.ON APRIL 2ND a gizmo looking like a snow equipment on the deck of the USS Hornet, an obsolete aircraft-carrier tied in San Francisco Gulf, started producing a mist of salted aerosol particles. The clinical partnership responsible for the project, the Marine Cloud Whitening (MCB) programme, led due to the College of Washington, is actually exploring whether such sprays could assist to slow weather modification via a form of "geoengineering". What performs this phrase method-- and why is it thus debatable?