The model is a bit too far. The average temperature of earth around the sphere is around 6.5 °C. several errors or incomplete pieces are the cause.This kind of blog does not show any reply, it does not allow attaching a work sheet.
What do you mean "This kind of blog does not show any reply, it does not allow attaching a work sheet."? What do I need to do so you can download it and make changes?
As regard the 6.5C average temperature, you have probably figured out by now that I was mostly guessing (estimating sounds better) most of the values I used, such as albedos etc.
Tha last bit on water vapor convection was pretty much a flight of fancy, but the entire (simple) model just shows how complicated a process it is to arrive at a realistic model of the energy balance between the Earth-Sun system.
I would be interested in hearing from you about any errors and incompleteness that you spotted.