GEOENGINEERING - COULD OR SHOULD WE DO IT

Schemes to modify large-scale environment systems or to control climat e have been seriously proposed for over 50 years, some to (1) increase temperatures in high latitudes, (2) increase precipitation, (3) decre ase sea ice, (4) create irrigation opportunities or to offset potentia l global warming by spreading dust in the stratosphere to reflect away an equivalent amount of solar energy. These and other proposed geoeng ineering schemes are briefly reviewed from a historical perspective. M ore recently, many such schemes to advertently modify climate have bee n proposed as cheaper methods to counteract inadvertent climatic modif ications than conventional mitigation techniques such as carbon taxes or pollutant emissions regulations. Whereas proponents argue cost effe ctiveness, critics of geoengineering argue that there is too much unce rtainty to either (1) be confident that any geoengineering scheme woul d work as planned, or (2) that the many decades of international polit ical stability and cooperation needed for the continuous maintenance o f such schemes to offset century long inadvertent efforts is problemat ic. Moreover, there is potential for transboundary conflicts should ne gative climatic events occur during geoengineering activities since, g iven all the large uncertainties, it could not be assured to victims o f such events that the schemes were entirely unrelated to their damage s. Nevertheless, although I believe it would be irresponsible to imple ment any large-scale geoengineering scheme until scientific, legal and management uncertainties are substantially narrowed, I do agree that, given the potential for large inadvertent climatic changes now being built into the earth system, more systematic study of the potential fo r geoengineering is probably needed.