The supporters of global warming, particularly the MSM who are mostly not scientifically literate, routinely fail to mention that water vapor is the primary "greenhouse gas." Here is a table showing the contribution of the important "greenhouse gases." (Note that water vapor provides 95% of the effect.) This is from the following site:

http://mysite.verizon.net/mhieb/WVFossils/greenhouse_data.html


Anthropogenic (man-made) Contribution to the "GreenhouseEffect," expressed as % of Total (water vapor INCLUDED)

Based on concentrations (ppb) % of all %Natural % Manmade
adjusted for heat retention Greenhouse
characteristics Gases

Water Vapor 95.000 94.999 0.001

Carbon Dioxide (CO2) 3.618 3.502 0.117

Methane (CH4) 0.360 0.294 0.066

Nitrous Oxide (N2O) 0.950 0.903 0.047

Misc. Gases (CFC's, etc.) 0.072 0.025 0.047

Total 100.00 99.72 0.28

If we assume that the total "greenhouse gas effect" on the Earth's average temperature is the usually accepted value of 60 F, then the addition due to manmade CO2 is about 0.07 F, and the total effect from all manmade greenhouse gases is about 0.17 F.

The IPCC seems to use a value of 20% for the greenhouse effect of CO2, which is part of the reason why the IPCC predictions indicate significant average temperature increases with predicted increases in CO2 concentration in the atmosphere.

The fact that water vapor is rarely acknowledged as the major greenhouse gas by supporters of the global warming dogma has always bothered me; it is a tipoff that they are acting in the manner of snakeoil salesmen. I suspect they would say that they don't want to confuse the ignorant masses.