Global Warming: is CO2 the real culprit?

F James Cripwell now lives in Ottawa, Canada but started his scientific career working in the Cavendish Laboratory in Cambridge under Sir Gordon Sutherland, the UK's if not the world's leading expert in infra red spectroscopy and the various interactions between infra red (heat) radiation and other substances. Global warming is undoubtedly caused by visible light falling on the earth's surface, which is re-radiated into the atmosphere, but is increasingly being trapped there, undoubtedly as a result of increased human activity. However, there is no complete agreement as to which human activity or activities are mainly to blame. The culprit most widely considered to be responsible is carbon dioxide but Jim Cripwell writes, "Assuming the earth is at 290 deg Kelvin, Wien's law shows that the maximum radiation is emitted at 10 microns. Water has a massive infrared absorption band centered on 8.5 microns, and in sufficient quantities that can exist in the atmosphere, absorbs all the radiation in a band from about 7 to 11 microns, accounting for about 70 per cent of the radiation. By contrast, carbon dioxide and methane have a very few intense, narrow absorption bands in this part of the spectrum. Those for carbon dioxide are at about 4 and 14 microns. However, the carbon dioxide absorptions are so intense that all the radiation that it is ever going to absorb is done by about 15 per cent of the atmosphere. So adding more carbon dioxide cannot increase its greenhouse effectiveness. The same is true of methane, except that the concentrations of methane in the atmosphere may be too low for it to have reached its maximum." (According to the US EPA, methane is considered to have a 100 year global warming potential about 21 times as great as that of carbon dioxide, but that is mainly because once it gets into the atmosphere, it tends to stay there). Jim Cripwell continues, "Whatever is causing warming, it is not an increase in levels of carbon dioxide. A more plausible theory is that it is water put into high altitudes by aircraft; this would have roughly the same time line." Jim Cripwell is not the first person to have made this suggestion, and in view of his knowledge, we consider his comments worthy of consideration. Emailed comments to Tom Shelley Group Technical Editor please. Jim Cripwell says he may be contacted at jim_jill@ncf.cajim_jill@ncf.ca. TS