.ON APRIL 2ND a gizmo being similar to a snowfall maker on the deck of the USS Hornet, an inoperative aircraft-carrier moored in San Francisco Gulf, began creating a haze of salty spray particles. The scientific partnership behind the task, the Marine Cloud Brightening (MCB) program, led by the Educational institution of Washington, is looking into whether such sprays could help to slow weather modification by means of a form of "geoengineering". What performs this term way-- and also why is it therefore disputable?