Dynamic Limitations on the Antarctic Iron Fertilization Strategy

MARTIN et al. have proposed an ingenious means by which the rise in atmospheric CO2 content generated by the burning of fossil fuels and deforesation might be partially compensated. The idea is that plant production in the nutrient-rich surface waters of the Antarctic could be stimulated by the addition of dissolved iron, thereby reducing the CO2 partial pressure in these waters and allowing CO2 to flow from the atmosphere into the Antarctic Ocean. We have used a box model calibrated with transient tracer data to examine the dynamical aspects of this proposal, and conclude that after 100 years of totally successful fertilization the CO2 content of the atmosphere would be lowered by only 10 +/- 5% below what it would have been in the absence of fertilization. So if after 100 years the CO2 content of the atmosphere were 500 mu-atm without fertilization, it would be between 425 and 475 mu-atm with full fertilization. In other words, if our model calibration is correct, even if iron fertilization worked perfectly it would not significantly reduce the atmospheric CO2 content.