By Jeremy Hance This is Part Two of a two-part story. Find Part One here. In April, researchers from the University of Washington sprayed sea salt particles into the air off the California coast in the nation’s first field test of this solar geoengineering concept. The idea: When certain types of aerosol particles, whether natural or synthetic pollutants, enter clouds, they cause them to brighten. Brighter clouds reflect more sunlight away from Earth, leading to localized cooling. Put into practice on a large scale, solar engineering could potentially offset rapidly worsening climate change im…