Ralph is professor of geochemistry in the Geosciences Research Division of Scripps Institution of Oceanography, University of California, San Diego. He was the first to demonstrate that the O2 content of air is decreasing due to the burning of fossil fuels and has directed a program to track this decrease since 1989. Since 2005 he has also directed the Scripps CO2 program which sustains the iconic record of carbon dioxide at Mauna Loa and other sites, begun by his father, Charles D. Keeling.