Tuesday, February 10, 2009

What global warming scientists can learn from greenhouse operators

Carbon dioxide is called a "greenhouse gas" because it is injected into greenhouses for the purpose of feeding the process of photosynthesis. A greenhouse is a heated building made of transparent material in which vegetables such as tomatoes are grown during weather when it would be too cold to grow these plants outside. Specially designed greenhouse heaters are used to keep the greenhouse warm. The heating requirement during daylight hours is computed as heat losses through the walls and ventilation less the heat gained by solar radiation. 

Carbon dioxide injection is used to maintain a CO2 level in the greenhouse of anywhere from 500 ppm to 5000 ppm according to the amount of solar radiation available for photosynthesis and other factors. If global warming scientists are right, that a change in atmospheric carbon dioxide from 300 to 380 ppm can cause a significant increase in heat entrapment, one would think that the heating requirements of greenhouses during daylight would be different for different CO2 levels. Yet, ceteris paribus, the heating requirement of greenhouses does not change measurably over a large range of carbon dioxide concentraton. In other words even at 5000 ppm, CO2 does not cause greenhouse warming.

Footnote: It should be noted that CO2 is normally generated by burning fossil fuels, and then fed to the greenhouse plants as a nutrient. In that way carbon from fossil fuels is recycled into living matter in the plant. A part of the weight of a hothouse tomato used to be a fossil fuel. And out here in the atmosphere with all that fossil fuel injecting CO2, our food chain surely contains carbon derived from fossil fuels. Part of your body weight used to be oil. 

Cha-am Jamal

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