.ON APRIL 2ND a contraption appearing like a snowfall device on the deck of the USS Hornet, a nonexistent aircraft-carrier anchored in San Francisco Bay, began making a moisture of salted aerosol particles. The scientific cooperation behind the project, the Marine Cloud Brightening (MCB) program, led by the Educational institution of Washington, is investigating whether such sprays might help to reduce temperature adjustment with a kind of “geoengineering”. What does this phrase method– and why is it thus questionable?