.ON APRIL 2ND a device being similar to a snowfall maker on the deck of the USS Hornet, a nonexistent aircraft-carrier anchored in San Francisco Gulf, started producing a mist of salty aerosol fragments. The clinical partnership responsible for the venture, the Marine Cloud Brightening (MCB) program, led due to the Educational institution of Washington, is exploring whether such aerosols may aid to reduce climate adjustment with a kind of "geoengineering". What does this condition mean-- as well as why is it so disputable?