.ON APRIL 2ND a device looking like a snow equipment on the deck of the USS Hornet, a nonexistent aircraft-carrier tied in San Francisco Bay, began generating a moisture of salty aerosol bits. The medical partnership responsible for the task, the Marine Cloud Whitening (MCB) program, led by the Educational institution of Washington, is looking into whether such sprays could help to slow down temperature improvement with a type of "geoengineering". What does this term method-- and why is it so disputable?