Abstract: | The historic development of the scientific interest in monitoring CO2 in the atmosphere is the subject of this article. Particular emphasis is placed upon activities initiated by the USA in the 1950s which led to the establishment of the Mauna Loa Observatory and further developed into the existing world-wide monitoring system for air constituents and air pollution operated under the auspices of the World Meteorological Organization, a major contributer to the Global Environmental Monitoring System of the UN Environment Programme. Recent studies on the feasibility of monitoring the background level of CO2 at stations throughout the world have indicated considerable difficulties resulting from the influences of the biosphere. These problems have led WMO to adopt new criteria for CO2 monitoring station locations which are presented in a discussion of future needs and plans for global monitoring of CO2 in the atmosphere. |