.ON APRIL 2ND a gizmo appearing like a snow device on the deck of the USS Hornet, an invalid aircraft-carrier tied in San Francisco Bay, started producing a moisture of salted aerosol fragments. The clinical collaboration responsible for the venture, the Marine Cloud Brightening (MCB) program, led due to the Educational institution of Washington, is exploring whether such aerosols may help to slow down temperature change with a type of "geoengineering". What performs this condition mean-- as well as why is it therefore debatable?