.ON APRIL 2ND a device being similar to a snow equipment on the deck of the USS Hornet, a nonexistent aircraft-carrier tied in San Francisco Gulf, began creating a moisture of salted spray particles. The medical collaboration behind the job, the Marine Cloud Brightening (MCB) programme, led due to the University of Washington, is actually checking out whether such sprays could aid to reduce environment change by means of a kind of “geoengineering”. What does this term way– and why is it so controversial?