.ON APRIL 2ND a device appearing like a snow device on the deck of the USS Hornet, an obsolete aircraft-carrier moored in San Francisco Gulf, began making a mist of salted spray particles. The clinical collaboration behind the task, the Marine Cloud Whitening (MCB) programme, led due to the College of Washington, is actually investigating whether such sprays may aid to reduce environment adjustment through a type of “geoengineering”. What performs this condition method– as well as why is it so debatable?