.ON APRIL 2ND a device looking like a snow maker on the deck of the USS Hornet, a defunct aircraft-carrier moored in San Francisco Gulf, started generating a haze of salty aerosol particles. The scientific collaboration behind the project, the Marine Cloud Whitening (MCB) program, led due to the College of Washington, is actually looking into whether such sprays may help to slow climate adjustment with a type of “geoengineering”. What performs this condition way– as well as why is it therefore controversial?