[adriannem]

The amount and the concentration of water in the atmosphere do matter. If the atmosphere is divided into two ‘warming’ or energy bearing mediums, more precisely water and greenhouse gases (CO2, methane, etc.), then the atmospheric humidity will have a warming capacity equal to a two-meter deep layer of the ocean surface, while greenhouse gases, a power equal to a one-meter deep layer. Practically, this means that a rise of the atmospheric temperature with 1?C must cause a drop of an equivalent amount in the upper three meters of the ocean. But because water vapor is usually in a much higher concentration at lower altitudes, its impact on the weather is much more powerful than CO2. CO2 is always equally distributed throughout the atmosphere. Their weather and temperature functioning are extremely different from ‘water in the air’. Water vapor is well above 95% responsible for the greenhouse effect; and on a foggy day, even 100%.