.ON APRIL 2ND a contraption appearing like a snow device on the deck of the USS Hornet, an obsolete aircraft-carrier tied in San Francisco Gulf, began making a moisture of salted spray bits. The medical collaboration behind the task, the Marine Cloud Brightening (MCB) programme, led due to the Educational institution of Washington, is checking out whether such aerosols could aid to slow down temperature adjustment with a form of "geoengineering". What does this condition method-- as well as why is it therefore debatable?