.ON APRIL 2ND a contraption resembling a snow device on the deck of the USS Hornet, a nonexistent aircraft-carrier tied in San Francisco Bay, started generating a haze of salted spray bits. The clinical partnership behind the task, the Marine Cloud Whitening (MCB) program, led by the College of Washington, is actually examining whether such aerosols may help to slow climate change by means of a type of “geoengineering”. What performs this condition method– as well as why is it so debatable?