One final thought on global warming. Sergey R. Kotov, Institute of Precambrian Geology and Geochronology, Saint Petersburg, Russia in a paper "Near-Term Climate Prediction Using Ice-Core Data from Greenland", (2001 from "Geologic Perspectives of Global Climate Change") has a graph of the twenty-year average record of 18O/16O abundances from ice core data over the last 10,000 years and another graph covering the last 16,000 years (the latter graph shows the ice age that occurred about 12,000 years ago quite well). This data was taken from the GISP2 core and it corresponds well with the Sargasso Sea surface temperature data. Using mathematical modeling of historical data he predicts we will have more than 200 more years of global warming based purely on natural causes followed by a precipitous drop in temperature. I am skeptical of projections from historical data, but if he is right and if CO2 from economic development also contributes significantly to global warming we could have some pretty warm days ahead. Other studies in the same book also shows a correspondence between high levels of CO2 and global warming but because high CO2 levels often lag global warming the question remains are high CO2 levels in the "historical" record the cause of global warming or are they the result of global warming. Clear Skies Don