Cost estimates of geoengineering North Atlantic Deep Water.

摘要

The increase in anthropogenic carbon in the atmosphere has a warming effect on global climate; the possible weakening of the NADW (North Atlantic Deep Water) would impose a negative impact on the mild European climate. One potential response to these effects is modification of downwelling ocean currents, by an increase in carbon concentration or volume.; This work screens seven possible methods of modifying downwelling currents, including using existing industrial techniques for exchange of heat between seawater and air. Increasing carbon concentration in the existing downwelling currents is not practical due to the high degree of saturation of high latitude surface seawater. A conceptual cost estimating model is developed to examine the cost of forming 1 Sv (106 m3/s) of incremental current by means of sea ice formation, the only method which shows marginal potential as a means of enhancing downwelling current volume. The cost of carbon sequestration by sea ice formation is at the high end of the range of estimates of the cost of direct injection of CO2 in the ocean. Sea ice formation is not a preferable strategy of ocean carbon sequestration but it sets a benchmark for any evaluation of cooling seawater on a large scale.