The Water Vapor Fallacy

ignoratio elenchi n.
A logical fallacy of presenting an argument that may in itself be valid, but has nothing to do with the proposition it purports to prove. Also known as “irrelevant conclusion”. [Lat. ignorance of refutation.]

In her comment to our Exxon post, Beth Wellington raises an important question: What can we do to make sure that our kids are being taught the real facts on climate change? Her question reminded me of a recent incident, and leads me to award this week’s Ignoratio Elenchi Award to an unknown teacher from an unspecified state. Let me explain.

A few weeks ago I was visiting with a senator about actions his state could take to prepare for national legislation on climate change. He suddenly changed the subject and said he had a science question. It seems the senator’s 11-year old son came home one day and announced that he learned in school that the whole global warming thing was hype. He said that the most significant greenhouse gas in the atmosphere is water vapor – not carbon dioxide – and therefore it makes no sense to cap emissions of carbon dioxide. How, asked the senator, should he respond to his son?

The water-vapor argument is a classic Ignoratio Elenchi fallacy. Yes, water vapor in the atmosphere contributes significantly to global warming. But this doesn’t mean that carbon dioxide need not be capped!

The amount of water vapor in the atmosphere is not directly affected by human activities. It’s controlled by atmospheric temperature – the higher the temperature, the more water the air can hold. When carbon dioxide – which is directly affected by human activities – is emitted into the atmosphere, the atmosphere warms slightly. But that modest amount of warming sets up a perverse amplification process: carbon dioxide emissions warm the atmosphere, which leads to more water vapor in the atmosphere, and thus more warming. It’s a vicious cycle.

We know from satellite measurements that this amplification process is, in fact, occurring. Water vapor in the atmosphere has increased over the past 25 years as carbon dioxide emissions have increased and the atmosphere has warmed. The only way to stop global warming is to stop the emissions of carbon dioxide, and that is why we must cap carbon dioxide emissions.

The senator’s son got his information from a teacher, and while I’m sure the teacher’s intentions were good, he or she got it very wrong. Yes, water vapor in the atmosphere strongly increases global warming, but it doesn’t follow that carbon dioxide emissions need not be capped. Hence this week’s Ignoratio Elenchi Award goes to this unknown teacher.

Next time I’ll tell you about something I’m doing to help make sure teachers have the real scoop on climate change.

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One Comment

  1. gwhoax
    Posted June 27, 2008 at 12:30 am | Permalink

    Typical “global warmist” response to a logical question, call the other person stupid. Admit it, “global warming” is your religion and requires no proof beyond pledging your belief! In fact there are several “inconvienent facts” global warmists neglect to mention.
    1. “global warming” is not new, it has happened several times in the distant past and caused the end of the ice ages, oh, and modern man was not walking the earth yet!!
    2. Water vapor does account for 95-97% of ALL green house gases and man has no control over water vapor!!
    3. Man is only the fourth largest producer of so called greenhouse gases after volcanoes, termites, and grazing animals, and possibly fifth after frozen methane deposits. This puts man’s contribution at approximately 1/10 of 1% or 0.01%. Man’s hubris has always caused him to take credit where none is due.
    4. Global warmists ignore the effect of solar radiation levels and the strength of the Earth’s magnetic field that helps keep that same solar radiation from incinerating the earth. The Earth’s magnetic field has decreased by approximately 10% since the 1900s, approximately the same time period global warmists claim global warming has been happening. Coincidence? I think not!
    5. “Sea ice” has the same exact displacement as sea water though it is lighter and therefor floats, melting sea ice will not raise the levels of the oceans one mm. Almost all of the artic ice is “sea ice” and a great deal of antartic ice is “sea ice”.
    6. NOAA and most “reputable” sources say that they believe the global temperature has risen 0.9 degrees in the last hundred years and if the trend continues they expect a total rise of 1.8 degrees by 2110. The fact is with winter temperatures at the poles hovering around -50 degrees a one, two or even six degree incerase will still freeze sea water solid. Anecdotal evidence of climate change has always been hard to quantify, but easy to quote. You have a couple of old guys that say they have never seen it this hot and you have a good discussion around the craker barrel, add a “scientist” looking for a grant, and suddenly you have “global warming”, and a TV special called “6 degrees”.
    7. No “scientist” ever got a grant to study the status quo, they need to have a crisis to get their money, even if they have to create one.
    8. The “same old thing” isn’t “news worthy”, the media have a vested interest in supporting the “scientists” looking for grant money.
    9. Most scientists who are not paid to advocate global warming as a man made disaster belive warmer global temperatures to be a positive thing, more rainfall, larger areas in higher latitudes could be farmed producing more food world wide, less energy needed to heat homes in winter.
    10. Not that it has any bearing, but how have we caused the “global warming” on Mars, it’s temperature has increased at about the same rate as Earths over the last 30 years?