Letter | Published:

Atmospheric carbon dioxide levels as indicated by the stable isotope record in wood

Naturevolume 247pages273275 (1974) | Download Citation



THE concentration of CO2 in the atmosphere has increased from about 290 parts per million (p.p.m.) by volume in 1900 (ref. 1) to 323 p.p.m. in 1972 (ref. 2) and this increase is generally held to be due chiefly to combustion of fossil fuels. Indeed by 1970 this artificial mechanism had introduced to the atmosphere an amount of CO2 equivalent to 22% of the natural or pre-industrial atmospheric inventory3. About half of the added CO2 seems to have been transferred to the other major reservoirs of the dynamic carbon cycle, the oceans and biosphere. Before examining the threat to global climate and marine life4, future CO2 levels from this source must be predicted. Before such extrapolations can be confidently applied, however, we must fully understand the past response of the atmosphere to fossil CO2 emission. Since direct measurements of atmospheric CO2 are either not available or considered unreliable indirect methods of assessing the CO2 buildup must be invoked. Here a novel and potentially valuable approach is presented.

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    Present address: Chemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Mass., 02543


  1. Chemistry Department, University of Glasgow, Glasgow, G12 8QQ



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