evidence: Given the potential threat that geoengineering could pose for the planet, it is important that the global community take steps to establish order in this space. While complete transparency among governments of the world would be ideal in theory, it is the unfortunate reality that some actors may pursue these activities unilaterally and in secret. The dangerous unknowns of such behavior require the capability to detect geoengineering activity wherever necessary. Early detection and localization of unannounced and unilaterally deployed geoengineering activities, either by private actors or states, requires adequate tools for rapid detection and response to maintain global security. The United States must develop its own realistic approach to preparing for emergency geoengineering scenarios. Given the danger that foreign geoengineering could present, the U.S. should establish proper security and deterrence mechanisms that can be carried out quickly and efficiently in case of potentially harmful geoengineering activity abroad.