Atmospheric carbon dioxide and radiocarbon in the natural carbon cycle: II. Changes from A. D. 1700 to 2070 as deduced from a geochemical model.

From carbon and the biosphere corference; Upton, New York, USA (16 May 1972). In carbon and the biosphere. A noniinear geochemical model of the interaction of atmospheric CO/sub 2/ with the oceans and land biota has been constructed to predict future changes in atmospheric CO/sub 2/ concentration in the next century. If production of CO/sub 2/ from fossil fuels continues, the perturbations from preindustrial times may become so large that a linear model is unrealistic, especially because it fails to take into account that ocean surface water will become progressively more acid and less able to absorb each new increment of industrial CO/sub 2/. On the assumption that industrial CO/sub 2/ production continues to increase at the rate of the past 20 years and that the ultimate increase in biomass of the land biota is no more than twice the present biomass, the atmospheric CO/sub 2/ concentration will reach a value six to eight times the preindustrial value in 100 years. When the /sup 14/C concentration in dated wood and the recent atmospheric increase in CO/sub 2/ are compared in the cortext of the model, it appears that the land biomass has increased 1 to 3% since the beginning ofmore » the industrial era. This calculation takes account of the actual year to year variations in industrial CO/sub 2/ production and the heliomagnetic variation in /sup 14/C production in the stratosphere. The inferred biomass increase, presumably owing to CO/sub 2/ fertilization, is too small to be verified by direct observation and is not considered to be established. On the other hand, the trend in atmospheric CO/sub 2/ apparently rules out any large recent change in biomass. (auth)« less