In a paper published on Saturday in the Journal of Geophysical Research – Atmospheres of the American Geophysical Union, scientists from the Goddard Institute of Space Studies (where scientists have generally been strong advocates of human-caused global warming) outlined the key atmospheric molecules that contribute to the greenhouse effect. Key quote from the abstract:

We find that water vapor is the dominant contributor (∼50% of the effect), followed by clouds (∼25%) and then CO2 with ∼20%. All other absorbers play only minor roles.

The scientists also noted that even if carbon dioxide in the atmosphere were to double, these percentages would not change significantly.

Does this mean that carbon dioxide is a minor player in creating global warming? This remains unclear. First, the above research is essentially only modeling, not actual data. Second, the scientists themselves note that the interplay of any two of these molecules (such as water and carbon dioxide or water and cloudiness) can have a greater effect than just one molecule alone, which makes these percentages by themselves incomplete.

Nonetheless, these results are important politically. These global warming scientists have placed themselves on record as admitting that cloudiness appears more significant that carbon dioxide in creating the greenhouse effect. And since the combination of water and clouds can have an even greater influence on the climate than either alone, the scientists are also admitting that water is by far the most important greenhouse molecule. Any future climate models as well as political action must take this fact into consideration.