There are so many problems with this article I frankly don't know where to begin and really don't have time to deal with all of them.
I'm a global warming "skeptic" (though it's important to define what that means - I accept there's been an increase in global average temperature, debateable how large that has been, though I am doubtful that it's mostly anthropogenic, but it's possible a good portion of it is in fact due to anthropogenic CO2, but we'll never really know if it was or not)...
But there are just so many silly, stupid arguments against "Global Warming" it's frankly an embarassment.
The main problems with the article :
1) The assertions about what percentage of the total greenhouse effect are H20 relative to CO2 seem, frankly, wrong and exaggerated compared to an assortment of other, legitmate sources.
2) The fundamental problem is the author seems to believe that the "Greenhouse effect" is simply any amount of warmth ABOVE a nice, comfortable, "normal" average temperature.
It's not. The "Greenhouse effect" keeps us alive and the earth from being a frozen wasteland. Without all the greenhouse gases the world average temperature would be 5 degrees F.
You are right, this article is more sloppy science that the global warmers can use to claim the science high ground. Another example besides yours, sure methane and CO2 are "mostly" natural origin in that their cycles have large natural inputs and outputs from the atmosphere compared to our inputs. However, the main reason both are rising is manmade inputs. How much of the increase is manmade versus natural needs to be resolved but it is not negligible.
I author of the article provides sources and data. Where is yours? As a physicist, I find the arguements quite reasonable. Water vapor is by far the predominant "greenhouse" gas, and its contribution to the temperature of the Earth overwhelms all other gases, whether that results in a temperature slightly above absolute zero or the comfortable temperture we actually have. The isea that man's miniscule contributions to CO2, which is a miniscule component of the total greenhouse gases, could make large swings in the global temperature is absurd. FInally, all of this is, as shown by the data, driven inexorably by the Sun. The Earth's temperatures track the Sun's activity whether we want it to or not. ALlgore is a fool, and he is dragging much of the climate change community into his fools paradise!
It is interesting to ponder what the political situation would look like in the hypothetical case of global cooling from entirely natural causes, say, solar variation. Imagine that the ice caps were growing and glaciers beginning to advance, with reduced growing seasons and some northern cities becoming uninhabitable.
Can anyone imagine the environmental lobby arguing that we should embark on a massive effort to pump more CO2 into the atmosphere to stabilize the earth's temperature? No way.
So, all of the human effects which supposedly justify a massive reorganization of advanced economies are just a smoke screen. The environmentalist position on global warming has absolutely nothing to do with saving Venice or Pacific islands. Those are just ways to enlist the masses to support anti-capitalist and anti-industrialist policies and reduce the competitive advantage of the United States in the world.
That said, whatever their motives, it is theoretically possible that the activists have accidentally reached the correct cost-benefit result. But knowledge of the political calculus cannot but cast doubt on the reliability of the catastrophic scenarios which are predicted.