Where's the Wolf? David K. McCombs The idea, if not the term Anthropogenic Global Warming (AGW) has been popular since a heat spell in early Eighties. I was quite susceptible then. The idea was mainstreamed by Carl Sagan as a result of his thoughts about Venus. As a planetary physicist, Sagan pondered the exceptionally hot conditions on Venus. The exceptional heat is caused by 'greenhouse' gases in the the Venusian atmosphere. The gases trap infrared radiation, so the atmosphere stays hot. Sagan inferred that a similar hostile climate on earth would result if the percentage of CO2 in the Earth's...