text: Update: I am intrigued by the argument made by Professor Murry Salby in a lecture here (and discussed by Judith Curry here ) that the increase in carbon dioxide in the earth's atmosphere over the past century or so may be attributable 80% to the warming of the oceans rather than to fossil fuel emissions. In other words that the warming generated the CO2, rather than vice versa -- as happened in most of the Vostok ice core record from Antarctica. He points out that the rate of increase dropped sharply after Mount Pinatubo in 1991 and rose sharply after the very warm El Nino in 1998. He also takes issue with the argument that the ratio of carbon 13 to carbon 12 is necessarily a fingerprint of fossil fuels.