Revelle, Roger (1909-1991), was an American oceanographer and a pioneer in deep-sea research. His work led to the discovery of sea-floor spreading and magnetic reversals (see Ocean; Magnetism. Revelle was also among the first to focus attention on the problem of Global warming and the Greenhouse effect caused by an increase in carbon dioxide in the atmosphere. In 1957, largely as a result of Revelle's lobbying efforts, gas recorders were put in place in Hawaii and at the South Pole to measure changes in the atmosphere.