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Is the world getting hotter?

The Earth has gone through many epochs of alternating ice ages and tropical heat, with great sheets of ice gradually advancing from the poles, then retreating again. It would be a great suprise to legitimate atmospheric scientists, if such changes were ever to cease for a very long period of time. For millions of years, this has taken place without the slightest intervention from man.

In recent decades, the theory was advanced (and promoted by the mass media), that the combustion of coal, oil, and natural gas by man generates such large quantities of carbon dioxide gas, that infrared radiation (radiated heat) was being trapped close to the earth, causing the earth's surface to warm up unnaturally.

The appeal of the theory was the simplistic notion that adding a gas [which actually does absorb infrared radiation] to the atmosphere is like placing a glass envelope around the earth, rather like a "greenhouse" for cultivating plants. Credibility was bolstered by using such a simple analogy that everyone could visualize, and boosted further using the ominous term popular with the press, "greenhouse effect". (Never mind that greenhouses trap heat using an unrelated phenomenon!)

As is usual with scientific issues in the press, no deep analysis was made of an emotional headline that easily grabbed large audiences. Instead, every time warm weather was at hand (a result of expected statistical variation), inevitable repetition was made of the supposed "greenhouse effect" or "global warming", as if these were established scientific explanations for such weather. Never was a similar notion of "global cooling" seriously postulated during unusually cool weather, nor the results averaged for any true statistical picture.

In fact, carbon dioxide is a relatively minor component of several atmospheric gasses which affect infrared transmission. In turn, mankind has only a small role to play in the amount of carbon dioxide actually present in the atmosphere. So, the idea of "greenhouse effect" was pretty far-fetched to begin with.

What is the true picture of solar heat being trapped and released from the Earth?

Firstly, ordinary water is vastly more important in controlling the flow of infrared radiation into and out of the atmosphere than carbon dioxide. Of course, water is constantly entering and leaving the atmosphere daily in tremendous quantities that have nothing whatever to do with man. The oceans and clouds of water (which can block infrared light with 100% efficiency) are practically limitless generators of this "greenhouse gas"!

Secondly, methane competes with carbon dixide for the minor role left for absorbing radiated heat in the atmosphere. Methane is generated in absolutely huge amounts in nature, by fermentation of grass, leaves and all manner of wet organic matter wherever it is. The intervention of man here is practically irrelevant. Swamps are the archetypal producers of bubbling methane gas, but its endless production in nature is almost ubiquitous, from cow stomachs to front-yard lawns to forest floors. The effect of methane gas may be much more important overall than that of carbon dioxide, even though both are far far less important than water.

Finally, how does mankind affect the level of carbon dioxide in the air? No doubt the use of fossil fuels contributes large amounts, easily calculated on the basis of the consumption of such fuels. However, extremely large amounts are also produced in nature. All green plants; trees, shrubs, grasses, algae, etc., consume carbon dioxide by day ("photosynthesis"), and then release it again by night as they respire. Also, respiration of bacteria, animals, and almost everything else that lives produces carbon dioxide. Forest and prairie fires also generate huge bursts of carbon dioxide. The amounts generated by these natural sources are more difficult to calculate, but doubtless are truly huge. Amazingly, much of the carbon dioxide not taken out of the atmosphere by green plants disappears into the oceans, as it is very soluble in water! (Carbon dioxide forms the fizz in soda, for example.) This is how the great layers of chalk and limestone in the earth were formed - they are carbon dioxide trapped as carbonates! (It is interesting to think that the carbon dioxide you exhale today might be part of a public building in a few thousand tears.) Overall, the effect of man on this minor component is probably minor.

With all this reasoning against it, "global warming" theory seems fairly preposterous. But, is there nevertheless empirical evidence that the earth is getting hotter anyway, for whatever the reason? No. Let's look at the record.

No signaificant measured change in rural areas in over 100 years! Temperatures measured in urban areas have risen very slightly on the average. A warming of cities is hardly any suprise, as cities generate heat, and asphalt and jet exhaust etc. can get quite hot! But, as any airplane passenger has seen, cities cover only a tiny, tiny fraction of the planet. What about comparing satellite observations?

Data courtesy of NASA.

This comparison shows no significant trend or change, just random fluctuation within a tiny range. Some might say the surface measurements might have gone up a hair. But, the error range of the thermometers used is probably larger than any percieved change. Most people think the satellite data is better (it does not bias in favor of cities and airports), but the changes there are hardly significant either.

"Global Warming" is a variation on the popular hysteria theme of "the sky is falling", "the End is Near", etc.. Unfortunately, this myth is llikely to be promoted as part of the standard mass-media disaster package, as long as it grabs large audiences.

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This page last updated 9 December, 1998.
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