as follows:
1. The dew point of the water vapour in any 'parcel' of air depends on three variables. For a start let's focus on i. air temperature and ii. air density/pressure. We'll get back to variable iii. Relative Humidity later, You can merge ii. and iii. into one variable called 'partial water vapour pressure', but it's easier to treat them separately:
The impact of temperature (for a given R.H.) - in warm air, water vapour is likely to stay as a gas; in cold air it is more likely to condense and fall as rain. There's a narrow range of temperatures where it remains as tiny droplets which remain suspended in the air:
a. All I can think of for now is that areas with higher R.H. tend to have lower clouds (as you would expect. If there's more water vapour it's more likely to condense at a lower altitude) and their sea level temperature tends to be a bit lower (lower cloud altitude means the difference in temperature between upper surface of clouds and sea level is lower, as there are fewer km to multiply by lapse rate) than in drier areas.
b. Higher R.H. and lower clouds also mean a much smaller day-night ('diurnal') temperature range - water vapour is good at holding on to thermal energy and the lower clouds are good at reflecting upwelling IR back down to sea level in the night time.
c. Venus and Mars follow exactly the same pattern, even though their atmospheres are nearly 100% CO2 and other 'greenhouse gases'.