COMPUTER-SIMULATIONS OF TERRESTRIAL CARBON AND ATMOSPHERIC INTERACTIONS

Terrestrial carbon modelling shows that the Goudriaan and Ketner and E sser simulations fit historical data well, but the results are sensiti ve to the decomposition rate coefficient of old sediment carbon. Modif ication of this rate constant over time, weighted by emission increase s or linear increases, changes the model results to fit historic ice c ore data. Very old sediment carbon decomposition has an effect on the model postdictions only when the rate constant is 10 times greater tha n that predicted from sediment studies. Future estimates show that a m aximum change from agriculture to forest has a small effect on abating emission increases. Controlling emission rates at 5.1 x 10(15) g C/a will result in almost a 50% increase in atmospheric CO2 in 200 years, and reducing emission rates to 1960 levels (approximately 2.5 x 10(15) g C/a) immediately will still result in an increase in atmospheric CO 2.