.ON APRIL 2ND a gizmo being similar to a snow device on the deck of the USS Hornet, a defunct aircraft-carrier anchored in San Francisco Gulf, began producing a haze of salted spray bits. The medical partnership responsible for the job, the Marine Cloud Brightening (MCB) programme, led due to the University of Washington, is actually examining whether such aerosols might aid to reduce weather adjustment via a type of "geoengineering". What performs this term mean-- and also why is it therefore debatable?