Carbon Dioxide and Climate (circa 1959)

The theories that explain worldwide climate change are almost as varied as the weather. The more familiar ones attribute changes of climate to Olympian forces that range from geological upheavals and dust-belching volcanoes to long-term variations in the radiation of the sun and eccentricities in the orbit of the earth. Only the so-called carbon dioxide theory takes account of the possibility that human activities may have some effect on climate. This theory suggests that in the present century man is unwittingly raising the temperature of the earth by his industrial and agricultural activities.

Even the carbon dioxide theory is not new; the basic idea was first precisely stated in 1861 by the noted British physicist John Tyndall. He attributed climatic temperature-changes to variations in the amount of carbon dioxide in the atmosphere. According to the theory, carbon dioxide controls temperature because the carbon dioxide molecules in the air absorb infrared radiation. The carbon dioxide and other gases in the atmosphere are virtually transparent to the visible radiation that delivers the sun's energy to the earth. But the earth in turn reradiates much of the energy in the invisible infrared region of the spectrum. This radiation is most intense at wavelengths very close to the principal absorption band (13 to 17 microns) of the carbon dioxide spectrum. When the carbon dioxide concentration is sufficiently high, even its weaker absorption bands become effective, and a greater amount of infrared radiation is absorbed [see chart on page 42]. Because the carbon dioxide blanket prevents its escape into space, the trapped radiation warms up the atmosphere.

What was their political agenda a half century ago- and whose was it?

Because the carbon dioxide blanket prevents its escape into space, the trapped radiation warms up the atmosphere.