re: #281 b_sharp

Carbon dioxide levels have indeed changed for various reasons, human and otherwise, just as they have throughout geologic time. Since the beginning of the industrial revolution, the CO2 content of the atmosphere has increased. The RATE of growth during this period has also increased from about 0.2% per year to the present rate of about 0.4% per year,which growth rate has now been constant for the past 25 years. However, there is no proof that CO2 is the main driver of global warming. As measured in ice cores dated over many thousands of years, CO2 levels move up and down AFTER the temperature has done so, and thus are the RESULT OF, NOT THE CAUSE of warming. Geological field work in recent sediments confirms this causal relationship. There is solid evidence that, as temperatures move up and down naturally and cyclically through solar radiation, orbital and galactic influences, the warming surface layers of the earth’s oceans expel more CO2 as a result.