The major force between ethanol and rubbing alcohol is hydrogen bond. Hydrogen bond are intermolecular force that are weaker than covalent bond but holds atoms together in a molecules. For an hydrogen bond to be formed, a molecule must contain an hydrogen atom that will be bonded to one of the most electronegative element.
The greenhouse effect is rightly called that because greenhouses allow heat to enter, but doesn't allow heat to leave, which warms plants.
On earth however, it's much bigger. Our own atmosphere acts similarly to this; it allows heat in, but doesn't allow it to leave which heats up the planet and causes global warming.
