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Mrs. Gorman
To ask the Secretary of State for the Environment what is the average concentration of carbon dioxide in the atmosphere.
Mr. Maclean
Continuous measurements of carbon dioxide in the atmosphere have been made in remote locations since the International Geophysical Year, 1957. The global average concentration estimated from these measurements has increased steadily every year. In its 1992 science supplementary report the intergovernmental panel on climate change estimated the present global average concentration of carbon dioxide to be 355 parts per million by volume.