.ON APRIL 2ND a contraption being similar to a snowfall device on the deck of the USS Hornet, an inoperative aircraft-carrier tied in San Francisco Gulf, started making a mist of salted aerosol particles. The scientific partnership responsible for the project, the Marine Cloud Brightening (MCB) program, led due to the University of Washington, is actually exploring whether such aerosols might assist to slow environment improvement via a type of "geoengineering". What performs this term method-- and also why is it thus controversial?