Argon Idly Watches The Clouds Go By

Argon: From the Greek word αργον, neut. of αργος [argos] "idle," from α- "without" + εργον "work." = lazy, inactive. Link

Argon is not completely inert. Voracious hydrogen fluoride coaxes some electronic juice out of it, but the two stay coupled only when frozen. Moving further down to krypton and especially to xenon, there is an increasing willingness to redistribute electrons among the noble gas atoms, a consequence of their electronic wealth being more remote from their core and thus more easily removed. 
 
Argon makes up nearly 1 percent of the atmosphere, making it almost 25 times more abundant than carbon dioxide, that vile and evil greenhouse gas. So why is lazy and shiftless argon not implicated in global warming?  For that matter, why isn't air itself (N₂ and O₂) blamed? And why is good ol' water vapor given a pass by the warmists? Those questions have both easy and inconvenient answers.

Greenhouse gases are invisible but retain heat. Argon, being just an atom, never quivers internally, which is how gas molecules absorb and trap heat. So argon has no real greenhouse gas capacity. Nitrogen and oxygen also absorb little heat, even though there are trillions and trillions tons more of them up there. Carbon dioxide absorbs infra red radiation (heat), the sine qua non signature of a greenhouse gas. But water vapor is not only a "better" greenhouse gas than carbon dioxide is--there are also many tons more of it in the sky! (methane is even better than water at greenhouse gassing, but there is so little methane in the air that the point is moot).

So water vapor is by far the most important greenhouse gas. But water vapor also makes clouds which reflect sunlight. That makes clouds the white elephant in the room that the warmists don't really like to talk about. Back in the old days, when environmentalism wasn't so fixated on carbon dioxide, things were more fair and balanced:

If large amounts of carbon dioxide enter the air, then it is quite obvious that a rise in worldwide temperature could result, bringing about the the melting of the polar ice caps. However, an increase in temperatures would also lead to an increased rate of evaporation; with more water vapor in the air, cloudiness would increase. This in turn would mean an increase in reflectivity of insolation, so that less of the sun's energy would reach the earth. The lower temperatures that would result could eventually produce another ice age. Thus we are left with the perplexing thought that increased pollution could cause either a glacial invasion or a worldwide rise in sea levels that could inundate millions of miles of dry land presently in use.

Burrus, T.L; Spiegel, H.J. Earth In Crisis: An Introduction To The Earth Sciences: C. V. Mosby Company: St Louis, 1976 

Talk about putting a damper on global warming.

[UPDATE: link]