The Many Pollutant Identities of Carbon Dioxide: Global Climate Monitoring and Air Pollution Research in New Zealand, 1968–1975

In the late 1960s, New Zealand and the United States collaborated to establish a southern hemispheric carbon dioxide (CO 2 ) monitoring station on New Zealand’s coastal cliffs. The New Zealand CO 2 Project, as it came to be known, is an underappreciated landmark in the history of environmental monitoring. The archival record of its early years reveals the extent to which efforts to measure atmospheric carbon dioxide concentrations interacted closely with one of the most hotly debated political issues of the mid-twentieth century: urban air pollution. The designation of CO 2 as air pollution on a planetary scale had profound legal implications in an era in which clean air legislation increasingly brought air pollution within the scope of governmental regulation, and administrative agencies began to jostle for control of the monitoring enterprise. The precise nature of CO 2 as an air pollutant, however, was difficult to pin down. In these initial years of concerted carbon dioxide monitoring, when the lines between climate science and air pollution research were still blurred, CO 2 developed its many pollutant identities. The nature of these identities – and the ways in which scientists and science administrators negotiated their boundaries – retain their relevance today, as nations continue to link air pollution and climate legislation in the twenty-first century.