.ON APRIL 2ND a gizmo resembling a snowfall machine on the deck of the USS Hornet, an invalid aircraft-carrier anchored in San Francisco Bay, started creating a mist of salty aerosol bits. The medical cooperation behind the project, the Marine Cloud Brightening (MCB) program, led by the College of Washington, is actually investigating whether such sprays might help to decrease environment adjustment with a kind of "geoengineering". What performs this term way-- as well as why is it therefore debatable?