Machta's concerns extended to other pollutants in the atmosphere including acid rain, ozone, and most significantly, greenhouse gases. He played a central role in establishing and, from 1971 to 1989, supervising the Geophysical Monitoring for Climatic Change program (now in the NOAA Climate Monitoring and Diagnostics Laboratory). The GMCC program incorporated the already existing Mauna Loa and South Pole Observatories operated by Charles David Keeling, whose long-term measurements of atmospheric carbon dioxide would eventually be recognized as essential for the study of global warming
