.ON APRIL 2ND a gizmo appearing like a snowfall device on the deck of the USS Hornet, an obsolete aircraft-carrier tied in San Francisco Bay, began creating a moisture of salted aerosol bits. The scientific partnership behind the job, the Marine Cloud Brightening (MCB) programme, led due to the College of Washington, is actually exploring whether such sprays might help to slow down climate change by means of a kind of “geoengineering”. What performs this term way– as well as why is it so disputable?