This oral history focuses on Machta's interest in the human impaction on the climate. It begins with a discussion of Machta's original exposure to meteorology in the late 1930s before going on to how he became interested in the specific topic of how humans impact the climate. Throughout the interview there is discussion of his relationship with and role in governmental programs and the relationship between those programs and academia. The majority of the time is spent on the monitoring of carbon dioxide at various measuring stations around the world as well as discussion of attempts to expand the monitoring beyond carbon dioxide. Also discussed is the way in which monitoring of carbon dioxide became a global pursuit.