.ON APRIL 2ND a contraption appearing like a snowfall equipment on the deck of the USS Hornet, an inoperative aircraft-carrier anchored in San Francisco Gulf, began creating a haze of salty spray particles. The clinical partnership behind the project, the Marine Cloud Whitening (MCB) programme, led due to the Educational institution of Washington, is actually looking into whether such sprays might aid to reduce weather adjustment with a form of "geoengineering". What performs this condition mean-- and also why is it therefore disputable?