NASA says Earth's greenhouse effect makes Earth 33 C hotter than the Moon. All of that warming can be explained by Earth having 1 bar of pressure compared to the Moon having no pressure. Going from the Moon to Earth is like going from the top of the troposphere to sea level, roughly speaking. This shows the increase in temperature as pressure increases. http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html As you can see, going from 16,000 feet to sea level, temperature increases from -17 C to 15 C. That's an increase of 32 C. This is NASA saying Earth is 33 C hotter than the Moon because Earth has greenhouse gases and the Moon does not. http://www.giss.nasa.gov/research/briefs/ma_01/ I also do not agree with NASA's claim that Earth's temperature is driven by the level of greenhouse gases in the air. If that were the case, Earth would be much hotter than it is today.