It is possible that a fleet of remotely controlled wind-driven spray vessels can exploit the Twomey effect to make useful reductions to the input of solar energy to the sea. It can also provide valuable meteorological and oceanographic data.
The Flettner rotor, perhaps with Thom fences, is an attractive alternative to sails owing to its high lift coefficients and high lift-drag ratios but mainly for easy control by computer and the convenience for housing spray plant producing an upward air flow.
Long-life ultrafiltration modules can deliver seawater with absolute filtration below 0.1 |xm but with the salt still present. This will not clog 0.8-^m nozzles manufactured in silicon wafers using lithographic techniques from the microfabrication industry. So far, this seems to be the most energy-efficient spray system that can be devised. With stronger notch-tolerant materials for the nozzle grid, the energy requirement can approach the absolute minimum needed for creation of new surface area against the force of surface tension.
Predictions for global cooling power as a function of spray rate depend strongly on assumptions of initial concentration of condensation nuclei and the lifetime of spray but only weakly on cloud liquid-water content and depth. It is possible that 50 spray vessels costing approximately £1-2 million each could cancel the thermal effects of a 1-year increase in world CO2.
The immediate effect of albedo control is local cooling of the sea surface. It could be targeted at vulnerable regions, such as coral reefs and diminishing polar ice. It may reduce the frequency and severity of hurricanes and extend the sea area suitable for phytoplankton growth. However, the oceans are an effective thermal store, and currents are an efficient transport mechanism, so initial effects will eventually spread worldwide.
Sea temperatures have a strong influence on world climate. Initially, the deployment of spray vessels in an attempt to replicate favourable historic oceanic temperature patterns will delay the need for perfect understanding of all the many complicated interactions.
Spray releases with control of time, place, quantity and drop diameter will give atmospheric physicists a rare chance to try controlled experiments and so help in the understanding of atmospheric aerosols that have such powerful effects on climate.
While a major effort should be put into the study of all possible side effects of keeping sea temperatures at present values (or other values of our choosing), many of the side effects appear to be benign and less dangerous than those of large, unbridled temperature rises. Unsuitable places can be avoided and spraying can be stopped instantly with all effects removed in a few days.
Albedo control can do nothing for ocean acidity.
Was this article helpful?